Water Systems on Earth Water Systems on Earth
OVERVIEW In this unit, students continue their study of Earth and Space Science by examining water systems and discovering the important roles of water on Earth. Students investigate salt water and fresh water, places where water is found on Earth, and different organisms that live in water. Students learn how the different physical states of water fit into the water cycle and contribute to our weather and climate. Finally, students create models to show how different geological features result from water processes and how oil spills can be cleaned up. Approximately 25 to 30 hours are needed to complete this unit. For a detailed curriculum correlation, refer to page xxxiii in the Overview section of this resource. PRESCRIBED LEARNING OUTCOMES
PLO1: explain the significance of salinity and temperature in the world’s oceans PLO2: describe how water and ice shape the landscape PLO3: explain variations in productivity and species distribution in marine environments
Chapter 7: The Water Cycle PLO1 PLO2 PLO3 Key Idea 1: The water on Earth is not ✓ distributed equally. Key Idea 2: All the water in, on, and around ✓ Earth circulates through the water cycle. Key Idea 3: Moving water and ice can change ✓ the shape of the land. Key Idea 4: The water cycle is affected by ✓ many factors.
Key Idea 5: Water systems are managed to protect them from the impacts of human activities.
488 Unit C: Water Systems on Earth NEL Chapter 8: Water Features PLO1 PLO2 PLO3 Key Idea 1: The shape of Earth’s surface ✓ determines how water flows over it. Key Idea 2: The movement of glaciers wears ✓ down and flattens the landscape. Key Idea 3: Temperature differences cause ✓✓✓ movement within a body of water. Key Idea 4: Large bodies of water, such as ✓ lakes and oceans, affect weather and climate. Key Idea 5: Ocean waves shape, and are ✓ affected by, geological features.
Key Idea 6: The regular movement of the oceans in tides is affected by geological features.
Chapter 9: Water and Our World PLO1 PLO2 PLO3 Key Idea 1: Many areas of Earth that are ✓ covered with water are unexplored.
Key Idea 2: Human use of natural resources affects water systems.
Key Idea 3: Saltwater or marine ecosystems are home to a variety of organisms that require ✓ proper conditions to survive and reproduce.
Key Idea 4: Fish farms have been established to raise fish for food because of decreasing ✓ wild populations.
NEL 489 UNIT PLANNING CHART—CHAPTER 7
Section Key Ideas Skills and Processes
Unit C Preview Observing 15–30 min
Chapter 7 Introduction The Water Cycle 15–30 min
7.1 Water in Our World The water on Earth is not distributed equally. 45–60 min
7.2 Inquiry Investigation: The water on Earth is not distributed equally. Conducting Comparing Salt Water Recording and Fresh Water Analyzing 45–60 min Communicating
7.3 The Water Cycle All the water in, on, and around Earth circulates 45–60 min through the water cycle. The water cycle is affected by many factors.
490 Unit C: Water Systems on Earth NEL Hands-on Activities Lesson Materials Program Resources
Try This: Water—What’s per student Unit Rubric the Difference? • apron Nelson Science Probe 8 Web site p. 191 per group www.science.nelson.com • test tube for each •magnifying glass water sample •microscope • test-tube rack or •masking tape for large beaker to hold labelling test tubes test tubes per station •labelled samples of • paper towels water from various •masking tape sources in •microscope slides containers with and cover slips spouts for pouring
BLM 0.0-9 Chapter Key Ideas BLM 0.0-10 Science Idea Box BLM 0.0-11 Vocabulary Wheel BLM 0.0-12 Term Box Rubric 7: Chapter 7 Nelson Science Probe 8 Web site www.science.nelson.com
BLM 7.1-1 Characteristics of Fresh Water and Salt Water SM 7.1 Water in Our World Nelson Science Probe 8 Web site www.science.nelson.com
Inquiry Investigation: per student Investigation Rubric 5: Inquiry Investigation Comparing Salt Water • apron • safety goggles Investigation Rubric 6: Inquiry Investigation— and Fresh Water per group Self-Assessment p. 195 •2 microscope slides • beakers BLM 7.2-1 Inquiry Investigation: Comparing Salt • medicine dropper • drinking straw or Water and Fresh Water • desk lamp pipette BLM 0.0-17 Developing a Science Portfolio •microscope • 30 cm wooden Science Skills and Processes Rubric 9: Conducting • 100 mL graduated dowel Science Skills and Processes Rubric 10: cylinder •marking pen or Conducting—Self-Assessment • triple-beam balance masking tape Science Skills and Processes Rubric 11: Recording or scale Science Skills and Processes Rubric 12: per station Recording—Self-Assessment • salt water (3.5 % • distilled water Science Skills and Processes Rubric 13: Analyzing saline solution) •food colouring Science Skills and Processes Rubric 14: • fresh water Analyzing—Self-Assessment Science Skills and Processes Rubric 17: Communicating Science Skills and Processes Rubric 18: Communicating—Self-Assessment Nelson Science Probe 8 Web site www.science.nelson.com SM 7.3 The Water Cycle BLM 0.0-9 Chapter Key Ideas BLM 7.3-1 Water Cycle Extensions Nelson Science Probe 8 Web site www.science.nelson.com
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NEL Chapter 7 The Water Cycle 491 UNIT PLANNING CHART—CHAPTER 7 (continued)
Section Key Ideas Skills and Processes
7.4 The Water Table Moving water and ice can change the shape of Creating Models 45–60 min the land. Measuring Inferring Interpreting Data
7.5 The Power of Water Moving water and ice can change the shape of Predicting 45–60 min the land. Creating Models Observing Inferring
Tech.Connect: The Dikes of Richmond, British Columbia 20 min
7.6 The Human Side of The water cycle is affected by many factors. Recording Water Systems Communicating 30–45 min Classifying
7.7 Water Treatment and Water systems are managed to protect them Disposal from the impacts of human activities. 45–60 min
Chapter 7 Review The Chapter Review provides an opportunity for 45–60 min students to demonstrate their understanding of and their ability to apply the key ideas, vocabulary, and skills and processes.
492 Unit C: Water Systems on Earth NEL Hands-on Activities Lesson Materials Program Resources
Try This: Capillary Action per student SM 7.4 The Water Table in Soil • apron • safety goggles BLM 0.0-9 Chapter Key Ideas p. 201 per group Nelson Science Probe 8 Web site • sheet of clear • approximately www.science.nelson.com plastic 500 mL water • adhesive tape • approximately 1 L •aluminum pie plate sand or pan per station • water • 3 L sand
Try This: A River’s per student SM 7.5 The Power of Water Response to Rain • apron • safety goggles BLM 7.5-1 Damage Caused by Water in My p. 206 • gloves Community per group Nelson Science Probe 8 Web site •2 aluminum pie • 1.5 L garden www.science.nelson.com plates or pans (potting) soil • 500 mL water per station •watering can
Try This: Water Use SM 7.6 The Human Side of Water Systems Survey BLM 7.6-1 Description of Water Use p. 210 BLM 7.6-2 Charter of Water Rights and Responsibilities BLM 7.6-3 Monitoring Water Use at Home Nelson Science Probe 8 Web site www.science.nelson.com BLM 7.7-1 Filtering Dirty Water SM 7.7 Water Treatment and Disposal BLM 7.7-2 A Water Map—From the Source to Where You Live Nelson Science Probe 8 Web site www.science.nelson.com
BLM 0.0-9 Chapter Key Ideas BLM 7.0 Chapter 7 Quiz Nelson Science Probe 8 Web site www.science.nelson.com
NEL Chapter 7 The Water Cycle 493 UNIT PLANNING CHART—CHAPTER 8
Section Key Ideas Skills and Processes
Chapter 8 Introduction Water Features 15–30 min
8.1 Geological Features The shape of Earth’s surface determines how Creating Models at Sea and on Land water flows over it. Observing 45–60 min
ScienceWorks: Footprints—Here Today, Gone Tomorrow 15 min
8.2 Glaciers: Rivers of The movement of glaciers wears down and Ice flattens the landscape. 30–45 min
8.3 Inquiry Investigation: Temperature differences cause movement within Conducting Water Temperature and a body of water. Recording Currents Analyzing 45–60 min Evaluating Communicating
8.4 Currents Temperature differences cause movement within Communicating 45–60 min a body of water. Creating Models Observing
494 Unit C: Water Systems on Earth NEL Hands-on Activities Lesson Materials Program Resources
BLM 0.0-9 Chapter Key Ideas BLM 0.0-10 Science Idea Box BLM 0.0-11 Vocabulary Wheel BLM 0.0-12 Term Box Rubric 8: Chapter 8 Nelson Science Probe 8 Web site www.science.nelson.com
Try This: Watersheds and per student BLM 8.1-1 Topographical Map of North America Divides • apron • safety goggles SM 8.1 Geographical Features at Sea and on Land p. 224 per group BLM 8.1-2 Making Watersheds and Divides •plastic dishpan • garbage bag BLM 0.0-19 Scrap and Keep Notes per station Nelson Science Probe 8 Web site • ball of string • roll of duct tape www.science.nelson.com •mixing bowl (large) • 3 L cornstarch •1 L water in plastic jug • measuring cup or 1 L • spoon or stirring rod plastic container
SM 8.2 Glaciers: Rivers of Ice BLM 8.2-1 Glaciers of Old BLM 0.0-20 Question Notes Nelson Science Probe 8 Web site www.science.nelson.com
Investigation: Water per student Investigation Rubric 5: Inquiry Investigation Temperature and • apron • safety goggles Investigation Rubric 6: Inquiry Investigation— Currents per group Self-Assessment p. 230 • two 600 mL beakers • tongs or plastic fork BLM 8.3-1 Inquiry Investigation: Water • hot plate • retort stand Temperature and Currents • ring clamp • watch with second BLM 0.0-21 Note Making Inventory hand Science Skills and Processes Rubric 9: Conducting per station Science Skills and Processes Rubric 10: • ice-cold water • coloured ice cubes Conducting—Self-Assessment •water at room (two different Science Skills and Processes Rubric 11: Recording temperature colours) Science Skills and Processes Rubric 12: • hot water (for Recording—Self-Assessment demonstration step 6) Science Skills and Processes Rubric 13: Analyzing Science Skills and Processes Rubric 14: Analyzing—Self-Assessment Science Skills and Processes Rubric 15: Evaluating Science Skills and Processes Rubric 16: Evaluating—Self-Assessment Science Skills and Processes Rubric 17: Communicating Science Skills and Processes Rubric 18: Communicating—Self-Assessment Nelson Science Probe 8 Web site www.science.nelson.com
Try This: Gyres in a Pan per student SM 8.4 Currents p. 234 • apron BLM 8.4-1 Gyres per group Nelson Science Probe 8 Web site •pie pan • coloured ice cubes www.science.nelson.com • water • lazy Susan • plastic spoon or tongs • towels
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NEL Chapter 8 Water Features 495 UNIT PLANNING CHART—CHAPTER 8 (continued)
Section Key Ideas Skills and Processes
Awesome Science: Studying Ocean Currents 15 min
8.5 Water, Weather, and Large bodies of water, such as lakes and oceans, Climate affect weather and climate. 30–45 min
8.6 Waves Ocean waves shape, and are affected by, Controlling Variables 45–60 min geological features. Creating Models Observing
8.7 Tides The regular movement of the oceans in tides is 30–45 min affected by geological features.
Chapter 8 Review The Chapter Review provides an opportunity for 45–60 min students to demonstrate their understanding of and their ability to apply the key ideas, vocabulary, and skills and processes.
496 Unit C: Water Systems on Earth NEL Hands-on Activities Lesson Materials Program Resources
SM 8.5 Water, Weather, and Climate Nelson Science Probe 8 Web site www.science.nelson.com
Try This: Making Waves per student SM 8.6 Waves p. 241 • apron Nelson Science Probe 8 Web site per group www.science.nelson.com •dishpan • about 4 L sand • about 2 L water • ruler • cloth towels
SM 8.7 Tides Nelson Science Probe 8 Web site www.science.nelson.com BLM 0.0-9 Chapter Key Ideas BLM 8.0 Chapter 8 Quiz Nelson Science Probe 8 Web site www.science.nelson.com
NEL Chapter 8 Water Features 497 UNIT PLANNING CHART—CHAPTER 9
Section Key Ideas Skills and Processes
Chapter 9 Introduction Water and Our World 15–30 min
9.1 Exploring the Deep Many areas of Earth that are covered with water 30–45 min are unexplored.
9.2 Oil: Wealth from the Human use of natural resources affects water Ocean Floor systems. 30–45 min
9.3 Inquiry Investigation: Human use of natural resources affects water Predicting An Oil Spill Simulation systems. Conducting 45–60 min Recording Analyzing Evaluating Communicating
9.4 Biodiversity Saltwater or marine ecosystems are home to a 60–75 min variety of organisms that require proper conditions to survive and reproduce.
498 Unit C: Water Systems on Earth NEL Hands-on Activities Lesson Materials Program Resources
BLM 0.0-9 Chapter Key Ideas BLM 0.0-10 Science Idea Box BLM 0.0-11 Vocabulary Wheel BLM 0.0-12 Term Box Rubric 9: Chapter 9 Nelson Science Probe 8 Web site www.science.nelson.com
SM 9.1 Exploring the Deep Science Skills and Processes Rubric 21: Research Science Skills and Processes Rubric 22: Research—Self-Assessment Nelson Science Probe 8 Web site www.science.nelson.com
BLM 9.2-1 Oil from the Ocean Floor—Benefits and Costs SM 9.2 Oil: Wealth from the Ocean Floor BLM 0.0-22 Becoming Test Wise Nelson Science Probe 8 Web site www.science.nelson.com
Inquiry Investigation: An per student BLM 9.3-1 Inquiry Investigation: An Oil Spill Oil Spill Simulation • apron • safety goggles Simulation p. 258 per group Investigation Rubric 5: Inquiry Investigation • 28 cm 19 cm • absorbent materials Investigation Rubric 6: Inquiry Investigation— 4 cm clear glass (e.g., paper towel, Self-Assessment baking dish cotton balls, old rag, BLM 0.0-8 Five-Column Table • water sponges, peat moss, Science Skills and Processes Rubric 5: Predicting •blue food colouring kitty litter) Science Skills and Processes Rubric 6: • 180 mL vegetable oil •5 mL liquid dish Predicting—Self-Assessment • 120 mL pure cocoa detergent Science Skills and Processes Rubric 9: Conducting powder •tweezers or tongs Science Skills and Processes Rubric 10: •5 mL table salt • stopwatch Conducting—Self-Assessment •5 craft sticks • bird feathers Science Skills and Processes Rubric 11: Recording • beaker or measuring (available at a pet or Science Skills and Processes Rubric 12: cup craft store) Recording—Self-Assessment Science Skills and Processes Rubric 13: Analyzing Science Skills and Processes Rubric 14: Analyzing—Self-Assessment Science Skills and Processes Rubric 15: Evaluating Science Skills and Processes Rubric 16: Evaluating—Self-Assessment Science Skills and Processes Rubric 17: Communicating Science Skills and Processes Rubric 18: Communicating—Self-Assessment Nelson Science Probe 8 Web site www.science.nelson.com SM 9.4 Biodiversity BLM 9.4-1 Diversity: Field Trip Investigation BLM 0.0-23 Create a Study-Test Plan Nelson Science Probe 8 Web site www.science.nelson.com
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NEL Chapter 9 Water and Our World 499 UNIT PLANNING CHART—CHAPTER 9 (continued)
Section Key Ideas Skills and Processes
9.5 Inquiry Investigation: Saltwater or marine ecosystems are home to a Hypothesizing Productivity of variety of organisms that require proper Predicting Organisms conditions to survive and reproduce. Conducting 30–45 min Recording Analyzing Evaluating Communicating
9.6 Inquiry Investigation: Saltwater or marine ecosystems are home to a Questioning The Salinity Experiment variety of organisms that require proper Hypothesizing 75–90 min conditions to survive and reproduce. Predicting Planning Conducting Recording Analyzing Evaluating Communicating
500 Unit C: Water Systems on Earth NEL Hands-on Activities Lesson Materials Program Resources
Inquiry Investigation: per student BLM 9.5-1 Inquiry Investigation: Productivity of Productivity of • apron • safety goggles Organisms Organisms per group Investigation Rubric 5: Inquiry Investigation p. 267 • 10 large test tubes • labels Investigation Rubric 6: Inquiry Investigation— • test-tube stand • graduated cylinder Self-Assessment • medicine dropper Science Skills and Processes Rubric 3: per station Hypothesizing • water • liquid plant fertilizer Science Skills and Processes Rubric 4: • phosphate solution solution Hypothesizing—Self-Assessment •algae suspension Science Skills and Processes Rubric 5: Predicting Science Skills and Processes Rubric 6: Predicting—Self-Assessment Science Skills and Processes Rubric 9: Conducting Science Skills and Processes Rubric 10: Conducting—Self-Assessment Science Skills and Processes Rubric 11: Recording Science Skills and Processes Rubric 12: Recording—Self-Assessment Science Skills and Processes Rubric 13: Analyzing Science Skills and Processes Rubric 14: Analyzing—Self-Assessment Science Skills and Processes Rubric 15: Evaluating Science Skills and Processes Rubric 16: Evaluating—Self-Assessment Science Skills and Processes Rubric 17: Communicating Science Skills and Processes Rubric 18: Communicating—Self-Assessment Nelson Science Probe 8 Web site www.science.nelson.com
Inquiry Investigation: The per student BLM 9.6-1 Inquiry Investigation: The Salinity Salinity Experiment • apron • safety goggles Experiment p. 269 per group Investigation Rubric 5: Inquiry Investigation • at least 5 identical • triple-beam or Investigation Rubric 6: Inquiry Investigation— containers (e.g., electronic balance Self-Assessment 30 mL test tubes, • plastic or metal Science Skills and Processes Rubric 1: Questioning 50 mL beakers, spoon Science Skills and Processes Rubric 2: 100 mL beakers, • approximately 10 g Questioning—Self-Assessment sterilized baby-food sea salt Science Skills and Processes Rubric 3: jars) •microscope Hypothesizing • 100 mL graduated • depression slide Science Skills and Processes Rubric 4: cylinder • medicine dropper Hypothesizing—Self-Assessment • large beaker to • container of distilled Science Skills and Processes Rubric 5: Predicting dispose of rinse water for rinsing Science Skills and Processes Rubric 6: water medicine dropper Predicting—Self-Assessment •masking tape or • plastic wrap to Science Skills and Processes Rubric 7: Planning labels to identify cover containers Science Skills and Processes Rubric 8: Planning— containers when mixing Self-Assessment per station Science Skills and Processes Rubric 9: Conducting • brine shrimp cysts • additional supply of Science Skills and Processes Rubric 10: (dry or in salt water, sea salt, or beakers Conducting—Self-Assessment depending on how of pre-mixed salt Science Skills and Processes Rubric 11: Recording students have water of different Science Skills and Processes Rubric 12: designed the salinities (e.g., 0.5 %, Recording—Self-Assessment experiment) 1.0 %, 1.5 %, 2.0 %, Science Skills and Processes Rubric 13: Analyzing 2.5 %, 3.0 %)
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NEL Chapter 9 Water and Our World 501 UNIT PLANNING CHART—CHAPTER 9 (continued)
Section Key Ideas Skills and Processes
9.6 Inquiry Investigation: The Salinity Experiment (Continued)
9.7 Explore an Issue: Fish farms have been established to raise fish for The Salmon Farming food because of decreasing wild populations. Debate 60–90 min
Chapter 9 Review The Chapter Review provides an opportunity for 60–75 min students to demonstrate their understanding of and their ability to apply the key ideas, vocabulary, and skills and processes.
Performance Task: The Performance Task provides an opportunity for Protecting Our Water students to demonstrate their understanding of and 150–165 min their ability to apply the key ideas in this unit, as well as the skills and processes of Planning, Conducting, Recording, Analyzing, Evaluating, and Communicating.
Unit C Review The Unit Review provides an opportunity for 60–90 min students to demonstrate their understanding of and their ability to apply the key ideas, vocabulary, and skills and processes.
502 Unit C: Water Systems on Earth NEL Hands-on Activities Lesson Materials Program Resources
Inquiry Investigation: Science Skills and Processes Rubric 14: Productivity of Analyzing—Self-Assessment Organisms Science Skills and Processes Rubric 15: Evaluating (Continued) Science Skills and Processes Rubric 16: Evaluating—Self-Assessment Science Skills and Processes Rubric 17: Communicating Science Skills and Processes Rubric 18: Communicating—Self-Assessment Nelson Science Probe 8 Web site www.science.nelson.com
Explore an Issue: The Investigation Rubric 1: Explore an Issue Salmon Farming Debate Investigation Rubric 2: Explore an Issue— p. 271 Self-Assessment BLM 9.7.1 Explore an Issue: The Salmon Farming Debate Science Skills and Processes Rubric 21: Research Science Skills and Processes Rubric 22: Research—Self-Assessment Nelson Science Probe 8 Web site www.science.nelson.com BLM 0.0-9 Chapter Key Ideas BLM 9.0 Chapter 9 Quiz Nelson Science Probe 8 Web site www.science.nelson.com
Unit C Performance Task: Unit C: Assessment BLM—Performance Task Protecting Our Water Unit C: Self and Peer Evaluation—Performance p. 280 Task Nelson Science Probe 8 Web site www.science.nelson.com
BLM UC Unit C Quiz Nelson Science Probe 8 Web site www.science.nelson.com
NEL Chapter 9 Water and Our World 503 EQUIPMENT AND MATERIALS
The number of items required is based on having six groups (of five students) per classroom (unless otherwise indicated). Where the term quantity is inappropriate, such as for a piece of tubing, masking tape, and so on, you will have to look at the individual activity or investigation and obtain appropriate quantities.
The equipment and materials included in this list may be ordered from Boreal Laboratories Ltd., www.boreal.com (phone 1-800-387-9393 or fax 1-800-668-9106).
Investigation/Activity Quantity Item Try This: Water—What’s the Difference? 30 • apron p. 191 1 • masking tape (60 yds.) –•container 3•microscope, cordless LED, 4 10 40 7.2 Inquiry Investigation: Comparing Salt 30 • apron Water and Fresh Water 30 • safety goggles pp. 195–196 1 • 3.5 % saline solution 1•distilled water, 3.8 L 1•medicine dropper, package of 6 1•50 slides and cover slips 4•desk lamp 2•microscope, cordless LED, 4 10 40 6•graduated cylinder, 100 mL 2•triple-beam balance 24 • beaker 1•straw, plastic, package of 250 1•food colouring, set of 4 1•wooden dowel, 30 cm, package of 12 Try This: Capillary Action in Soil 30 • apron p 201 1 • pan, aluminum foil, package of 10 1•playground sand, 1 kg Try This: A River’s Response to Rain 30 • apron p. 206 1 • safety goggles 1•rubber gloves, package of 50 1•pan, aluminum foil, package of 10 Try This: Watersheds and Divides 30 • apron p. 224 30 • safety goggles 1•cotton string, 200 ft. 1•cornstarch, 500 g 6•stirring rod 8.3 Inquiry Investigation: Water 30 • apron Temperature and Currents 30 • safety goggles pp. 230–231 12 • beaker, 600 mL 1•food colouring, set of 4 6•tongs 6•hot plate 6•retort stand and rod 6•ring clamp 6•stopwatch Try This: Gyres in a Pan 30 • apron p. 234
504 Unit C: Water Systems on Earth NEL Investigation/Activity Quantity Item Try This: Making Waves 30 • apron p. 241 1 • pan, aluminum foil, package of 10 1•playground sand, 1 kg 6•ruler, 30 cm 9.3 Inquiry Investigation: An Oil Spill 30 • apron Simulation 30 • safety goggles pp. 258–260 1 • food colouring, set of 4 1•table salt, 737 g 1•craft sticks, package of 500 6•beaker or measuring cup, 500 mL 1•cotton balls, package of 300, or sponges or peat moss, 1.35 kg 6•tweezers or tongs 6•stopwatch 9.5 Inquiry Investigation: Productivity of 30 • apron Organisms 30 • safety goggles pp. 267–268 1 • test tube, large 20 mm 150 mm (34 mL), package of 72 1•labels, white (includes dispenser) 6•test-tube stand, wood 6•graduated cylinder 1•medicine dropper, package of 6 1•liquid plant fertilizer solution, 1 L 1•phosphate solution, quick prep 0.001 molar 9.6 Inquiry Investigation: The Salinity 30 • apron Experiment 30 • safety goggles pp. 269–270 6 • beaker 6•graduated cylinder 3•triple-beam balance 1•microscope, cordless LED, 4 10 40 6•test tube, large, 20 mm 150 mm (34 mL), package of 72 2•test-tube stand, wood • medicine dropper, package of 6
NEL Equipment and Materials 505 UNIT PREVIEW Page 191
Time TEACHING NOTES 15–30 min •If you have not already reviewed the Preface at the beginning of the Skills and Processes student book, you may wish to do so now. Have students answer the Observing questions in the Preface. Lesson Materials • This unit is organized around hands-on activities and has students working with scientific equipment. Review procedures and the per student • apron appropriate handling of equipment to establish laboratory safety. Also per group review the importance of • test tube for each water sample –reading and checking directions before beginning an investigation or • test-tube rack or large activity beaker to hold test tubes – thinking about the purpose of the investigation or activity •magnifying glass •microscope – asking other members of their group or their partner, if they have a • masking tape for labelling question, before asking their teacher test tubes per station • Establish an orderly way in which students can get your attention • labelled samples of water from various sources in during an investigation or activity. containers with spouts for pouring •Review the features of the student book with students (e.g., Learning • paper towels Tips, Inquiry Investigations, Try This activities, Chapter Review, Skills •masking tape Handbook). •microscope slides and cover slips •Review the assessment resources in the Assessment Tools section of the Program Resources Teacher Resource to decide which rubrics you may want to use or Unit Rubric adapt for this unit. Nelson Science Probe 8 •Introduce the Unit Rubric to students (found in the Assessment Tools Web site www.science.nelson.com section). Take the time to describe the four levels of performance for each of the four categories: – Concepts: How accurately and fully do you understand the science concepts (key ideas)? –Skills and Processes: How accurately and independently do you use the skills and processes of science? – Connections: How independently do you relate what you are learning in science to everyday life? – Communication: How effectively do you record and share scientific ideas? Adapt the rubric as needed (or as suggestions arise from the discussion). You may want to use the rubric at various times during this unit to assess students.
Activate Prior Knowledge •Focus students’ attention on the Unit Preview. Catch students’ interest by asking questions such as these: What colours can you see in the photograph? (e.g., blue, white, brown) What do you think each colour is? (e.g., water, clouds, land)
506 Unit C: Water Systems on Earth NEL •Use the table of contents to help students discover what they will be learning and to connect the ideas to the photograph. •Have students complete Try This: Water—What’s the Difference?
TRY THIS: WATER—WHAT’S THE DIFFERENCE? Purpose •Students compare water that is collected from various sources around the community. Notes •The following alternative materials could be used: 10 magnifying glass; small beakers or baby food jars instead of test tubes •Read through the activity with students •Ask them to make a chart to record their data. •Review the correct use of a microscope. •Assign partners, materials, and work stations. • At the end of the class, spend some time reviewing and summarizing what students have learned. Take up the questions at the end of the activity. •Additional questions to ask might include the following: – What did you find the same about the water samples? – What differences did you notice? – Did you notice any layering at the bottom of the jars or test tubes? What might have caused it? (differences in types and size of soil particles: the heaviest (gravel and sand) falling first; the lighter ones (clay and silt) falling last) – Based on your previous knowledge, what can you say about the importance of each of these water samples? (See if students can independently recognize the importance of water as habitat, as a solvent for many materials, and as a vital component of living organisms. This will indicate topics that require greater emphasis and topics that elicit the most interest, and can serve as an introduction to the unit. Have students record and share unanswered questions. They can come back to these questions as the unit progresses.) Suggested Answers (a) Some water samples will contain floating material. Floating material is usually organic (once living), although it too will sink as it becomes waterlogged. Most inorganic material is heavier than water and sinks, with the heaviest particles settling first. Water samples from streams and ponds may contain living organisms. Any shaking of these samples should be done gently by slowly inverting the test tube once or twice. (b) The colour, odour, and clarity of the water may differ, depending on the source. (c) Under a microscope, small bits of detritus (dead material) and sometimes micro-organisms can be observed in pond water samples. Roundish objects with a dark, smooth border are likely air bubbles trapped under the cover slip.
Extend Prior Knowledge •Suggest that students continue the Try This activity at home using different water samples from those they studied in class. Tell students that they must have an adult with them if they collect water from rivers, streams, ponds, or lakes.
NEL Chapter 7 The Water Cycle 507 Meeting Individual Needs Extra Support •Bulletin-board displays showing different forms and uses of water can provide visual support for students who are having difficulty. Rephrase the expectations and clarify the language for some students.
ESL • Ask a bilingual student or community member to read the text with ESL students, and allow ESL students to take the student book home. •You can use the Unit Overview to design a student-parent-teacher contract to ensure that all parties understand what is expected for the unit.
Extra Challenge •Invite students to brainstorm issues related to water and make a visual display of these issues for your bulletin board. Alternatively, have students use the Internet to locate Web sites about water. This can lead into a discussion about how to use key word searches to locate information and what criteria should be considered for an effective Web site search. •Introduce the Performance Task on page 280. Encourage students to gather ideas and review the Performance Task as they progress through the unit.
508 Unit C: Water Systems on Earth NEL 7 The Water Cycle Page 192
Key Ideas Vocabulary
The water on Earth is not distributed equally. fresh water weathering salinity erosion All the water in, on, and around Earth estuaries deposition circulates through the water cycle. water cycle delta precipitation flood plain Moving water and ice can change the shape ground water dikes of the land. percolation acid precipitation saturated zone sanitary sewage The water cycle is affected by many factors. water table stormwater aquifers sludge Water systems are managed to protect them capillary action effluent from the impacts of human activities. sediment
Science Skills Related Resources and Processes 7.1 7.2 7.3 7.4 7.5 7.6 7.7 Greater Vancouver Regional Inquiry Skills District Questioning Communications and Education Department Hypothesizing 4330 Kingsway Predicting ✓ Burnaby, British Columbia V5H 4G8 Planning 604-432-6339 ✓ Conducting BC Water and Waste Recording ✓✓Association 1777 Harbour Drive Analyzing ✓ Coquitlam, British Evaluating Columbia Communicating ✓✓V3J 5W4 604-936-4982 Additional Inquiry Skills (Try This Activity) Environment Canada, Controlling Variables Environment Protection Creating Models ✓✓ Services 25 St. Clair Avenue East, Observing ✓ 6th Floor Estimating Toronto, Ontario M4T 1M2 ✓ Measuring Local office: Classifying ✓ 224 West Esplanade North Vancouver, British Inferring ✓✓ Columbia Interpreting Data ✓ V7M 3H7 604-666-5900
(Continued)
NEL Chapter 7 The Water Cycle 509 SCIENCE BACKGROUND Related Resources (Continued) • Humans need water for many life •Water used in farming and in our Environmental Youth functions, as well as for the homes eventually returns to the river, Alliance production of food and other lake, or stream from which it came. PO Box 34097 Station D products. Along the way, it may pick up Vancouver, British • Human activities waste a lot of pollutants. Columbia water and can lower the quality of •Water is home to many of the V6Y 4M1 water. Thus, our use of water can organisms we use for food. As with 604-737-2258 affect other organisms. all types of farming, harvesting from Science World • In British Columbia, water is the sea requires that the organisms 1455 Quebec Street relatively easy to get—we just turn be free from disease and not suffer Vancouver, British on our taps! It is also reasonably because of careless farming Columbia inexpensive. People in many other methods. Over-harvesting of water V6A 3Z7 industrialized countries pay over life can upset the ecosystems of 604-687-8414 twice as much as Canadians pay for lakes, streams, rivers, and oceans. water. Seymour Demonstration Forest North Vancouver, British Columbia TEACHING NOTES 604-432-6286 Society Promoting •If possible, arrange a class visit to a water treatment plant or a sewage Environmental treatment plant. Conservation 2150 Maple Street • Check for Misconceptions Vancouver, British – Identify: Some students may think that water has only a liquid Columbia form. V6J 3T3 604-736-7732 – Clarify: Explain to students that water can take many forms: Cannings, Sydney G. The liquid, solid, and gas. Review the states of matter from Unit B: World of Fresh Water. Fluids. Discuss water vapour in the atmosphere. Explain that when Vancouver: Greystone, liquid water freezes, it turns to ice (solid). 1998. – Ask What They Think Now: Ask students to name the three phases Nelson Science Probe 8 Web site of matter—solid, liquid, and gas—and to explain the transitions www.science.nelson.com from solid to liquid to gas and from gas to liquid to solid. •Discuss students’ understanding of water systems, the effects of water systems on landforms and climate, and human use and abuse of water systems. As you progress through the unit, refer back to students’ answers to the questions at the beginning of the chapter. Students might change these answers as they learn more about water systems. •Prepare a bulletin-board display showing many forms and uses of water. Students can record interesting questions on index cards, sign the cards, and place them on the bulletin board next to the most appropriate picture. These cards could be used for later discussions or for brief research activities as the unit proceeds. •Read through the chapter introduction with the whole class to clarify meaning and to encourage students to think of water in all its forms. •Take only two or three answers for each of the two questions, and let students know that a more complete discussion will follow. Record the answers in point form on the board. •Divide students into four groups. Give each group one piece of chart paper and a felt marker. Assign two groups to each of the two questions in the second paragraph. Also ask them to answer the
510 Unit C: Water Systems on Earth NEL following question: What other system (i.e., combinations of interacting parts that form a unified whole) can you come up with that happens in everyday life? •Allow the groups five minutes to develop their answers. Then ask the two groups working on the same questions to share their answers with each other. • After a few minutes, ask the combined groups to share their answers with the class. •Keep students aware of these questions, and encourage them to develop more answers as they work through the chapter. •You can use the key question on each scaffolding master to review the ideas in the section. • As students work, prompt them to connect their science learning to other learning experiences, world events, and/or personal learning experiences. •Hand out BLM 0.0-9 Chapter Key Ideas. Inform students that this will be a place to record key vocabulary and personal experiences, as well as what they learn from the student book. •You can use any or all of the following BLMs to help students study the vocabulary in this chapter. – BLM 0.0-10 Science Idea Box – BLM 0.0-11 Vocabulary Wheel – BLM 0.0-12 Term Box •To assess students, you may want to use or adapt Rubric 7: Chapter 7.
Meeting Individual Needs Extra Support •Teacher encouragement, prior notice before being called upon, and additional wait time after being called upon often help reluctant speakers. Assigning specific roles to group members (e.g., recorder, encourager, summarizer) may help to ensure that everyone has a chance to contribute.
ESL •Encourage the use of a first language/English dictionary. Allow students to sign out the student book before beginning each section to preview the section at home.
Extra Challenge • The open-ended nature of the discussion and activity allows students to contribute in ways that are appropriate to their needs. For example, asking a student to take the role of summarizer in a group keeps the student focused on the contributions of others. The student can provide helpful reminders of what was discussed before group members make entries in their notebooks.
NEL Chapter 7 The Water Cycle 511 7.1 Water in Our World Page 193
Time PRESCRIBED LEARNING OUTCOMES 45–60 min • explain the significance of salinity and temperature in the world’s oceans Key Ideas The water on Earth is not KNOWLEDGE distributed equally. •sources of fresh water Vocabulary •properties of salt water and fresh water • fresh water SKILLS AND ATTITUDES • salinity • estuaries •relate cause to effect Program Resources ICT OUTCOMES BLM 7.1-1 Characteristics of • demonstrate the ability to formulate questions and to use a variety of Fresh Water and Salt Water sources and tools to access, capture, and store information SM 7.1 Water in Our World •use a variety of information technology tools to help solve problems Nelson Science Probe 8 •apply predetermined search criteria to locate, retrieve, and evaluate Web site www.science.nelson.com information
SCIENCE BACKGROUND
•The hydrosphere consists of all the carry, the amount of human use, and Related Resources water environments on Earth: biological processes. Elder, Danny, and John oceans, lakes, rivers, streams, •Water is essential to life on Earth. If Pernetta (eds.). The icecaps, glaciers, and ground water. there is a drought, agriculture is Random House Atlas of •The oceans cover about 70 % of impossible and many people starve. If the Oceans. New York: Earth’s surface and store vast too much ground water is used, some Mitchell Beazley amounts of heat. areas of soil sink or subside, Publishers, 1991. • Salinity refers to the amount of damaging buildings. If water is dissolved salts in water. Salinity is transported long distances to quench MacQuitty, Miranda, and low near the shores of oceans, dry areas, some scientists believe that Frank Greenaway especially near the mouths of rivers. the balance of nature will be upset, (photographer). Ocean It is high in surface water near the causing climate change. (Eyewitness Books). equator because the heat leads to a • Earth’s oceans are all connected to Toronto: Stoddart, 1995. higher evaporation rate. Fresh water each other. Until fairly recently, there Parker, Steve, and Philip also contains dissolved salts, but the were four recognized oceans: Pacific, Dowell (photographer). salinity of fresh water is very low. Atlantic, Indian, and Arctic. In the Pond and River • Most rivers, lakes, and ground water spring of 2000, the International (Eyewitness Books). are fresh water. The mineral content Hydrographic Organization delimited Toronto: Stoddart, 1998. in bodies of fresh water depend on a new ocean, the Southern Ocean, Pernetta, John (ed.) The their source, the rocks surrounding which surrounds Antarctica and Rand McNally Atlas of them, the rain that falls in them, the extends northward to 60° latitude. the Oceans. New York: sediments and organic material they Rand McNally & Co, 1991. Ocean Area (km2) Average depth Deepest depth Pacific Ocean 166 241 000 4638 m Mariana Trench, 11 000 m
Atlantic Ocean 86 560 000 3930 m Puerto Rico Trench, 8605 m
Indian Ocean 73 430 000 3960 m Java Trench, 7725 m
Southern Ocean 20 327 000 4000 to 5000 m southern end of the South Sandwich Trench, 7235 m
Arctic Ocean 13 220 000 1200 m Eurasia Basin, 5450 m
512 Unit C: Water Systems on Earth NEL TEACHING NOTES
1 Getting Started
• Check for Misconceptions – Identify: Although students know that most of Earth’s surface is covered with water, they may not realize that most of this water is salt water. As well, they may think that dissolved salts in the ocean means just sodium chloride (table salt). – Clarify: Explain to students that the main difference between fresh water and salt water is the amount of dissolved salts in the water. Oceans contain a variety of dissolved salts (magnesium and calcium). – Ask What They Think Now: Ask students if they have swum in both fresh water and the ocean and, if so, what the differences are.
2 Guide the Learning •Refer to a world map or atlas to identify the general distribution of fresh water and salt water on Earth. •To help students understand the information in the diagrams, use Reading and Thinking Strategies: Analyze Diagrams. •Encourage students to examine the photographs and make inferences regarding the amount of fresh water per person in countries where supplies are lower than in Canada. Encourage students to make inferences regarding the economic significance of having a large supply of fresh water. •UseBLM 7.1-1 Characteristics of Fresh Water and Salt Water to compare the characteristics of fresh water and salt water. Students can make a similar chart on the bulletin board and add to it throughout the unit. A sample chart is given in the Answer Key. •Review the three states of matter, reiterating that the amount of heat energy is the determining factor. Relate this fact to water distribution on Earth. •As a class, read through the text about the three states of water. At Home Suggest that students be Focus on how the ability of water to occur naturally as a solid, aware of water around liquid, or gas is crucial to life on Earth. them at home and on their way home from school: •A field trip to a local water body (e.g., swamp, stream) will enhance rain, snow, lawn watering, students’ understanding of its significance and the impact of humans bodies of water, clouds, on the environment. and so on. •For students who need extra support with the reading in this section, use SM 7.1 Water in Our World.
3 Consolidate and Extend •Discuss the importance of caring for water resources, since other living things eventually end up using the same water again.
NEL Chapter 7 The Water Cycle 513 •Refer to the chapter introduction questions to see which questions Te c hnology Connections Begin to teach the have been answered in this section. (In what ways does water in all concept of Boolean its forms make up a system? How might the parts of a water system searches. Ask students to interact?) use the word water for an Internet search and record •Ask students, How is the water in the air connected to the water in the the number of hits they oceans? What would happen if the characteristics or movement of the get. Then ask them to water in the oceans suddenly changed? generate a list of other words they could use with •Assign the Check your Understanding questions. water (e.g., climate, disaster, pollution) to conduct a more precise CHECK YOUR UNDERSTANDING—SUGGESTED ANSWERS search. Students can comment on how using 1. Solid water: glaciers, polar icecaps, icebergs, frozen ponds and lakes, frost, hail word combinations, rather Water vapour: water vapour from evaporation, respiration, clouds, fog, humidity than single words, affects Salt water: oceans, seas, saltwater marshes, saltwater swamps, salt lakes, the number of Internet estuaries hits and the usefulness of Fresh water: rivers, lakes, ground water, runoff, bodies of living things, rain, the sites they encounter. snow, icebergs, glaciers 2. Most of Earth’s water is salt water or nonpotable fresh water. The remaining fresh water is not distributed evenly around Earth, and some of it is contaminated through human use. A water shortage would affect the amount of water each person is permitted to use daily: showers would be less frequent, toilets would not be flushed each time they were used, lawn watering would be prohibited, and so on.
Reading and Thinking Strategies: Analyze Diagrams Water in Our World 7.1 •Read the title of Section 7.1, the first paragraph, and the paragraph under Water Distribution with students. Imagine that you are on a space mission, orbiting Earth. As you travel above Africa, Europe, and Asia, you might think that there is a lot of •Have them look at Figure 2 and the caption. Note that land below you. As you pass over the Pacific Ocean, however, you begin to realize that most of Earth’s surface is composed of water (Figure 1). Figure 2 is about water distribution on Earth. Water Distribution •Ask how the information is presented (circle or pie Most of Earth’s liquid water is salt water in the oceans. In fact, less than 3% ofEarth’s water is fresh water (Figure 2).Fresh water is water, graphs). Ask students questions that will help them whether liquid, solid, or gas, that contains a low concentration of dissolved salts. Figure 1 Water covers 71 % of Earth’s analyze the data from the graphs to Distribution of Water Distribution of Fresh Water surface. on Earth on Earth –extract specific data values from the graphs (literal) lakes and rivers fresh water 0.58 % atmosphere 2.8 % 0.04 % –integrate information from different parts of the graphs (integrate) groundwater 22.04 % –make predictions or notice trends (infer)
salt water ice 97.2 % 77.34 % •For example, you could ask the following questions: How much water on Earth is salt water? (97.2 %) If you had a (a) Only 2.8 % of all the water (b) More than 77 % of the on Earth is fresh water. fresh water on Earth is solid, in glaciers or icecaps. container with 100 L of water that represented all the Figure 2 Water distribution on Earth water on Earth, approximately how many litres would
Salt Water represent water that people can use? (0.7 L) Oceans contain most of the world’s salt water (Figure 3). The salinity •Ask students to react to the following statement: Quite (average concentration of salt) of ocean water is about 3.5 %. Most of the salt in ocean water comes from the land. As fresh water seeps through the soil, it dissolves some of the salt and other minerals. We likely, fresh water will turn out to be the factor that limits cannot taste the salt in this water because the concentration is too low. Figure 3 This water, known as runoff, eventually makes its way in rivers and Most of the world’s salt water is population growth. In the discussion, remind students to streams to the oceans. The dissolved salt and other minerals in runoff found in oceans. consider population pressures, such as the demand for NEL 7.1 Water in Our World 193 water, drought, and human activities that cause water pollution.
514 Unit C: Water Systems on Earth NEL Strategies for Success Organizing and Managing Time • “I don't know where to begin.” Ask students if this sounds familiar. Encourage them to set priorities by listing all the things they have to do, and then assigning a number (1, 2, or 3) to each task according to its importance. Tell them to estimate the time required to complete each task, and to cross each one off the “To Do” list as it is completed. Conclude by suggesting to students that they will worry less and get more accomplished by using this strategy.
Meeting Individual Needs ESL •Students can answer the questions in the student book orally or have another student record their answers. •Photographs of different geographical locations where water is found will enhance students’ understanding.
Extra Support •Focus on key words, and build a concept map on the board using these words. •For students who need extra support with the reading in this section, use SM 7.1 Water in Our World.
Extra Challenge •Ask students to use atlases and/or the Internet to compare the locations of different bodies of water with the population densities in these areas. Students should note whether the bodies of water are fresh water or salt water. They can summarize their findings in a T-chart, comparing proximity of water with population density. •Have students brainstorm ways they use fresh water in their daily lives. Guide and encourage them to include secondary activities that they may not initially think of (e.g., water used for growing and processing food and for manafacturing items they use). Have students try to estimate how much fresh water they use on an average day as individuals, as a family, as a class, and so on. Students could then research fresh water consumption rates on the Internet and report both their findings and ways to reduce their consumption to the class. As a related extension activity, students could research the average rate of water consumption by people in different parts of the world and report their findings to the class.
ASSESSMENT FOR LEARNING
What To Look For in Student Work Suggestions for Teaching Students Who Are Having Difficulty Evidence that students can Have students express their ideas in point form. Have them refer to photographs • explain how science and technology affect or illustrations to enhance their understanding. individuals (e.g., ways a water shortage For students who have difficulty reading long passages, a class discussion of the would affect your life) text related to the questions will help. • identify examples of forms of water (e.g., solid, vapour, salt, and fresh water) •use technical language (fresh water, salinity, estuaries)
NEL Chapter 7 The Water Cycle 515 7.2 Inquiry Investigation: Comparing Salt Water and Fresh Water Page 195
Time PRESCRIBED LEARNING OUTCOMES 45–60 min • explain the significance of salinity and temperature in the world’s oceans • demonstrate safe procedures Key Ideas • perform experiments using the scientific method The water on Earth is not • demonstrate ethical, responsible, cooperative behaviour distributed equally. • demonstrate competence in the use of technologies specific to Skills and Processes investigative procedures and research Conducting Recording KNOWLEDGE Analyzing •sources of fresh water Communicating •properties of salt water and fresh water Lesson Materials per student SKILLS AND ATTITUDES • apron • use given criteria for evaluating evidence and sources of information • safety goggles (e.g., identify supporting or refuting information and bias) per group •2 microscope slides •relate cause to effect • medicine dropper • desk lamp ICT OUTCOMES •microscope • demonstrate the ability to formulate questions and to use a variety of • 100 mL graduated cylinder • triple-beam balance or sources and tools to access, capture, and store information scale •use a variety of information technology tools to solve problems • beakers • drinking straw or pipette •apply predetermined search criteria to locate, retrieve, and evaluate • 30 cm wooden dowel information •marking pen or masking •create electronic text documents tape per station • synthesize information from a variety of electronic sources for • salt water (3.5 % saline presentations solution) • fresh water SCIENCE BACKGROUND • distilled water •food colouring •Buoyancy is the upward force that a its volume, or the amount of mass Program Resources fluid exerts against a submerged or per unit of volume: partially submerged object. When an mass density Investigation Rubric 5: Inquiry object enters water, it makes room volume Investigation for itself by displacing a volume of •Whether an object sinks or floats Investigation Rubric 6: Inquiry water that is equal to its own depends on its density relative to the Investigation— volume. When water is displaced, a density of the fluid. Self-Assessment •The weight of liquid displaced by a BLM 7.2-1 Inquiry force pushes upward. The net force floating object is equal to the weight Investigation: Comparing is the difference between the weight Salt Water and Fresh of the object and the weight of the of the object. In other words, a floating Water displaced water. This force is known object is seemingly weightless. An BLM 0.0-17 Developing a as the buoyant force and is object sinks if its weight is greater Science Portfolio measured in newtons. If the buoyant than the weight of the volume of fluid Science Skills and Processes force is greater than the weight of it displaces. Any object will float, Rubric 9: Conducting the object, the object floats. If the however, if it is shaped to displace Science Skills and Processes buoyant force is not sufficient to enough fluid. A ship floats because it Rubric 10: Conducting— completely counteract the force of has a large overall volume, which Self-Assessment gravity (weight) of the object, the allows it to displace a volume of water object sinks. with a weight greater than the ship’s (Continued) •The density of a substance is weight. The density of the ship, expressed as a ratio of its mass to including the air inside, is less than the density of the water.
516 Unit C: Water Systems on Earth NEL INVESTIGATION NOTES Program Resources (Continued) Student Safety Science Skills and Processes Remind students never to taste or drink anything used in a science Rubric 11: Recording Science Skills and Processes class. Also remind them not to put the straw or pipette in their Rubric 12: Recording— mouth. Self-Assessment Science Skills and Processes Caution students to be careful when distributing equipment. Tell Rubric 13: Analyzing them to inform you immediately if anything is broken. Science Skills and Processes Rubric 14: Analyzing— Remind students that if glass is broken, they should inform you Self-Assessment Science Skills and Processes immediately. Use a dustpan and hand broom to clean it up. Dispose Rubric 17: Communicating of the broken glass in a specially marked broken-glass container. Science Skills and Processes Vacuum to remove the remaining glass particles. Rubric 18: Communicating— Self-Assessment •Since the water samples look the same, students may not realize that Nelson Science Probe 8 Web site all of them contain dissolved substances: the distilled water the least, www.science.nelson.com and the salt water the most. Tap water contains a variety of dissolved materials, including gases and minerals. Related Resources •Some students feel that if their experiment supports their hypothesis, Davies, Anne; Cameron, then they have done good science. Explain that a hypothesis is merely Caren; Politano, Colleen; a statement to be tested; its purpose is to focus the attention of the Gregory, Kathleen. experimenter. Results that contradict the hypothesis are as valid as Together Is Better: Collaborative results that support it, as long as the results are based on careful Assessment, Evaluation observation. The appropriate use of evidence to support carefully & Reporting. Winnipeg: drawn conclusions is what makes good science. Peguis, 1992 Reeves, William W. (ed.). •To assess students, you may want to use or adapt Investigation Technology of Fluid Rubric 5: Inquiry Investigation and/or Investigation Rubric 6: Inquiry Power. Albany, NY: Investigation—Self-Assessment. Delmar Publishing, 1997. Gregory, Kathleen; Question Cameron, Caren; Davies, Anne. Self Assessment •Have students examine the Question as the starting point of the and Goal Setting. Investigation. Remind them that all scientific investigations start with Merville, BC: a question. Students should be able to describe, in general terms, what Connections Publishing, the Investigation entails by reading and understanding the Question. 2000. Gregory, Kathleen; Hypothesis Cameron, Caren; Davies, Anne. Setting and Using • The Hypothesis in the student book outlines the differences between Criteria. Merville, BC: salt water and fresh water. It is not stated in the “if …, then …” Connections Publishing, 1997. format, however. Since students are usually asked to use the “if …, A Primer on Fresh Water. then …” format, help them rewrite the Hypothesis in this format. For Environment Canada, example: If the densities of salt water and fresh water are calculated, 1994. then salt water will be shown to have the higher density. Weller, Phil. Fresh Water Seas: Saving the Great Materials Lakes. Toronto: Between the Lines, 1990. •Students should collect all the necessary materials before beginning the Investigation, and should ask you to check the materials to ensure that they are safe.
NEL Chapter 7 The Water Cycle 517 •If microscopes are not available, use dissecting microscopes or magnifying glasses that magnify at least 10 . •Beakers can be used instead of graduated cylinders, but their volume markings are much less accurate. •If a desk lamp is not available for each group, ask students to complete other parts of the Procedure while their drops evaporate at room temperature.
Procedure •Organize the investigation in advance by – establishing groups (pairs are recommended) – putting all or most of the materials for each group in a container (plastic basket or dishpan) to facilitate distribution –identifying particular locations in the room where students will work –clarifying the routines of distributing and collecting the materials – explaining the safety procedures (see Student Safety) •Before starting the Investigation, –review the concepts of density, buoyancy, and residue formation – go through the materials listed to ensure that each group has everything needed – demonstrate the techniques required for students who need help – explain how students can record their observations –have students review Designing Your Own Investigation and Using a Microscope in the Skills Handbook •Remind students to label the containers of water. •Remind students what the meniscus is, and review the proper way to At Home measure a liquid in a graduated cylinder. Students may want to review Ask students to find Measurement and Measuring Tools in the Skills Handbook. something that sinks in fresh water and floats in •Remind students to label the two slides they use. salt water by testing items found around their home •Have extra glassware available in case any gets broken. Have extra (e.g., plastic toys, a potato water samples and distilled water in case of spillage. or carrot, small wooden items). Students can make •For students who have never used the materials or completed an salt water by mixing experimental investigation, demonstrate the procedures: writing a 10 mL of salt per 250 mL hypothesis, measuring and calculating mass, and recording of water. This is approximately a 3.5 % information in a chart. (This could be done as a class demonstration.) solution—roughly ocean Refer to Thinking as a Scientist in the Skills Handbook. concentration. •Since several pieces of equipment are used in this Investigation, direct Have students discuss with family members their students to have only the equipment they are presently using out on outdoor experiences with the table. (Except for the microscope, the rest should remain in the salt water (e.g., fishing, materials container.) This will help to minimize accidents and swimming). How do encourage organization. activities in salt water differ from the same activities in •Remind pairs or groups of students to divide the tasks equally so that fresh water? each student has specific responsibilities and is accountable for successful completion of the entire Investigation.
518 Unit C: Water Systems on Earth NEL Data and Observations •Have students record their data and answer the questions on BLM 7.2-1 Inquiry Investigation: Comparing Salt Water and Fresh Water. •As students investigate the physical properties of salt water and fresh water, they will discover more differences than just salt content. Students should recognize that the properties studied are determined by the amount of dissolved salt in the water, and are significantly different in the two kinds of water. The density and buoyancy of water affect many of its properties, such as flotation for ships and the organisms that can survive in it.
Characteristic Fresh water Salt water Appearance (including colour) clear clear to slightly cloudy
Odour odourless odourless
Residue after evaporation very little residue—perhaps a small grainy white residue around edges and amount of white residue around edges, perhaps in centre of drop; crystalline depending on hardness of tap water structure of salt is visible with a dissecting microscope Density
•mass of empty graduated cylinder will vary will vary
•mass of graduated cylinder and 100 100 g more than above depends on salt concentration mL of water
• mass of 100 mL of water 100 g depends on salt concentration
• density of water sample (per 100 mL) 100 g/100 mL depends on salt concentration
• density of water sample (per 1 mL) 1 g/mL depends on salt concentration (natural sea water is approximately 1.03 g/mL)
Buoyancy
• depth to which dowel sank Dowel sinks about 2 to 4 mm below level Dowel sinks about 2 to 4 mm above level in salt water. in fresh water.
• float test: fresh water over salt water Coloured fresh water forms a layer above the salt water, showing fresh water floats when placed in salt water.
• float test: salt water over fresh water Coloured salt water accumulates at bottom or mixes in with fresh water, showing that salt water sinks when placed in fresh water..
Analysis—Suggested Answers (b) The saltwater residue will likely be more abundant and whiter, and will appear more crystalline under a microscope. Salt makes up most of the saltwater residue, and calcium (or minerals from the tap, as students may describe it) makes up most of the freshwater residue. (c) The densities are different because the additional mass comes from the mass of the salt dissolved in the salt water. (d) The dowel floated higher in salt water.
NEL Chapter 7 The Water Cycle 519 Strategies for Success Developing Portfolios •Discuss with students the goals and objectives for selecting portfolio entries. A suggested plan for helping students collect portfolio samples can be found in BLM 0.0-17 Developing a Science Portfolio.
Meeting Individual Needs ESL •Students should be encouraged to set their own language communication goals for this section and work toward achieving these goals. You might use the following ideas to promote understanding: –Provide labelled visuals of the materials and equipment to be used, and refer to these visuals as you demonstrate the Procedure. –If possible, allow students to work in their first language with the assistance of a bilingual student or community member. Emphasize the vocabulary used in this investigation: density and buoyancy.
Extra Support •For students who have never used the equipment or completed a scientific investigation, demonstrate the Procedure in advance and partner them with students who have had these experiences before. Students who have not used a microscope before will need assistance to focus the objectives. •Some students may have difficulty using their results to answer the Analysis questions, without some prompting. Ask these students to answer the questions as they complete the appropriate parts of the Procedure. At the same time, review the concepts being investigated. For example, ask, What is a residue? Why does it occur? How can we predict what is in it?
Extra Challenge •Ask students to consider all the physical characteristics of salt water and fresh water, and to determine whether an organism could survive in both types of aquatic environments. Have them use the information from this Investigation and determine which characteristics are critical to the survival of a marine species. •Have students use the Internet to research the different desalination techniques available or one type of desalination in more detail. Ask them to create reports or posters outlining their findings. Encourage them to include information about the ratio of water to salt extracted, as well as the amount of time and energy involved in the extraction.
ASSESSMENT FOR LEARNING
What To Look For in Student Work Suggestions for Teaching Students Who Are Having Difficulty Evidence that students can Have students work with a partner, helping to set up and recording observations. • compare the characteristics of salt water Have students review Using Graphic Organizers in the Skills Handbook. and fresh water • analyze and interpret observations Work with students, providing assistance as necessary to complete BLM 7.2-1 • create products that are complete Inquiry Investigation: Comparing Salt Water and Fresh Water. (e.g., tables)
520 Unit C: Water Systems on Earth NEL 7.3 The Water Cycle Page 197
KNOWLEDGE Time • sources of fresh water 45–60 min SKILLS AND ATTITUDES Key Ideas •relate cause to effect All the water in, on, and • assess human impact around Earth circulates through the water cycle. ICT OUTCOMES The water cycle is affected • demonstrate the ability to formulate questions and to use a variety of by many factors. sources and tools to access, capture, and store information Vocabulary •apply predetermined search criteria to locate, retrieve, and evaluate •water cycle information •precipitation •use a variety of software to present messages • ground water Program Resources SM 7.3 The Water Cycle SCIENCE BACKGROUND BLM 0.0-9 Chapter Key Ideas BLM 7.3-1 Water Cycle •Water moves among freshwater form around dust particles and may Extensions bodies, the oceans, the air, and the pick up more dust on the way down). Nelson Science Probe 8 ground in an endless cycle, called •When precipitation falls to Earth, it Web site the water cycle or hydrologic cycle. becomes absorbed into the soil, runs www.science.nelson.com Solar energy evaporates liquid water off into lakes and streams, remains to a gas (water vapour). as snowdrifts or glaciers, or • When the warm air close to Earth’s evaporates into the atmosphere. surface rises, it cools and cannot Water that remains in the ground, hold as much water vapour as called ground water, flows Related Resources warmer air. Much of the water underground to the oceans or other Exploring Your World—The vapour condenses into water bodies of water. Adventure of Geography. droplets, forming clouds. • Some water is held in one location National Geographic •Water returns to Earth as for a long time, for example, in a Society, 1989. precipitation (rain, snow, sleet, or glacier or icecap, an underground hail) from these clouds. All aquifer, a very deep lake, or a deep A Primer on Water. precipitation is fresh water, but not ocean. Environment Canada, necessarily pure water (drops often 1991. Turk, Jonathan, and Amos Turk. Environmental Science. Philadelphia: TEACHING NOTES Saunders College Publishing, 1998. •This section provides students with an opportunity to demonstrate Water: No Time to their understanding of the water cycle and its processes. Students Waste—A Consumer’s develop thinking skills as they examine cause-and-effect Guide to Water Conservation. relationships—the processes that contribute to the water cycle and the Environment Canada, impact of these processes on the environment. 1990.
1 Getting Started
• Check for Misconceptions – Identify: Some students may think that as water vapour rises, it defies the force of gravity.
NEL Chapter 7 The Water Cycle 521 – Clarify: Explain to students that a molecule of water vapour is lighter than a molecule of oxygen or carbon dioxide, so it tends to rise, even without winds and updrafts. As temperatures cool with increasing altitude, water molecules condense, become liquid, and collect around dust particles, eventually becoming heavy enough to fall to the ground as precipitation. Emphasize that chemical reactions of water vapour in the atmosphere happen with chemicals that are already present, usually due to human activities or natural phenomena such as forest fires and volcanic eruptions. – Ask What They Think Now: Ask students to recall what happens when two fluids of different densities are mixed together. The less dense fluid will float on the more dense fluid. Students should be able to explain that water vapour is less dense than the surrounding air and therefore “floats” on the air. •Review the following concepts before starting this section: –Water occurs naturally in three states on Earth—as a solid, a liquid, and a gas. –Water can occupy different states within the hydrosphere and atmosphere. –Temperature determines the state of water. •Establish with students the meaning of the term cycle. Suggest or ask students to suggest examples of cycles (e.g., the school year, the seasons, the trajectory of Halley’s comet, phases of the Moon). Discuss why students identify these examples as cycles. •Define a cycle as a series of events that recur regularly (dictionary definition). Students may refer to the circular pattern that water seems to take (also acceptable). The changes of state in the pathway water takes through the water cycle occur repeatedly and regularly. Water takes a circular path (with some side trips and shortcuts) from lakes and oceans to atmosphere to land (ground water or runoff) to rivers and back to lakes and oceans. •This section provides students with an opportunity to demonstrate their understanding of the water cycle and its processes. Students develop an understanding of cause-and-effect relationships, using the processes that contribute to the water cycle and their impact on the environment.
2 Guide the Learning •Have students look at the diagram of the water cycle (Figure 1). When examining a diagram or photograph, begin by developing a holistic impression. Ask, What does this show? Then have students look at each part of the diagram or photograph, starting with the largest and most pronounced part (often in the foreground). One strategy is to begin by asking students to list everything in the diagram or photograph.
522 Unit C: Water Systems on Earth NEL •Have students study and follow the diagram of the water cycle while you read aloud the paragraph describing it. Review the water cycle and its processes. Ask questions such as the following to determine students’ prior knowledge: – What three forms does water exist in? (liquid water, solid ice, and gaseous water vapour) – What words do we use to describe changes from one form to another? (liquid to solid: freezing; liquid to gas: evaporation; solid to liquid: melting; solid to gas: sublimation; gas to liquid: condensation; gas to solid: sublimation) – Which of these changes require energy to be added? (evaporation, melting, sublimation of a solid to gas) Which require that energy be removed? (freezing, condensation, sublimation of a gas to a solid) – What are some common examples of these changes in nature? (evaporation from all liquid water surfaces, from the skin and lungs of animals, and from the leaves of plants; condensation at higher altitudes as temperature drops, or where warm moist air meets cold air or surfaces; sublimation (gas to solid) in the formation of frost (e.g., on a windshield); sublimation (solid to gas) at most ice surfaces and in glaciers; melting during spring thaw and from glaciers; freezing during cold seasons and at high altitudes) – How does water that falls on land make its way to the ocean? (Figure 1, page 197) – What are some of the different types of bodies of water that you know of? (student book, pages 194 and 198) •Use Reading and Thinking Strategies: Interpret Visuals and Graphics to examine the context and the science involved in Figure 1. Make sure that students can define each process, identify its cause, and determine its effects on the water cycle and the environment. •Since a large amount of information is presented in this section, focus mainly on the processes, the terms used to define these processes, their interdependence, and the way they fit into the water cycle. •For students who need additional support with the reading in this section, use SM 7.3 The Water Cycle.
3 Consolidate and Extend •Encourage students to consider the importance of caring for water resources, since humans and other living things use the same water over and over again. •Have students add details to BLM 0.0-9 Chapter Key Ideas. •Use BLM 7.3-1 Water Cycle Extensions as an extension activity for students. •Have students create a computer-based multimedia presentation to illustrate and model the water cycle. • Assign the Check Your Understanding questions.
NEL Chapter 7 The Water Cycle 523 CHECK YOUR UNDERSTANDING—SUGGESTED ANSWERS
1. The water cycle is the movement of water as it changes state over, on, and in Earth. 2. Some examples will come from the section; others will come from students’ prior knowledge. •Freezing: ice formation on lakes in winter, hail formation in the atmosphere, water to snow in clouds • Melting: snow to water in spring, ice to water as icebergs move to warmer areas, ice to water at the edges of glaciers •Evaporation: water evaporating from the surface of water bodies, water evaporating from plants through transpiration or from animals through respiration and perspiration • Condensation: water vapour turning to liquid in clouds • Sublimation: water vapour turning to frost, ice (e.g., hail, snow) turning back to water vapour in the atmosphere, ice from the surface of glaciers turning directly to water vapour without melting first 3. Since this presentation integrates science, language, and the arts, you may want to take time from English and/or Fine Arts to give students time to prepare and present their work. Consult with other teachers as necessary to arrange this. Ensure that students understand that even though all water goes through a cycle, it is extremely unlikely that the same water droplet will return to its original position in the environment. For example, a water droplet evaporating from Niagara Falls could be carried by a cloud to Greenland, where it may fall as snow and become part of a glacier. A thousand years later, it may melt and run into the ocean, where it will evaporate again. It does not return to Niagara Falls, although other water droplets keep the Niagara River flowing.
Reading and Thinking Strategies: Interpret Visuals and Graphics The Water Cycle 7.3 •Have students look at Figure 1 and read the caption. Ask what the diagram is about (the water cycle). Water is always on the move, sometimes quickly and sometimes slowly. LEARNING TIP It is forever changing its state and location. The movement of water is Active readers interact with the • Have students scan the diagram and look for clues to see not restricted to Earth’s surface—water sinks deep below the ground text. As you read, note the highlighted words. These are and rises high into the atmosphere. It is this movement of water, words that you should learn known as thewater cycle (Figure 1), that influences our weather, keeps and use them when you how it is organized (cycle flow chart: arrows used to show rivers and lakes full, purifies water, and sustains many forms of life. answer questions. The words are also defined in the Glossary at the back of your student directions and the interactions among a series of connected book. condensation processes in the water cycle). • Read the subsection called The Water Cycle with students.
precipitation sublimation • Arrange students in pairs. Ask them to explain to each other, evaporation glacier evaporation using Figure 1, what might happen to a water droplet from a
ocean lake as it goes through the water cycle. A possible explanation follows:
ground water – Heat from the Sun changes the water droplet to water vapour (evaporation).
Figure 1 –The water vapour rises, cools, and then becomes liquid again Earth’s water is in a continuous cycle, always moving and changing state. (condensation). The Water Cycle Heat energy from the Sun causes liquid water on Earth’s surface –Water droplets collect around dust particles in the air and form to change to water vapour in a process called evaporation (recall Section 4.1). Water also evaporates from soil, animals, and plants. a cloud. Salts, pollutants, and impurities are left behind as water rises into the air as water vapour. –When the cloud becomes so heavy that the air currents can As the air rises, it cools. Cool air cannot hold as much water vapour as warm air. The cooled water vapour in the air becomes liquid again, a no longer keep it up, the droplet returns to Earth as rain, sleet,
NEL 7.3 The Water Cycle 197 snow, or hail (precipitation). –The droplet runs off the surface of Earth to the oceans or seeps into the ground. •Create an opportunity for critical thinking by asking, Is the water we have on Earth today the same water that was here thousands of years ago? Why or why not? (Yes, because water never disappears; it just goes through the water cycle over and over again. Some water may become frozen in a glacier or stored underground for a long period of time, however. All the water we have on Earth is the same water that was here thousands of years ago in one form or another.
524 Unit C: Water Systems on Earth NEL Meeting Individual Needs ESL •Focus on the new vocabulary in this section by asking students to list the vocabulary words and illustrate the meaning of each (e.g., moisture can be shown as rain falling, saturation can be shown as a sponge dripping with water, percolation can be shown as coffee dripping through a filter). •This section requires a fair amount of reading. Place ESL students with bilingual peers, make an audiotape of the text in advance so that ESL students can review it, and/or read the text aloud with the class. This will involve ESL students in the reading to the extent of their ability. Discuss the key ideas as you go, clarifying the meanings with dialogue and questions.
Extra Support •For students who need additional support with the reading in this section, use SM 7.3 The Water Cycle.
Extra Challenge • Ask students to consider all the physical characteristics of salt water and fresh water, and determine whether an organism could survive in both types of aquatic environments. Have them use information from Investigation 7.2 and determine which characteristics are critical to the survival of a marine species. •Encourage students to question how the different processes in the water cycle can affect the salinity of surface water on Earth. Evaporation, condensation, precipitation, the effects of temperature, and the fact that water is an excellent solvent are key concepts needed to address this topic.
ASSESSMENT FOR LEARNING
What To Look For in Student Work Suggestions for Teaching Students Who Are Having Difficulty Evidence that students can Ask students who have difficulty writing reports to give oral reports or to display • explain the water cycle their information as illustrations or diagrams. • use technical language (water cycle, precipitation, ground water)
NEL Chapter 7 The Water Cycle 525 7.4 The Water Table Page 199
Time PRESCRIBED LEARNING OUTCOMES 45–60 min • explain the significance of salinity and temperature in the world’s oceans Key Ideas Moving water and ice can KNOWLEDGE change the shape of the land. •sources of fresh water Vocabulary ICT OUTCOMES • percolation • saturated zone • demonstrate the ability to formulate questions and to use a variety of •water table sources and tools to access, capture, and store information • capillary action •use a variety of information technology tools to solve problems • aquifers •apply predetermined search criteria to locate, retrieve, and evaluate Skills and Processes information Creating Models •create electronic text documents Measuring • synthesize information from a variety of electronic sources for Inferring Interpreting Data presentations •use a variety of software to present messages Lesson Materials per student • apron SCIENCE BACKGROUND • safety goggles per group • Clay soil holds water and dissolved zone, the upper surface of which is • sheet of clear plastic minerals very effectively. Sandy soils, the water table. Above the saturated • adhesive tape with their larger particle and pore zone is the zone of aeration, which •aluminum pie plate or pan sizes, have higher permeability. has many of its pores filled with air. • approximately 500 mL water Sandy soils tend to dry out quickly • Humans affect the depth of the • approximately 1 L sand and do not hold minerals well. water table. If more water is taken per station •Water percolates downward until it from wells than falls as precipitation, • water reaches an impermeable (also called the water table lowers. •3 L sand impervious) layer of rock or clay • An aquifer is water trapped in a layer Program Resources (called an aquitard), through which it of permeable rock, which is trapped travels very slowly. Above the between two layers of impermeable SM 7.4 The Water Table aquitard, ground water fills all the rock. Wells are often drilled into an BLM 0.0-9 Chapter Key Ideas pores in what is called the saturated aquifer to provide fresh water. Nelson Science Probe 8 Web site www.science.nelson.com TEACHING NOTES
1 Getting Started •To review the water cycle briefly, have students work in pairs to explain it to each other. •As students examine Figure 1, ask the question What does this show? Use Reading and Thinking Strategies: Paraphrase/Predict to relate the information in the text to the information in Figure 1. •Focus students’ attention on the stickiness of water. Take two pieces of paper, and hold them together. Show students that the pieces of paper do not stick. (Hopefully, there is no static electricity!) Then, wet the papers and hold them together. They stick because of the
526 Unit C: Water Systems on Earth NEL attraction of the water molecules to each other and also to the paper molecules. Transfer this concept to making sandcastles at the beach. Related Resources Bang, Molly. Common Sand will not stick together unless it is wet. The water sticks to itself Ground: The Water, and to the sand. Ask students, When rainwater enters the soil, in which Earth, and Air We Share. direction does it move? Why? (downward because of gravity, sideways or New York: Blue Sky upward because of forces of attraction) How do we know there is water Press, 1997. in the ground? (e.g., wells, cave exploration, springs, geysers) Compass Resource. Analysis Report, Management Plan #5, 2 Guide the Learning Greater Vancouver Water District. Vancouver: •Read this section aloud with the class. Ask students, What else does Greater Vancouver water do when it hits the ground? (e.g., forms puddles, runs off, Regional District, 1999. loosens the soil by physical force) How does the surface of the ground SCBV Consultants Inc. affect what happens when the rain hits the ground? (If the surface is Greater Vancouver Water rocky or paved, more of the water runs off.) District Predesign and Planning Studies for •Mention that organisms, both living and dead, affect the moisture Drinking Water Quality content of the soil. Litter (dead leaves and branches) on the surface Management Plan reduces evaporation, humus in the soil allows more absorption of Summary Report. water, and plant roots draw water out of the soil. The type of soil Vancouver: SCBV Consultants Inc., 1993. (sand, silt, clay) also affects absorption and percolation. Van der Leeden, Frits. The •For students who need additional support with the reading in this Water Encyclopedia. section, use SM 7.4 The Water Table. Chelsea, MI: Lewis Publishers, 1990. TRY THIS: CAPILLARY ACTION IN SOIL
Student Safety
Remind students to wear gloves when handling soil and to wash their hands at the end of this activity.
Purpose •Students build a model to demonstrate capillary action in the soil. Notes •Have students reread Thinking as a Scientist in the Skills Handbook, starting with Predicting. • Explain to students what capillary action means. Show how water rises in a capillary tube, but not in a tube with a wider diameter. •To demonstrate capillary action, ask students to examine the fibres in a small piece of paper towel under a microscope. (Use a dissecting microscope or a 10 lens.) Have them use a medicine dropper to add a drop of coloured water at the edge of the paper towel, and then watch as the coloured water moves. The molecules of water are attracted to the molecules of paper and move through the connecting pore spaces. •A tube with a diameter of 5 to 7 cm and a height of about 30 cm works well. Although the tube should stand by itself with the sand in it, caution students to be ready to catch it if it falls. Pour water into the pan, about 2 cm deep, to provide an adequate demonstration. •Students can also try different combinations with the same apparatus. Have them test soils such as clay, fine-grained sand, beach sand, and rich garden soil. All soils should be dry. (Other testable liquids include salt water, vinegar, and cooking oil.) • Ensure that students understand they must control all the variables, except the variable being tested. For example, if students are testing the type of soil, they must control the diameter of the tube, the amount of soil, the type of liquid, the level of liquid in the pan, and the amount of time allowed.
NEL Chapter 7 The Water Cycle 527 •To save time and materials, assign each group a different soil or liquid, and arrange for the groups to share their results. •Have students draw a chart to illustrate how high the liquid travels in different materials. •Students may choose to measure maximum height, height after a given time (thus controlling time as one of the variables), or height every 10 or 30 s. Students could graph their results (e.g., histogram comparing different materials in a set time, line graph showing height versus time). Suggested Answers (a) The smaller the diameter of the tube is, the higher the water will move up. (b) The more porous the soil is (the bigger the grains are), the faster the rate of capillary action will be, although the liquid will not climb as high. The viscosity of the liquid also affects the rate of capillary action: the more viscous the liquid is, the slower the rate. (c) As water near the surface dries up, more water is drawn up from the ground below, due to the force of cohesion between water molecules and the force of adhesion between water molecules and soil particles. In real life, this can cause At Home the water table to drop. Have students think about where they might see or experience the effects of evaporation and condensation in their 3 Consolidate and Extend homes. They can look for these effects as they take •Have students add details to BLM 0.0-9 Chapter Key Ideas. a shower, cook their food, or humidify their home. •Students can test percolation using three coffee filters, a coffee-filter holder, two measuring cups, 125 mL of rice, 125 mL of coffee grounds, 125 mL of flour, and a watch with a second hand. Have them follow these steps: –Put a filter in the filter holder and add the rice.
Te c hnology Connections –Put the filter holder on top of a measuring cup. Pour one cup of Have students use a water directly on the rice. computer graphics –Time how long it takes for 175 mL of water to percolate through program to create a poster the rice. explaining how the concepts of the water –Repeat with the coffee grounds and then with the flour. table and capillary action – Ask, How clear is the water that percolates through the rice? through relate to the operation of a the coffee grounds? through the flour? If soil were used instead, which septic field. Encourage type of soil would rainwater soak into? Which type of soil would students to draw their own illustrations using rainwater run off? Which type of soil would rainwater run through? computer graphic tools or This activity could also be used as a class demonstration. With to locate suitable graphics enough filter holders and measuring cups, you could hold a on the Internet, and then use text boxes and percolation race. directional arrows to •Assign the Check Your Understanding questions. explain how the system “flows.”
528 Unit C: Water Systems on Earth NEL CHECK YOUR UNDERSTANDING—SUGGESTED ANSWERS
1. The water that does not collect in streams, rivers, ponds, or lakes eventually makes its way underground. 2. Aquifers can be depleted if water is removed faster than it is being replenished by water percolating from above. 3. As rain falls or snow melts, water percolates into the soil and the water table rises. In winter, as water accumulates as snow on the frozen surface, the water table may drop. On hot days, when evaporation exceeds precipitation, the water table will drop. Following a rain, ground water from a nearby higher area tends to move downward, causing the water table of the surrounding area to rise slightly. 4. The water is attracted to soil particles and therefore spreads out in the top layers of the soil. 5. (a) Water moves upward by capillary action through the narrow spaces between soil particles. In this way, it can travel from deep within the soil and evaporate at the surface. (b) Water percolates downward through the narrow spaces between soil particles, dissolving minerals as it travels. 6. Since water can seep into a well, it can also seep out. Water moved from the well into the dry soil and rock around it.
Reading and Thinking Strategies: Paraphrase/Predict The Water Table 7.4 •Read the first two paragraphs of the section with The next time it rains, watch the raindrops hitting a window. You will students. Have them look at Figure 1 and read the notice that some of the raindrops run down the glass while others seem to stay stuck to the window. Two forces appear to act on the water: the force of gravity pulling it downward and a force of attraction to the caption. glass. Because of its structure, water shows a “stickiness,”an attraction to many materials. This stickiness is the force of adhesion, which causes •Arrange students in pairs to read the Learning Tip on water to cling to other surfaces (recall Section 4.3). page 199. Using Figure 1 and the related information Water is composed of hydrogen and oxygen. The chemical formula for water is H2O, since there are two hydrogen atoms for every oxygen atom. One side of a molecule has a slightly positive charge, and the from the text, have one student explain to the other why opposite side has a slightly negative charge (Figure 1). These charges cause a cohesive force among the molecules and they act like tiny some water droplets cling to each other and other water magnets, with the positive and negative charges attracting one another. The adhesive force makes them stick to other types of molecules as well,like those in the window glass. These charges also affect how droplets cling to the sides of a glass. A possible answer water behaves underground. follows: Because water molecules have both a negative ++ ++ HH HH LEARNING TIP O O As you study Figure 1, ask ++ charge and a positive charge, they act like tiny magnets, – – yourself “What does this HH show?” Relate the information O from the text to the attracting one another (the cohesive force of water). The ++– information in the figure. HH positive and negative charges of water molecules also O Figure 1 make them stick to other materials, such as the sides of Water molecules have a slightly positive and a slightly negative charge at opposite ends. a glass (the adhesive force of water). Water in the Ground •Have students reverse roles. Most of the rain that strikes the ground runs off over the surface and collects in streams, rivers, ponds, and lakes. The rain that does not •Ask students to predict how the forces of adhesion and collect in bodies of water eventually makes its way underground. Figure 2 shows the part of the water cycle that involves water gravity affect rainwater underground. A possible response movement through the ground. Rain seeps into the soil. The force of adhesion between water molecules and soil particles causes the water to spread outward, follows: The force of adhesion between water molecules moistening the ground where it hits. Gravity causes the water to sink
and soil causes water to spread outward. Gravity pulls on NEL 7.4 The Water Table 199 the water, which causes the water to sink farther into the ground. •Have students confirm their predictions by reading Water in the Ground.
NEL Chapter 7 The Water Cycle 529 Meeting Individual Needs Extra Support • Ask students to draw their own diagram of the water table and explain each key term in their own words. Classify information about the water table into four areas: sources of water (precipitation, melting); forces involved (gravity, capillary action); resulting processes (percolation, absorption of water by roots, wells); and moisture conditions (wet or dry soil, saturated zone, aquifers, aquitards). Ask students to use arrows on their diagrams to identify where the different processes take place. •For students who need additional support with the reading in this section, use SM 7.4 The Water Table.
Extra Challenge •Challenge students to design and perform tests in order to investigate how different factors (e.g., temperature, movement of air, amount of surface area) affect evaporation. For each test, the independent variable (the variable that is systematically changed), the dependent variable (the property that is being measured), and the control variables (the variables that are kept the same) should be identified. •Have students use the Internet to research and report on some aspect of ground water contamination in the area in which they live. Encourage students to locate and use local information (i.e., information from provincial, regional, and/or municipal Web sites) when conducting their research.
ASSESSMENT FOR LEARNING
What To Look For in Student Work Suggestions for Teaching Students Who Are Having Difficulty Evidence that students can Ask students who have difficulty writing reports to give oral reports or to display • identify the sources of water below the their information as illustrations or diagrams. water table •create models (e.g., model of capillary action in soil) • analyze and interpret observations • use technical language (percolation, saturated zone, water table, capillary action, aquifers) •display data in tables
530 Unit C: Water Systems on Earth NEL 7.5 The Power of Water Page 202
PRESCRIBED LEARNING OUTCOMES Time • describe how water and ice shape the landscape 45–60 min • use models to explain how systems operate Key Ideas KNOWLEDGE Moving water and ice can • effect of ocean currents and winds on regional climates change the shape of the land. • effect of water and ice on surface features Vocabulary •weathering and erosion • sediment •weathering SKILLS AND ATTITUDES • erosion •relate cause to effect • deposition • delta • assess human impact • flood plain • show respect and sensitivity for the environment • dikes Skills and Processes ICT OUTCOMES • demonstrate the ability to formulate questions and to use a variety of Predicting Creating Models sources and tools to access, capture, and store information Observing •use a variety of information technology tools to solve problems Inferring •apply predetermined search criteria to locate, retrieve, and evaluate Lesson Materials information per student •create electronic text documents • apron •evaluate information retrieved electronically for authenticity, bias, and • safety goggles timeliness • gloves per group • synthesize information from a variety of electronic sources for •2 aluminum pie plates or presentations pans • 1.5 L garden (potting) soil •use a variety of software to present messages • 500 mL water per station SCIENCE BACKGROUND •watering can
•When precipitation falls, some of the •Machines called dredges dig up Program Resources water flows over the land surface as sediments to deepen or widen SM 7.5 The Power of Water runoff, picking up particles of clay, waterways. BLM 7.5-1 Damage Caused sand, and gravel. As the water and •The most familiar floods are spring by Water in My sediments travel downhill, they cut floods, when rivers cannot contain a Community into the soil and form tiny grooves heavy runoff. Spring floods are worst Nelson Science Probe 8 called rills. As more precipitation when the spring thaw is rapid, the Web site falls, this process of erosion riverbank has been clear-cut, or www.science.nelson.com continues and the rills become heavy rainstorms accompany the deeper and wider, forming gullies, thaw. Flash floods, which follow which act as channels for the runoff. violent rainstorms, often cause •Human activities, such as cutting extensive damage. trees, removing vegetation, and •Avalanches can be set off by several cultivating land, can seriously factors, such as temperature, sudden increase erosion by decreasing the vibrations, and shearing of creeping ability of the soil to retain water. If snow masses. Avalanche patrols use rain hits soil directly rather than explosives to cause smaller, less landing on vegetation, the soil destructive movements of snow. A particles are loosened and will erode landslide is massive movement of more easily. soil and water, often after heavy rain. •Many streams and rivers deposit Like avalanches, landslides and large amounts of sediment at their mudslides can be extremely mouths, where the water slows. destructive.
NEL Chapter 7 The Water Cycle 531 TEACHING NOTES Related Resources Downs, Sandra. Shaping 1 Getting Started the Earth. Brookfield, CT: Twenty-First Century Books, 2000. • Check for Misconceptions Groulx, B.J. (ed). Fraser – Identify: Students may think that considerable force is required to River Delta, British wash away soil from mountains. Columbia: Issues of an – Clarify: Ask students to think about erosion that they have seen Urban Estuary. Ottawa: around their homes during a rainstorm, when water runs off roofs. Geological Survey of Canada, 2004. Emphasize that even mild rainfalls remove some soil as it runs off, Kittrick, J.A. (ed). Soil although torrential downpours and floods certainly speed the Mineral Weathering. New process of erosion. Yo rk: Van Nostrand – Ask What They Think Now: Ask students what things they can do Reinhold, 1986. to prevent soil from washing away.
2 Guide the Learning •Review the term erosion, and compare it with the term weathering. (Weathering is the physical and chemical breakdown of rocks by agents such as landslides, acid rain, water freezing and thawing in rocks, and plant root growth in rock crevices. Erosion, on the other hand, is simply the removal of the products of weathering by transporting agents such as water, wind, and ice.) •Use Reading and Thinking Strategies: Determine the Meanings of Scientific and Technical Terms to help students understand the vocabulary in this section. •Ask students to identify agents of erosion and give an example of each (e.g., runoff, wind, rivers, glaciers, gravity, wave action). Explain that each agent of erosion actually moves rock materials from one place to another. Focus on the particle size of the eroded material and the force of the eroding agent. For example, fast-moving rivers, such as the Niagara River, carry larger rock particles and sediment than slow-moving rivers do, and carry the rock particles and sediment farther. •When discussing avalanches, you may need to explain the term undercut. Wind patterns may remove snow from a lower area of a mountain, leaving this area thinner and weaker than areas farther up the mountain. Eventually, enough snow is removed and the snow above, which is no longer supported, slides down and begins an avalanche. •Discuss the effects of eroding agents on deposition. Ask, When and where does deposition occur? (when and where the force of the eroding agent is reduced) Explain what happens when the Fraser River slows down as it empties into the Pacific Ocean. (The silt and other particles it is carrying are deposited, creating a large delta known as Richmond.) •Read Section 7.5 as a class, or ask students to read in pairs.
532 Unit C: Water Systems on Earth NEL • As a class, organize the information in the section into a chart called The Power of Water. Compare erosion, flooding, and avalanches under the following headings: Definition, Cause, Impacts on society (negative and positive), Prevention. •Have students complete Try This: A River’s Response to Rain. •For students who need additional support with the reading in this section, use SM 7.5 The Power of Water.
TRY THIS: A RIVER’S RESPONSE TO RAIN Purpose •Students simulate what happens when rain strikes a riverbed at different rates. Notes •In the first step, students form a spout by bending the edge and rim on only one side of the pie pan. They should not bend the whole pie pan in half. •Make sure that the soil is partly moist so that it sticks when it is patted down. •The river in the pie pan should exit at the spout. Suggested Answers (a) If the soil were not pressed down, some soil would fall out when the pans are tipped. More water would be able to penetrate the soil, especially if the water is poured quickly. Thus, the amounts collected from both pans might be more similar. (b) When water is poured more quickly, more of it flows off the pan. This is because the soil in the slow pan has a greater chance to absorb more of the water. (c) The water from the fast pan will be more muddy, as the faster-moving water can carry more soil particles. (d) The pattern would be the same, but the amount of water runoff and the amount of soil in the water would differ. (e) The harder the rainfall is, the greater the soil erosion.
3 Consolidate and Extend •Review the new concepts of flood plains and dikes. •Ask students to make suggestions about the causes of flooding and how to prevent them. •Have students complete BLM 7.5-1 Damage Caused by Water in My Community. The worksheet can be assigned for homework if not completed in class. •You may want to discuss why some residents choose to remain in a flood-prone area when they know the danger (e.g., Richmond at the mouth of the Fraser River) • Assign the Check Your Understanding questions.
NEL Chapter 7 The Water Cycle 533 CHECK YOUR UNDERSTANDING—SUGGESTED ANSWERS At Home In the winter, suggest that 1. (a) Erosion is the carrying away of soil particles by wind and water. students look for (b) Roots trap soil and water, and vegetation reduces the force of the rain overhanging snow on striking the ground. Thus, maintaining forests can control erosion. rooftops. Often, the snow 2. By ploughing furrows perpendicular to the slope, water is prevented from can hang a long way flowing freely down the slope. The furrows act like little dams that catch the before it finally falls off. water, allowing it more time to seep into the soil. The goal is to reduce the In the early spring, velocity of the water, directly affecting its capacity to carry sediment. students could find a tiny 3. Dredging is the removal of sand and silt from the bottoms of river mouths, stream of melting snow estuaries, and lakes. The Fraser River is dredged regularly to facilitate ship (meltwater) and dam it to traffic. Dredging disturbs the sediment under the water, making the water see what happens as the temporarily more silty and giving the water a brownish colour. This may cause water builds up behind the short-term harm to micro-organisms, insects, and fish. dam. Then, they could break the dam to see if the 4. Dikes hold back water, preventing the water from flooding towns and fields. rushing water causes They also give flood-control engineers time to plan solutions for impending erosion. large floods. If a dike is breached, however, it can prevent the floodwater from flowing back into the river when the water level goes down. Dikes prevent Encourage students to look flooding, so they make it possible for more people to move into flood-prone for evidence of erosion in areas. their community. During a rainstorm, students can 5. Avalanches are deliberately caused to reduce their destructiveness. The goal is watch raindrops hitting hard to prevent a sudden avalanche, and thus save lives and reduce the risk of surfaces, bare ground, and property damage. vegetation. Can they see 6. Some examples of water damage follow. Students will provide other examples, raindrops bounce? Is any as well. soil loosened on the bare •The freeze/thaw process can break up roads, driveways, and concrete ground? structures, and produce frost boils and the resulting potholes on gravel roads. •When water freezes on the edge of a roof, causing an ice dam, it can lift shingles. •Wet snow is heavy and can cause roof cave-ins, so the building code specifies the strength of roof supports for the snow load in the area. •Moisture seeping into a building allows moulds and fungi to develop, so builders try to prevent moisture from entering a building or from undermining it. • Hail destroys property and crops, but there is little that humans can do to prevent the damage. 7. Levees and dikes can be built along rivers that are prone to flooding. They can also be built while a river is flooding, generally using sandbags. Floodways can be built. A floodway is a concrete river channel designed to carry floodwaters safely away from homes and other buildings. A floodway is usually straight; therefore, water flows faster and more easily through a floodway than through a meandering river.
534 Unit C: Water Systems on Earth NEL Reading and Thinking Strategies: Determine the Meanings of Scientific and Technical Terms 7.5 The Power of Water •Read the title of the section with students. Have them Imagine that you are standing on a riverbank after a rainstorm. You scan the subheadings, figures, and captions on pages 202 notice that the water is unusually brown. Runoff from riverbanks and the surrounding land carriessediment, which includes gravel, sand, and 203. Ask them what they think the subsections will silt, and mud, into the river. In the sediment-laden waters, water plants receive less light and some fish may not get sufficient oxygen. Farther be about (moving water can change the land around it). downriver, where the current slows, the sediment settles to the bottom. Most river organisms adapt to moderate amounts of sediment and suffer little damage. A heavy sediment load in a river or stream, •Have students scan pages 202 and 203 to look for however, can change the habitat of the plants and animals living there. Earth’s surface, caused by the movement of materials from one place to vocabulary words (screened and bold): sediment, another, is callederosion. Erosion can be causedWeathering by the force of gravity, running water, waves, moving ice (mainlyThe sediment glaciers), that and is beingwind. washed away by the river comes from the soil. weathering, erosion, deposition, and delta. But where does the soil come from? Many millions of years ago Earth was When vegetation is removed from the landbasically above aa river,big ball soil of rock and water. Over time, the rocks were broken •Have students discuss the meanings of the words they particles wash into the river, filling it with sediment.down through Plant aroots process help called to weathering.Weathering is the breakdown hold the soil, while trees and other vegetationof reduce rock into the sediments. force of These sediments of various sizes make up the soil. falling rain. Ploughing farmland removes vegetation for a short period know, and ask them to predict possible meanings of the of time, while practices such as clear-cutting (theThere cutting are several of all trees ways that rock can be weathered. Water can over a large area) remove vegetation for a muchweather longer rocks period. in two Without ways. Have you ever accidentally left a glass bottle plants, soil is easily carried away by surface runoff.of water (Figure in the 2freezer). until it froze solid? If so, you know that when words they do not know. water freezes it expands and can exert enough force to break the bottle. As the current of a sediment-laden river slows,Water thethat sediment freezes in begins tiny cracks in a rock expands and wedges the rock •Have students read pages 202 and 203 and write their to settle to the bottom, a process calleddepositionapart. Repeated. Heavier freezingparticles and thawing can eventually break the rock (rocks, stones, and pebbles) settle first, whileinto sand small and pieces.silt are Watercarried can also weather a rock by dissolving certain own definitions for the vocabulary words, using the clues farther along. The settled particles, or sediment,minerals. can fill As in these a lake minerals or areFigure removed, 2 the rock becomes unstable build up a delta at the mouth of a river. Adeltaand isis amore flat area easily of broken land into Aftersediments. a forest Plants,is clear-cut, too, soil are responsible washes away more easily. in the text. formed by sediment that has settled at the mouthfor some of aweathering. river over many In their search for water and nutrients, small thousands ofFigure years. 1 roots can force their way into cracks and help break a rock apart The roots of plants exert enough The Fraserforce River in the delta cracks is ofthe rocks largest to split river delta(Figure in Canada. 1). All of It thesewas processes over many millions of years have •Have students share their definitions. Discuss how formed by sandthe rock and apart. silt from the last major producedice age, about a layer 10 of 000 soil years that can be moved from one place to another. ago. The sediments are up to 40 m thick in the oldest part of the delta. figuring out the meanings of some words depends on Of course, the delta is still growing today as Erosionthe Fraser River continues to bring tonnes of material each year to be depositedHave you on ever the had outside to shovel snow from a long driveway or carry a large understanding the meanings of other words. For edge of the delta (Figure 3). pail of water a long distance? You probably realized very quickly how heavy water is. Now imagine this weight multiplied 100 000 times and The bottom sediment is sometimes removed through a process hurtling directly toward you! The force of water causes considerable called dredging (Figure 4). The Fraser River delta is regularly dredged example, to understand what a delta is, you need to damage to plants, animals, land, and buildings across Canada and the to remove built-up sediment that can be dangerous in shipping lanes. rest of the world. The damage can be swift and dramatic, as in the case know what sediment and deposition are. Also discuss of avalanches and floods. Or it can make changes that take years to whether the text confirmed and added to students’ notice, such as when land is slowly worn away. The wearing away of 202 Unit C Water Systems on Earth NEL understanding of the words they knew. •Conclude by asking students how working with clues in the text helps them determine the meanings of
vocabulary words. Figure 3 Figure 4 The greyish-blue area of this satellite image River and lake bottoms are often dredged to make the water deeper and shows water carrying sediments and depositing thus safer for ships. them in the Fraser River delta.
NEL 7.5 The Power of Water 203
Meeting Individual Needs ESL •Use pictures to illustrate the effects of erosion, flooding, and avalanches. Ask students to make a concept map (including diagrams) for each term. •Pair ESL students with their peers to read, and encourage them to explain the concepts in their own words.
Extra Support •Review the concepts of erosion, flooding, and avalanches, and ask students to explain the meanings to you in their own words. •For students who need additional support with the reading in this section, use SM 7.5 The Power of Water.
Extra Challenge •Invite students to research the societal and environmental impact of the Fraser River. •Have students use the Internet to research flood control or avalanche control in British Columbia. Students could then create position papers and/or debate the need, true cost, and environmental impact of selected programs. While students are conducting their research, encourage them to evaluate sources for accuracy of information and bias.
NEL Chapter 7 The Water Cycle 535 Tech.CONNECT: The Dikes of Richmond, British Columbia
PAGE 208 •Early settlers in the Fraser River Estuary quickly learned the importance of dike building to hold back both the ocean’s high tides and the river’s annual floodwater. Much time and energy had to be spent diking and draining the low-lying land. Lulu Island, the largest in the delta and home to the city of Richmond, is embraced by all three arms of the Fraser River. Seven bridges and the George Massey Tunnel connect it to the rest of the Lower Mainland. The Fraser River’s constant flow is responsible for filling in the shoreline of the Strait of Georgia with silt. Two expansive tracts of tidal marshland front the delta—Sturgeon and Roberts Banks— without providing much in the way of beaches. Instead, the shoreline has tall stands of bulrushes and is strewn with driftwood. Most students will know about or will have seen a dike. Have them research and identify various dike systems that are used around the world (e.g., in Holland, New Orleans, Richmond). •Show a video on building dikes and levees. • Arrange for a guest speaker from Richmond to talk about dike maintenance.
ASSESSMENT FOR LEARNING
What To Look For in Student Work Suggestions for Teaching Students Who Are Having Difficulty Evidence that students can Ask students to identify the simple cause-and-effect relationship between • define weathering and erosion, and erosion and deposition, using a graphic organizer. describe how these processes shape the Go over key words and phrases, such as environmental issues, and historical surface of Earth levels. • explain the social and environmental risks of floods and avalanches, and give Have students work with a partner to discuss the photographs and captions, and examples of efforts that reduce these risks then reread the section together. • create models (e.g., erosion from runoff) Students who have difficulty writing their answers can use point-form notes • use technical language (sediment, (including vocabulary words) or record their answers on audiotapes so that you weathering, erosion, deposition, delta, flood can assess their understanding of the key concepts. plain, dikes)
536 Unit C: Water Systems on Earth NEL 7.6 The Human Side of Water Systems Page 209
PRESCRIBED LEARNING OUTCOMES Time • explain the significance of salinity and temperature in the world’s 30–45 min oceans • explain variations in productivity and species distribution in aquatic Key Ideas environments The water cycle is affected • demonstrate scientific literacy by many factors. Vocabulary SKILLS AND ATTITUDES • acid precipitation • use given criteria for evaluating evidence and sources of information Skills and Processes (e.g., identify supporting or refuting information and bias) •relate cause to effect Recording Communicating • assess human impact Classifying • show respect and sensitivity for the environment Program Resources ICT OUTCOMES SM 7.6 The Human Side of Water Systems •use a variety of information technology tools to solve problems BLM 7.6-1 Description of •create electronic text documents Water Use •evaluate information retrieved electronically for authenticity, bias, and BLM 7.6-2 Charter of Water Rights and timeliness Responsibilities •use a variety of software to present messages BLM 7.6-3 Monitoring Water • demonstrate the ability to arrange information in different forms to Use At Home Nelson Science Probe 8 create new meaning Web site www.science.nelson.com SCIENCE BACKGROUND
•Although water is considered to be a privies, dumped raw sewage, and renewable resource, most is salt farms. The indicator species— water in the oceans and therefore bacteria that show the presence of not suitable for drinking, irrigation, or such pathogens—are coliform industry. Most fresh water is also bacteria. Coliforms are essential to not suitable for drinking because it our health, because they help to contains impurities and must be break down the waste products of treated to make it safe to drink. digestion in the large intestine. •Many freshwater systems are Finding them in swimming areas, becoming polluted from dumped however, means that dangerous sewage, sediment, and wastes. pathogens could also be present. Some impurities are naturally filtered • When fossil fuels are burned, by soil and rock, but soluble nitrogen oxides and sulfur dioxide substances are not. Also, most are released into the air. These gases pollutants do not evaporate when react with water vapour in the water does. Therefore, they become clouds, forming droplets of nitric acid concentrated in lakes, seas, and and sulfuric acid. The acid droplets oceans, making the water even more fall as acid precipitation. Industry, polluted. vehicle use, and electrical generating •Pathogenic bacteria in animal waste plants are the major producers of can enter bodies of water from acid rain.
NEL Chapter 7 The Water Cycle 537 TEACHING NOTES Related Resources Firor, John. The Changing 1 Getting Started Atmosphere: A Global Challenge. New Haven, •Introduce Section 7.6 by reviewing what students already know CT: Yale University Press, about the water cycle and water table, emphasizing the connections. 1990. Ask a few students to take turns describing the processes that water Hunter, Beatrice Trum. Air and Your Health. North goes through, each student picking up where the previous student Bergen, NJ: Basic Health left off. Students could draw the water cycle on the board or chart Publications, 2004. paper. A Primer on Water. Environment Canada, 2 Guide the Learning 1991. Turk, Jonathan, and Amos •Use Reading and Thinking Strategies: Locate Needed Turk. Environmental Information/Make Inferences to help students infer information Science. Philadelphia: from the text. Saunders College Publishing, 1998. •Have students brainstorm some of the ways in which humans Water: No Time to interact with water systems. Students tend to focus on pollution, Waste—A Consumer’s with the general idea that pollution is bad, but not knowing the Guide to Water Conservation. specifics. Reading this section will help them understand some of the Environment Canada, effects of pollution. In the Try This activity, students will explore 1990. other ways in which humans use water, both wisely and wastefully. Wellburn, Alan. Air Pollution and Climate •Ask students if they have ever had to leave a beach because of signs Change: The Biological such as those shown in Figure 1 on page 209. Use recent, local beach Impact. Harlow, England: closings or water-quality reports to focus students’ attention on the Longman Scientific & consequences of poor water quality. Technical, 1994. Wroble, Lisa A. The •As a class, read Section 7.6 and discuss the main ideas. Oceans (Endangered Animals & Habitats). San •Have students complete Try This: Water Use Survey. Diego: Lucent Books, •For students who need additional support with the reading in this 1998. section, use SM 7.6 The Human Side of Water Systems.
TRY THIS: WATER USE SURVEY Purpose •Students conduct a survey to identify water use at home and school, and then analyze and interpret the data they collected. Notes •Students can use BLM 7.6-1 Description of Water Use and BLM 7.6-2 Charter of Water Rights and Responsibilities to record their findings. Their qualitative data about water use and their Charter of Water Rights and Responsibilities will help them recognize how interpretations and conclusions depend on the quality of the data collected. •Discuss some of the ways that students use water at home, such as cleaning and cooking, and ask them where they think water is used the most in their homes. •Ask students if they practise conservation of water at home, and invite them to give examples. Suggested Answers (a) Water wise at home: • When brushing teeth, run the water only at the beginning and the end. •Take showers instead of baths, and be quick when showering.
538 Unit C: Water Systems on Earth NEL •Water the lawn during the cooler parts of the day. In dry periods, do not water the lawn—the grass will survive. • Do not discard hazardous substances, such as paint thinners and motor oil, down the drain. Dispose of them at appropriate centres. Water wise at school: • Do not discard lab chemicals down the drain. •Alert the caretaker if a water problem exists (e.g., running water fountain or tap, overflowing toilet). •Water waste: Opposite of water wise answers • Suggestions on how to conserve: See Charter of Water Rights and Responsibilities below. (b) Charter of Water Rights and Responsibilities Water rights: • to drink safe, clean water •to be able to use water for recreation •to have an adequate supply of water for safety purposes (e.g., fighting fires) •to have water available for hygiene •to have adequate water for industries and farming • to experience precipitation that is not harmful to wildlife, buildings, and crops Water responsibilities: •to conserve water as much as possible • to reduce pollution in water • to adopt a lifestyle that preserves water quality (e.g., driving less, using biodegradable products) •to support government agencies that oversee water quality in the environment •to support laws that encourage industries to clean the water they use before returning it to the environment • to ensure that the municipality upgrades its sewage treatment facilities when necessary (c) Students’ charters can be shared in small groups or as a class. At Home Ask students to be aware of any pollution in their neighbourhood: cars idling for long periods of time, 3 Consolidate and Extend harmful chemicals being dumped in drains or road •Ask students to suggest other ways to protect waterways. For sewers, and litter. Remind example, dams help to prevent erosion because they control the flow them that much of the air of water, breakwaters reduce the effects of waves and boat wakes, and and ground pollution laws ensuring that cottagers have septic tanks (rather than outhouse eventually works its way into the water system. pits) may prevent waste from flowing into lakes. Reducing emissions Ask students to record from cars and industries reduces acid rain. their family’s water use and •Ask students to estimate the amount of money that their community calculate the total amount of water used in litres. earns each year for water-related recreation. If possible, approach the Distribute BLM 7.6-3 local chamber of commerce for an estimate. Monitoring Water Use at Home for students to • Conclude by asking students how the water cycle contributes to the record their data. Students development of acid lakes (condensation of acid droplets in the can then use their data to clouds, acid precipitation, runoff of acid precipitation into water calculate their family’s daily reservoirs). average consumption. • Assign the Check Your Understanding questions.
NEL Chapter 7 The Water Cycle 539 CHECK YOUR UNDERSTANDING—SUGGESTED ANSWERS Te c hnology Connections E-mail could be used to 1. Answers here will depend on where students live. Students in urban areas may establish links with a concentrate on pollution in local streams, rivers, and sources of drinking water, school in a different area caused by industries, sewage treatment, and outdoor activities such as boating or province. Students and water sports. Students in rural areas may concentrate on local noise and could discuss water speed bylaws for waterways, as well as sewage treatment. concerns in two (or more) 2. Nausea, vomiting, and diarrhea are associated with the presence of ingested very different areas. They coliform bacteria. could maintain a class database of responses, 3. The summer has ideal growing conditions. Warmer temperatures and increased allowing a comparison of body waste from other organisms increase the reproduction rate of lake (and results from student to other) bacteria. student, class to class, 4. Acid precipitation is caused when water vapour reacts with airborne pollutants, and year to year. particularly sulfur dioxide and nitric oxide. Acid precipitation slows plant growth, kills aquatic organisms, and even dissolves rocks and building materials (see Figure 3).
Reading and Thinking Strategies: Locate Needed
Acid precipitation slows plant growth, kills aquatic organisms, and even dissolves rocks and building materials (Figure 3). Information/Make Inferences Economic losses due to acid rain include reduced agriculture and timber production, the death of fish stocks, injuries to livestock, and •Ask students how using features in the student book can damage to buildings. The governments of some countries, such as Canada, limit the types and amounts of pollution that industries can help them to locate information to answer questions. Figure 3 emit. Some industries voluntarily control their emissions. The Acid precipitation has killed most reduction of air pollution is the only sure way to reduce acid of the trees in this area. (They can look at headings, figures and captions, tables, precipitation. and vocabulary words to find the part of the text that TRY THIS: Water Use Survey Skills Focus: classifying, recording, communicating might answer a question.) Each Canadian uses about 350 L of water daily for drinking, cooking, bathing or showering, doing laundry, flushing the toilet, and other •Discuss how questions sometimes require students to household needs. (a) Using a table like the one below, identify activities in your home and school think beyond the given information to infer or draw that use water wisely and those that are wasteful. Make suggestions to help reduce the waste and encourage the wise use of water. conclusions, based on what they have learned about a Table 1 Survey of Water Use Description of Water waste or Suggestions on water use water wise? how to conserve topic and their own background knowledge. In other words, the answers may not be stated exactly in the text. (b) Using the results of your survey, write a Charter of Water Rights and Responsibilities. Research information to add to your charter. Be sure to include •Before students complete the Check Your • five water rights you think every Canadian should have • five water responsibilities every Canadian should fulfill Understanding questions, arrange them in pairs to read (c) Be prepared to share your charter with the class. the questions and then scan the section, using text
7.6 CHECK YOUR UNDERSTANDING features to decide if the answers are in the text or will 1. Give three examples of how human activities can affect water systems. 2. What health risks are associated with the presence of coliform bacteria? have to be inferred. 3. Why are populations of lake bacteria usually higher in the summer? 4. What causes acid precipitation? What problems are caused by acid 1. Give three examples of how human activities can affect precipitation? water systems. (Students need to infer answer.) 2. What health risks are associated with the presence of 210 Unit C Water Systems on Earth NEL coliform bacteria? (Answer is in section.) 3. Why are populations of lake bacteria usually higher in the summer? (Answer is in section.) 4. What causes acid precipitation? What problems are caused by acid precipitation? (Answer is in section.) •Have students answer the questions on their own.
540 Unit C: Water Systems on Earth NEL Meeting Individual Needs ESL •Involve students as participants in an oral reading of the section. Reading with a peer or as part of a group will improve confidence. •Identify which activities in the home and school use water, and list these for students. Visual representations of these activities or key words will assist ESL students.
Extra Support •As the section is read, ask students to make notes about the important words and concepts. Discuss their meanings and their connections to this topic; for example, micro-organisms, coliform bacteria, digestive system, parasite, biodegradable, sewage, acid precipitation, sulphur dioxide, nitric oxide, economic losses. •For students who need additional support with the reading in this section, use SM 7.6 The Human Side of Water Systems.
Extra Challenge •Invite students to design a procedure to investigate chemical weathering of rock by acid rain or the effects of acid rain on plants. •Have students identify and use the Internet to research a water quality issue related to the area they live in (e.g., pollutants in storm drains, leaching from farms or a mine, acid rain, unsafe swimming locations). Challenge students to present their findings in a way that both informs others of the issue and promotes a positive solution to the problem (e.g., poster, multimedia presentation to be shown at a local mall, letter to a government agency and/or local paper, petition).
ASSESSMENT FOR LEARNING
What To Look For in Student Work Suggestions for Teaching Students Who Are Having Difficulty Evidence that students can Ask students to illustrate one concept in this section, using arrows and labels to •give examples of the impact of human show evidence of its existence, its cause, and its direct effects on humans. activities on natural water systems For students with organizational difficulties, divide the Try This activity into stages • use technical language (acid precipitation) to help them complete it on time. • create products that are complete (e.g., tables) Remind students that some everyday materials are acidic (e.g., vinegar, citrus fruit juices, tomatoes, soft drinks).
NEL Chapter 7 The Water Cycle 541 7.7 Water Treatment and Disposal Page 211
Time PRESCRIBED LEARNING OUTCOMES 45–60 min • explain the significance of salinity and temperature in the world’s oceans Key Ideas Water systems are managed SKILLS AND ATTITUDES to protect them from the •relate cause to effect impacts of human activities. • assess human impact Vocabulary • show respect and sensitivity for the environment • sanitary sewage •stormwater ICT OUTCOMES • sludge • demonstrate the ability to formulate questions and to use a variety of • effluent sources and tools to access, capture, and store information Program Resources •use a variety of information technology tools to solve problems BLM 7.7-1 Filtering Dirty •apply predetermined search criteria to locate, retrieve, and evaluate Water information SM 7.7 Water Treatment and Disposal •create electronic text documents BLM 7.7-2 A Water Map— •evaluate information retrieved electronically for authenticity, bias, and From the Source to Where timeliness You Live Nelson Science Probe 8 • synthesize information from a variety of electronic sources for Web site presentations www.science.nelson.com •use a variety of software to present messages
SCIENCE BACKGROUND
•Many cities draw drinking water •The Greater Vancouver Regional from the same body of water where District (GVRD) has recently they dump their treated sewage. developed a liquid waste Clearly, water and sewage treatment management plan (LWMP) for the are important. region. The LWMP will be a master •Filters remove particles but not plan for sewage and drainage solutes or bacteria. Sand, gravel, and programs in the Lower Mainland. The charcoal are inexpensive and plan will be used to guide effective filters. If a well is the water investments in new and existing source, filtering is not needed. Water facilities and programs, including is aerated to remove dissolved stormwater management. gases. Alum or ammonium • In urban areas, household sewage aluminum sulfate is added to flows through sanitary sewers to a flocculate small particles together so sewage-treatment facility. In the they settle. Chlorine, a toxic past, people often dumped untreated chemical, is added to kill bacteria, sewage directly into water bodies, and fluorine is added to help prevent relying on the diluting effect. Now, tooth decay. Ozone or ultraviolet light most sewage is treated. Primary may be used to kill micro-organisms. treatment removes only floating and Then, the water is pumped into a suspended solids, usually by water tower, which maintains a filtration, before returning the constant pressure (by gravity) in the effluent to a water body. Secondary water distribution system. treatment uses biological methods,
542 Unit C: Water Systems on Earth NEL such as bacterial decomposition, to •In rural areas, each home has a Related Resources treat the waste. Tertiary treatment septic tank and drainage field. Allwest Reporting Ltd. removes all bacteria and organic Sewage from the home flows into GVRD Drinking Water components from the sewage, and the septic tank. Solids settle on the Treatment and Supply chlorine is added as a disinfectant. bottom of the tank or are degraded Strategies: Transcripts of The remaining solids, called sludge, by bacteria, while the liquid flows Public Meetings Held can be used as farm fertilizer or dried into the drainage field and seeps into Between April 12 and 21, and incinerated. The ash is buried in the ground. 1994. Burnaby, BC: a landfill site. Some communities do Greater Vancouver not treat the sludge, but simply Regional District, 1994. dump it in a local landfill site. Alth, Max. Wells and Septic Systems. Blue Ridge Summit, PA: Tab TEACHING NOTES Books, 1992. Pries, John. Wastewater 1 Getting Started and Stormwater Applications of Wetlands in Canada. Ottawa: North • Check for Misconceptions: First Possible Misconception American Wetlands – Identify: Many students think that fresh water means pure water. Conservation Council – Clarify: Most fresh water is not potable, or suitable for drinking, (Canada), 1994. without treatment. Demonstrate the first stage in the treatment A Primer on Water. Environment Canada, process using BLM 7.7-1 Filtering Dirty Water. 1991. – Ask What They Think Now: Ask students, What can be done to Water: No Time to make fresh water suitable for drinking? Waste—A Consumer’s Guide to Water • Check for Misconceptions: Second Possible Misconception Conservation. – Identify: Students often think that any water related to toilets is Environment Canada, dirty. 1990. – Clarify: Explain that all water entering a home comes from the same source. The water in a toilet tank is as clean as the water in a bathtub. Using the toilet contaminates the water. – Ask What They Think Now: Students should understand that there are two types of sewer systems: sanitary sewers that handle household wastes and some industrial wastes (shown in Figure 1) and storm sewers that handle precipitation runoff (not shown in Figure 1). Explain that intake and outlet pipes are never as close as those shown in Figure 1. This was done to conserve space, but does not depict reality. •Use Reading and Thinking Strategies: Identify Main Ideas/Summarize to help students understand the concepts in this section.
2 Guide the Learning •There is a considerable amount of information in this section for students to learn. Introduce the information by focusing on the main concepts in Figure 1. •Water treatment involves the following processes: – filtration (screens after intake pipe, as well as filtration tank) –flocculation (with added chemicals, mainly alum) – settling
NEL Chapter 7 The Water Cycle 543 – chemical treatment (chlorine and fluorine) – pumping (through water mains into water tower, and then by gravity to homes and industries) •Sewage treatment involves these processes: –sewage collection (sanitary sewers and storm sewers) – aeration – bacterial decomposition (in settling tanks) – final filtration •Highlight the main processes by asking students to identify what they are and why they are needed during water and sewage treatment. •Review the concept of a filter (a material that separates substances from a mechanical mixture; filters cannot separate substances in a solution). Mention filters in everyday life (kitchen-sink plug, air filters) and the common property of filters (small openings or pores that trap some substances and allow others to pass through: the smaller the openings, the smaller the particles that pass through). • Along with filtering, water is treated with charcoal, which absorbs At Home organic molecules. Demonstrate this by pouring water that contains Suggest that students find dissolved vegetable dye (organic) through powdered charcoal. The out where their water comes from at home. (If dye will be removed. they live in an apartment, • Alum can be purchased in drug and grocery stores. Pouring a small is there a tank on the roof? If they live in a amount into muddy water effectively demonstrates its properties. house, suggest that they •Read the text with students. Encourage them to follow the flow of look in the basement to find where the pipe enters the water in Figure 1. the house.) Where does •For students who need additional support with the reading in this their wastewater go? How large are the water pipes section, use SM 7.7 Water Treatment and Disposal. and drain pipes? (Water pipes are usually 1.25 cm. 3 Consolidate and Extend Drain pipes range from 5 cm diameter to 10 cm or • Ask students to draw their own flow diagram or to create a two- more.) Encourage column chart with the headings “Actions” and “Effects.” students to investigate how a toilet works or •Have students research the path that water follows in your where the pipes are community, from its source to the place where it is returned to the located in their homes. environment. Students can use BLM 7.7-2 A Water Map— From the Suggest that they read a simple home-plumbing Source to Where You Live as a starting point for their research. book. (Check a local •If possible, arrange a field trip to a local water-treatment or sewage- library.) treatment facility, or both. Remind students that these are two separate facilities, because we do not want sewage effluent in our drinking water! •Assign the Check Your Understanding questions.
544 Unit C: Water Systems on Earth NEL CHECK YOUR UNDERSTANDING—SUGGESTED ANSWERS Te c hnology Connections 1. Water is forced through layers of sand, gravel, and charcoal, which filter out fine Ask students to research sediment. the type(s) of water treatment and disposal 2. The water is pumped through water mains (large delivery pipes) and up into a used in their community, water tower. The force of gravity then helps to send the water through street and to create mains and secondary mains to homes, businesses, and institutions. presentations to share 3. The two main types of sewer systems are storm sewers and sanitary sewers. their findings. Also ask Storm sewers carry precipitation from streets and eavestroughs on homes them to share their directly to rivers and lakes. Sanitary sewers collect water that was used by research techniques (e.g., humans in homes, businesses, and some industries, and transport it to sewage- different search engines treatment facilities. and key word searches). 4. Urban students: kitchen sink to drain pipe, to sanitary sewer in street, through Encourage them to look sewage treatment plant, to lake or river for bias in the sources Rural students: kitchen sink to drain pipe, to septic tank, to drainage field, to soil they found. Have students 5. Bacteria digest organic matter in sewage. (They are rarely used in water pay particular attention to treatment.) Anaerobic bacteria break down the solid waste in digestion any social/political issues chambers. Micro-organisms in the environment complete the final breakdown of related to their research waste material. topic and be prepared to state and defend their 6. Many household chemicals cannot be properly treated at a sewage plant, so position on the issues. they should not be poured down household drains. Chemicals that are dumped down street drains receive no treatment, travelling directly (by storm sewer) into the natural water cycle.
Reading and Thinking Strategies: Identify Main Ideas/Summarize Water Treatment and Disposal 7.7
• Explain that when summarizing a section of text, students first Canada’s geography includes 9 % of the world’s fresh water. Most fresh LEARNING TIP water requires treatment to remove living organisms, dissolved Identifying key words helps the need to decide what is important (the main ideas), and then minerals, suspended sediment, and human-caused pollutants. Used reader determine the most important concepts in a water may need to be treated again before it can be safely returned to section. To help you determine rephrase the main ideas in their own words and in a condensed the environment (Figure 1). key words, look for words that are highlighted, repeated, and water used in headings. chlorine tower form. Have students read the Learning Tip, and note that looking chemicals added added settling for key words can help them identify the main ideas in text. tank filters street service main •Arrange students in pairs, and ask them read the first paragraph main
secondary and look at Figure 1. Then ask them to read the remaining main screens sanitary settling tank sewage paragraphs on pages 211 and 212, pausing after each paragraph reservoir main bacteria aeration tank beds
to summarize the main idea in their notebooks under the heading intake pipe gravel final beds of the subsection. Tell students that the vocabulary words filtration
(sanitary sewage, stormwater, sludge, effluent) need to be water returned to lake
included in their summaries. Figure 1 Water and sewage facilities •To help students write in a condensed form, tell them that each Intake and Treatment Most of the water that is used by municipal water systems comes from word they use will cost 10¢ and they have $1.50 to spend for lakes and rivers. Water is taken from the source through a large intake pipe. Screens across the end of the pipe keep out fish, garbage, and each paragraph. This limits their summaries to 15 words. other debris as water is drawn in. The water is pumped into a reservoir, where larger particles settle. •Have students add up the cost for each paragraph and each The water then passes through a series of progressively finer screens on its way to a treatment plant. The screens remove small fish, leaves, and subsection. If they go beyond the set amount for each paragraph, some algae. As the water enters the treatment plant, chemicals, such as alum, are ask them to condense further. added to make any floating particles clump together and settle in a •Below are sample summaries of the three paragraphs under NEL 7.7 Water Treatment and Disposal 211 Intake and Treatment (total $3.50): – Source water screened before entering intake pipe to remove large debris. ($1.10) –Water pumped from reservoir to treatment plant; fine screens remove small debris. ($1.20) –Chemicals make particles clump and settle; fine sediment filtered; chlorine kills micro-organisms. ($1.20) •Conclude by having students use their summaries and Figure 1 to review the treatment of water to make it drinkable and the treatment and disposal of wastewater.
NEL Chapter 7 The Water Cycle 545 Meeting Individual Needs ESL •Present the information in chunks, referring to the diagrams in the student book. Encourage students to summarize the information in their own words as each chunk is completed. •Encourage students to formulate questions about the information they do not understand and to work with a classmate for clarification. Asking a classmate to explain information benefits both students.
Extra Support •Reduce the amount of written work required by focusing on diagram notes. Students could write answers in point form, use diagrams, or give oral answers. •For students who need additional support with the reading in this section, use SM 7.7 Water Treatment and Disposal.
Extra Challenge •Students could use the Internet or talk to a plumber to research the history of plumbing and plumbing fixtures. Canadian cities have had sewage systems and piped water for only about 100 years.
ASSESSMENT FOR LEARNING
What To Look For in Student Work Suggestions for Teaching Students Who Are Having Difficulty Evidence that students can Clarify and explain the meanings of the new vocabulary. • describe the processes of water treatment Present the information in chunks so that students are not overwhelmed or and waste disposal confused. • describe the potential impacts of water treatment and waste disposal on natural Focus on the main concepts in each process. water systems •use technical language (sanitary sewage, stormwater, sludge, effluent)
546 Unit C: Water Systems on Earth NEL 7 Review Page 214
Chapter 7 Review Chart Time •If BLM 0.0-9 Chapter Key Ideas has not been used throughout this 45–60 min (may depend on the class and the time chapter, use it now. Instruct students to insert personal experiences available) that match the key ideas. Skills and Processes • Arrange students in pairs to review what they have learned in The Chapter Review provides Chapter 7, using the Chapter 7 Review Chart. Instruct students to an opportunity for students to read each key idea and discuss with their partner what they remember demonstrate their about the topic. Then, they can use the vocabulary page references in understanding of and their ability to apply the key ideas, the chart to scan for additional information in the chapter. vocabulary, and skills and •Ask students to write each key idea in their notebook. Beside each key processes. idea, ask them to create labelled diagrams or sketches, including any Program Resources vocabulary words, to illustrate it. BLM 0.0-9 Chapter Key Ideas BLM 7.0 Chapter 7 Quiz •Have students complete BLM 7.0 Chapter 7 Quiz, to review the Nelson Science Probe 8 vocabulary and concepts in this chapter. Web site www.science.nelson.com Review Key Ideas and Vocabulary—Suggested Answers 1. List (a) is correct. 2. Students might include the following ideas:
Fresh water Salt water covers 2 % of Earth’s surface covers 71 % of Earth’s surface
is found in rivers, lakes, streams, and is found in oceans, some salt lakes, and underground some marshes
is less dense than salt water is more dense than fresh water
has less buoyancy than salt water has greater buoyancy than fresh water
contains approximately 200 to 1000 ppm of contains approximately 35 000 ppm of dissolved salts dissolved salts
is drinkable (with treatment) is not drinkable (without treatment to remove salt)
3. Feature Location liquid water rivers, streams, lakes, ocean, estuaries, marshes, precipitation, taps, living things
solid water glaciers, ice on lakes, snow, ice crystals in clouds
water vapour atmosphere or air
salt water oceans, salt lakes, lagoons, saltwater swamps and marshes
saturated zone the ground just below the water table
sediment ground water, muddy water, rivers, streams
NEL Chapter 7 The Water Cycle 547 4. If raw or improperly treated sewage is discharged into the water, coliform bacteria can increase rapidly. During the summer, warm temperatures provide ideal growing conditions for the bacteria and more beaches are closed. 5. (c) Acid rain can damage the foliage on many trees. If enough damage is done to the leaves, the trees may die.
6. Rural treatment Urban treatment After use, water goes down the drain and Water goes down the drain, into a sewer, into a septic tank. and to a sewage treatment plant.
Solids sink to the bottom of the septic tank Solids are shredded, and then sink to the and are broken down by bacteria. bottom of settling tanks, where they are broken down by bacteria. Water flows into tiles in the drainage field Water is piped to bacteria beds where and seeps into the ground, where bacteria bacteria break down organic matter. Then, break down any organic matter. the water is filtered and returned to a lake or river.
Every few years, the septic tank is pumped The sludge is allowed to decompose and any sludge is removed. The sludge is further, producing methane gas (burned to used for fertilizer or discarded in a landfill keep the mixture warm). Solid sludge is site. dried and used as a fertilizer, incinerated, or discarded in a landfill site.
7. The water line will be lower (i.e., the ship will float higher in the water) once the ship is on the ocean. Salt water has greater buoyancy than fresh water, causing the ship to float higher.
Use What You’ve Learned—Suggested Answers 207 g 8. Sample A: density 1.15 g/mL 180 mL 42 g Sample B: density 1.05 g/mL 40 mL Sample B would float on top of sample A, because sample B has the lower density. 9. Students’ answers will vary. Look for evidence that students have identified relevant, credible resources, and selected appropriate information to include in the report. 10. Distilled water has no dissolved materials in it—it is pure water. Depending on its source, fresh water can have a variety of dissolved materials and suspended particles in it. 11. Students’ answers will vary. Ensure that students look at both sides of the issue. Draining wetlands can increase erosion. Runoff is faster after a rainfall or in the spring, which can lead to drought conditions. 12. Students need to design a simple investigation to compare the volumes of displaced liquid when clay boats float in fresh water and salt water. (Sea water contains about 3.5 % salt. Students can make 500 mL of artificial sea water by adding 17.5 g of table salt or NaCl to about 400 mL of water in a flask, and then adding enough water
548 Unit C: Water Systems on Earth NEL to make 500 mL of solution.) Ask students what will happen when a fully loaded cargo ship travels from the ocean into a large river, such as the Amazon. They can simulate this by making a clay boat and filling it with as many marbles (from the Clay Boats activity, page 128) as it will hold without sinking in salt water. Then they can carefully move the boat and the same load into a container of fresh water, where it will most likely sink. Buoyancy is controlled by differences in density between the object and the fluid. For example, if you have a block of ice with a density of 0.91 g/cm3 and float it in water with a density of 1.0 g/cm3, the ice will sink into the water until 91 % of its mass is submerged. Since salt water is more dense than fresh water, an object will float higher in salt water (less of its mass will be submerged). This is particularly noticeable in hypersaline waters, such as the Great Salt Lake or the Dead Sea. You can’t sink! 13. Students’ answers may vary. A sample concept map is given below:
water in atmosphere
condensation evaporation evaporation
precipitation
rivers, lakes glaciers ground water
oceans
14. Students’ answers will vary. Look for the 10 words. Use a sample poem, such as “Acid Rain” by Sean O’Huigin from Scary Poems for Rotten Kids (Black Moss Press), as an example.
Think Critically—Suggested Answers 15. The waterproof barrier underneath a landfill site protects the ground water by not allowing the rainwater that flows through the garbage (dissolving biological compounds and chemicals) to enter the ground water. Instead, the rainwater collects in a container at the bottom of the landfill site and is pumped to a sewage-treatment plant.
NEL Chapter 7 The Water Cycle 549 16. Fish populations would be low. Algae and phytoplankton are the major producers in most bodies of water. If they are absent, little of the Sun’s energy is available to the lake ecosystem. In other words, the fish have nothing to eat. 17. Students’ answers will vary. One type of pollution that students could research is acid precipitation. This occurs when water vapour reacts with pollutants in the air, particularly sulfur dioxide and nitric oxide. The resulting sulfuric acid and nitric acid dissolve in the atmospheric moisture and fall back to Earth as acid rain or acid snow. The most common sources of sulfur dioxide emissions are ore smelters and coal-burning power stations. Oxides of nitrogen originate from residential and commercial heading, vehicle exhaust, and power plants. Canadian officials are introducing measures to control acid rain emissions. We can do our part by recycling, saving electricity, and reducing our use of cars and other vehicles. The average household can lessen its annual contribution to the acid rain problem fivefold just by recycling its cans, bottles, and paper. Making new products from old products takes a lot less energy and fewer resources. 18. Not only do we contribute to the causes of floods, but reckless building in vulnerable areas, poor watershed management, and failure to control flooding can also help to create disaster conditions. Scientists have recently found that human endeavours may directly affect the weather conditions that produce extensive and heavy rains. Irrigation of dry lands creates moisture conditions that contribute to increased humidity and evaporation, which, in turn, lead to increased rainfall. This is particularly heightened in desert areas, where large lakes are built to provide water for either irrigation or nearby settlements. 19. If sewage were not treated adequately, disease organisms and other harmful substances would enter the waterways. If water were not treated properly, those disease organisms and other disease organisms in the natural population could enter the drinking water. The health risks could be enormous. 20. The global human population is increasing rapidly, so there is a greater demand for fresh water. The overuse of existing fresh water supplies can create environmental stress and damage. 21. Students’ answers will vary. The arguments against requiring people to move from flood plains include their enjoyment of waterfront living—beautiful views and proximity to recreational activities, wildlife, and the outdoors. The arguments for this legislation include protecting public safety, public health, and human life and property from the hazards of periodic flooding; promoting the safety and purity of the water; and containing and controlling sewage during a flood.
550 Unit C: Water Systems on Earth NEL Reflect on Your Learning—Suggested Answers 22. Students’ answers will vary. Students may include general water safety rules, descriptions of water and sewage treatment, and environmental stewardship. 23. Hopefully, most students will say that they know more about what to do and what needs to be done. The second half of the question is likely to produce a variety of responses, depending on students’ attitude. 24. This question is likely to produce a variety of responses, depending on students’ background and attitude. Examples of items that may surprise students are acid precipitation and its effects; water distribution (both fresh water and salt water) around the world, and the fact that fresh water is not necessarily potable water.
Meeting Individual Needs ESL •Ask students to write their reflections in their first language and visually depict the key ideas.
Extra Support •Provide specific direction and assistance for students who have weak organizational skills. •Students with weak written skills can record their thoughts using key words, visual diagrams such as concept maps, or point-form notes.
Extra Challenge •In addition to writing their personal reflections, students could draw a concept map representing what they now know and can do after completing this chapter. •Challenge students to use a multimedia program to build an interactive multimedia quiz based on the vocabulary, concepts, and key ideas in the unit. Students could create a multiple-choice quiz that allows other students to select answer buttons that either indicate they are correct or return them to the question page so they can try the question again.
NEL Chapter 7 The Water Cycle 551 8 Water Features Page 218
Key Ideas Vocabulary
The shape of Earth’s surface determines how continental shelf moraines water flows over it. continental slope eskers continental rise striations The movement of glaciers wears down and abyssal plains erratics flattens the landscape. seamount icebergs volcanic island current Temperature differences cause movement guyot convection current within a body of water. canyons gyres trenches specific heat capacity Large bodies of water, such as lakes and watershed weather oceans, affect weather and climate. Continental Divide climate glaciers land breeze Ocean waves shape, and are affected by, crevasses sea breeze geological features. cirques tsunami arête tides The regular movement of the oceans in tides is horn tidal range affected by geological features. hanging valley tidal bulges fiords Water systems are managed to protect them from human activities.
Science Skills and Processes 8.1 8.2 8.3 8.4 8.5 8.6 8.7 Inquiry Skills Questioning Hypothesizing Predicting Planning Related Resources Conducting ✓ Nelson Science Probe 8 Recording ✓ Web site: Analyzing ✓ www.science.nelson.com Evaluating ✓ Communicating ✓✓ Additional Inquiry Skills (Try This Activity) Controlling Variables ✓ Creating Models ✓✓✓ Observing ✓✓✓ Estimating Measuring Classifying Inferring Interpreting Data
552 Unit C: Water Systems on Earth NEL TEACHING NOTES •Ask students what they see in the photograph on page 218. Encourage students to discuss and describe the significance of water features. Ask the questions in the first paragraph. Possible responses: –Weather and climate involve the entire water cycle. –Water can carve and shape land over a period of time by erosion. •Have students brainstorm everything that comes to mind when they think about the term water features. List students’ thoughts on the board. •You can use the key question on each scaffolding master to review the ideas in the section. • As students work, prompt them to connect their science learning to other learning experiences, world events, and/or personal learning experiences. •Hand out BLM 0.0-9 Chapter Key Ideas. Inform students that this will be a place to record key vocabulary and personal experiences, as well as what they learn from the student book. •You can use any or all of the following BLMs to help students study the vocabulary in this chapter. – BLM 0.0-10 Science Idea Box – BLM 0.0-11 Vocabulary Wheel – BLM 0.0-12 Term Box •To assess students, you may want to use or adapt Rubric 8: Chapter 8.
Meeting Individual Needs ESL •Encourage the use of a first language/English dictionary. Allow students to sign out the student book before each section to preview the section at home. •Have students make word webs or diagrams, labelling objects to illustrate the features of water. Display charts and posters that show water in various states and ways that water affects the environment.
Extra Support •Teacher encouragement, prior notice before being called upon, and additional wait time after being called upon often help reluctant speakers. Assigning specific roles to group members (e.g., recorder, encourager, summarizer) may help to ensure that everyone has a chance to contribute. •Encourage participation in the brainstorming activity by modelling and offering individual support as needed.
Extra Challenge •Have students use a computer graphics program to create a mind map or another type of concept organizer to record their knowledge and understanding of the vocabulary and concepts. Encourage students to revise their concept organizer as they work through the chapter.
NEL Chapter 8 Water Features 553 8.1 Geological Features at Sea and on Land Page 219
Time PRESCRIBED LEARNING OUTCOMES 45–60 min • describe how water and ice shape the landscape • use models to explain how systems operate Key Ideas The shape of Earth’s surface KNOWLEDGE determines how water flows • effect of water and ice on surface features over it. •weathering and erosion Vocabulary • continental shelf SKILLS AND ATTITUDES • continental slope •use the Internet for research • continental rise • use given criteria for evaluating evidence and sources of information • abyssal plains • seamount (e.g., identify supporting or refuting information and bias) • volcanic island •relate cause to effect • guyot • canyons ICT OUTCOMES • trenches •watershed • demonstrate the ability to formulate questions and to use a variety of •Continental Divide sources and tools to access, capture, and store information Skills and Processes •use a variety of information technology tools to solve problems • synthesize information from a variety of electronic sources for Creating Models Observing presentations •use a variety of software to present messages Lesson Materials per student • apron SCIENCE BACKGROUND • safety goggles per group •The ocean floor has higher can be eroded to become flat-topped •plastic dishpan mountains, a longer mountain range, mountains, called guyots, below the • garbage bag more volcanoes, deeper canyons, surface of the ocean. per station larger plains, a thinner crust, and •Where a continental plate and an • ball of string more frequent earthquakes than any oceanic plate collide, the oceanic • roll of duct tape continent! plate slowly plunges under the •mixing bowl (large) • On the continental shelves of continental plate because it is •3 L cornstarch tropical oceans, there are often long heavier/denser than the continental •1 L water in a plastic jug ridges of limestone surmounted by plate. The V-shaped depression • spoon or stirring rod coral. The limestone was formed where the plates collide is called a •measuring cup or 1 L plastic container from the external skeletons, called trench. exoskeletons, of previous • Oceanic mountains are formed Program Resources generations of coral. The Great where magma from Earth’s mantle BLM 8.1-1 Topographical Barrier Reef off the east coast of flows through cracks on the ocean Map of North America Australia is an excellent example. floor. The magma cools and piles up. SM 8.1 Geographical • At the edge of a continental shelf, (Cracks in the ocean floor are most Features at Sea and on the ocean floor plunges steeply likely to occur at mid-ocean ridges, Land toward the ocean floor. This area is where the oceanic plates are being BLM 8.1-2 Making called the continental slope. It marks pulled away from each other.) Watersheds and Divides the boundary between continental • Lakes are essentially puddles on BLM 0.0-19 Scrap and Keep crust and oceanic crust. Earth. A lake will dry up if the Notes • Seamounts are volcanic mountains amount of water flowing out of it Nelson Science Probe 8 that can rise more than 1000 m exceeds the amount of water Web site: above the surrounding ocean floor. If flowing in, or if the rate of www.science.nelson.com they break the surface of the ocean, evaporation is greater than the water they are called volcanic islands. Over flowing in. time, seamounts and volcanic islands
554 Unit C: Water Systems on Earth NEL •A river begins at a source, such as a •A watershed, or drainage basin, is an Related Resources glacier, lake, or spring, and flows area of land in which all the water Cherington, John A. The between its banks to a mouth, runs to a common destination. Fraser Valley. Madeira where it empties into a larger river, a Park, BC: Harbour lake, or an ocean. Publishing, 1992. Clague, J.J., J.L. Luternauer, and D.C. TEACHING NOTES Mosher (eds.). Geology and Natural Hazards of the Fraser River Delta, 1 Getting Started British Columbia.Victoria, BC: The Ministry, 1998. • Although oceans, lakes, and mud puddles are formed by water Exploring Your World—The flowing into basins of various sizes, students should know that Adventure of Geography. oceans, many lakes, and puddles were not formed by volcanic craters National Geographic or glaciers. Society, 1989. Fraser River Estuary •Most Canadian lakes are glacial lakes. The depressions were formed Management Program by glaciers and icesheets during the last ice age. Meltwater from (Canada). A Living Working River: The retreating glaciers filled the depressions. Estuary Management •Some students may wonder why the sources of rivers do not run out Plan for the Fraser River. New Westminster, BC: of water. The headwaters of rivers are higher in altitude and often The Program, 2003. receive more precipitation than the lower, surrounding areas. As well, Haig-Brown, Alan. The a vast amount of underground water, seeping through surface Fraser River. Madeira material or forming springs, feeds most permanent rivers. Glaciers Park, BC: Harbour, 1996. provide a reasonably consistent source of water to some rivers. Still, Kennett, Kristal Dawn. The even in headwaters, water levels can and do fluctuate. Fraser River Estuary: An Overview of Changing •Some students may have heard that watersheds can be referred to as Conditions. New drainage basins. Westminster, BC: Fraser River Estuary Management Program, 2 Guide the Learning 1988. •You could divide Section 8.1 into two parts and deal with each part Watmough, Don. The Discoverer’s Guide to the during a separate period. Introduce this section by reviewing the Fraser River Delta: layers of Earth (crust, mantle, outer core, inner core) and plate Exploring the Living River. tectonics. Refer to Unit C: Earth’s Crust in B.C. Science Probe 7. Edmonton: Lone Pine Publishing, 1992. •Use Reading and Thinking Strategies: Sketch to help students learn the vocabulary in this section. •Since the diagram of the trench (Figure 5) has no blue to represent water, students may initially think that it is on land. Ensure that students read the caption and understand that a trench occurs on the ocean floor, usually at the edge of a continental plate. •You might mention to students that two categories of processes alter Earth’s surface: destructive (erosion and weathering) and constructive (volcanism and mountain building). • Link the topics in this section to topics discussed previously.
NEL Chapter 8 Water Features 555 • As you review the geographical features, suggest that students Art Connections After completing the Tr y organize the information in a common format, such as the one This activity, groups of below: students could make a larger, more permanent Name of feature continental shelf watershed at home, using Description sloping extension of the continents under the sea plaster and foam packing material (either large Physical appearance gentle slope pieces or “peanuts”). For low vegetation, they could Example Grand Banks use green-painted coarse Scientific implication abundant sea life sawdust attached with waterproof glue. For trees, Diagram See Figure 3 on page 220 of the student book. they could use pieces of foam and wire. Ask them to predict how the water •Ask students to classify each feature as being the result of a will flow, and then let it rain on their watershed. destructive or a constructive process. Ask students why both Students need to make processes are necessary. sure that the watershed has a container for the •While examining Figure 8, ask students the following questions: water to run into. What do the arrows represent? (the direction of water flow) How does the drainage pattern of an area contribute to the destructive and constructive processes that alter Earth’s surface? (erosion and sedimentation) What impact would the drainage pattern of an area have on human settlement? (climate, flooding, water transport, availability of fresh water) •Using both Figure 8 and BLM 8.1-1 Topographical Map of North America, identify the largest watershed in North America (The Mississippi River basin is the largest.) Ask students, What characterizes this area? (low elevation, many tributaries) •Have students complete Try This: Watersheds and Divides. •For students who need additional support with the reading in this section, use SM 8.1 Geographical Features at Sea and on Land.
TRY THIS: WATERSHEDS AND DIVIDES Purpose •Students use their knowledge and understanding of watersheds to create a model of a watershed (or drainage basin). Students will modify their watershed to demonstrate its different features. Notes •Refer to BLM 8.1-2 Making Watersheds and Divides. This blackline master can be used as a handout or a transparency. • Cut the strings, and measure the cornstarch in advance. •Put all the materials needed for the activity into containers for each group of students. •Ask students to work in groups of no more than three. •Cover the workstations with plastic garbage bags to facilitate clean-up. • Gently pulling the two strings away from each other (this may require two people working together) raises a ridge of plastic, or Great Divide. Suggested Answers (a) Students may have made mountains, lakes, or glaciers, and different watersheds.
556 Unit C: Water Systems on Earth NEL (b) Depending on how many strings were attached and how close the strings were to each other, the number of watersheds will vary. The goo will flow in a Te c hnology Connections different direction for each watershed. Below are four ways that (c) Students have made a Great Divide if they form a large ridge of plastic, causing students could use the glacial goo to flow to opposite sides of the dishpan. technology to further their study of geological (d) Raising and lowering individual strings likely changes the flow of some of the features: glacial goo, forming different lakes, changing watersheds, and possibly adding •Use a computer to draw or removing a Great Divide. the cross-section of the ocean floor in Check Your Understanding question 1. •Find some examples of 3 Consolidate and Extend scientists who use technology to increase •It is important for students to apply their learning and new their understanding of knowledge from Try This: Watersheds and Divides and Earth. BLM 8.1-1 Topographical Map of North America to a new situation. •On a map of Earth, locate a seamount, a trench, and Give students a topographical map of British Columbia, and ask other geological features. them to identify watersheds for major river systems (e.g., Fraser, •Research the educational Thompson, Columbia, Stikine). requirements to become an Earth scientist (e.g., •Refer to Reading and Thinking Strategies: Sketch. Have students geologist, hydrologist). work in pairs to summarize the section, using the suggested strategies to view and discuss the photographs. • Assign the Check Your Understanding questions
CHECK YOUR UNDERSTANDING—SUGGESTED ANSWERS
1. Students will probably include the following features in their drawings: continental shelf, continental slope, canyon, trench, and underwater mountain. Ensure that they label each feature correctly. 2. Fast-flowing rivers can carve their way down through solid rock, forming steep- sided canyons. After the end of the last ice age, sea levels started to rise, “drowning” the steep-sided river valleys. Rivers that had enough velocity and flow continued to erode the material on the sea floor, making the valleys deeper and wider. 3. Glacial lakes are formed in depressions that were gouged in Earth’s surface by glaciers and ice sheets during the last ice age. As the ice retreated, meltwater pooled in these depressions, forming lakes. Lakes that continue to receive a supply of fresh water from a river or underground spring continue to be freshwater lakes. If a glacial lake stops receiving fresh water or experiences high evaporation rates in the summer and a limited addition of fresh water throughout the year, or if runoff into the lake contains large amounts of salts, then the salt content of the lake increases rapidly. Lakes in the interior of British Columbia, near Kamloops, can have high salinity.
NEL Chapter 8 Water Features 557 LEARNING TIP Reading and Thinking Strategies: Sketch •Before reading pages 219 to 221, list the vocabulary words on the board: Stop and think. When you continental shelf, continental slope, continental rise, abyssal plains, come across words in bold seamount, volcanic island, guyot, canyons, trenches. print, think about each word •Have students read the Learning Tip on page 219, and then identify any of and ask yourself, “Is this word the vocabulary words they know. familiar? Where have I seen it •Tell students that one way to remember some vocabulary words is to before?” sketch pictures that represent the words. Have them read pages 219 to 221, and then sketch pictures in their notebooks. Suggest that they add any text needed to their pictures to help them remember the meanings of the words. For example, they may sketch a picture similar to Figure 3, but add words to note that the continental shelf, slope, and rise are part of the continental crust, and the abyssal plains are part of the ocean floor. •Conclude by having students sort the words into categories under the headings “Features that are extensions of the continental crust” (continental shelf, continental slope, continental rise, canyons) and “Features that are part of the ocean floor” (abyssal plain, seamount, volcanic island, guyot, trenches).
Strategies for Success Summarizing and Making Notes •When making notes, students need to know how to make decisions about what to write on and how much to write. To help students distinguish between important and unimportant information, teach them the Scrap and Keep sorting strategy for textbook reading and note making. On the “Scrap” pile, they should place items of minor relevance, which can be used to fill in gaps. On the “Keep” pile, they should include items that are highly relevant and necessary to know. •A suggested plan for making Scrap and Keep notes can be found in BLM 0.0-19 Scrap and Keep Notes.
Meeting Individual Needs ESL •Encourage students to use the illustrations in the student book to explain the text in their own words. •Gather other pictures that illustrate the text, for students’ reference.
Extra Support •Provide BLM 8.1-1 Topographical Map of North America for students to trace water flow. •For students who need additional support with the reading in this section, use SM 8.1 Geographical Features at Sea and on Land.
Extra Challenge •Challenge students to explain why the Red River floods or how river deltas (e.g., the Fraser Delta) are formed. •Have students create a computer multimedia presentation or animation (e.g., PowerPoint or HyperCard program) that shows and explains a geological process, related to a feature discussed in this section (e.g., formation of river deltas or underwater mountains).
558 Unit C: Water Systems on Earth NEL ScienceWORKS: Footprints—Here Today, Gone Tomorrow
PAGE 225 •Tracks also show that dinosaurs sometimes travelled in groups, which probably helped them protect themselves from enemies. •Dinosaur footprints can be as small as a few centimetres across, but they can also be as big as about a metre across. Dinosaur footprints have been found at over 1500 sites throughout the world, including sites in British Columbia. • Trackways are groups of footprints. • Scientists are not the only people who find dinosaur tracks—kids can too! Eleven-year-old Mark Turner and nine-year-old Daniel Helm discovered dinosaur tracks in British Columbia. •Paleontologists and other people interested in studying dinosaurs are working to save the trackways from activities such as construction and mining. •Dinosaurs appear to have left their mark on Canada’s Pacific coast about 125 million years ago. •A geologist with British Columbia’s Ministry of Energy and Mines found turtle fossils in the Bowser Basin, north of Terrace, BC, while conducting a routine mapping survey for oil and gas resources. Scientists at Alberta’s Royal Tyrrell Museum and the Royal British Columbia Museum in Victoria confirmed that these fossils are from the early Cretaceous period.
ASSESSMENT FOR LEARNING
What To Look For in Student Work Suggestions for Teaching Students Who Are Having Difficulty Evidence that students can Focus on the pictures to enhance descriptions and explanations. Encourage • create models (watersheds and divides) students to put in their own words what each illustration represents. Where a • describe the geological features of the process is illustrated by arrows, ask students to explain the force involved, its ocean basin from the continental slope to cause, and its effect. Pre-teach the main concepts necessary to understand each the abyssal plains feature. For example, discuss continents, slopes, and sea life before introducing • explain why some lakes contain salt water continental shelves. and others contain fresh water One group member can read the Try This activity aloud to accommodate students • use technical language (continental shelf, with reading difficulties. continental slope, continental rise, abyssal plains, seamount, volcanic island, guyot, If students have difficulty working in a group, assign them a specific role in the canyons, trenches, watershed, Continental group to ensure that they participate. Divide) Teach students how to look for important information (main ideas and supporting details) when they read, ignoring information that is less significant.
NEL Chapter 8 Water Features 559 8.2 Glaciers: Rivers of Ice Page 226
Time PRESCRIBED LEARNING OUTCOMES 30–45 min • describe how water and ice shape the landscape
Key Ideas KNOWLEDGE The movement of glaciers •sources of fresh water wears down and flattens the •properties of salt water and fresh water landscape. • effect of water and ice on surface features Vocabulary •weathering and erosion • glaciers • evidence and effects of glaciation • crevasses • cirques SKILLS AND ATTITUDES • arête • horn •use the Internet for research • hanging valley • use given criteria for evaluating evidence and sources of information • fiords (e.g., identify supporting or refuting information and bias) •moraines •eskers •relate cause to effect • striations • assess human impact • erratics • show respect and sensitivity for the environment • icebergs Program Resources ICT OUTCOMES SM 8.2 Glaciers: Rivers of Ice • demonstrate the ability to formulate questions and to use a variety of BLM 8.2-1 Glaciers of Old sources and tools to access, capture, and store information BLM 0.0-20 Question Notes •apply predetermined search criteria to locate, retrieve, and evaluate Nelson Science Probe 8 Web site information www.science.nelson.com • synthesize information from a variety of electronic sources for presentations •use a variety of software to present messages
SCIENCE BACKGROUND
• Glaciers and ice sheets contain 2 % •Rocks and dirt (drift) are pushed of the world’s water, which is about ahead of the advancing glacier. When Related Resources 70 % of the available fresh water. the glacier retreats, mounds of dirt, Bender, Lionel. The Story •As snow accumulates on a glacier, called moraines, are left behind. of the Earth—Glacier. the weight of new snow compresses •A moraine is an accumulation of New York: Franklin Watts, the lower layers of snow into ice. unsorted, rocky material, such as 1988. The thick and heavy layer of ice gravel, stones, and boulders (called Benton, Michael. The begins to move down the slope of till) that have been carried and Penguin Historical Atlas the mountain. deposited by a glacier. Moraines are of the Dinosaurs.London: • Plastic flow occurs within the ice given different names, depending on Penguin Group, 1996. when the overlying pressure is where they are located in relation to approximately the mass of 50 m of the glacier or how they were Exploring Your World—The ice. Basal slip occurs when the created. Adventure of Geography. entire mass of ice slips over the • Lateral moraines (lateral means National Geographic ground because of a layer of “side”) run along the outside edges Society, 1989. meltwater between it and the of a glacier, closest to the valley bedrock. The glacier flows fastest in walls. The rocky material in the the centre and slowest at the moraine comes from the sides of outside edges (closest to the valley the mountain. walls).
560 Unit C: Water Systems on Earth NEL •Medial moraines occur when two •A valley glacier is a long, narrow glaciers merge into one. Their lateral glacier between the steep sides of a moraines combine to form a medial mountain valley, usually following a moraine. channel worn by running water. •A ground moraine occurs when a Continental glaciers form when glacier starts to recede because of a snow and ice accumulate on polar warming climate. It is formed from land. When a glacier melts, it the debris that is carried on the deposits the debris (till) that it surface or inside the glacier. captured during its journey. • End or terminal moraines are formed •When a glacier meets a lake or the from the till that is deposited by a ocean, huge blocks of ice can break glacier at its point of farthest off. This process is called the calving advance. of icebergs. •Recessional moraines occur when a •The continental glaciers of Greenland receding glacier temporarily stops, and Antarctica are the major sources depositing till in ridges. of icebergs. Icebergs float in the • Bulldozed or push moraines are ocean because ice is less dense mounds or ridges of rock material, than liquid water is. formed by an advancing glacier pushing material in front of it.
TEACHING NOTES
1 Getting Started
• Check for Misconceptions – Identify: Some students might fear that an ice age will overtake them within their lifetime. – Clarify: Reassure students that most geological events occur over long periods of time and that only four ice ages have occurred in the last 2 million years. With our current technology, many global catastrophes can be predicted and prepared for. – Ask What They Think Now: Ask students, Do you think we will have an ice age during your lifetime? •Introduce Section 8.2 by reviewing the water cycle.
2 Guide the Learning •Ask students, What happens to precipitation that falls at high elevations or latitudes? (Much of it is snow.) •Use Reading and Thinking Strategies: Determine the Meaning of Vocabulary and Technical Terms to help students with the vocabulary in this section. •Go through the information in the student book, reading a paragraph at a time and asking relevant questions to enhance students’ understanding of the information (e.g., Has any student been to the Columbia Ice Fields?) and to determine what prior knowledge they have about glaciers and the fresh water glaciers contain. •A glacier is said to flow. Ask students, What does this mean? Is glacial flow the same as fluid flow? (Recall Unit B, Chapter 4.)
NEL Chapter 8 Water Features 561 •Show students photographs of glaciers, beginning with Figure 1 in At Home In the winter, suggest that the student book. Ask students, What do you notice about the surface students cut into a of a glacier? (The surface has cracks and crevasses, and it is often snowdrift to see the layers dirty.) Why? (The rate of glacial flow is irregular, and the glacier of snow. Snow can erodes rock from the sides of mountains.) change in only a few weeks. Old snow •For students who need additional support with the reading in this becomes more granular section, use SM 8.2 Glaciers: Rivers of Ice. and feels more like ice. Students could read a book 3 Consolidate and Extend about exploring the Arctic or Antarctic, climbing •Ask, How might scientists observe the flow rate of a glacier over a period Mount Everest, or setting up Arctic research stations of time? (coloured markers, satellite images) on ice islands. Although •Hand out BLM 8.2-1 Glaciers of Old for students to complete. these books are not about water per se, students can Students may use the Internet or other resources for their research. easily make connections •Review erosion and sedimentation. Ask, How is a glacier like running between what they have learned and the experiences water? (It erodes, transports, and deposits sediments.) of the people in the books. •Ask students to locate the Antarctic and Greenland continental glaciers on a world map or globe. Ask, What do these two areas have in common, which sustains their glaciers? (They are continental, very dry, and extremely cold.) Why does a glacier remain on Greenland even though Greenland is surrounded by water? (The water is too cold Te c hnology Connections to moderate the climate.) Ask students to search the Internet for •Cracks and crevasses can form in a glacier when the slope of the •how and why scientists mountain underneath the glacier changes. and other people travel to the North and South •Assign the Check Your Understanding questions. Poles •how scientists estimate the volume of an iceberg CHECK YOUR UNDERSTANDING—SUGGESTED ANSWERS •what is done to ensure the safety of ships that 1. Glaciers affect the environment in the following ways: travel through water that • Glaciers are responsible for creating a number of different landforms. has icebergs •Glacial ice can affect the local climate (e.g., cold air flows down from glaciers). • Glaciers provide a source of water for streams and rivers. • Glaciers grind down mountains and can carve steep U-shaped valleys. 2. Cirques, arêtes, and horns are related in the following ways: •A cirque is a bowl-like depression in the side of a mountain, where a glacier originates. As the glacier grows, the eroding action of the ice in the glacier enlarges the cirque. • If two cirques form back to back on a mountain, they eventually create a ridge between them, called an arête. An arête is quite sharp and thin. • If three or more cirques form on a mountain, they create a horn. 3. Benefits of icebergs: •Icebergs are a potential source of fresh, pure water for humans. •Tracking icebergs can provide scientists with information about ocean currents. Risks of icebergs: • Icebergs may collide with ships and oil drilling rigs. •The presence of many icebergs can indicate a warming phase in the climate.
562 Unit C: Water Systems on Earth NEL Reading and Thinking Strategies: Determine The polar icecap is a large sheet of ice covering the Arctic Ocean. It is DID YOU KNOW ? the Meaning of Vocabulary and Technical Terms not a glacier because it lies over water, not land. The icecap produces Dangerous Ice similar weather effects to those caused by continental glaciers. Figure 3 Icebergs contributed to the Exxon Valdez oil disaster. •Have students scan the subsection called Glacial shows floating ice that has broken into large ice floes. Icebergs had broken off the Columbia Glacier in Alaska and drifted into the normal Features to look for vocabulary words: cirques, arête, shipping route. This forced the large tanker to follow an alternate route where it ran horn, hanging valley, fiords, moraines, eskers, aground on a reef, spilling its oil into the ocean. striations, erratics, icebergs. List the words on the board, and ask students to identify words they know and words that are new. Figure 3 Spring conditions cause the ice to •Arrange students in pairs to read this subsection. Ask break up into large ice floes.
them to stop at the ends of sentences with vocabulary Glacial Features The great weight of glaciers can grind down mountains, as gravity words and take turns explaining the meanings of these pulls the ice downhill. Rocks, gravel, and sand that are dragged along by a glacier erode the bedrock. Over thousands of years, the erosion by words to each other. Encourage students to look at the glaciers changes the shape of mountains and creates many geological accompanying figures to help with their explanations. features (Figure 4). These features are evidence of past glaciation.
horn
•Conclude by having students explain the relationship arête cirque between a cirque, an arête, and a horn.
moraine
Figure 4 Glacial landscape features
NEL 8.2 Glaciers: Rivers of Ice 227
Strategies for Success Summarizing and Making Notes • “I’ve read pages and I can’t remember a thing!” Ask if this sounds familiar. Suggest that students turn subheadings into questions and read to answer those questions. A suggested plan for making Question Notes can be found in BLM 0.0-20 Question Notes. Encourage students to develop a system of abbreviations and symbols to help them be more efficient note makers.
Meeting Individual Needs ESL •Use several pictures of glaciers and their effects to illustrate the text.
Extra Support •Have students compare the Antarctic continental glacier and the Arctic ice sheet using a two-column table (e.g., features, location, and climate). •For students who need additional support with the reading in this section, use SM 8.2 Glaciers: Rivers of Ice.
Extra Challenge •Have students explain the idiom “It is just the tip of the iceberg.” •Have students use the Internet to research a topic related to glaciers (e.g., formation, effects of glaciers on geography, effects of global warming on glaciers, scientific/historical information stored in glaciers). ASSESSMENT FOR LEARNING
What To Look For in Student Work Suggestions for Teaching Students Who Are Having Difficulty Evidence that students can If students have difficulty writing, allow them to write their answers and research • describe the effects of glaciers on the findings in point form using key vocabulary, or allow oral responses to questions. environment Use photographs of glaciers, cirques, and U-shaped valleys to illustrate the text. •use technical language (glaciers, crevasses, cirques, arête, horn, hanging valley, fiords, Encourage students to describe orally what they understand about glaciers. moraines, eskers, striations, erratics, icebergs)
NEL Chapter 8 Water Features 563 8.3 Inquiry Investigation: Water Temperature and Currents Page 230
Time PRESCRIBED LEARNING OUTCOMES 45–60 min • explain the significance of salinity and temperature in the world's oceans Key Ideas • describe how water and ice shape the landscape Temperature differences • demonstrate safe procedures cause movement within a body of water. • perform experiments using the scientific method • demonstrate ethical, responsible, cooperative behaviour Skills and Processes Conducting KNOWLEDGE Recording •properties of salt water and fresh water Analyzing Evaluating • effect of water and ice on surface features Communicating •impact of waves, tides, and water flow on surface features Lesson Materials SKILLS AND ATTITUDES per student •use the Internet for research • apron • safety goggles • use given criteria for evaluating evidence and sources of information per group (e.g., identify supporting or refuting information and bias) • two 600 mL beakers •relate cause to effect • tongs or plastic fork • hot plate • assess human impact • retort stand • show respect and sensitivity for the environment • ring clamp • watch with second hand ICT OUTCOMES per station • ice-cold water • demonstrate the ability to formulate questions and to use a variety of •water at room temperature sources and tools to access, capture, and store information • coloured ice cubes (two different colours) •use a variety of information technology tools to solve problems • hot water (for demonstration step 6) SCIENCE BACKGROUND Program Resources •Within the ocean are rivers of water from below is drawn up by Investigation Rubric 5: Inquiry warm and cold water, called the movement of the warm water, Investigation currents, which are driven by creating a convection current. The Investigation Rubric 6: Inquiry differences in density. current of warm water is modified Investigation— •The maximum density of water is by winds, Earth’s rotation, nearby Self-Assessment at 4 °C. As a result, the water continents, and variations in BLM 8.3-1 Inquiry temperature at the bottom of an salinity and temperature. Investigation: Water ocean tends to be 4 °C. Both •As the current of warm water Temperature and Currents warmer water and cooler water moves away from the equator, it BLM 0.0-21 Note Making are less dense. As water freezes, becomes slightly more saline due Inventory Science Skills and Processes its density decreases further. Thus, to evaporation. As long as it Rubric 9: Conducting ice floats in water. This is the exact remains warmer than the water Science Skills and Processes opposite of most other liquids. below it, it flows along the Rubric 10: Conducting— When other liquids solidify (or surface. As it enters the polar Self-Assessment freeze), they become more dense regions, however, it cools rapidly. Science Skills and Processes and sink to the bottom of their Denser because of its salinity, it Rubric 11: Recording container. sinks to the bottom of the ocean, Science Skills and Processes •At the equator, the surface water where it enters the current being Rubric 12: Recording— is warmed by the Sun. This warm pulled south to replace the rising Self-Assessment water spreads both north and water at the equator. south from the equator. Colder (Continued)
564 Unit C: Water Systems on Earth NEL Program Resources • Sea ice forms from ocean water in water) and the Sun’s heat at the (Continued) the northern and southern equator (producing warm water) latitudes. Sea ice has a lower produce falling and rising columns Science Skills and Processes salinity than the water below it, so of water, which form ocean Rubric 13: Analyzing the cold, salty water sinks to the currents that drive the world’s Science Skills and Processes bottom. Polar ice formation climate. Rubric 14: Analyzing— (producing salty, cold, dense Self-Assessment Science Skills and Processes Rubric 15: Evaluating Science Skills and Processes INVESTIGATION NOTES Rubric 16: Evaluating— Self-Assessment Science Skills and Processes Student Safety Rubric 17: Communicating Science Skills and Processes Review the safety procedures when using a hot plate (step 9). Rubric 18: Instruct students to unplug the hot plate immediately following its Communicating— use. Assign a group member to be responsible for this task. Remind Self-Assessment Nelson Science Probe 8 students that the hot plate remains hot for some time after it is Web site unplugged. www.science.nelson.com
•It is recommended that students work in pairs at a station near an electrical outlet. Have all the materials required for each station in a plastic dishpan or another suitable container. This reduces the time spent distributing the materials.
•Encourage students to make up an observation sheet with a series of At Home diagrams (e.g., beakers with water) before starting the Procedure, so Students can extend this the only thing to add is the ice cube and the movement of the food Investigation at home by colouring. For each step, include space for writing the time intervals using different temperatures of water in and for brief observations. glasses. (Short, wide •Although this investigation examines the movement of melting ice glasses would be best.) They can make ice cubes water in baths of different temperatures, the patterns noticed by with coloured salty water students are caused by the temperature difference between the melting and different-coloured ice and the water bath. The closer the temperatures of the two water fresh water, and see samples are, the more similar their densities are, and the more slowly which combines more quickly with the water in the mixing occurs. the glasses. They may •You may wish to hand out BLM 8.3-1 Inquiry Investigation: Water need a deep freezer (not just a fridge freezer) to Temperature and Currents for students to record their work. freeze the salty ice cubes. •Refer students to Getting Off to a Safe Start, Safe Science, Designing Remind them, however, that both types of ice Your Own Investigation, and Creating Data Tables in the Skills cubes should come from Handbook. the same freezer so that both are exactly the same •To assess students, you may want to use or adapt Investigation temperature at the Rubric 5: Inquiry Investigation and/or Investigation Rubric 6: Inquiry beginning. Many students Investigation—Self-Assessment. think that ice is at 0 °C, regardless of the air Experimental Design temperature around it. A deep freezer is usually •Students will observe how coloured water from a melting ice cube kept at about –20 °C. moves in water of different temperatures. • This design should provide evidence to answer the question. Modify the design and procedure if necessary, however.
NEL Chapter 8 Water Features 565 Materials (a) A sample observation table is given below.
Water Observations of water from coloured ice cube temperature 1 min 2 min 3 min 4 min 5 min cold Ice cube Coloured Coloured Coloured Most of ice starts to water water water sinks cube has melt. starts to continues to bottom melted and sink very to sink to of beaker. sunk to slowly. bottom of bottom of beaker. beaker.
room Ice cube Coloured Coloured Most of ice Coloured temperature starts to water water sinks cube has water is at melt. starts to to bottom melted and bottom of sink more of beaker. sunk to beaker. quickly. bottom of beaker.
hot Ice cube Coloured Coloured Coloured Coloured starts to water water sinks water is at water is in melt starts to to bottom bottom of a layer at immediately. sink much of beaker. beaker. bottom of more beaker. quickly.
Procedure 3. The cold, coloured water from the ice cube falls slowly to the bottom of the beaker, and then moves across the bottom and up the other side. The coloured water slowly mixes with the clear water. 4. The coloured water mixes more quickly with the room-temperature Te c hnology Connections If temperature probes are water. Water temperature is a measure of the kinetic energy of the available, you could set up water molecules. a demonstration of step 9, 5. with one probe placed in The higher the temperature, the higher the kinetic energy is and the the water just above the faster the molecules move. This causes the coloured water and room- hot plate and another temperature water to mix more quickly. probe placed in the water on the opposite side. 8. The hot water causes the colour to mix even more quickly. Students could observe 11. the resulting double-line The coloured water from both ice cubes will sink. The coloured water graph as the coloured from the ice above the hot plate will then be pushed up along with water and hot water begin the heated water, as will the coloured water sinking from the far side to mix. that has moved along the bottom of the beaker. This rising and Students could use an sinking of water will repeat. The final result will likely be a electronic temperature probe with graphing two-colour mixture: the bottom layer being the colour of the ice capabilities or a cube farthest from the hot plate, and the layer above it being a computer-based mixture of the two colours of the ice cubes. spreadsheet/graphing program and two Analysis—Suggested Answers thermometers to record and graph their results, or (b) Cold water appears to have a higher density. When the ice cube was they could graph their placed in the beaker of room-temperature or warmer water, the results manually. melting (cold) water travelled down to the bottom of the beaker first.
566 Unit C: Water Systems on Earth NEL (c) The colour mixed more quickly in the warmer water because of the faster movement of the warm-water molecules. (d) Refer students to Writing a Lab Report and Writing for Specific Audiences in the Skills Handbook.
Evaluation—Suggested Answers (e) Look for answers that indicate students would attempt to control variables or eliminate inconsistencies better (e.g., “I would measure the water more accurately”), repeat trials (e.g., “I would try this three times”), or improve accuracy (e.g., “I would try to draw better diagrams”). (f) Students might suggest rearranging their observation table, using different headings, using better notes, or including or eliminating specific columns. Some students will say that no changes are necessary. If this is not true, it may require feedback from you.
Strategies for Success Summarizing and Making Notes • “I hate reading my notes; they’re a mess.” Ask students if this sounds familiar. Discuss the most important point about making notes: they come in useful later when students need to prepare for exams. •A suggested rubric for helping students write effective notes can be found in BLM 0.0-21 Note Making Inventory. Conclude by suggesting that students compare their notes with a friend's notes.
Meeting Individual Needs ESL •Encourage students to explain the Purpose in their own words. •Make sure that students understand all the safety procedures involved (e.g., handling a hot plate).
Extra Support •One group member could read the Investigation aloud to accommodate students with reading difficulties. •Show students how arrows on scientific drawings indicate movement.
Extra Challenge •Research the overturn of a lake in temperate regions of Earth. Explain how the density changes of water throughout the year in a lake affect the distribution of its organisms. •How might volcanic activity in an ocean affect the water above it?
ASSESSMENT FOR LEARNING
What To Look For in Student Work Suggestions for Teaching Students Who Are Having Difficulty Evidence that students can Prepare an observation table for students who have difficulty organizing their work, • explain how temperature differences in but encourage them to record their observations without assistance. water can cause convection currents Identify and describe the tasks that are not described in the procedure. Explain how • handle chemicals and equipment safely and to carry out these tasks (e.g., observing time intervals, setting up materials). responsibly • analyze and interpret observations For students who have difficulty working in groups, assign the tasks for them.
NEL Chapter 8 Water Features 567 8.4 Currents Page 232
Time PRESCRIBED LEARNING OUTCOMES 45–60 min • explain the significance of salinity and temperature in the world’s oceans Key Ideas • explain variations in productivity and species distribution in marine Temperature differences environments cause movement within a body of water. • use models to explain how systems operate
Vocabulary KNOWLEDGE • current •properties of salt water and fresh water • convection current • effect of ocean currents and winds on regional climates •gyres •impact of waves, tides, and water flow on surface features Skills and Processes •productivity and species distribution in aquatic environments Communicating Creating Models SKILLS AND ATTITUDES Observing •use the Internet for research Lesson Materials • use given criteria for evaluating evidence and sources of information per student (e.g., identify supporting or refuting information and bias) • apron •relate cause to effect per group • lazy Susan ICT OUTCOMES •pie pan • water • demonstrate the ability to formulate questions and to use a variety of • plastic spoon or tongs sources and tools to access, capture, and store information • coloured ice cubes • towels •create electronic text documents • synthesize information from a variety of electronic sources for Program Resources presentations SM 8.4 Currents •use a variety of software to present messages BLM 8.4-1 Gyres Nelson Science Probe 8 Web site www.science.nelson.com SCIENCE BACKGROUND •Because cold water is denser than northern hemisphere is westerly, the warm water, it sinks. Warm water usual direction of the currents is rises and floats on top of cooler eastward. (The pattern of air water. A convection cell can form circulation in the atmosphere is and circulate water in oceans and similar to the pattern of surface lakes. This circulation is a current. ocean currents. Air above equatorial •Warm surface water flows from areas is heated and rises. This warm equatorial areas to higher (more air moves north and south, cools, northern or southern) latitudes, and sinks back to Earth’s surface, driven by prevailing winds and where it is transported back to Earth’s rotation (Coriolis force). equatorial regions.) • In northern and southern oceans, • Gyres are circular patterns of water water is cooled, sinks, and moves flow, comprising two or more back toward the equator. This currents. Gyres move clockwise in circulation of ocean waters distributes the northern hemisphere and heat energy, salts, nutrients, and counterclockwise in the southern pollution, and is a major influence on hemisphere. Ocean currents and air the world’s climate. currents are influenced by the •Winds also affect ocean currents. Coriolis effect—the apparent Because the prevailing wind in the deflection of objects moving across
568 Unit C: Water Systems on Earth NEL Earth’s surface. The deflection is to • Ocean currents are organized flows Related Resources the right in the northern hemisphere that persist over a geographical Dipper, Frances. Oceans and to the left in the southern region for a period of time, and Rivers (The Changing hemisphere. transporting water from one part of World Series). Surrey, •Because lakes are much smaller than the ocean to another part of the England: Dragon’s World, oceans, their currents are less ocean. Currents also transport 1996. noticeable and have less influence plankton, fish, heat, momentum, and on the world’s climate. Most lake chemicals, such as salts, oxygen, Rogers, Daniel. Waves, currents are flow currents rather and carbon dioxide. Tides and Currents (The than convection currents, because • Currents are a significant component Sea Series). Surrey, water flows from a lake’s inlets to its of the global biogeochemical and England: Dragon's World, outlets. hydrological cycles. 1990. •Most lakes in temperate regions • Knowledge of ocean currents is experience overturn. Water from the extremely important for marine lake bottom mixes with surface operations involving navigation, water, stirring up sediment and search and rescue at sea, and the refreshing the lake’s supply of dispersal of pollutants. nutrients and oxygen.
TEACHING NOTES
1 Getting Started
Check for Misconceptions – Identify: Students may think that the water in a sink or toilet rotates one way as it drains in the northern hemisphere and the other way as it drains in the southern hemisphere, due to the rotation of Earth. – Clarify: Explain to students that, compared with familiar rotations (e.g., a compact disc playing music or even a draining sink), the rotation of Earth is very small—only one rotation per day. The water in a sink might make one rotation in a few seconds, and so have a rotation rate that is 10 000 times higher than the rotation rate of Earth. The Coriolis force is so small that it plays no role in determining the direction of rotation of a draining sink, any more than it determines the direction of a spinning CD. The direction of rotation of a draining sink is determined by the way that the sink was filled or by vortices that were introduced while washing. The direction of rotation of a draining toilet is determined by how the water is squirted into the bowl when it is flushed. – Ask What They Think Now: Ask students to check the next time they wash their hands in the sink or flush the toilet. They will find that the drainage can occur in both directions. •Introduce this section by discussing the definition of a current—the movement of water. (Some students may mention air currents, which are also caused by convection.) Ask students to discuss any experiences they have had with water currents.
NEL Chapter 8 Water Features 569 2 Guide the Learning •To connect this section to students’ prior knowledge, review the Learning Tip using Reading and Thinking Strategies: Take a Point of View. •Ask students, When swimming in a lake, why does deep water always feel much cooler than shallower water? (See the explanation of layers in a lake in the Science Background. Deep water does not usually feel cooler in a swimming pool because the purification system mixes the water continuously.) Christina Lake, BC, is an example of a lake where there is little surface mixing, so it has a significant layer of warm water at the surface in the summer and cooler water below. •If students did not do Inquiry Investigation 8.3, then explain and demonstrate what a convection current looks like in water. Ask students, Why does the water move? (Warm water is less dense than cooler water, so it rises to the surface as the cooler water sinks.) •Ask students to read how convection currents distribute nutrients and oxygen in lakes that are ice-covered in the winter. Invite students to draw a diagram to show this phenomenon. •Read the subsection called Ocean Currents with students, and show students a world map with the ocean temperatures in the different regions. Ask students to relate the information on the map to the information in the student book. •Have students complete Try This: Gyres in a Pan. •For students who need additional support with the reading in this section, use SM 8.4 Currents.
TRY THIS: GYRES IN A PAN Purpose •Students observe the effect of rotation on the direction of current flow. Notes •Have plenty of old fabric towels (more environmentally friendly than paper towels) to mop up spills. At Home • Ensure that the pie pans are placed in the middle of the lazy Susan, not at the edge. Encourage students to • Some groups could use smooth pie pans, and other groups could use pie pans attempt the Tr y This with ridges on the sides (bumps). Ask the groups to compare their results. Do activity at home if they the bumps make any difference? (They stir up the water, making the melting ice have a lazy Susan. water mix more quickly with the tap water.) •Have students complete BLM 8.4-1 Gyres by labelling the five main gyres of the world. Ensure that students use a different colour for each gyre. Students may need to refer to Figure 2. Suggested Answers (a) Turning of the pan simulates the rotation of Earth. The coloured water makes a swirling pattern in the pan.
570 Unit C: Water Systems on Earth NEL 3 Consolidate and Extend Te c hnology Connections Students can use a •To prepare for Section 8.5, have students speculate about how the CD-ROM encyclopedia or movement of warm water from one area of an ocean to another the Internet to research the might influence climate. Coriolis effect. • Assign the Check Your Understanding questions.
CHECK YOUR UNDERSTANDING—SUGGESTED ANSWERS
1. In both lakes and oceans, convection currents stir up and redistribute nutrients and dissolved oxygen throughout the water, thus contributing to the survival of aquatic organisms. Most aquatic organisms require oxygen. Cool water can hold more dissolved oxygen. As well, the upwelling of cold water brings the nutrients that organisms at the bottom of a food web require to survive. 2. Similarities: •Both are moving water, therefore both are types of currents. •Both are restricted to and named for a specific location. •Both affect the climate and movement of nutrients. Differences: • Gyres are larger and composed of currents. • Gyres are circular in nature. Currents are more linear or semicircular. • Gyres circle half an ocean. Currents flow in a smaller part of an ocean. 3. The positions of the continents, the warming of water near the equator, and the cooling of water near the North and South Poles lead to the formation of convection cells. The shape of ocean basins and the rotation of Earth cause gyres to move in circular patterns.
Reading and Thinking Strategies: Take a Point of View •Before reading the subsection Ocean Currents, have students LEARNING TIP read the Learning Tip on page 232. Discuss what they already know about ocean currents. Make connections to your prior •Tell students that one way to synthesize information they read knowledge. Ask yourself, is to take the point of view of a specific person or group, and “What do I already know about to think about how the information might be important to this ocean currents?” Consider the person or group (how they might use the information). information that you have •Ask students to think about the following questions and to use learned in school, read on your information from the student book and information from their own, or observed and own experiences to answer the questions. experienced. – How could boat operators planning to cross the Georgia Strait use knowledge about ocean currents to save time and money? (To save time, boat operators could plan their route to avoid the current if they are heading against the flow of the current. To save fuel costs, boat operators who want to go in the same direction as the current will want to know where the current is, so they can ride with it. ) – Why do boaters who plan to go fishing in local waters need to know about currents? (Some ocean life moves with the currents. If boaters know where the currents are and fish there, they have a better chance of catching fish.) – Why would boaters planning a trip from Vancouver to Prince Rupert need to be aware of currents along the BC coastline? (Along the BC coastline, there are hundreds of spots where currents and landmasses can cause unexpected or dangerous water conditions.)
NEL Chapter 8 Water Features 571 Awesome SCIENCE: Studying Ocean Currents
PAGE 235 •Ocean water is constantly on the move. Ocean currents transport heat from the tropics to the North and South Poles, partially equalizing Earth’s surface temperatures. Without ocean currents, the equatorial areas would be too hot and the polar areas would be too cold for most organisms. •Ocean circulation patterns influence climate and living conditions for plants and animals, even on land. They also affect the routes taken by ships carrying goods and people across the oceans. •Ocean currents flow in complex patterns that are affected by winds, salinity and heat content of the water, bottom topography, and Earth’s rotation. Ocean currents and the resulting global circulation patterns interest scientists who are studying Earth’s systems and global change. • Scientists have released hundreds of drifter buoys to study ocean circulation patterns. Data from the buoys are used to better understand ocean currents, the El Niño phenomenon, and the oceans’ influence on climate. Most of the buoys have sensors for detecting temperature. Some determine salinity or measure barometric pressure. The temperature measurements are used to verify data from satellites that map sea-surface temperature using remote-sensed data.
Meeting Individual Needs ESL •Encourage students to develop a concept map that shows the information in the student book.
Extra Support •Have atlases with good ocean maps available. •For students who need additional support with the reading in this section, use SM 8.4 Currents.
Extra Challenge •Suggest that students use the Internet to research El Niño and explain the role that ocean currents play in this phenomenon. Have students present their findings in poster form, using pictures and graphics imported from the Internet and text boxes to explain the pictures and graphics.
ASSESSMENT FOR LEARNING
What To Look For in Student Work Suggestions for Teaching Students Who Are Having Difficulty Evidence that students can Students who have difficulty writing their answers can use diagrams or point- • create models (gyres in a pan) form notes (including vocabulary words) or record their answers on audiotape so • describe the similarities and differences that you can assess their understanding of the key concepts. between convection currents and gyres Students who have difficulty reading can work with a partner who can read the • use technical language (current, convection text aloud. current, gyres) Some students may find that expressing the information in diagram form helps them organize it.
572 Unit C: Water Systems on Earth NEL 8.5 Water, Weather, and Climate Page 236
PRESCRIBED LEARNING OUTCOMES Time • explain the significance of salinity and temperature in the world’s 30–45 min oceans •represent and interpret information in graphic form Key Ideas Large bodies of water, such KNOWLEDGE as lakes and oceans, affect •properties of salt water and fresh water weather and climate. • effect of ocean currents and winds on regional climates Vocabulary •specific heat capacity SKILLS AND ATTITUDES • weather •use the Internet for research • climate •land breeze • use given criteria for evaluating evidence and sources of information • sea breeze (e.g., identify supporting or refuting information and bias) •relate cause to effect Program Resources • assess human impact SM 8.5 Water, Weather, and Climate • show respect and sensitivity for the environment Nelson Science Probe 8 Web site ICT OUTCOMES www.science.nelson.com • demonstrate the ability to formulate questions and to use a variety of sources and tools to access, capture, and store information •create electronic text documents •use a variety of software to present messages Related Resources Arnold, Caroline. El Niño— Stormy Weather for SCIENCE BACKGROUND People and Wildlife.New •Weather refers to short-term, local 4. Large land masses have more Yo rk: Clarion Books, 1998. conditions of temperature, humidity, extreme climates because land “El Niño/La Niña: Nature’s wind speed and direction, cloud heats and cools more rapidly Vicious Cycle.” National cover, and precipitation. than water does. Geographic, March 1999. •Climate refers to the average 5. Earth’s oceans drive the world’s weather conditions at a given climate. The oceans heat or cool location over a long period of time. the winds above them. •Five rules of climate explain much of •The atmosphere is constantly the world’s weather: moving. Air is less dense than water, 1. The farther north or south of the yet the two behave in very similar equator a location is, the cooler it ways. Both form convection currents is. The equator gets the greatest when heated. Hot air rises and amount of direct sunlight and the draws in cooler air. The cooler air Poles get the least. becomes heavier and sinks, which 2. The higher above Earth’s surface, draws in warmer air. These air the cooler the air temperature is convection currents are the because there is less reflected prevailing winds. heat to warm the air. • Gyres are circular patterns of water 3. Large bodies of water tend to flow, comprising two or more moderate temperature. Water has currents. a higher specific heat capacity, therefore it warms and cools more slowly than land does.
NEL Chapter 8 Water Features 573 TEACHING NOTES
1 Getting Started
• Check for Misconceptions – Identify: Students often believe that patterns and trends are absolutes. In other words, a city near water will always be cooler in summer and warmer in winter, and have more precipitation. – Clarify: Explain that climate and weather patterns are very complex, making it necessary to use qualifying statements such as “large water bodies often have a cooling effect in summer” and “the presence of a lake tends to result in greater precipitation”. – Ask What They Think Now: Ask students to generalize, based on their experiences, what the weather is like in their area. Are their generalizations accurate? •Weather is included in the elementary school curriculum, so many students have already studied it. Finding out what students know can determine the emphasis and the approach for this section. Ask students the difference between weather and climate. Then ask them to describe the factors that affect weather and climate. At Home Suggest that students 2 Guide the Learning watch the weather reports and record the local •Read through the first part of this section with students, and discuss weather for a few days. In the answer to the question about pizza. Discuss why weather and class, discuss examples of ocean currents or climate patterns are not absolutes, and why qualifying words, such as prevailing winds over trends, tendency, and often, are used when discussing climate. water (or land) appearing to affect local weather • Ask students if (and how) the presence of large bodies of water patterns. affects the weather. Refer to specific local bodies of water if possible. If there is no large body of water nearby, ask how and why the local climate might be different if there was one. •For students who need additional support with the reading in this section, use SM 8.5 Water, Weather, and Climate. Te c hnology Connections Ask students to construct 3 Consolidate and Extend their graphs using computers or graphing •Discuss how the graphs for Vancouver and Winnipeg (Figures 2 and calculators. 3) were drawn from the data tables. Use Reading and Thinking Visit the Web site of the Strategies: Interpret Visuals and Graphics to help students Canadian Meteorological understand the graphs. Centre, Climate and Water Information, 1961–1990 •Emphasize that line graphs are generally used to graph temperatures Canadian Climate Normals, and bar graphs are generally used to graph precipitation. Circulate to to compare precipitation and temperature for other help students who are having difficulty. Canadian locations. •Ask students to finish reading the section and to complete the Check Your Understanding questions on their own.
574 Unit C: Water Systems on Earth NEL CHECK YOUR UNDERSTANDING—SUGGESTED ANSWERS
1. Specific heat capacity (of a substance) is a measure of how well a substance keeps its heat. Later, students will learn that specific heat capacity is defined as the amount of heat required to raise the temperature of one gram of a substance by one degree Celsius. 2. Land heats up more quickly than water because it has a lower heat capacity than water does. 3. Weather refers to short-term, local conditions that cannot be predicted accurately more than a few days in advance. Climate refers to the long-term trends in an area, based on the statistical analysis of past weather patterns. 4. The Labrador Current is a cold current, and the Gulf Stream is a warm current. Labrador is colder than other locations at the same latitude, while the island of Newfoundland is milder in winter and cooler in summer. 5. During the summer, a lake or ocean might affect the weather of the surrounding area by cooling it and possibly increasing precipitation. During the winter, the water body tends to warm the area and again possibly increases precipitation. If the water body freezes, the modifying effects of the water cease. 6. Vancouver’s climate is warmer in winter and slightly cooler in summer than Winnipeg’s. Vancouver has more precipitation in the winter, and Winnipeg has more in the summer. The differences are due to Vancouver’s nearness to the Pacific Ocean, which moderates its climate. Although Winnipeg is on Lake Winnipeg, it is far from an ocean. The prairies to the west of Winnipeg are very cold and dry in the winter, causing the cold, dry winter climate of Winnipeg. 7. This answer will probably require some research by students. The excellent article in National Geographic (see Related Resources) can help, as can several Internet sites. El Niño tends to warm the climate of North America. In the El Niño year of 1998, many storms and freak weather occurrences caused widespread loss of life and economic losses.
Reading and Thinking Strategies: Interpret Visuals Table 1 Average Monthly Temperatures (°C) Average Monthly Temperature ( ϒC) in and Graphics in Vancouver and Winnipeg Vancouver and Winnipeg 25.0 Month Vancouver Winnipeg 20.0 J3.3–17.8 •Ask students to read the headings for Tables 1 and 2. Note 15.0 F4.8–13.6 ) C
ϒ 10.0 (
M6.6–6.1 e
that these tables compare average monthly temperatures r 5.0 A9.24.0u a t r
M 12.5 12.0 e 0.0 p
(Table 1) and precipitation (Table 2) in Vancouver and Winnipeg. m
J 15.2 17.0 e –5.0 T •Ask students how temperature and precipitation are J 17.5 19.5 –10.0 A 17.6 18.5 –15.0
S 14.6 12.3 –20.0 measured, and what symbols are used in the tables. O 10.1 5.3 JFMAMJJASOND N6.0–5.3 Month (Temperature is measured in degrees Celsius (°C), and D3.5–14.4 Vancouver Winnipeg Figure 2 precipitation is measured in measured in millimeters (mm).) Average monthly temperatures (°C) in Vancouver and Winnipeg
Table 2 Average Monthly Precipitation (mm) Average Monthly Precipitation (mm) in •Have students scan the tables to see how they are organized. Vancouver and Winnipeg in Vancouver and Winnipeg 200.0 Review the structure of the tables. Check that students are Month Vancouver Winnipeg 180.0 J 153.6 19.7 160.0 F 123.1 14.9 ) 140.0
able to read the tables for information by asking questions m M 114.3 21.5 m (
120.0
A 84.0 31.9 n o i
t 100.0
such as these: In which month did both Vancouver and a
M 67.9 58.8 t i p
i 80.0 J 54.8 89.5 c e r Winnipeg experience similar average temperatures? (May) In J 39.6 70.6 P 60.0 A 39.1 75.1 40.0 which months did Winnipeg experience more precipitation S 53.5 52.3 20.0 O 112.6 36.0 0.0 than Vancouver? (June, July, August) N 181.0 25.0 JFMAMJJASOND D 175.7 18.5 Month •Ask students to look at Figures 2 and 3. Note that a line graph Vancouver Winnipeg Figure 3 is used to graph the information in Table 1, and a bar graph is Average monthly precipitation (mm) in Vancouver and Winnipeg used to graph the information in Table 2. •Have students compare how the information in the tables is shown on the graphs. NEL 8.5 Water, Weather, and Climate 237 •Conclude by asking students when they might prefer to use the tables and when they might prefer to use the graphs to find information. A possible response follows: I would use the tables if I needed to know the exact temperature or the exact amount of precipitation. I might use the graphs if I wanted to see trends, or if I wanted to know which city generally has the highest temperature or the greatest amount of precipitation.
NEL Chapter 8 Water Features 575 Meeting Individual Needs ESL •Students from other parts of the world would likely welcome the opportunity to compare the precipitation and temperatures in their homeland with the precipitation and temperatures in other locations at the same latitude. Invite them to describe the climate of their homeland and compare it with the climate of British Columbia.
Extra Support •For students who need additional support with the reading in this section, use SM 8.5 Water, Weather, and Climate.
Extra Challenge • Compare the climate of your community with the climate of a community that is either nearer to or farther from a large body of water. Find the data you need at the Canadian Weather Web site.
ASSESSMENT FOR LEARNING
What To Look For in Student Work Suggestions for Teaching Students Who Are Having Difficulty Evidence that students can Students with reading difficulties can work with a partner who can read aloud to • describe how large bodies of water can them. influence regional weather and climates • use technical language (specific heat capacity, weather, climate, land breeze, sea breeze)
576 Unit C: Water Systems on Earth NEL 8.6 Waves Page 240
PRESCRIBED LEARNING OUTCOMES Time • describe how water and ice shape the landscape 45–60 min • use models to explain how systems operate Key Ideas KNOWLEDGE Ocean waves shape, and are • effect of water and ice on surface features affected by, geological •weathering and erosion features. •impact of waves, tides, and water flow on surface features Vocabulary • tsunami SKILLS AND ATTITUDES •use the Internet for research Skills and Processes • use given criteria for evaluating evidence and sources of information Controlling Variables Creating Models (e.g., identify supporting or refuting information and bias) Observing •relate cause to effect Lesson Materials • assess human impact • show respect and sensitivity for the environment per student • apron per group ICT OUTCOMES •dishpan • demonstrate the ability to formulate questions and to use a variety of • about 4 L sand sources and tools to access, capture, and store information • about 2 L water •ruler •use a variety of information technology tools to solve problems • cloth towels •apply predetermined search criteria to locate, retrieve, and evaluate Program Resources information SM 8.6 Waves •create electronic text documents Nelson Science Probe 8 • synthesize information from a variety of electronic sources for Web site presentations www.science.nelson.com •use a variety of software to present messages
SCIENCE BACKGROUND Related Resources •Virtually all waves are caused by •When the wind dies down, the Rogers, Daniel. Waves, wind blowing across the surface of water surface (ocean or lake) Tides and Currents (The water, creating a low-pressure area gradually calms. The waves may Sea Series). Surrey, above it. This low-pressure area continue for some time after, England: Dragon’s World, causes the water to rise very slightly. however, driven by the energy that 1990. The wind then pushes the “bump” has been stored. “Tsunami: Could It Happen of water along, causing it to rise • An earthquake on the ocean floor in BC?” Vancouver Sun, higher. The molecules of water in the can cause a rapid and abrupt drop or Saturday, February 25, wave move in a more or less circular rise in the column of water directly 2006. pattern, however, not forward with above the epicentre. This vertical the wave. An object floating on the motion causes low-amplitude, surface also moves up and down, long-wavelength waves called not along with the wave. tsunamis to form. Although tsunamis • Some of the energy stored in the are often called tidal waves, they waves is released as sound energy, have nothing to do with tides except as the waves crash onto the that they become more destructive if shoreline. The water regains some they happen to coincide with a high energy as it reflects off the beach, tide. Tsunamis can travel very quickly but the amount of energy is (up to 800 km/h) and cause a great diminished each time the water hits deal of damage when they reach a an object. coastline.
NEL Chapter 8 Water Features 577 •Waves are the major cause of around the University of British shoreline erosion. The constant Columbia (Point Grey) to the Spanish battering of rock by the water in the Banks. To combat this effect, waves breaks large rock formations shoreline communities often install into smaller boulders and stones. breakwaters—barriers designed to Continued wave action (battering and break the waves and dissipate their rolling) will eventually grind the rock energy before the waves reach the material into pebbles and then sand. actual beach. Rock walls, wood •Longshore drift is the motion of pilings, or concrete walls are often water along a shoreline, moving sand built at a 90° angle to the beach to along a beach. One of the best prevent the movement of sand up examples of longshore drift is the and down a beach (e.g., Crescent movement of sand from the cliffs Beach in Surrey) by longshore drift.
TEACHING NOTES
1 Getting Started
• Check for Misconceptions – Identify: Students may think that waves move water over long distances. – Clarify: Explain to students that when waves appear to move across water, it is energy that is moving, not the water. If you were floating in the water, you would not be swept across the surface at the same speed as the waves. You would simply move up and down in a vertical circular pattern. – Ask What They Think Now: Ask students where all the water would go if the waves moved it (and not just the energy) across an ocean or lake. •Use Reading and Thinking Strategies: Synthesize to help students understand Figures 1 and 2.
2 Guide the Learning •Tell students that a storm with heavy winds lasts for several hours. Then, ask students, What can happen to buildings near the shore of a large lake or an ocean? What might happen to the sand on the beach? •Show posters or a video of surfers, or a video of a hurricane or strong windstorm along a shoreline, to set the atmosphere for this section. •Have students complete Try This: Making Waves. •For students who need additional support with the reading in this section, use SM 8.6 Waves.
578 Unit C: Water Systems on Earth NEL TRY THIS: MAKING WAVES At Home Purpose Encourage students to •Students create a model of a beach from sand and observe the effects of wave make waves in a bathtub action on their beach. They will then repeat the activity, changing the angle of at home to see what the incoming wave. waves do when they hit a flat wall. Notes •After students complete the Try This activity, ask them to compare the effects Several Web sites have of waves on a beach with the effects of waves in a shallow pond. videos that show the •Have cloth towels handy to mop up any spills. Cloth towels work faster and are December 2004 Indonesia less wasteful than paper towels. and Thailand tsunami •Ask students to record what happens to the wavelengths of the waves as the striking the coast. These waves approach the beach. videos should be viewed • Use students’ observations to lead into a discussion of how waves are produced with a parent. The by wind and how they affect a beach. Discovery Channel and the Learning Channel have Suggested Answers both shown documentaries (a) Sand particles will likely be moved back and forth at right angles to the about the cause and shoreline. Students may notice that some particles are carried out into the aftermath of the water, and that the beach becomes slightly undercut. Indonesian earthquakes. (b) Students will likely see some particles being moved along the length of the beach. This effect is called longshore drift. The amount and severity of longshore drift will vary, depending on the angle at which the wave strikes the beach. The closer the wave is to striking the beach at 90°, the less the effect of Te c hnology Connections longshore drift is. Students could use electronic encyclopedias or the Internet to research wave action, tsunamis, storm surges, breakwaters, 3 Consolidate and Extend longshore drift, or coastal erosion. Students could •Discuss the effects of a tsunami. (Tsunami is the Japanese word for also “harbour wave.”) • use the Google search engine to find •Watch for media reports of storms that you can tie into this section. photographs of the Storm surges that accompany large storms, such as hurricanes, can different features listed as push large waves onto a shoreline. vocabulary words •locate satellite •Assign the Check Your Understanding questions. photographs on the Internet showing the Indonesian coastline CHECK YOUR UNDERSTANDING—SUGGESTED ANSWERS before and after the tsunami 1. Students’ diagrams should be similar to Figure 1 on page 240. Some may be • use the Internet to two-dimensional. research what happened 2. Similarities: Both tsunamis and wind waves involve energy moving across water. in Port Alberni, BC, on Differences: Wind waves are caused by the wind blowing over water, while March 27, 1964 (Hint: The tsunamis are waves caused by a sudden earthquake, landslide, or volcanic great Alaska Earthquake eruption under the ocean. Tsunamis can strike land thousands of kilometres caused it.) away from their source. Ask students, How do 3. The bottle would take a long time to travel to land, because it would be moved scientists monitor the mostly in an up-and-down pattern by the waves. The bottle would move faster if oceans around the world it were caught in a strong current or pushed along by strong surface winds. for potential tsunamis? 4. Waves cause rocks and stones to abrade each other, which weathers and smoothes their edges. The rocks and stones rub against each other as they are pushed up the beach by the incoming water and pulled back down the beach by the outgoing water. Rocks that have recently broken off larger rock formations will still have jagged edges.
NEL Chapter 8 Water Features 579 Reading and Thinking Strategies: Synthesize 8.6 Waves •Read the subsection Waves and Wind, including the Learning
LEARNING TIP On December 26, 2004, a wall of water up to 10 m high slammed onto Tip, with students. After reading, ask students to summarize The word tsunami comes from the shores of Indonesia, Sri Lanka, Thailand, and other countries in the the Japanese word for harbour Pacific Ocean. It tore through villages within seconds, and left (tsu) and the word for wave what they learned about wind-generated waves. A possible (nami). Working with a partner, hundreds of thousands of people homeless. Many people died when what real-world examples can the wave first hit. Others perished as the water rushed back into the response follows: Waves are caused by the wind moving over you think of that relate to your ocean, carrying them with it. In total, nearly 300 000 people were killed reading about tsunamis? or missing as a result of the tsunami. water. The crest (high) and trough (low) are high and low points A(tsunami formerly called a tidal wave) is one of the largest, most devastating types of wave known. Tsunamis are barely noticeable When waves make their way across water,where it is energy they first that formis moving, in the ocean. Caused by earthquakes, volcanic on the wave, and the distance between them is the not water. If you were floating in the water, youeruptions, would ornot giant be swept underwater landslides, tsunamis may be less than across the surface at the same speed as the waves.50 cm Instead, high on you the wouldsurface, yet they carry the weight of the ocean’s wavelength. Waves move in a circular motion. Waves begin to be moved up and down in a circular pattern,depth as shown with inthem Figure and 2 can. travel at speeds of up to 800 km/h. When this energy is squeezed into shallow waters, it becomes concentrated, and topple over when they reach shallow water. The wind pushes the wave speeds up and increases in height.
(c) Unfortunately, all areas of the oceans that are at risk for tsunamis are the tops of the waves forward, and the returning water slows (b) not monitored. Advancements in satellite technology are improving our ability to predict these waves, however, and provide an opportunity the bottoms of the waves, making the waves curl and break. for evacuation. •Create opportunities for critical thinking by asking these Waves and Wind LEARNING TIP Less dramatic (a)than tsunamis, but much more common, are waves questions: Why would a surfer choose a moderately steep Illustrations help readers caused by the wind. Waves on lakes and oceans may begin when the visualize the text and help with wind pushes down unevenly on their surfaces. As the wind continues reader comprehension. As you beach rather than a gently sloping or very steep beach? (Waves Figure 2 study Figures 1 and 2, ask to blow across the surface of the water, the waves swell larger. The top Cross section of wavesyourself, hitting “What a beach have I learned of a wave is called the crest, the bottom is the trough, and the distance about the influence of wind on between crests is the wavelength(Figure 1). coming into a gently sloping beach would break a long way out. water?” The circular motion of the water is smaller at greater depths wavelength (Figure 2(a)). As a wave approaches shallow water, the circular motion Waves coming into a very steep beach might not break at all becomes distorted. The bottom layers move more slowly, and the wave begins to topple over (Figure 2(b)). The wind catches the top of the before they hit the beach. If you were a surfer, you would want wave and pushes it forward. At the same time, water returning from the beach slows the bottom layers even more, and the wave curls and waves to break close to shore so you could get a longer ride.) breaks (Figure 2(c)). Figure 1 TRY THIS:The Makingdistance between Waves one wave How is a tsunami the same as and different from a wind- crest and the next is called the crest Skills Focus: creating models, observing, controlling variables wavelength. trough generated wave when it enters shallow water? (Both a wave In this activity, you will use a model to investigate the action of waves on 240 Unit C Water Systems on Earth NEL beach. and a tsunami act the same when they enter shallow water— 1. Put on an apron. Using wet sand, make a sloped beach acr of a shallow dishpan. Pack the sand tightly its deepest side. the bottom of the wave slows down and the top speeds up, 2. Slowly add water to a depth of 2 cm to 3 cm. Using a rule series of waves directly in front of your beach, so they strike your beach head on. breaks, and curls. A tsunami has much more energy than a (a) How do the waves affect your beach? 3. Make waves that strike the beach at an angle. wave, however. This energy becomes concentrated when the (b) What effect do these waves have? How does changing the angle of the waves affect your beach? tsunami is squeezed into shallow water—the top of the wave
NEL 8.6 Waves 241 moves much faster and its height increases significantly.)
Meeting Individual Needs ESL •Introduce the vocabulary through labelled diagrams.
Extra Support •Media reports of storms can be used as resources. •For students who need additional support with the reading in this section, use SM 8.6 Waves.
Extra Challenge •Ask students to pretend to be news reporters on the coast of British Columbia just after it was struck by a major tsunami in March 1964. They should report on the cause of the tsunami and on the effects along the coast. •Have students use the Internet to research surfing and waves. Ask them to locate and present information on wave formation, types of waves, and surfing techniques. Students’ presentations should explain how understanding the science helps to improve the activity.
ASSESSMENT FOR LEARNING
What To Look For in Student Work Suggestions for Teaching Students Who Are Having Difficulty Evidence that students can Students who have difficulty writing their answers can use point form or • describe how waves can change the shape diagrams to illustrate the concepts, or record their answers on audiotape. of the land •create models (e.g., waves on a beach) • use technical language (tsunami)
580 Unit C: Water Systems on Earth NEL 8.7 Tides Page 244
PRESCRIBED LEARNING OUTCOMES Time • describe how water and ice shape the landscape 30–45 min • explain variations in productivity and species distribution in marine environments Key Ideas The regular movement of the KNOWLEDGE oceans in tides is affected by •weathering and erosion geological features. •impact of waves, tides, and water flow on surface features Vocabulary •productivity and species distribution in aquatic environments • tides • diversity of aquatic life forms • tidal range • tidal bulges SKILLS AND ATTITUDES Program Resources •use the Internet for research SM 8.7 Tides • use given criteria for evaluating evidence and sources of information Nelson Science Probe 8 (e.g., identify supporting or refuting information and bias) Web site: www.science.nelson.com •relate cause to effect • show respect and sensitivity for the environment
ICT OUTCOMES • demonstrate the ability to formulate questions and to use a variety of sources and tools to access, capture, and store information •use a variety of information technology tools to solve problems •apply predetermined search criteria to locate, retrieve, and evaluate information •create electronic text documents • synthesize information from a variety of electronic sources for presentations •use a variety of software to present messages
SCIENCE BACKGROUND
•Tides result from the pull of gravity •The highest predictable tides, with a from the Moon and Sun, with the tidal range averaging 14 m, occur in Moon’s effect dominant. When the Bay of Fundy between Nova Scotia Sun and Moon line up—either on the and New Brunswick. (The average Related Resources same side of Earth (a new Moon) or tidal range globally is 2.5 m.) As the Rogers, Daniel. Waves. on opposite sides (a full Moon)— ocean water is pulled into the Bay of Tides and Currents (The they cause the highest tides. Fundy, it is forced to rise because Sea Series). Surrey, •As Earth rotates on its axis, the the bay is V-shaped—narrower at the England: Dragon's World, ocean closest to the Moon bulges. far end (the head) than at the 1990. The tide rises in this ocean as the opening. The bay is also shallower Moon approaches the closest point nearer the head. The water is (high tide) and falls as the Moon compressed inward and upward by moves away. Low tide occurs when the land. the Moon is on the horizon. In most •The slope of a shoreline affects the places, successive high tides are tidal range, as well. A sloping about 12.5 h apart, giving two high shoreline on a wide beach, for and two low tides in just over a day. example, allows the water to spread
NEL Chapter 8 Water Features 581 out, reducing the tidal range. A steep not just in the oceans. But since cliff stops the water, increasing the water is “flexible” and land is not, tidal range. only water is seen to be affected by •The Moon revolves around Earth in this pull. the same direction that Earth rotates •Kris Freeman (Encyclopedia of Earth on its own axis (this rotation is and Physical Sciences) wrote of another major cause of the tides). “more than 400 different factors that Because this Earth–Moon cycle takes cause and influence the movement about 24 h 50 min to complete, there of tides,” with “extremely complex” is an average interval of 12 h 25 min interactions among these forces. The between two high tides. shape of the continents and friction •At any point in time, two high tides with the ocean floor are major are happening on Earth’s surface: the disruptions. Locally, tides respond to direct tide on the side facing the the depth, shape, and size of the Moon and the indirect tide on the ocean basins. Weather conditions, opposite side. These two tidal bulges such as wind, lingering zones of high move around the globe as Earth or low pressure, and sudden change rotates, lagging slightly behind the in barometric pressure, can also Moon and Sun as they move affect the tidal range. westward over Earth’s surface. •The gravitational pull from the Moon can be measured around the world,
TEACHING NOTES
1 Getting Started
•Introduce Section 8.7 by asking if students have ever walked along an ocean beach. Connect this experience to the section by asking these questions: What happens to the width of the beach during the day? (It varies from wide to narrow, unlike a lake beach.) How does the sand farthest from the water compare with the sand closest to the water? (The far sand is dry, while the closer sand is wet.) If you pushed a stick into the sand where the last wave front reached and left it there for 15 minutes, where would the stick be relative to the wave fronts? Why? (There are two possible positions: high and dry, or washed around by waves, depending on whether the tide is going out or coming in, respectively.) •Read the first paragraph with students, and have them look at Figure 1. Ask them to recall what they already know about the causes of tides.
2 Guide the Learning •Use Reading and Thinking Strategies: Check Understanding to support students’ understanding. •From Figure 3, students may get the impression that the tides are gigantic because of the size of the water bulges relative to the size of Earth. Explain to students that, in both Figure 2 and Figure 3, the water bulges representing the positions of the tides have been exaggerated to show where they are located on Earth. •For students who need additional support with the reading in this section, use SM 8.7 Tides.
582 Unit C: Water Systems on Earth NEL 3 Consolidate and Extend At Home Students could tilt •Ask students, When is the best time to collect shells that have been different-shaped containers that are washed up on shore— as the tide is coming in or going out? (just after partially filled with water the tide has turned and is starting to go out) and compare the tidal ranges in the containers. • Ask students to find pictures of the Sechelt Rapids or other areas For example, does tilting a with tidal rapids or very high tides. square container toward a flat side result in a •Help students recognize that the intertidal zone is one of the different tidal range than harshest environments in which organisms can live. Organisms are tilting the container immersed in water at high tide and then high and dry at low tide, toward a corner? How either baking in heat from the Sun or freezing. does tilting a tall, narrow container compare with • Assign the Check Your Understanding questions. tilting a short, wide container if both containers have the same CHECK YOUR UNDERSTANDING—SUGGESTED ANSWERS amount of water?
1. Tidal ranges are often larger where a coastline funnels the water, forcing it into a narrow inlet (e.g., Bay of Fundy, Iqaluit, and, to a lesser degree, Saint John and Prince Rupert). Students may find an atlas useful when answering this question, Te c hnology Connections since an atlas shows coastlines in greater detail than Figure 4 does. Have students use the 2. Most of the high tidal ranges seem to be in bays with narrow openings (e.g., Internet to research tidal Iqaluit, Prince Rupert, the Bay of Fundy). power. Ask students to 3. The gravitational pull from the Moon causes ocean water to bulge on the side of identify the potential Earth facing the Moon and on the opposite side of Earth. benefits and drawbacks of this type of power 4. (a) Low tidal ranges probably have little effect on the life of the people living on generation and the shore. In contrast, people who live in areas with high tidal ranges must be conditions that are aware of the tide times for each day. In these areas, tide tables are required to make tidal published in the newspapers. Fishers must time their departure and return power feasible. to coincide with the high tide. (b) Locations with high tidal ranges are good for recreation (e.g., Skookumchuk Narrows). Some of these locations are being considered for power generation.
NEL Chapter 8 Water Features 583 Reading and Thinking Strategies: Check 8.7 Tides Understanding Imagine that you are walking along an ocean beach. You see marks left •Have students scan Figures 2 and 3. Tell them that Figures by the water and a line of debris washed ashore. As you continue to explore, you notice that the water level seems to change during the day. You are observing the effects of tides.Tides are high and low water 2 and 3 are important visuals, which will help them levels caused by the gravitational pull of the Moon and Sun and the rotation of Earth. The difference between the water levels at high tide understand tides. and low tide is called thetidal range (Figure 1). The line of debris shows the high water mark—that is, the water level at high tide. •Arrange students in pairs to read the first paragraph under
The gravitational pull of the Sun also influences the tides on Earth, Causes of Tides. Then ask them to explain to each other but not as significantly as the gravitational pull of the Moon. Whenline of debristhe Sun and Moon are pulling at right angles to each other, the tidal range is high tide how the Moon causes tides, using Figure 2. Have students the smallest, producing what are called neap tides.tidal range When the Sun, Moon, and Earth are aligned, the tidal range is the greatest, producing spring tides (Figure 3). This alignment occurs twice each lunar month (the low tide follow the same procedure for the next paragraph and period duringFigure which 1 the Moon rotates around Earth, approximately 29.5 days). The tidal range is the difference between high tide and low tide. Figure 3, explaining how the Sun causes tides.
Causes of Tides •Conclude by bringing students together and asking question The 4.primary neap tides cause of ocean tides is the gravitational pull of the Moon on Earth. The water responds to this pull by bulging out toward the such as the following to check their understanding: Moon. On the opposite side of Earth, there is also a bulge of water tidal bulges caused by the rotation of Earth (Figure 2). Thesetidal bulges appear – What causes tidal bulges on the surface of Earth that to move continuously around Earth as it rotates. Most locations on 3. spring tides Earth experience two high tides and two low tides each day as the tidal faces the Moon? (the gravitational pull of the Moon) bulges meet the coast. Earth – What causes tidal bulges on the surface of Earth that is
2. neap tides Moon opposite the Moon? (the rotation of Earth)
gravitational force – Why do most locations on Earth experience two high Moon
Figure 2 The gravitational attraction of the 1. spring tides tides and two low tides each day? (High tide occurs Moon on Earth and the rotation of Earth pull the water in the oceans into tidal bulges. (The tidal bulges when the location is directly facing the Moon, and low Figure 3 are exaggerated in this diagram.) tidal bulges Spring and neap tides occur twice each lunar month. Spring tides in position 1 are higher than spring tides in position 3. Can you explain why? tide occurs when the location is one-quarter around 244 Unit C Water Systems on Earth NEL
In the middle of the ocean, the tidal bulge is not very noticeable— Earth’s rotation. High tide occurs again when the location probably around 1 m. When the tidal bulge moves into shallower water and meets the land, or moves into narrowing channels, it becomes is on the opposite side of Earth from the Moon, and low much more pronounced. The tidal range varies considerably depending on the location (Figure 4, on the next page). tide occurs again when the location is three-quarters The shape of the ocean floor and shoreline affect the tidal range. A smooth ocean floor near the coast and a gently sloping shoreline allow around Earth’s rotation.) the bulge to rise over the land. The Bay of Fundy between New Brunswick and Nova Scotia, has geographical features that contribute – When is the tidal range the greatest? (when the Moon,
NEL 8.7 Tides 245 Earth, and Sun are in a straight line) – Why does each location have two spring tides and two neap tides each lunar month? (The Moon is aligned with the Sun twice a month and is at right angles to the Sun twice a month.)
Meeting Individual Needs ESL • Ask students to draw two cross-sections of a beach 12 h apart and label the two diagrams with the appropriate terms.
Extra Support •Some students may never have witnessed the phenomenon of tides. Videos or pictures of intertidal zones would help these students. •For students who need additional support with the reading in this section, use SM 8.7 Tides.
Extra Challenge •Students can use e-mail to contact a school that is close to an area with a high tidal range and ask if any students at this school would be willing to describe the effects of the tides. •Provide students with tide charts and maps for the West Coast Trail. Can students find parts of the trail that are submerged at high tide?
ASSESSMENT FOR LEARNING
What To Look For in Student Work Suggestions for Teaching Students Who Are Having Difficulty Evidence that students can If possible, have diagrams labelled and photocopied for students. •explain the causes and effects of tides Ask another student or an adult volunteer to read the section with students, and • use technical language (tides, tidal range, allow students to take the student book home. tidal bulges)
584 Unit C: Water Systems on Earth NEL 8 Review Page 248
Chapter 8 Review Chart Time •Use the Chapter 8 Review Chart to review what has been learned. 45–60 min Have students work in pairs to read each key idea and discuss what Skills and Processes they remember about the topic. They can then use the vocabulary The Chapter Review provides page references in the chart to scan for additional information in the an opportunity for students to chapter. demonstrate their understanding of and their •Paraphrasing—putting information into your own words—is an ability to apply the key ideas, important way to check for understanding. Model paraphrasing with vocabulary, and skills and processes. the class, and then ask students to work with a partner to paraphrase each key idea. Encourage students to use the related vocabulary words Program Resources as they are paraphrasing. BLM 0.0-9 Chapter Key Ideas BLM 8.0 Chapter 8 Quiz •Ask students to write each key idea in their notebook or use Nelson Science Probe 8 BLM 0.0-9 Chapter Key Ideas. Beside each key idea, ask them to create Web site labelled diagrams or sketches, including any vocabulary words, to www.science.nelson.com illustrate it. •Have students complete BLM 8.0 Chapter 8 Quiz to review the vocabulary and concepts in this chapter.
Review Key Ideas and Vocabulary—Suggested Answers 1. Diagrams should be similar to Figure 3 on page 220. 2. Answer (b) is correct. 3. The water in the water cycle does not always move quickly. Eventually, the water in the glaciers will melt or evaporate and begin to cycle again. 4. Advantages: protect dwellings along the shores, protect harbours, and reduce erosion Disadvantages: cause erosion and scouring at other previously unaffected beaches 5. The waters would not mix, or they would mix very slowly at the surface where they contact one another. This is because the cold, more dense water is already at the bottom and the hot, less dense water is already at the top. If they were reversed, the cold water would flow down into the hot water.
NEL Chapter 8 Water Features 585 6. Characteristic River currents Ocean currents movement can flow quickly or slowly; flow can flow quickly or slowly; flow in a somewhat straight path, in large circular patterns, but guided by the banks are guided by the continents’ coasts cause are caused by water flowing are usually caused by water downhill due to gravity temperature and salinity differences water fresh salt
effects can erode shores and carry can carry heat and nutrients; material downstream and shape continental shelves
7. As a wave approaches shore, the circular motion of the water becomes distorted. The deeper water begins to move more slowly than the water above, and the wave begins to topple over. Water flowing back from the beach also helps to slow the deeper water, and wind blowing toward shore helps to push over the top of the wave. Students’ diagrams should resemble Figure 2 on page 241.
Use What You’ve Learned—Suggested Answers
8. (a) Average Monthly Temperature (°C) in City A and City B 25.0 20.0 15.0 C)
° 10.0 5.0 0.0
mperature ( –5.0 Te –10.0 –15.0 –20.0 JFMAM J J A SOND Month City A City B
Average Monthly Precipitation (mm) in City A and City B 350.0
300.0 C08-F07-SP8TR.eps
250.0
200.0
150.0
Precipitation (mm) 100.0
50.0
0.0 JFMAM J J A SOND Month City A City B
586 Unit C: Water Systems on Earth NEL (b) City B is closer to water. In the winter, its average temperature is warmer than City A’s average temperature because of the moderating influence of water. In the summer, City B is cooler than City A, once again due to the cooling effect of the water. 9. Make three samples of water with different salinities. Add a different food colouring to each sample. Carefully add a small amount of one saltwater sample to a column of fresh water, and time how long it takes for the salt water to “sink” or dissipate. The columns of fresh water should be left standing for a while to ensure that there is no movement. The prediction is that the water with the highest salinity will “sink” or dissipate fastest. Students could conclude that the salinity of water does affect the movement—that the higher the salinity is, the greater the effect on currents. Alternatively, students could set up three small aquariums containing water with different salinities. Attach a pump to one side of each aquarium, halfway between the surface and the bottom, positioned so that it will direct a stream of water in a circular motion around the aquarium. Place a barely floating or neutrally buoyant (suspended) object in each aquarium. Leave the water standing to ensure that there is no movement at the start. Run each pump for a fixed period, and then turn it off. Measure the time it takes for the water to stop moving again (as indicated by the suspended object). This would enable students to determine if the more dense water had more inertia, which could affect the establishment of a current. 10. Students’ answers will vary depending on their location. For the vast majority of students, however, the stick will travel to the Pacific Ocean. 11. The key point is that high boat and jet ski speeds cause excessive wake. These waves can cause erosion of sensitive shorelines. 12. If land use was not regulated, a person or a company could • dump garbage and sewage into the drinking supply of downstream users • take as much water as they wanted •clear-cut forests to the water’s edge instead of leaving an area of trees 13. Information about the Coriolis effect was given earlier in the chapter. There are several Web sites with excellent information. If Earth rotated in the other direction, the effect would be the opposite of what currently happens.
Think Critically—Suggested Answers 14. There may be different answers to this question. Ideally, all communities in a watershed should work together to make decisions that are in the best interest of the sustainability of the watershed and the needs of the communities. In reality, a majority decision does not always make everyone happy.
NEL Chapter 8 Water Features 587 15. In areas with large tidal ranges, owners of moored or anchored boats must be aware that the boats will rise and fall with the tide, and perhaps even sit on their hulls at low tide. Boat operators need to know the best times to travel in order to avoid fast currents. Builders should not construct homes or other buildings too close to the waterfront, because the shoreline may erode (especially if there is a high tide combined with a storm surge). 16. Erosion caused by wave action combines the force of the water pounding into rock material as well as the pounding/grinding effect of materials, such as sand, pebbles, and boulders, in the water. This is similar to both sandblasting and cutting with high-powered water jets. 17. Possible ideas for both topics are given below: Continued global warming will result in glaciers and polar icecaps melting more quickly. There will be a loss of habitat for animals and plants in polar regions, which could cause the extinction of some species. Weather patterns could be disturbed, including patterns of rain and snowfall. The sea level will rise, affecting coastal communities. If worldwide temperatures rise, the temperature difference in the oceans’ waters may not be great enough to drive the atmospheric and oceanic convection cells. The geological record suggests that the central portion of the North American continent was covered in the past by a large, warm, shallow inland sea. Marine animals were abundant in this sea, and their preserved remains are uncovered as fossils. 18. If an ocean current changed from warm to cold, the local climate would start to cool. Cold water cools the air above it, and less water can evaporate into colder air. Less moisture in the atmosphere means less cloud cover and precipitation. The average temperatures would be cooler in both summer and winter.
Reflect on Your Learning—Suggested Answers 19. Students’ answers will vary. Students may mention convection currents as air circulates in their homes (e.g., hot air rising from a radiator) or during cooking (in a pot of boiling water or a convection oven). 20. Students will likely indicate that they previously did not appreciate how powerful moving water is. Researching and observing evidence of the destructive power of water usually helps students develop understanding and appreciation.
Meeting Individual Needs Extra Challenge •Have students use a HyperCard program to build an interactive multimedia quiz based on the vocabulary, concepts, and key ideas in the unit. Students could create a multiple-choice quiz that allows other students to select answer buttons that either indicate they are correct or return them to the question page so they can try again.
588 Unit C: Water Systems on Earth NEL 9 Water and Our World Page 252
Key Ideas Vocabulary
Many areas of Earth that are covered with scuba water are unexplored. biodiversity productivity Human use of natural resources affects water aquaculture systems.
Saltwater or marine ecosystems are home to a variety of organisms that require proper conditions to survive and reproduce.
Fish farms have been established to raise fish for food because of decreasing wild populations.
Science Skills and Processes 9.1 9.2 9.3 9.4 9.5 9.6 9.7 Inquiry Skills Questioning ✓ Hypothesizing ✓✓ Predicting ✓✓✓ Planning ✓ Conducting ✓✓✓ Recording ✓✓✓ Analyzing ✓✓✓ Evaluating ✓✓✓ Communicating ✓✓✓ Additional Inquiry Skills (Try This Activity) Controlling Variables Creating Models Observing Estimating
Measuring Related Resources Classifying Nelson Science Probe 8 Inferring Web site www.science.nelson.com Interpreting Data
NEL Chapter 9 Water and Our World 589 TEACHING NOTES •Have students study the photographs in the introduction and speculate about the content of the chapter. •Play the song “The Wreck of the Edmund Fitzgerald” by Gordon Lightfoot to introduce this chapter. •Students consolidate their understanding of the role that water systems play in global ecosystems. As well, they investigate some of the ways that human activities influence, and are influenced by, Earth’s water systems. •Water is a powerful force as it cycles through the world’s ocean and freshwater systems, over land and back again. Water can carve river valleys, erode beaches, influence climate, destroy homes, and replenish life. You can use the key question on each scaffolding master to review the ideas in the section. • As students work, prompt them to connect their science learning to other learning experiences, world events, and/or personal learning experiences. •Hand out BLM 0.0-9 Chapter Key Ideas. Inform students that this will be a place to record key vocabulary and personal experiences, as well as what they learn from the student book. •You can use any or all of the following BLMs to help students study the vocabulary in this chapter. – BLM 0.0-10 Science Idea Box – BLM 0.0-11 Vocabulary Wheel – BLM 0.0-12 Term Box •To assess students, you may want to use or adapt Rubric 9: Chapter 9.
Meeting Individual Needs Extra Challenge •Invite students to brainstorm potential issues related to water and make a visual display of these issues for your bulletin board.
590 Unit C: Water Systems on Earth NEL 9.1 Exploring the Deep Page 253
PRESCRIBED LEARNING OUTCOMES Time • explain the significance of salinity and temperature in the world’s 30–45 min oceans • explain variations in productivity and species distribution in marine Key Ideas environments Many areas of Earth that are covered with water are • describe the relationship between scientific principles and technology unexplored.
KNOWLEDGE Vocabulary • effect of ocean currents and winds on regional climates • scuba •productivity and species distribution in aquatic environments Program Resources • diversity of aquatic life forms SM 9.1 Exploring the Deep Science Skills and Processes SKILLS AND ATTITUDES Rubric 21: Research •use the Internet for research Science Skills and Processes • use given criteria for evaluating evidence and sources of information Rubric 22: Research— Self-Assessment (e.g., identify supporting or refuting information and bias) Nelson Science Probe 8 •relate cause to effect Web site • assess human impact www.science.nelson.com • show respect and sensitivity for the environment
ICT OUTCOMES • demonstrate the ability to formulate questions and to use a variety of sources and tools to access, capture, and store information •use a variety of information technology tools to solve problems •use a variety of software to present messages
SCIENCE BACKGROUND
•The ocean is divided into two distinct •Because of advances in underwater zones: the upper layer (reservoir) and exploration technologies since the the deep. The reservoir, warmed by 1950s, scientists have learned much sunlight and stirred by wind, is home about the oceans’ physical, chemical, to most of the ocean’s plants and and biological conditions and their animals. It accounts for only 2 % of rich deposits of gold, oil, and other Related Resources the volume of the ocean. minerals. •Water temperatures in the deep are •The Newt Suit was developed by Dr. MacQuitty, Miranda, and only about –1 to 5 °C. Phil Nuytten, an engineer and owner Frank Greenaway. Ocean • No sunlight penetrates into the deep of a Vancouver business. Dr. Nuytten (Eyewitness Books). water, yet it is filled with life. also designs and manufactures Toronto: Stoddart, 1995. •Many deep-water species never underwater vehicles (submersibles), Parker, Steve, and Philip enter the upper zone. They feed on atmospheric diving suits, and Dowell. Pond and River decaying matter that falls from remotely operated vehicles (ROVs). (Eyewitness Books). above. •The ocean floor has been mapped Toronto: Stoddart, 1998. • Deep-sea fish are mysterious and using echo sounding (sonar), and Pernetta, John (ed.). The fascinating. Many have spectacular deep-sea currents have been Random House Atlas of adaptations to their dark world, such mapped using ultrasound. the Oceans.New York: as large, oversized jaws filled with Rand McNally & Co., sharp teeth, small bodies, and 1994. bioluminescence.
NEL Chapter 9 Water and Our World 591 TEACHING NOTES
1 Getting Started
• Check for Misconceptions – Identify: Many students know a great deal about underwater exploration from television programs and think it would be a glamorous career. – Clarify: Remind them that oceanographers require many years of education, studying biology, physics, chemistry, and engineering. Also, the dangers associated with underwater exploration are at least as great as the dangers associated with space exploration. – Ask What They Think Now: Ask students, How many of you would still consider a career in underwater exploration?
2 Guide the Learning •Use Reading and Thinking Strategies: Predict/Anticipate to help students discover what they will learn. •Invite a member of a local diving club to talk with the class about training and experiences. •For students who need additional support with the reading in this section, use SM 9.1 Exploring the Deep.
3 Consolidate and Extend •This section provides an excellent opportunity for research. Students can form cooperative groups and use Web browsers, electronic encyclopedias, and libraries. Different groups can investigate At Home techniques such as scuba, sonar, Nautile, and satellite imaging. Ask Many television specials on deep-sea exploration students to examine the role of their technique in marine research. are available on video, •Sudents can research scientists and engineers who have contributed to either from a video store or a public library. our knowledge of the oceans (e.g., Jacques Cousteau, Phil Nuytten, Encourage students to Jacques Piccard, Sylvia Earle, William Beebe, Robert Ballard). watch a video with their family, and then discuss •Sporting goods stores or travel agencies might be willing to provide what they learned with posters that show diving. the class. Make sure that students can identify •Make a connection between the exploration of the deep sea and the specific things they exploration of outer space. Ask students why astronauts spend a learned from the video, considerable amount of time training for their space missions in a which they did not know deep swimming pool. How are spacecraft and submersibles similar? before watching it. Students who like to make •Assign the Check Your Understanding questions. models could construct a submersible. An accurate CHECK YOUR UNDERSTANDING—SUGGESTED ANSWERS model would clearly illustrate the necessary 1. The Newt Suit has the following advantages compared with scuba gear. thickness of the walls. •The cast-aluminum body of the Newt Suit allows the diver to operate inside at normal atmospheric pressure. There is no need to worry about getting “the bends” (nitrogen bubbles in the bloodstream). •The diver can work at depths greater than 300 m. •All the joints on the Newt Suit’s body are fully articulated (full range of motion), so the diver can move more easily underwater.
592 Unit C: Water Systems on Earth NEL •The suit contains a 6 to 8 h supply of air. • In case of an emergency, the suit has a backup system that can supply air for Te c hnology Connections an additional 48 h. Use the Internet to learn •The diver can talk to the support ship. more about deep-sea submersibles and their 2. The ocean floor can be explored by using remotely operated vehicles (ROVs) to role in underwater collect samples and to record a site or shipwreck with video or still cameras. If exploration, create a time the site is too deep for a ROV, then scientists can use sonar to get images of line of major events in the the bottom. history of underwater 3. Remote exploration is more appropriate when scientists want a quick survey of exploration, and/or draw a a site. ROVs can do this more quickly and with less expense than a submersible map that shows the with people inside. Also, ROVs are more suitable in very deep and/or dangerous location of major situations. Human exploration using scuba is more appropriate for shallow sites shipwrecks along the because humans can manipulate equipment more easily than robot arms can. coast of British Columbia. 4. British Columbia is a world leader in using decommissioned battleships as artificial reefs, thus creating new habitat for marine life and new reefs for recreational divers to enjoy. This practice has both positive and negative effects. Positive effects: – allows scuba divers to discover the wonders and fragile nature of the oceans – increases marine life – creates a safe and controlled area for scuba divers – promotes tourism (land and sea), thus generating revenue for the area Negative effects: – puts more trash/garbage into the water system – increases recreational water use in the area – is accessible to only a few people (scuba divers) –disturbs bottom sediment, which otherwise would be undisturbed
Reading and Thinking Strategies: Predict/Anticipate •Read the chapter opener and the Learning Tip on page 252 with students. Exploring the Deep 9.1 •Read the title of Section 9.1 with students, and note that this section is about exploring oceans. Have Humans have always been intrigued by the sea, with its hidden caverns and darkest depths. Today’s technology allows us to explore and research the ocean in ways that early explorers could hardly have students scan the subheadings on pages 253 and 254. imagined. For example,scuba (self-contained underwater breathing apparatus) gear was invented in the 1940s. It is widely used today for Ask them to predict what they might learn in the recreation, the study of underwater ecosystems, and underwater work, such as oil rig maintenance. Underwater photography, which once subsections (different ways to explore oceans). required sophisticated equipment, is now possible for casual explorers. Personal diving was greatly improved with the development of the •Before students read pages 253 and 254, have them Newt Suit Duringby Phil Nuytten,his 50 years a Métis of ocean engineer research, and Cousteaubusiness owner helped in to perfect the Vancouver.aqualung, The Newt an Suit early is a type pressurized of scuba suit gear. that Cousteau allows anhelped individual the public turn the subheadings into questions to guide their to dive to debecomepths of aware more of than the 300 wonders, m (Figure complexity, 1). and fragile nature of the oceans through his television specials. Beneath the Surface reading. For example: How can we explore beneath the Technology, such as remote video (Figure 3), sonar (Figure 4),Figure and 1 Since the latecore 1700s, sampling, more allows sophisticated researchers methods to explore of underwater the bottom of the oceanPhil Nuytten is wearing a Newt Figure 3 without ever venturing below the surface. In World War I, echo Suit. A thruster pack on the back transportation have been developed. Today’s nuclear-powered of the suit allows him to move ocean’s surface? This remote video camera can be sounding was used for simple depth measurements. Single sound steered into places too small,submarines too can stay submerged for weeks and travel thousands of around underwater. deep, or too dangerous forkilometres.pulses The technologies were sent down developed from a forship. building Knowing submarines how fast soundhave waves •Have students read one subsection at a time and, as human exploration. Becauseled it isto deep-seatravelled submersibles. in water, the These time submersibles taken for the have echo to to be return specially indicated how less expensive to operate, it can deep the sea floor was at that point. By World War II, sonar (sound also be used for scouting tripsdesigned to survive the incredible pressure of the deep ocean. The hull they read, make point-form notes under the appropriate before launching a submersible.of the Frenchnavigation submersible and rNautanging)ile ( Figureequipment 2) is wasmade used from to locatetitanium ships and metal, withsubmarines. thick curved Cartographers Plexiglas for thenow portholes. use sonar Launched for mapping from the a sea floor. question in their notebook. ship, researchersOceanographers in the Nautile cancan study work bottom on the deposits,ocean floor nutrient at depths concentrations, of 6000 m andfor fivethe hours.presence The of Naut organismsile is equipped without leavingwith sonar, the ship. Core samplers •Arrange students in pairs to share their notes and make floodlights,are a videolowered camera, to collect and undisturbeda remote-controlled layers of arm bottom for retrievingsediment. objects on the sea floor. any changes or additions they want. Oceans from Above Aerial photography can give scientists and geologists additional information when studying such things as shoreline movement and the source and extent of chemicalFigure and 2 thermal pollution (the addition Figure 4 of excess heat to a water body).The submersible Nautile was used by The Deep Tow Seismic System is explorers to photograph and retrieve sonar equipment that was Meteorologists (scientists whoitems investigate from the Titanic. weather)(The Titanic use satellite developed by a Canadian firm. lies at 3780 m below sea level.) Scientists use it to map sediment imaging to gather information about the force, path, and potential on the continental shelf. From thedestructiveness Surface of hurricanes and tropical storms. Oceanographers use satellite imaging to look at oceans in ways that were never before Oceans also can be explored using surface vessels. Jacques Cousteau possible. Using special imaging programs, they can see patterns of captained one of the most famous ocean research vessels, the Calypso. depth, thermal activity, phytoplankton production, and global pollution. NEL 9.1 Exploring the Deep 253 9.1 CHECK YOUR UNDERSTANDING
1. What advantages does the Newt Suit have over scuba? 2. List and briefly describe ways we can explore the ocean floor without actually going there. 3. In what situations might remote exploration be more appropriate than human exploration? In what situations might human exploration be more appropriate? 4. In some harbours, decommissioned (no longer useful) battleships are being sunk for recreational scuba diving expeditions. Discuss the positive and negative effects of this practice.
254 Unit C Water Systems on Earth NEL
NEL Chapter 9 Water and Our World 593 Strategies for Success Remembering Information •Ask students, What is the number one enemy of remembering information? (boredom) Tell students that when they feel bored, information in short-term memory is quickly lost and never passes on to long-term memory, and so they end up “forgetting.” Ask students to suggest ways to avoid boredom (try hard to stay interested; start with short study periods and increase time daily; keep active by making notes and asking questions; read aloud; when starting to fade, try standing up and stretching or munching on a nutritious snack). Suggest that students take a short break when they find their minds wandering.
Meeting Individual Needs ESL •Encourage other students to watch deep-sea exploration videos with ESL students and to help ESL students with the language. Videos or DVDs are preferable to television programs because they can be rewound and/or stopped. •Writing answers to the questions will be particularly difficult for students with limited English proficiency. Encourage oral discussion.
Extra Support • The Knowledge Network, PBS, the Discovery Channel, and the Learning Channel often show undersea exploration documentaries. Ask students to scan the television listings while studying this section. •For students who need additional support with the reading in this section, use SM 9.1 Exploring the Deep.
Extra Challenge •Have students use the Internet to research a career related to water (e.g., oceanographer, meteorologist, diver). In their reports and/or presentations, encourage them to include information such as educational requirements, conditions of work, prospects for employment, and pay.
ASSESSMENT FOR LEARNING
What To Look For in Student Work Suggestions for Teaching Students Who Are Having Difficulty Evidence that students can Students who have organizational difficulties may need time-management • describe the technologies that are used to strategies to help them complete the Check Your Understanding questions on explore the ocean below the surface, at the time. surface, and from above Some students may need written guidelines to remind them how to research a • use technical language (scuba) topic.
594 Unit C: Water Systems on Earth NEL 9.2 Oil: Wealth from the Ocean Floor Page 255
PRESCRIBED LEARNING OUTCOMES Time • describe how water and ice shape the landscape 30–45 min • explain variations in productivity and species distribution in marine environments Key Ideas Human use of natural KNOWLEDGE resources affects water •productivity and species distribution in aquatic environments systems. • diversity of aquatic life forms Program Resources BLM 9.2-1 Oil from the Ocean SKILLS AND ATTITUDES Floor—Benefits and Costs •use the Internet for research SM 9.2 Oil: Wealth from the Ocean Floor • use given criteria for evaluating evidence and sources of information BLM 0.0-22 Becoming Test (e.g., identify supporting or refuting information and bias) Wise •relate cause to effect Nelson Science Probe 8 Web site • assess human impact www.science.nelson.com • show respect and sensitivity for the environment
ICT OUTCOMES • demonstrate the ability to formulate questions and to use a variety of sources and tools to access, capture, and store information •use a variety of information technology tools to solve problems •apply predetermined search criteria to locate, retrieve, and evaluate information •create electronic text documents •evaluate information retrieved electronically for authenticity, bias, and timeliness • synthesize information from a variety of electronic sources for presentations •use a variety of software to present messages
SCIENCE BACKGROUND
• Drilling for oil, either on land or at securely anchored. In the Hibernia oil sea, follows the same basic field off the coast of Newfoundland, Related Resources procedure. First, geologists locate the platforms are equipped with the likely rock formations. Then test latest technology to detach and MacQuitty, Miranda, and wells are drilled, using a drill with reattach the shaft to the wellhead Frank Greenaway. Ocean three rotary “bits” on the end of a (the top of the well, where the shaft (Eyewitness Books). long shaft. When oil is reached, it enters the ocean floor). Oil is Toronto: Stoddart, 1995. usually flows up the shaft to the brought to the shore by tanker or surface because it is under pressure. through pipes. Oil often contains natural gas, which •Refineries separate crude petroleum is burned off (in a process called into various products, such as fuel oil flaring) at many oil wells. and natural gas for heating, gasoline, •Oil platforms at sea either sit firmly jet fuels, lubricating oils for on legs that are embedded in the machinery, greases, plastics, and ocean floor or float on rafts that are polyesters.
NEL Chapter 9 Water and Our World 595 •We usually think of oil spills as soak it up with a variety of materials, disasters that involve huge oil break it up with chemicals, and tankers spilling their contents into attack it with oil-eating bacteria. the oceans. Only one-third of the oil Unfortunately, no method is 100 % spills are accidental, however. Some effective. oil is deliberately discharged when •The Gulf of Alaska, where the Exxon tankers and other ships are cleaned, Valdez accident occurred, looks clean and some comes from land-based today. Scientists know, however, that polluters. oil still lies on the ocean floor and •To clean up oil spills, people have under the sand on the beaches. tried to scoop the oil off the water,
TEACHING NOTES
1 Getting Started
• Check for Misconceptions – Identify: Students may think that all oils are petroleum products. – Clarify: Remind students that not everything labelled “oil” is a petroleum product. Petroleum oils include motor oils and other industrial oils, such as hydraulic and brake fluids. Petroleum products include most plastics—in cars, homes, toys, computers, and clothing. However, many common oils, such as vegetable oil, canola oil, peanut oil, linseed oil, and cod liver oil, come from plants or animals – Ask What They Think Now: Ask students if they are familiar with non-petroleum oils. •Introduce this section by revisiting the term fossil fuel, focusing on oil. Explain how an oil deposit forms.
2 Guide the Learning •Use a map to locate Oil Springs and Petrolia, Ontario. Why is oil found there? Encourage students to make some inferences (e.g., Petrolia might be located near the shoreline of an ancient inland sea). •Have students complete BLM 9.2-1 Oil from the Ocean Floor— Benefits and Costs. They may find the section Researching in Reading for Information in the Skills Handbook helpful. •Discuss the implications of an oil spill to the environment, the economy of an area, the oil company, the company that owns the tanker, the personnel in charge of the tanker, and the clean-up crew. •Ask students to recall, or quickly review, Awesome Science: Nature’s Oil Recyclers (page 48). Discuss how this technology is relevant to the extraction of oil from the ocean floor.
596 Unit C: Water Systems on Earth NEL •Use Reading and Thinking Strategies: Offer Opinions with students. •For students who need additional support with the reading in this section, use SM 9.2 Oil: Wealth from the Ocean Floor.
3 Consolidate and Extend •Collect, or ask students to collect, a variety of photographs of offshore oil fields and oil spills, maps of offshore oil-production locations, and other related visual materials. These could be part of a bulletin-board display. •Ask, Should British Columbia lift the moratorium on offshore oil exploration? Review benefits and costs, as noted above. Unfortunately, oil spills continue to be a threat to the aquatic environment. The significance of the effects of the grounding of the Exxon Valdez in 1989 remains a controversial topic between industries and government scientists. The controversy reflects the problems associated with the timely and quantitative determination of the effects, as well as socio-economic values and concerns. Possible offshore oil and gas exploration along the coast of British Columbia is once again being debated, with the same level of concern for the well-being of aquatic resources that was expressed during the public review in 1985. • Assign the Check Your Understanding questions.
CHECK YOUR UNDERSTANDING—SUGGESTED ANSWERS At Home Have students conduct a 1. Geologists locate likely oil-bearing rock formations. ➔ Test wells are drilled. ➔ mini-experiment at home Results are analyzed to determine if the quantity and quality of the oil is good to see what happens to oil enough for commercial production. ➔ An oil rig is moved into place. ➔ A when it spills into the sea production well is drilled. or ocean. They could pour some vegetable oil into an 2. Students’ posters will vary. Possible effects will most likely be effects on the aquarium partially filled environment, effects on wildlife (e.g., birds and marine life, such as mammals, with water, and observe it invertebrates, fish, and whales), and socio-economic effects. daily for a few days or 3. Human error is the most likely cause of oil spills, whatever the source (e.g., weeks. spills when tankers run aground, spills when tankers are loaded or unloaded, oil released when tanks are cleaned, or oil leaks from sunken ships). 4. Not all oil floats on water. Heavy crude oil can form “balls” that sink to the bottom of the ocean and/or are washed up on the beach. As the oil on the surface breaks down, the resulting products can sink to the bottom. 5. Extraction means the process of removing oil from the ocean floor, which involves drilling, followed by pumping into pipelines or tankers. Transportation is the process of moving oil from a drilling site to consumers, usually by oil tankers or pipelines.
NEL Chapter 9 Water and Our World 597 Reading and Thinking Strategies: Offer Opinions
During production, the natural gas found in pockets above the •Brainstorm with students to discover how they think oil liquid oil may be burned off, piped to shore through pipelines, or loaded into an oil tanker for transportation to refineries. spills can affect marine and coastal ecosystems. List Some platforms are stationary, fixed permanently to the ocean floor. Figure 3 shows the Hibernia platform, which sits on the ocean floor. their ideas on the board. Floating platforms are moored securely but can be moved if, for example, there is an approaching iceberg or severe storm. Another type of • Have students read Oil Spills, and ask what new production platform is the Floating Production Storage Offloading vessel, or FPSO vessel. information they have learned. Have them check the list on the board to see if their ideas have been confirmed by their reading.
Figure 3 • Arrange students in small groups to discuss and The Hibernia oil platform is located on the Grand Banks, off the coast of Newfoundland and Labrador. offer opinions about oil spills. To guide their Oil Spills discussions, suggest questions such as these: Oil extraction comes with risks to the environment. The most common risk to the environment is oil spills. Over the past 30 years, – Should offshore oil drilling be allowed? most of the oil spilled into the oceans has been from tanker accidents—groundings, hull failures, and collisions. – What should be done to prevent oil spills? Following a spill (Figure 4) from either extraction or transportation, some oil settles on the ocean bottom, some evaporates, and some is – Who should be responsible for cleaning up oil spills? dispersed by the sea. A large portion, however, washes onto the nearby coast. Clean-up can last for months or years as waves continue to deposit oil clumps on the shore. – What can an ordinary person do about oil spills?
Figure 4 Because oil is less dense than water, most of an oil spill floats on the surface of the ocean and eventually washes up on the shore.
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Strategies for Success Taking Tests •Students need to know how to answer different kinds of test questions such as multiple choice, modified true/false, fill in the blank, matching, and short answer. Help students by using BLM 0.0-22 Becoming Test Wise. Suggest to students that, when a test is returned, they shouldn't just stick it in their binder or locker. They could try the ATA (After Test Audit) strategy: figuring out why errors were made and finding out the answers to missed questions.
Meeting Individual Needs ESL •Provide several photographs of oil exploration, drilling platforms, etc.
Extra Support •For students who need additional support with the reading in this section, use SM 9.2 Oil: Wealth from the Ocean Floor.
Extra Challenge •Have students use the Internet to research an issue related to oil extraction from the ocean. Have them identify and record what, if any, bias is evident in their sources of information. Discuss with them how bias may affect the reliability of the information they obtained.
ASSESSMENT FOR LEARNING
What To Look For in Student Work Suggestions for Teaching Students Who Are Having Difficulty Evidence that students can This section can be read aloud to assist students with weak reading skills. • explain how the extraction of resources Focus on the figures in the student book to enhance students’ understanding of from the ocean floor can affect water the concepts. Relate the figures to the text during the class discussion. systems Demonstrate how oil behaves in water at different temperatures.
598 Unit C: Water Systems on Earth NEL 9.3 Inquiry Investigation: An Oil Spill Simulation Page 258
PRESCRIBED LEARNING OUTCOMES Time • explain the significance of salinity and temperature in the world’s 45–60 min oceans • demonstrate safe procedures Key Ideas • perform experiments using the scientific method Human use of natural resources affects water • demonstrate ethical, responsible, cooperative behaviour systems.
KNOWLEDGE Skills and Processes •properties of salt water and fresh water Predicting • effect of ocean currents and winds on regional climates Conducting Recording Analyzing SKILLS AND ATTITUDES Evaluating •use the Internet for research Communicating • use given criteria for evaluating evidence and sources of information Lesson Materials (e.g., identify supporting or refuting information and bias) per student •relate cause to effect • apron • assess human impact • safety goggles • show respect and sensitivity for the environment per group • 28 cm 19 cm 4 cm clear glass baking dish ICT OUTCOMES • water • demonstrate the ability to formulate questions and to use a variety of •blue food colouring • 180 mL vegetable oil sources and tools to access, capture, and store information • 120 mL pure cocoa powder •use a variety of information technology tools to solve problems •5 mL table salt •apply predetermined search criteria to locate, retrieve, and evaluate •5 craft sticks • beaker or measuring cup information • absorbent materials (e.g., •create electronic text documents paper towel, cotton balls, old rag, sponges, peat • synthesize information from a variety of electronic sources for moss, kitty litter) presentations •5 mL liquid dish detergent •use a variety of software to present messages •tweezers or tongs • stopwatch • demonstrate the ability to arrange information in different forms to • bird feathers (available at a create new meaning pet or craft store) Program Resources SCIENCE BACKGROUND BLM 9.3-1 Inquiry Investigation: An Oil Spill •The most frequently found items in •The amount of spilled oil from the Simulation beach clean-ups are pieces of plastic, Exxon Valdez was 38 800 t (metric BLM 0.0-8 Five-Column Table plastic foam, plastic utensils, pieces tonnes). This amount of oil can fill Investigation Rubric 5: Inquiry of glass, and cigarette butts. about 125 Olympic-sized swimming Investigation • Air pollution is responsible for almost pools. The Exxon Valdez was Investigation Rubric 6: Inquiry one-third of the toxic contaminants repaired and renamed the Sea River Investigation— and nutrients that enter water bodies. Mediterranean. It is used now to Self-Assessment •Within 30 years, a billion more haul oil across the Atlantic. It is Science Skills and Processes Rubric 5: Predicting people will be living along the coasts prohibited by law from returning to Science Skills and Processes than there are today. Prince William Sound. Rubric 6: Predicting— Self-Assessment Science Skills and Processes Rubric 9: Conducting (Continued)
NEL Chapter 9 Water and Our World 599 Program Resources INVESTIGATION NOTES (Continued) Science Skills and Processes Student Safety Rubric 10: Conducting— Have students wear safety goggles and an apron during this Self-Assessment Science Skills and Processes investigation. Remind students that food colouring can stain their Rubric 11: Recording skin and clothing. Science Skills and Processes Rubric 12: Recording— Self-Assessment •You may want to hand out BLM 9.3-1 Inquiry Investigation: An Oil Science Skills and Processes Rubric 13: Analyzing Spill Simulation for students to record their work. Science Skills and Processes •To assess students, you may want to use or adapt Investigation Rubric 14: Analyzing— Self-Assessment Rubric 5: Inquiry Investigation and/or Investigation Rubric 6: Inquiry Science Skills and Processes Investigation—Self-Assessment. Rubric 15: Evaluating Science Skills and Processes Question Rubric 16: Evaluating— Self-Assessment •In this investigation, students simulate oil spills in fresh water and salt Science Skills and Processes Rubric 17: Communicating water to determine if they behave differently. Science Skills and Processes •Investigating question (ii) will help students understand why cleaning Rubric 18: Communicating— up an oil spill is such a difficult task. Self-Assessment Nelson Science Probe 8 Prediction Web site www.science.nelson.com (a) Students’ predictions will vary, based on their prior knowledge. Sample predictions follow: (i) Yes, oil spills behave differently in fresh water and salt water. Oil floats more easily on salt water because salt water is denser than Related Resources fresh water. Benchley, Peter, and Judith (ii) Gradwohl. Ocean Planet: Oil spills are extremely difficult to clean up. For example, only Writings and Images of 14 % of the oil spilled by the Exxon Valdez was recovered. the Sea. New York: Harry N. Abrams Inc. 1995. Experimental Design •Decide whether students will work in pairs or groups, or on their own. •Begin by reading the Experimental Design with students. •Address any questions about the Investigation and/or Procedure. Post the useful questions, with answers, on chart paper. •Students should measure and record everything they can think of. •Suggest that students make two data tables (one for fresh water and one for salt water) similar to Table 1 on page 259. You can hand out copies of BLM 0.0-8 Five-Column Table for students to use. • Let students decide how they will report their findings. Students’ conclusions should be supported by their data. If different groups have different conclusions, you can use these conclusions as the basis of a class discussion about experimental error and the need to repeat investigations.
600 Unit C: Water Systems on Earth NEL Procedure •Have students record their observations in their data tables. •Remind students to set specific times to record their observations (e.g., every 5 min). Making observations at specific, regular intervals is important when investigating the rate at which something is happening. •Ask several students to explain why they chose their particular solution.
Analysis—Suggested Answers (c) Oil tends to sit on top of water because it is less dense, thus making it easier to contain. (d) Students can use a variety of absorbent materials to clean up the oil. Because this is a simulation, the materials used may or may not be feasible for an actual spill. Students can experiment with paper towels, newspapers, wool, sawdust, and even cattail fluff, as well as the items mentioned in the Materials list. (e) Floatation depends on the relative densities of two substances. A substance with a lower density will float on a substance with a higher density. The density of crude oil is 0.86 to 0.88 g/mL. Salt water has a density of 1.03 g/mL, and fresh water has a density of 1.00 g/mL. Therefore, crude oil floats on both fresh water and salt water. (f) Students’ answers will vary. Most students will probably find little difference in how the absorbent materials worked in fresh water and salt water. (g) Yes, the absorbent materials pick up water. They get soggy and break down. (h) Oil-covered feathers lose their insulating ability, so birds may die from hypothermia. Also, birds ingest the oil when they preen their feathers.
Evaluation—Suggested Answers (i) Detergent binds the oil molecules so they can mix better with water. Students can try this at home when washing greasy dishes. (j) For a small amount of oil, detergent is effective to disperse it. If a large tanker had a spill, however, detergent would spread the oil farther, affecting a larger area. (k) A real oil spill would not be contained, but it would spread over a much larger area. The simulation does not take into account the conditions of the oceans (i.e., winds, waves, currents, tides). The type of oil used in the simulation does not have the same physical characteristics as crude oil. Crude oil would likely be much more difficult to deal with. Also, the amount of oil in the simulation does not realistically represent a real oil spill. Using real crude oil, and adding waves, currents, and wind, would make the simulation more realistic.
NEL Chapter 9 Water and Our World 601 Strategies for Success Taking Tests •Suggest to students, if they get “butterflies” in their stomachs before a big test, that they try talking to themselves in a positive manner. When students first get their test, they should do the following: look over the entire test to become familiar with the types of questions asked; budget time to allow for completion; read directions twice and circle key words; answer known questions first and unknown second; and check all answers. • Conclude by asking students what they think they should do when they get stuck on one particular question.
Meeting Individual Needs ESL •If possible, allow students to take home the student book or a handout describing the Experimental Design. •Encourage students to write labels on drawings and simple descriptions in their first languages, as well as in English.
Extra Support •Use a video camera for students to record their findings. For added interest, students can report in documentary or news reporting style.
Extra Challenge •Have students design and conduct experiments to investigate the effects of different types and concentrations of detergents on a stationary oil spill in fresh and/or salt water. Encourage students to develop a method for quantifying their results and for predicting the outcomes with different concentrations (e.g., using computer-generated graphs). As a follow-up, have students discuss the pros and cons of using detergents to help clean up oil spills and the limitations on applying their experimental results in open-water situations.
ASSESSMENT FOR LEARNING
What To Look For in Student Work Suggestions for Teaching Students Who Are Having Difficulty Evidence that students can Students who have difficulty writing can use a combination of diagrams, labels, •identify the difficulties in cleaning up an oil and point-form descriptions when developing and describing their experimental spill designs. • handle chemicals and equipment safely and Some students may need help developing appropriate charts for recording data. responsibly (e.g., handle glassware safely) • analyze and interpret observations Extra time may be needed. • evaluate the evidence obtained during the investigation • evaluate the scientific process used to obtain the evidence •display data in tables
602 Unit C: Water Systems on Earth NEL 9.4 Biodiversity Page 261
PRESCRIBED LEARNING OUTCOMES Time • explain variations in productivity and species distribution in marine 60–75 min environments Key Ideas KNOWLEDGE Saltwater or marine •productivity and species distribution in aquatic environments ecosystems are home to a variety of organisms that • water quality problems require proper conditions to • diversity of aquatic life forms survive and reproduce. Vocabulary SKILLS AND ATTITUDES •use the Internet for research • biodiversity • use given criteria for evaluating evidence and sources of information Program Resources (e.g., identify supporting or refuting information and bias) SM 9.4 Biodiversity •relate cause to effect BLM 9.4-1 Diversity: Field Trip • assess human impact Investigation BLM 0.0-23 Create a • show respect and sensitivity for the environment Study–Test Plan Nelson Science Probe 8 ICT OUTCOMES Web site • demonstrate the ability to formulate questions and to use a variety of www.science.nelson.com sources and tools to access, capture, and store information •apply predetermined search criteria to locate, retrieve, and evaluate information •create electronic text documents • synthesize information from a variety of electronic sources for presentations •use a variety of software to present messages
SCIENCE BACKGROUND
•Biological diversity is a measure of •A habitat is the place where a the number of different species in a specific organism lives. Each given ecosystem. The more diverse organism is adapted to the particular an ecosystem is, the more stable it physical conditions of its habitat. For is. example, a duck’s habitat is the • Some ecosystems, such as arctic water and shoreline, and its and human-created monocultures adaptations include webbed feet and Related Resources (crop fields), have low diversity. If waterproof feathers. A water lily’s MacQuitty, Miranda, and one species is removed, the habitat is shallow water, and its Frank Greenaway. Ocean ecosystem may be disrupted more adaptations include long stems and (Eyewitness Books). than ecosystems with high diversity the ability of its roots to cope with Toronto: Stoddart, 1995. would be. waterlogged soil. Parker, Steve, and Philip • Ecology is the study of relationships • An organism’s role in a community, Dowell. Pond and River among organisms (biotic component) called its niche, includes how and (Eyewitness Books). and between organisms and their what it eats, what eats it, and its Toronto: Stoddart, 1998. physical surroundings (abiotic interactions with other organisms. component). For example, a duck’s niche includes Pernetta, John (ed). The •An ecosystem, which is a eating water plants, becoming prey Rand McNally Atlas of community of living things in their to foxes and falcons, providing a the Oceans.New York: environment, may be as small as a niche for parasites, and defecating Rand McNally & Co., tidal pool or as large as an ocean. food for decomposers. A water lily’s 1994.
NEL Chapter 9 Water and Our World 603 niche includes obtaining enough •The first level of a food web is carbon dioxide for photosynthesis occupied by plants and other and other nutrients for growth, and producers, which are called being eaten by ducks and other autotrophs because they produce aquatic animals. If two species share their own food. Higher trophic levels a niche, they are competing for include consumers or heterotrophs, resources. organisms that must consume other •Food chains and food webs illustrate organisms for food. The second level the transfer of energy through an always contains herbivores (plant ecosystem. In almost all ecosystems, eaters), while carnivores (meat the source of energy is the Sun. Each eaters) are at higher levels. step in a food chain is called a trophic Decomposers or scavengers feed on (feeding) level. A food web consists dead matter, feces, and feathers and of several interconnected food skin shed by other organisms. chains.
TEACHING NOTES
1 Getting Started
• Check for Misconceptions – Identify: Students may think that if one species dies, everything that feeds on it will also die. – Clarify: Explain to students that this assumes the dependent species has no other food source and/or is unable to adapt. Although such total dependency is possible in a monoculture, it rarely happens. While all species are affected by the extinction of another, they are unlikely to die off completely. – Ask What They Think Now: Ask students what would happen to the deer population if one species of tree disappeared. (Deer would eat other species.) •Introduce Section 9.4 by addressing the main concepts first: biodiversity and ecosystems.
2 Guide the Learning •Develop a diagram on the board to illustrate an ecosystem. Start with a triangle that has producers, consumers, and abiotic factors at the points. • Connect the three points with arrows in both directions, labelled with words such as consumption, decomposition, and respiration. Show that carbon dioxide, oxygen, and water move in and out, and that radiant energy from the Sun drives the system. •Review the definitions of food chain and food web, and note the difference between the two. •Use Reading and Thinking Strategies: Pause and Think. •Discuss the meaning of the term biodiversity. •The student book describes a variety of aquatic ecosystems. Students can organize this information using a comparison chart with the
604 Unit C: Water Systems on Earth NEL following headings: Ecosystem, Location, Abiotic Factors, Producers, At Home Consumers, and Special features. Some students enjoy •For students who need additional support with the reading in this exploring shallow marshes or streams. Encourage section, use SM 9.4 Biodiversity. them to take photographs of the plants and animals 3 Consolidate and Extend they see and show their photographs to the class. • Ask students to work in small groups and choose two ecosystems Remind them to be careful that may be dependent on each other. Have students draw a diagram around bodies of water. that illustrates the connections. Students can add labels, arrows, and pictures, and then present their diagram to the class. •Additional pictures of the different ecosystems would enhance Te c hnology Connections Use CD-ROM student understanding. encyclopedias to research • As you discuss each ecosystem, clarify the terms that are unique to food webs for question 2 in Check Your each (e.g., phytoplankton, abyss). Draw attention to the factors that Understanding. make it an ecosystem (both biotic and abiotic factors), and identify the energy source and energy output. •Plan a field trip to a tidal pool (e.g., Second Beach, Stanley Park). Suggest that students explore tidal pools and dig into the sand after the tide has gone out. Students can record their observations on BLM 9.4-1 Diversity: Field Trip Investigation. • Assign the Check Your Understanding questions.
CHECK YOUR UNDERSTANDING—SUGGESTED ANSWERS
1. Biodiversity is a measure of the number of species in an ecosystem. 2. Producers are the only organisms that can make their own food, using energy from the Sun. All other organisms must eat producers, eat other organisms that eat producers, or eat dead matter or waste products from other organisms. 3. The deeper you go in an ocean, the fewer producers there are because of the reduced (or absence of) sunlight. Fewer producers and producer species means a reduced number of different consumers that can feed on them. Fewer types of organisms means less biodiversity. 4. Organisms in the deepest parts of lakes and oceans consume other consumers, dead organisms (both producers and consumers) that sink to the bottom, or waste materials from organisms above. All consumed organisms can be traced back through a food chain to producers. There are a few producers in the deep ocean, however. Chemosynthesis is a process by which specific types of bacteria survive by using inorganic chemicals, such as sulfates and ammonia, for their energy. These bacteria have been found in and around geothermal vents on the ocean floor.
NEL Chapter 9 Water and Our World 605 Reading and Thinking Strategies: Pause and Think •Read the title of the section and the first three Biodiversity 9.4 paragraphs with students, ensuring that they understand what biodiversity is. As you walk along the seashore, you see pools of water captured in rocky hollows after the tide has fallen. These tide pools are temporary •Arrange students in pairs to read the rest of the section homes for a host of marine organisms. Algae or seaweed have become established in these tide pools because there is always water in them. using the pause-and-think strategy. For example, for Periwinkles, crabs, and isopods hide among the seaweed. Starfish and sea urchins creep slowly on suctioned feet over the bottom of the pool Biodiversity in Marine Ecosystems, suggest that and feed on the algae. Barnacles and mussels cling to the exposed rocks, their shells closed tightly, and wait for the tide to return. students pause after each paragraph and take turns A tide pool is a miniature ecosystem. It is a glimpse into the life of some of the many organisms of an ocean ecosystem. This daily life is a struggle for survival against predators and other hazards of the marine explaining to each other, in their own words, what they environment, and a complex network of interactions between the various organisms. have read. Encourage students to look at the many There are a number of different marine ecosystems, each with its own variety of organisms that live there. The measure of the number photographs in the section to help them understand of different types of organisms in an area is known as biodiversity. Some marine ecosystems have a greater biodiversity than others. This what they read. section will examine some of the marine ecosystems and the diversity of organisms that live in each. •Conclude by bringing students together and asking Biodiversity in Marine Ecosystems them to share the most surprising fact they read with There are many different types of marine or saltwater ecosystems, such as continental shelves, estuaries, marshes, and the abyssal plain. The the class. oceans are home to the majority of living things on Earth. Figure 1 (on the next page) shows the Pacific Ocean ecosystem and a very small sample of the many organisms that live within it. Canada’s Atlantic and Pacific coasts have two very different marine ecosystems. The Atlantic coast has an extensive continental shelf, which includes the Grand Banks, one of the world’s richest fishing grounds. The Pacific coast has, in contrast, a smaller continental shelf that drops off quite quickly to the abyssal plain. The Pacific Ocean is an average of 4 °C to 5 °C cooler than the Atlantic Ocean as a result of the different ocean currents. The water over the Grand Banks off the coast of Newfoundland and Labrador is warmed by the Gulf Stream, a warm current that flows up from the tropical regions.
NEL 9.4 Biodiversity 261
Strategies for Success Taking Tests • “I’m going to stay up all night until I get this!” Ask students if this sounds familiar. Suggest to students that a more effective use of study time and efforts is to create a test-study game plan. One such method can be found in BLM 0.0-23 Create a Study–Test Plan. Ask students why it is important to develop good study habits.
Meeting Individual Needs Extra Support •For students who need additional support with the reading in this section, use SM 9.4 Biodiversity.
Extra Challenge •Ask students to design and perform an experiment to investigate the effects of acid rain, thermal pollution, and/or dirty water on an aquatic ecosystem, such as a pond, lake, or stream. Invite students to research and report on how energy is transferred through an aquatic ecosystem. •Have students research and create posters of marine diversity at different ocean levels or in different oceans.
ASSESSMENT FOR LEARNING
What To Look For in Student Work Suggestions for Teaching Students Who Are Having Difficulty Evidence that students can Ask students to work with a partner when making notes and answering the • define biodiversity Check your Understanding questions. • explain why biodiversity is important in Allow students who have difficulty writing answers to use point form (including marine ecosystems key vocabulary) or, where appropriate, drawings to illustrate the concepts. •use technical language (biodiversity)
606 Unit C: Water Systems on Earth NEL 9.5 Inquiry Investigation: Productivity of Organisms Page 267
PRESCRIBED LEARNING OUTCOMES Time • explain the significance of salinity and temperature in the world’s 30–45 min oceans • explain variations in productivity and species distribution in marine Key Ideas environments Saltwater or marine ecosystems are home to a • demonstrate safe procedures variety of organisms that • perform experiments using the scientific method require proper conditions to • demonstrate ethical, responsible, cooperative behaviour survive and reproduce. Vocabulary KNOWLEDGE • productivity •properties of salt water and fresh water •productivity and species distribution in aquatic environments Skills and Processes • water quality problems Hypothesizing • diversity of aquatic life forms Predicting Conducting Recording SKILLS AND ATTITUDES Analyzing •use the Internet for research Evaluating • use given criteria for evaluating evidence and sources of information Communicating (e.g., identify supporting or refuting information and bias) Lesson Materials •relate cause to effect per student • assess human impact • apron • show respect and sensitivity for the environment • safety goggles per group • 10 large test tubes ICT OUTCOMES • labels • demonstrate the ability to formulate questions and to use a variety of • test-tube stand sources and tools to access, capture, and store information •graduated cylinder • medicine dropper •use a variety of information technology tools to solve problems per station •apply predetermined search criteria to locate, retrieve, and evaluate • water • liquid plant fertilizer information solution •create electronic text documents • phosphate solution • synthesize information from a variety of electronic sources for •algae suspension presentations Program Resources •use a variety of software to present messages BLM 9.5-1 Inquiry Investigation: Productivity SCIENCE BACKGROUND of Organisms Investigation Rubric 5: Inquiry • Organisms in any aquatic ecosystem (chemicals such as phosphates and Investigation Investigation Rubric 6: Inquiry depend on several factors. The most nitrates that are needed to make the Investigation— important of these factors is various molecules in organisms) Self-Assessment sunlight. must also be present. Science Skills and Processes • Plants and algae (and some bacteria) •Runoff carries dissolved salts from Rubric 3: Hypothesizing require sunlight to perform organic materials and eroded rocks Science Skills and Processes photosynthesis—the chemical into bodies of water. Gases such as Rubric 4: Hypothesizing— reaction that converts carbon dioxide carbon dioxide and oxygen Self-Assessment and water into sugar and oxygen. constantly dissolve in the water. Science Skills and Processes • Photosynthesis alone is not enough Oxygen is given off by plants, and Rubric 5: Predicting for growth, however. Nutrients carbon dioxide is given off by both (Continued)
NEL Chapter 9 Water and Our World 607 Program Resources (Continued) animals and plants. These nutrients lower down) and reduce wave action and gases enrich the water, allowing (reducing the amount of oxygen Science Skills and Processes the plants and algae to flourish. The dissolving from the air). When the Rubric 6: Predicting— plants and algae are eaten by algae die, decomposers feed on Self-Assessment microscopic animals, which are then them and use up any remaining Science Skills and Processes eaten by larger animals. oxygen. A prolonged algal bloom can Rubric 9: Conducting • Phosphate (–PO ) is found in asphyxiate the fish in a body of Science Skills and Processes 4 molecules such as DNA and water because of the diminishing Rubric 10: Conducting— high-energy compounds and is oxygen level in water. Self-Assessment Science Skills and Processes essential for the metabolism of all •Agricultural fertilizers, animal waste, Rubric 11: Recording organisms. With too little phosphate and detergents from untreated Science Skills and Processes in an aquatic ecosystem, plant sewage contribute large amounts of Rubric 12: Recording— growth and reproduction slow. With phosphate to bodies of water. In Self-Assessment too much phosphate, the ecosystem North America, anti-pollution Science Skills and Processes becomes overpopulated with legislation now restricts the use of Rubric 13: Analyzing organisms, particularly algae. These phosphate in cleaning products and Science Skills and Processes “algal blooms” make the water less curtails some polluting farm Rubric 14: Analyzing— transparent (blocking light to plants practices. Self-Assessment Science Skills and Processes Rubric 15: Evaluating Science Skills and Processes INVESTIGATION NOTES Rubric 16: Evaluating— Self-Assessment Student Safety Science Skills and Processes Rubric 17: Communicating Have students wear safety goggles and an apron during this Science Skills and Processes investigation. Remind students that fertilizer and phosphate Rubric 18: Communicating— solutions are irritants and are toxic. Caution students to handle Self-Assessment materials with care and wash their hands well afterward. Nelson Science Probe 8 Web site www.science.nelson.com •Prepare the algae suspension and the fertilizer and phosphate solutions before the investigation. •Make the fertilizer solution from a commercial houseplant fertilizer. Since students will add this to water, you may wish to make it double strength. Phosphate solutions and algae may be purchased from science-supply retailers. •A suspension of single-celled algae is recommended for this experiment. The amount used for each test tube can be controlled reasonably well by agitating the suspension and adding an equal number of drops to each test tube. •Read the Procedure aloud to students to ensure that they understand what is required. The Investigation could be done as a class investigation by recording class data on a large chart. Although this is less likely to encourage student creativity, it provides a greater range of fertilizer and phosphate concentrations for comparison. •For quantitative observations, ask students to draw a light horizontal line on a small piece of white paper. As they look through the front of the test tube, they hold the paper against the back. They gradually move the paper away from the test tube until they can no longer see the line and record the distance from test tube to paper. As the number of algae increases, this distance decreases. (Remind students to use the same piece of paper each time!) Cards with several lines of varying darknesses are commercially available for this purpose.
608 Unit C: Water Systems on Earth NEL •Have a container available for discarding solutions at the end of the investigation. •You may want to hand out BLM 9.5-1 Inquiry Investigation: Productivity of Organisms for students to record their work. •Refer students to Conducting an Investigation (specifically, the sections Predicting and Hypothesizing), Designing Your Own Investigation, and Creating Data Tables in the Skills Handbook. •To assess students, you may want to use or adapt Investigation Rubric 5: Inquiry Investigation and/or Investigation Rubric 6: Inquiry Investigation—Self-Assessment.
Prediction (a) Students’ predictions will vary. The most likely prediction is that algae production will (or will not) increase with added phosphate or fertilizer.
Experimental Design (b) Students need to design an observation table in which they can record their observations for each test tube, as well as the amounts of materials used. You may need to help students create their observation tables. One possible table is shown here: At Home Plant fertilizer is a Date A1 A2 A3 A4 A5 commercial product. Many people have “home Jan. 5 added 0 added 2 added 4 added 8 added 16 remedies” to help their began drops drops drops drops drops plants grow and do not experiment; fertilizer fertilizer fertilizer fertilizer fertilizer use commercial fertilizers. all tubes Students could survey slightly older family members to green determine other materials Jan. 6 no change no change no change slightly slightly that can be used as greener greener fertilizers. Could any of these materials harm local Jan. 7 water systems? Ask students to predict the etc. effects on algae growth if such materials are added to Procedure a body of water. •Observations will differ, depending on the concentrations of the solutions and the amounts of algae used. Students will generally notice, however, that some of their water samples will become greener or more translucent as time passes, indicating increased algae populations. •If students use a wide range of drops (e.g., 0 to 50, 0 to 100) in each set of test tubes, one sample may result in the greatest growth between end points. This will represent the optimum growing conditions. If students use a smaller range of drops, the algae will grow best in the
NEL Chapter 9 Water and Our World 609 sample with the most fertilizer, but they may not have created the Te c hnology Connections Students could use a optimum growing conditions. word-processing or •Students’ observations for phosphate will tend to mirror their spreadsheet program to design a data table for observations for fertilizer, since phosphate is a major component of recording observations. most commercial fertilizers. They could use a spreadsheet program, Analysis—Suggested Answers graphing software, or a graphing calculator to (c) Students’ answers will vary because of the individual nature of the construct graphs of algae experiment (see previous page). The critical issue is whether students’ growth versus the amount answers are supported by their observations (i.e., their evidence). of fertilizer or phosphate added. (d) A control is the part of an experimental set-up that contains none of the manipulated variable or that exists under the most “natural” conditions. Some students may say that they did not use a control in the B set of test tubes. Other students may recognize, however, that their control for the A set (A1) is also their control for the B set, since no fertilizer or phosphate solution was added to A1. (e) Students should see that both fertilizer and phosphate enhanced algae growth. They may speculate (and could confirm) that fertilizer contains phosphate.
Evaluation—Suggested Answers (f) Answers will vary depending on what the students originally predicted. (g) Because algae production increased, the students will be able to say that the phosphate was a source of nutrients for the algae. A possible hypothesis might be the following: If you add fertilizer to an aquatic environment, then algae growth will increase.
Meeting Individual Needs ESL •Students would benefit from working with a bilingual student or parent volunteer. •You may want to have some general instructions translated into several languages and available on a handout for students with limited English. For example: –Draw a picture to show how you will use the materials. – Label the picture in your own language and in English. Use your dictionary to help. –Draw a series of small sketches to show what happened in each test tube. Use coloured pencils to shade the test tubes to the same intensity as the algal blooms. –Write a sentence to tell what you observed. Write it first in your own language, and then in English. – Consult your dictionary, family, or friends for help. Have this ready for the next class.
610 Unit C: Water Systems on Earth NEL Extra Support •Students with weak organizational or time management skills may need a strategy to ensure that they complete their daily observations. With these students, plan a time when they will be expected to record their observations.
Extra Challenge •Challenge students to use a microscope to estimate actual numbers of algae in each sample, using the following formula: number of algae per sample (number of algae per drop) (number of drops per mL) (number of mL per sample) •Have students compare the graphed results from several other students and/or groups. Encourage them to compare and analyze the results with particular focus on identifying and attempting to explain discrepancies in results.
ASSESSMENT FOR LEARNING
What To Look For in Student Work Suggestions for Teaching Students Who Are Having Difficulty Evidence that students can Some students may need guidance in deciding how to increase concentrations • assess how fertilizers and phosphates can or make quantitative observations. It may be appropriate for these students to affect the productivity of algae make qualitative observations only. •make a hypothesis and/or prediction to answer a testable question • handle chemicals and equipment safely and responsibly (e.g., handle glassware safely) • analyze and interpret observations •use technical language (productivity) • create products that are complete (e.g., tables)
NEL Chapter 9 Water and Our World 611 9.6 Inquiry Investigation: The Salinity Experiment Page 269
Time PRESCRIBED LEARNING OUTCOMES 75–90 min • explain the significance of salinity and temperature in the world’s oceans • explain variations in productivity and species distribution in marine Key Ideas environments Saltwater or marine • demonstrate safe procedures ecosystems are home to a variety of organisms that • perform experiments using the scientific method require proper conditions to • demonstrate ethical, responsible, cooperative behaviour survive and reproduce. KNOWLEDGE Skills and Processes •properties of salt water and fresh water Questioning Hypothesizing •productivity and species distribution in aquatic environments Predicting • diversity of aquatic life forms Planning Conducting SKILLS AND ATTITUDES Recording Analyzing •use the Internet for research Evaluating • use given criteria for evaluating evidence and sources of information Communicating (e.g., identify supporting or refuting information and bias) Lesson Materials •relate cause to effect per student • assess human impact • apron • show respect and sensitivity for the environment • safety goggles per group ICT OUTCOMES • at least 5 identical containers (e.g., 30 mL test • demonstrate the ability to formulate questions and to use a variety of tubes, 50 mL beakers, sources and tools to access, capture, and store information 100 mL beakers, sterilized baby-food jars) •create electronic text documents • 100 mL graduated cylinder •use a variety of software to present messages • large beaker to dispose of rinse water • demonstrate the ability to arrange information in different forms to •masking tape or labels to create new meaning identify containers • triple-beam or electronic balance • plastic or metal spoon SCIENCE BACKGROUND • approximately 10 g sea salt •microscope • Brine shrimp are invertebrates, a state of suspended metabolism • depression slide closely related to shrimps, crabs, and (diapause). This is an extremely • medicine dropper lobsters. They are found in salty important adaptation because salt • container of distilled water waters worldwide. The most lakes often dry up during droughts. for rinsing medicine common commercial species, When the rains return, the cysts dropper Artemia francescana, comes from absorb water and release the first • plastic wrap to cover Great Salt Lake, Utah, and from San growth stage, called a nauplius larva. containers when mixing Francisco Bay. Brine shrimp live in During this stage (12 h), the larva per station waters with salt content as high as lives off its yolk reserves. Then, it • brine shrimp cysts (dry or in salt water, depending on 25 %. Lakes with a salinity this high moults (sheds its covering) and how students have are called hypersaline. Consequently, emerges as the second nauplius designed the investigation) the shrimp have few predators or stage. During this stage, it feeds on • additional supply of sea competitors, and a lot of food (algae). small algal cells and detritus. Nauplii salt, or beakers of pre-mixed •A brine shrimp begins life as a tiny, moult about 15 times before salt water of different salinities (e.g., 0.5 %, 1.0 %, dormant cyst (an egg-like formation). becoming 10 mm long adults. 1.5 %, 2.0 %, 2.5 %, 3.0 %) The cyst contains a single embryo in
(Continued)
612 Unit C: Water Systems on Earth NEL INVESTIGATION NOTES Program Resources (Continued) Student Safety BLM 9.6-1 Inquiry Ensure that students get your approval before starting their Investigation: The Salinity Experiment investigation. Also ensure that they wear safety goggles and aprons. Investigation Rubric 5: Inquiry Investigation If glassware is broken, use a dustpan and hand broom to clean it up. Investigation Rubric 6: Inquiry Dispose of the glass in a specially marked broken-glass container. Investigation— Vacuum or use a hand broom to remove remaining glass particles. Self-Assessment Science Skills and Processes Remind students to consider laboratory safety when designing their Rubric 1: Questioning Science Skills and Processes investigation. They should include safety reminders in their designs. Rubric 2: Questioning— For example: Tie back long hair. Clean up broken glassware with a Self-Assessment dustpan and hand broom, and discard it in a designated broken- Science Skills and Processes Rubric 3: Hypothesizing glass container. Science Skills and Processes Rubric 4: Hypothesizing— Self-Assessment •Order brine shrimp cysts ahead of time, and read the instructions Science Skills and Processes carefully. Keep the cysts in a refrigerator until needed. The way they Rubric 5: Predicting are packaged will affect how you present the lesson to students. Since Science Skills and Processes Rubric 6: Predicting— cysts are extremely small (some commercial producers estimate Self-Assessment 250 000 cysts per gram), it is impractical to count equal numbers for Science Skills and Processes each container. Rubric 7: Planning Science Skills and Processes •If cysts come packaged separately from the food and salt, students can Rubric 8: Planning— Self-Assessment make their own saline solutions and simply add the required amount Science Skills and Processes of cysts. Note that the saline concentrations suggested in the student Rubric 9: Conducting book are lower than the concentration in the hypersaline lakes Science Skills and Processes Rubric 10: Conducting— mentioned in the Background Information. Read the instructions that Self-Assessment come with the cysts, and then vary the salinity in small stages on Science Skills and Processes either side of the recommended value. Rubric 11: Recording Science Skills and Processes •Alternatively, if cysts come packaged with salt and food, remove the Rubric 12: Recording— salt, replacing enough to make a 0.5 % saline solution (5 g salt/1 L Self-Assessment Science Skills and Processes water). Keeping the cysts mixed with the water, the mixture can then Rubric 13: Analyzing be poured into ten 100 mL graduated cylinders. Students can increase Science Skills and Processes salinity by adding salt to the cylinders. Rubric 14: Analyzing— Self-Assessment •Shake the mixture to keep the cysts well distributed. Students can Science Skills and Processes Rubric 15: Evaluating pour the mixture into their test tubes. Science Skills and Processes •Students must use a procedure that allows them to assume that the Rubric 16: Evaluating— Self-Assessment number of cysts in all the test tubes is roughly equal. (You may want Science Skills and Processes to discuss the role that such assumptions play in investigations, Rubric 17: Communicating particularly biological investigations in which it may be unlawful or Science Skills and Processes Rubric 18: unethical to manipulate all the variables.) Communicating— •Make solutions of approximate salinities by mixing the following Self-Assessment Nelson Science Probe 8 amounts of sea salt with 1 L of water: 0.5 %–5 g; 1 %–10 g; Web site 1.5 %–15 g; and so on. www.science.nelson.com
NEL Chapter 9 Water and Our World 613 •Organize the investigation in advance by establishing work groups, identifying where in the room to find materials, clarifying routines for altering salt concentrations, and identifying safety procedures such as the safe disposal of broken glass. •Refer students to the following sections in the Skills Handbook: Getting Off to a Safe Start, Safe Science, Conducting an Investigation, Researching, and Communicating in Science. •You may wish to hand out BLM 9.6-1 Inquiry Investigation: The Salinity Experiment for students to record their work. •After the brine shrimp hatch, in 18 to 40 h (check the instructions that come with the cysts), additional time (30 min) will be needed for making and recording observations. •If saline solutions are pre-mixed, students will only require triple-beam balances and sea salt to make the solutions that are not provided. •Ensure that students label each container. •Plain glass microscope slides can be used if depression slides are not available. •If stereo microscopes are not available, use dissection microscopes or magnifying glasses that magnify at least 10 . •When counting hatched brine shrimp, discuss the need to take repeat samples (e.g., three) from the water being tested and then average the count. This gives a quantitative basis for comparison, such as “seven shrimp per five drops of water.” •Alternatively, students could place a piece of paper (e.g., loose-leaf paper), with a small hole cut for a “window,” against the test tube. The number of shrimp seen in the window in a certain period of time could give a quantitative reading. A magnifying glass could be used to see the shrimp. •Remind students to turn off the microscope light when not using the microscope. If a slide of shrimp is on the stage, the shrimp may become overheated and die. •Hatched brine shrimp are extremely small, so students may want to let them grow for a day or two before counting. If so, mix the test tubes several times each day. Cover and invert the test tubes to keep the shrimp and the food from settling at the bottom. •Clean a small aquarium or a 4 L jar with salt, not soap, and fill it with an appropriate salt concentration. Students can put their brine shrimp in the aquarium at the end of the experiment. •To assess students, you may want to use or adapt Investigation Rubric 5: Inquiry Investigation and/or Investigation Rubric 6: Inquiry Investigation—Self-Assessment.
614 Unit C: Water Systems on Earth NEL Question At Home (a) Students’ questions will vary, based on their interests. Below are two Students may want to sample questions: raise brine shrimp at •Does the salinity of the water affect the hatch rate of brine shrimp home. Starter kits can be purchased from science cysts? suppliers and some •What is the optimal salinity for hatching brine shrimp cysts? aquarium retailers. Students can search Prediction Internet sites for more information on maintaining (b) Students will need to predict their results based on their original brine shrimp populations. question. For example, suppose that the question is “What is the optimal salinity?” For this question, students could predict that they will get the best hatch rate at 20 g/L salt concentration.
Hypothesis (c) Students’ hypotheses will vary, depending on their question. For example, students might make the following hypothesis: If an organism’s productivity depends on its environment, then there is an optimal salinity for brine shrimp productivity.
Experimental Design (d) Students’ investigations will vary, depending on their hypothesis. •Ensure that students will be able to complete all their steps in the time available. •Ensure that students have controlled all the variables except salinity. •Suggest that students create a data table. Students should measure and record everything they can think of. •Students’ conclusions should be supported by their data. If different groups have different conclusions, you can use these conclusions as the basis of a class discussion about experimental error and the need for repetition when sampling populations. Let students decide how they will report their findings.
Materials (e) The list of materials will depend on what students choose and may vary greatly between groups. See Lesson Materials in the margin chart at the beginning of this section for suggested materials.
Procedure •Ensure that students receive your approval before beginning their investigation. •Ensure that students record any changes they make to their investigation and record all their observations.
NEL Chapter 9 Water and Our World 615 Analysis—Suggested Answers Te c hnology Connections Have students use the (f) Depending on students’ question, the constant variables could be Internet to research brine amount of water, size of test tubes or other containers used, amount shrimp. They could try of light each container received, temperature, and degree of mixing typing in sea monkeys or brine shrimp to begin their for comparison purposes. The set-up suggested by the instructions search. that came with the shrimp cysts would likely be the most natural control. (g) Students’ reports will vary, based on their approach. See the report format in the Skills Handbook.
Evaluation—Suggested Answers (h) Students’ answers will depend on their hypothesis. Remind students that there is no “right answer”. If their observations do not support their hypothesis, students should evaluate to determine if their hypothesis was appropriate or if there was some problem with the evidence they obtained. If their hypothesis was appropriate and their evidence is valid, then they have to reject their hypothesis. (i) Students’ answers will vary, based on their experiences. For example, students may have difficulty counting and/or estimating the populations of brine shrimp. Ensure that students attempt to solve their own difficulties before receiving help from you. Their answers will depend on the conclusions they drew from their investigation and the information they gathered in research.
Meeting Individual Needs ESL •Provide labelled visuals of the materials and equipment to be used. •Students can make a series of pictures to explain steps in their procedure, as well as their observations. These pictures can be labelled in their first language and in English. Encourage students to bring a first language/English dictionary to each class.
Extra Support •If students are unable to use a microscope, they can use a magnifying glass or observe with the unaided eye to describe the populations qualitatively. Some students may need assistance using depression slides on a microscope. •Use a video camera for students to record their findings. For added interest, students can do the reporting in documentary style or news reporting style.
Extra Challenge •Students could investigate how temperature affects brine shrimp cysts, given various salinities. Students could then try to combine the data from both experiments to find the optimal salinity and temperature conditions for brine shrimp cysts.
616 Unit C: Water Systems on Earth NEL •Have students use the Internet to research the ethics and issues of live subject research. Encourage them to discuss the benefits and costs of such research, the types of organisms that should be used, and the idea that the pursuit of knowledge should or should not have restrictions placed on it.
ASSESSMENT FOR LEARNING
What To Look For in Student Work Suggestions for Teaching Students Who Are Having Difficulty Evidence that students can Some students may require assistance to measure appropriate quantities of salt • propose a question that forms the basis of when making saline solutions. You might wish to have some samples already a scientific investigation (e.g., How does the prepared. salinity of water affect the productivity of Students who have difficulty writing can use a combination of diagrams, labels, brine shrimp?) and point-form descriptions when developing and describing their experimental •make a hypothesis and/or a prediction to design. Some students may need help developing appropriate charts for provide an answer to a testable question recording data. (e.g., if the salinity of the water decreases or increases above the normal, then the Students with physical challenges can be observers/recorders during the hatch rate of brine shrimp cysts will preparation of the water samples. decrease) • design a controlled experiment, identifying the dependent variable (e.g., water loss through osmosis) and the independent variables (e.g., salt concentration), and other variables that might affect the outcome • handle chemicals and equipment safely and responsibly (e.g., handle glassware safely) •write a conclusion that relates to the hypothesis (e.g., how salinity affects productivity of brine shrimp)
NEL Chapter 9 Water and Our World 617 9.7 Explore an Issue: The Salmon Farming Debate Page 271
Time PRESCRIBED LEARNING OUTCOMES 60–90 min • explain the significance of salinity and temperature in the world’s oceans Key Ideas • explain variations in productivity and species distribution in marine Fish farms have been environments established to raise fish for food because of decreasing • demonstrate scientific literacy wild populations. • demonstrate ethical, responsible, cooperative behaviour Vocabulary KNOWLEDGE • aquaculture •properties of salt water and fresh water Program Resources •productivity and species distribution in aquatic environments Investigation Rubric 1: • water quality problems Explore an Issue • diversity of aquatic life forms Investigation Rubric 2: Explore an Issue—Self- SKILLS AND ATTITUDES Assessment BLM 9.7-1 Explore an Issue: •use the Internet for research The Salmon Farming • use given criteria for evaluating evidence and sources of information Debate (e.g., identify supporting or refuting information and bias) Science Skills and Processes Rubric 21: Research •relate cause to effect Science Skills and Processes • assess human impact Rubric 22: Research— • show respect and sensitivity for the environment Self-Assessment Nelson Science Probe 8 Web site ICT OUTCOMES www.science.nelson.com • demonstrate the ability to formulate questions and to use a variety of sources and tools to access, capture, and store information •use a variety of information technology tools to solve problems •evaluate information retrieved electronically for authenticity, bias, and timeliness
SCIENCE BACKGROUND
• Salmon farming began in the 1960s many companies relocated to more in Norway and Scotland. Rather than remote sites on Vancouver Island. releasing the salmon for a portion of Companies also began to culture their life cycle, aquaculturists Atlantic salmon, which now account developed a way to retain them, for more than 90 % of British growing them in pens close to shore Columbia’s farmed-salmon production. so they could be harvested easily •A relative newcomer among British and delivered quickly to markets that Columbia resource-based industries, were ready and willing to pay a the salmon farming sector has premium price for fresh salmon. grown rapidly. It has become a vital • Salmon farming began in Canada in part of the local economy in many the 1970s in the Bay of Fundy. On the coastal communities. West Coast, salmon farming was first •There are 17 salmon farming established around Sechelt. There companies, including three of the were problems with water world’s largest, in British Columbia. temperature and algal blooms, so They operate 105 active salmon
618 Unit C: Water Systems on Earth NEL farms. It is estimated that, in 1999, tears. In the 1990s, it was estimated they contributed $677 million to the that about 38 000 Atlantic salmon province’s economy. escape annually from British •Farmed salmon routinely escape, Columbia salmon farms. however, as a result of net failures or
TEACHING NOTES •To assess students, you may want to use or adapt Investigation Rubric 1: Explore an Issue and/or Investigation Rubric 2: Explore an Issue—Self-Assessment. •When students have completed this activity, have them complete the Check Your Understanding questions.
The Issue: Impacts of Salmon Farming STATEMENT •The statement is always stated so that students must either agree or disagree with it. There are pros and cons to salmon farming, but do the risks outweigh the benefits?
SALMON FARMING METHODS • The salmon farming operation begins when salmon eggs are collected in the late fall and incubated in fresh water. In the late winter or early spring, they hatch as sac fry and are kept in tanks designed for feeding. In the late spring, they are graded for uniformity and size, and transferred to rearing tanks where they feed throughout the summer. Once the salmon smolts have reached a weight of about 60 g and are strong enough to survive in the ocean, they are transported to salt water and placed in sea cages (net enclosures that are supported by floating frames made of plastic or steel). There, they are fed a mixture of fish meal, fish oil, grains, minerals, and vitamins until they reach market size. It takes approximately 30 months after hatching for a salmon to reach market size.
Make a Decision IDENTIFY POSSIBLE ALTERNATIVES •Students often think that they can make a persuasive argument based on passion alone. They need to realize that opposing sides have significant points to offer each other. Ignoring valid but opposing points often leads to a weaker stance. Students will have to decide how to deal with such points when they arise. It is often useful to have students argue for the side they disagree with, although students often dispute this. Encourage students to question absolute statements, such as “all salmon farming is bad for the environment,” in their own and others’ arguments.
NEL Chapter 9 Water and Our World 619 •Acknowledging someone else’s perspective in a rational manner can be very difficult for students. This is one of the basic principles for round-table discussions, so it may require coaching during the role-play. •Students may need to hear other perspectives or solutions more than once. It may help to have a recorder list the suggested alternatives on a chart as they are presented, so group members can keep track of these alternatives. This may also help when the group needs to make a decision and communicate their decision. •It is not necessary for every group to conduct their round table in front of the class. •If possible, invite someone from the community who has been involved in such decision-making processes. •Students can use BLM 9.7-1 Explore an Issue: The Salmon Farming Debate to record their results. •Remind students that the decision-making process requires the group to come to a generally accepted decision—a consensus. As many perspectives as possible should be taken into consideration. •Remind students that the community has to live with their decision. The community includes not only humans who live nearby, but any other living things that will be affected.
Communicate Your Decision •Students’ written reports should include what the decision is and how it was reached. The reports could explain the alternatives that were presented and how each alternative was incorporated into the final decision, or why it was excluded.
CHECK YOUR UNDERSTANDING—SUGGESTED ANSWERS
1. Criteria Aquacultural farm Agricultural farm location ocean land
methods raise salmon in a net pen or net plant crops and raise animals; cage; rely on machinery and rely on machinery and labour labour
products various stocks of fish vegetables, grains, meat, poultry, dairy products, eggs
problems disease (e.g., sea lice can habitat loss, water and land spread to wild population), pollution, non-native species water pollution, non-native introduced into area, use of species introduced into area fertilizers and pesticides (e.g., Atlantic salmon in the Pacific) public health concerns (e.g., hormones widely accepted, concern over acceptance or antibiotics in feed), direct transmission of diseases (e.g., competition with fishers who BSE, or mad cow disease) harvest wild salmon
620 Unit C: Water Systems on Earth NEL 2. Commercial salmon fishers are losing market share not only to overseas competitors but also to local farming operations. Salmon aquaculture was virtually nonexistent in the Pacific Northwest prior to 1985, but today, 70 % of the salmon produced in British Columbia and Washington come from salmon farms. 3. People are opposed to aquaculture for many reasons, including the following: • pollution caused by salmon aquaculture operations • diseases and parasites (sea lice) that could be transmitted to wild populations • the possibility that fish escaping from farms could establish populations in the wild, which would compete with native species •the competition for fishers who rely on harvesting wild salmon for a living.
Meeting Individual Needs Extra Support •Ensure that all students have opportunities to speak and participate actively. They can practise at home, be given a script, or officiate. They can ask questions that have been written by the whole class and practised in advance. •Coming to a consensus may be a very different for most students. Modelling this approach with another subject or circumstance would benefit students. For example, have the class vote on several possible free-time activities and work as a class to build consensus.
Extra Challenge •Have students use the Internet to research fish farming in British Columbia. Ask students to look at as many sites as they can find and select the one that they think provides the best information. This activity could not only support the salmon farming debate, but also lead to a class discussion on defining criteria for evaluating Web-based sources of information. Criteria may include the amount, immediacy, and ease of access, as well as the visual appeal of the Web site and any bias inherent in the information presented and not presented.
ASSESSMENT FOR LEARNING
What To Look For in Student Work Suggestions for Teaching Students Who Are Having Difficulty Evidence that students can Some students may need to have you choose the role for them. A role that is the • compare aquacultural and agricultural most similar to the student’s perspective would be helpful. farms Some students may benefit from observing a replay of a successful round table • make a reasoned decision (i.e., give reasons before participating in one. and provide evidence to support the reasons) • describe examples of the impact of human activity on marine environments • use technical language (aquaculture) • contribute to group efforts (e.g., a perspective on an issue)
NEL Chapter 9 Water and Our World 621 9 Review Page 276
Time Chapter 9 Review Chart 60–75 min •Use the Chapter 9 Review Chart to review what has been learned. Skills and Processes Have students work in pairs to read each key idea and discuss what The Chapter Review provides they remember about the topic. They can then use the vocabulary an opportunity for students to page references in the chart to scan for additional information in the demonstrate their chapter. understanding of and their ability to apply the key ideas, •Paraphrasing—putting information into your own words—is an vocabulary, and skills and processes. important way to check for understanding. Model paraphrasing with the class, and then ask students to work with a partner to paraphrase Program Resources each key idea. Encourage students to use the related vocabulary words BLM 0.0-9 Chapter Key Ideas as they are paraphrasing. BLM 9.0 Chapter 9 Quiz Nelson Science Probe 8 •Ask students to write each key idea in their notebook or use Web site BLM 0.0-9 Chapter Key Ideas. Beside each key idea, ask them to create www.science.nelson.com labelled diagrams or sketches, including any vocabulary words, to illustrate it. •Have students complete BLM 9.0 Chapter 9 Quiz to review the vocabulary and concepts in this chapter.
Review Key Ideas and Vocabulary—Suggested Answers 1. Scuba was an important invention because it allows divers to spend more time underwater without needing to come to surface for air. As well, it allows divers to go deeper than before. Scuba has allowed humans to explore and discover more about marine ecosystems and the organisms that belong to these ecosystems. 2. (a) true (b) false (c) false (d) false 3. (d) the diversity of marine life is greater because there is more light than in the deeper levels 4. Biodiversity is an important characteristic of ecosystems because it allows ecosystems to withstand change more easily.
Use What You’ve Learned—Suggested Answers 5. Fertilizer causes algae growth to increase in an aquatic ecosystem. A slight increase in fertilizer would add more oxygen to the water and also provide additional food for consumers. A larger increase in fertilizer could cause algae growth to outstrip the ability of consumers to eat the algae. As the algae and other organisms die, their decomposition would deplete the oxygen.
622 Unit C: Water Systems on Earth NEL 6. Oil spills can have the following effects on marine organisms: •Oil coats birds’ feathers, which reduces their insulating capacity. When the birds try to clean themselves, they ingest the oil. This can poison the birds. As well, oil removes the water repellency of the feathers and birds can die of cold. Birds of prey that eat dead animals coated in oil will also be poisoned by the oil. •Marine mammals, such as seals, can become coated with oil. Their fur loses its buoyancy and its ability to keep the mammal warm. Ingesting oil can also kill them. •Organisms such as barnacles, mussels, and clams cannot escape the oil. They are covered by the oil, and smothered or poisoned.
7. (a) Algal Growth vs Temperature 6
5 A 4 D 3 B C 2
Mass of Algae (g) 1 0 0 1234567 Time (days)
(b) The test tube kept at room temperature provided the best environment for algae growth. It had the greatest mass of algae (5 g). Students should conclude that the warmer water from the nuclear power plant could cause an increase in the growth of algae in the lake. 8. Students’ reports should establish the connection between the aims of the project and the two principles—“everything is one” and “respect”. 9. (a) All variables except temperature should be kept constant for all the containers that contain cysts. Students might suggest leaving one test tube at room temperature (measured). Another test tube could be placed in a beaker of water warmed by an aquarium heater. A third test tube could be placed in a beaker in a sink, and cold water could trickle into this beaker to keep the test tube cold. (b) Students should observe the test tubes regularly. They should choose a suitable method for counting (or estimating) and recording population numbers. As well, they should measure the temperature in each condition. (c) Students might do a sample count (e.g., the number of shrimp in three drops of water), using a microscope. Such a count would be especially useful if the numbers of shrimp were not obviously different in each set-up. Students could make a qualitative statement if the numbers of hatched shrimp were obviously different, but they would have to state this qualifier.
NEL Chapter 9 Water and Our World 623 (d) Unlike the addition of fertilizer, where adding none is a control, it is impossible to have “no temperature”. The closest thing to a control in this situation is to use the temperature suggested on the instruction sheet that comes with the cysts, or to use normal room temperature (20 °C) as the control. (e) Students will likely state a variety of expectations. The reasoning behind the expectations is most important. Possible answers are given below: •I would expect the temperature mentioned on the instruction sheet to have the greatest hatch rate, because retailers would want happy customers. •I would expect the cold temperature to produce the greatest hatch rate, because salt-lake water is often colder than room temperature and salt lakes are the natural environment of brine shrimp. •I would expect the vial closest to (student states a temperature here which might differ from the instruction sheet) because I looked up where brine shrimp come from and this is the temperature at which they hatch in nature. 10. Posters should concentrate on environmental effects or conservation actions, and be directed to the level of the younger students. 11. Most street drains enter storm sewers and do not normally lead to treatment facilities. (Treatment facilities usually cannot handle oil and paint residues, either.) Therefore, students’ answers should emphasize that the materials being discarded will enter the local water system without any form of treatment. Students can discuss, in general terms, how such waste products affect the lives of aquatic organisms.
Think Critically—Suggested Answers 12. Some of the problems that must be resolved when living underwater are given below: •a continuous supply of fresh oxygen •a continuous supply of fresh drinking water •a way to get food on a regular basis •a way to remove waste from the underwater living compartment without polluting the environment •methods of escaping the compartment quickly in case of a leak or another emergency •a source of electricity to power all the lights and equipment •a source of heating/cooling to keep the inhabitants warm or cool
624 Unit C: Water Systems on Earth NEL 13. A possible concept web is shown below:
irrigation of crops
waste disposal industrial (e.g. sewage) production
Human Uses of Water electricity production source of food through hydroelectric (e.g. fish, molluscs, and tidal power birds, etc.)
source of drinking transportation water e.g. ships
14. Water is referred to as “blue gold”. Gold is an extremely valuable substance, and so is water. People and countries with an abundance of fresh water are “wealthy” with drinking water, hydroelectric power, water for irrigation, inland transportation routes, and so on. People and countries with a minimum of water are always looking for more water and must pay a great deal, both in terms of money and environmental costs, to get more. 15. Students’ tables will vary. A possible table follows:
Challenge Possible solutions not enough drinking water water conservation (e.g., low-volume toilets), desalination to produce fresh water from salt water, use of water from icebergs increased pollution of water systems with improved sewage treatment, better sewage and industrial waste regulations for waste disposal
additional demand for water for agriculture improved agricultural technologies that conserve water
16. Students’ ratings of the technologies, and their choice of the three most important, will vary. Here are some ideas: • Scuba will continue to be important in the exploration of shallow water. • The Newt Suit (and its replacement model) is used when scientists want to explore greater depths than scuba gear is good for and when workers need to stay below for extended periods of time.
NEL Chapter 9 Water and Our World 625 •A submersible is good for very deep exploration. •Remote video is good for situations that are too dangerous for human explorers. It is usually much cheaper than other methods. • Core sampling is an effective tool when climatologists and geologists need information on things such as previous climates or rates of sedimentation. •Sonar is very helpful for locating specific features underwater. It is commonly used to find sunken ships. •Aerial photography is effective for noting changes in coastlines and other surface features. It can be done relatively quickly and with high-resolution cameras. •Satellite imaging is very useful to scientists, since the satellite cameras can record infrared and UV wavelengths. Surface features that are not obvious using regular cameras can be seen. • An ROV can carry video and still cameras to great depths. 17. “Pollution can never go away” means that humans just move the pollutants from one place to another. The pollutants cannot leave Earth. For example, human waste (sewage) is often flushed into a river or stream with little or no treatment. The effects of the sewage can be seen downstream, however, where the water is no longer drinkable or there are damaging effects on plants and animals. “Out of sight, out of mind” has the opposite meaning. 18. A sudden change in environmental conditions would have a very damaging effect on the diversity of an ecosystem. Species that are not able to adapt to the changes would die off. This would reduce the food supply for consumers above them in their food web. 19. The Canadian government regulated the amounts of phosphates in soaps and detergents to help prevent the damage to aquatic ecosystems caused by phosphates. Algae are fertilized by phosphates, and their increased growth can seriously harm an aquatic ecosystem. 20. (a) Herbicides and pesticides can get into the local water systems by two methods: (1) Surface runoff of rain and snow carries any herbicides and pesticides on plants and the soil surface into local streams and rivers. (2) Water percolating through the soil carries pesticides and herbicides into the ground water. (b) Herbicides and pesticides can kill or harm beneficial species in addition to the insects and weeds. Too high a concentration of these chemicals can make water undrinkable. (c) The only way to reduce the negative effects of pesticides and herbicides is to reduce their use. The impact can be minimized if common sense is used—do not spray near waterways, use only the amount listed in the directions, and do not use them if there are better alternatives. 21. Students’ answers will vary significantly, depending on their interests.
626 Unit C: Water Systems on Earth NEL Reflect on Your Learning—Suggested Answers 22. Students’ answers will vary, but ensure that the technologies are chosen for their ocean research value and not just because they are interesting technologies. 23. Petroleum products include most plastics—in cars, homes, toys, computers, and clothing. Asphalt used in road construction is a petroleum product, as is the synthetic rubber in tires. Paraffin wax comes from petroleum, as do fertilizers, pesticides, herbicides, detergents, phonograph records, photographic film, furniture, packaging materials, surfboards, paints, and artificial fibres used in clothing, upholstery, and carpet backing. Helium, sulfur, and other valuable materials are produced from oil wells along with petroleum itself. Packaging materials, herbicides, and some fertilizers are examples of petroleum products that students might be willing to do without. 24. These ideas may come as much from students’ prior experiences as from their reading of the unit. Students should suggest a number of conservation and preservation strategies, such as taking shorter showers, flushing the toilet only when necessary, watering lawns and gardens only when necessary, disposing of solvents and other chemicals properly, and protecting water bodies from pesticides and fertilizers.
Meeting Individual Needs Extra Challenge •Have students use a HyperCard program to build an interactive multimedia quiz based on the vocabulary, concepts, and key ideas in the unit. Students could create a multiple-choice quiz that allows other students to select answer buttons that either indicate they are correct or return them to the question page so they can try again.
NEL Chapter 9 Water and Our World 627 Performance Task: Protecting Our Water Page 280
Time This Performance Task allows students to explore what they have learned 150–165 min about water and water systems. They will apply their knowledge to determine their own idea of an action plan for protecting and improving Skills and Processes a water system in their community. The Performance Task provides an opportunity for students to demonstrate their TEACHING NOTES understanding of and their ability to apply the key ideas •To assess students, you may want to use or adapt Unit C: Assessment in this unit, as well as the BLM—Performance Task and/or Unit C: Self and Peer Evaluation— skills and processes of Performance Task. Planning, Conducting, Recording, Analyzing, Looking Back Evaluating, and Communicating. •Collaborate with students to decide if they should do this project in Program Resources groups or pairs, on their own, or as a combination. Unit C: Assessment BLM— •Ask students to come up with their own words to describe a four-level Performance Task Unit C: Self and Peer evaluation scale. Encourage them to use words such as these in their Evaluation—Performance evaluations: 4 outstanding, 3 super, 2 good, 1 needs work. Task Nelson Science Probe 8 • Local community newspapers are often a good source of information Web site about environmental issues and the efforts of local citizens to improve www.science.nelson.com a situation. • The key to this Performance Task is to choose a manageable problem. The problem may be a large one, as long as it can be broken down. Students can then choose to work on one or some aspects of the problem, with the class completing the entire project as a group.
Demonstrate Your Learning
PART 1: IDENTIFY A PROBLEM •The goal, identified in the student book, is to ensure that present and future generations will have an adequate supply of safe drinking water and access to healthy water systems for recreational purposes. •Students can contact their local city or municipal hall for information that may help them develop their action plan. •Students can talk to their neighbours about using and maintaining water systems. •Students can read the local community newspaper for environmental issues related to water systems. • Ask at the local library if they host meetings for local community groups who work on environmental issues.
628 Unit C: Water Systems on Earth NEL PART 2: DEFINE THE TASK •Students should be able to define the task in clear and simple terms, so they can formulate a possible action plan. •The student book clearly identifies what needs to be completed for this task: –a list of suggestions for those affected, plus a product that delivers the suggestions (pamphlet) –a set of by-laws that will govern the plan and provide a way to enforce the plan –two proposals for improving the current situation, along with very specific outcomes •Students should have a say in how they will pursue the goal of this task—through direct action or education. •You may need to help students narrow down the number of issues, or focus on a key issue, so the task is manageable. •Some issues may require the attention of larger community groups. Students may present their information to, or work with, such groups.
PART 3: DEFINE THE CRITERIA FOR SUCCESS •Students need to be able to explain how they will determine if their action plan is successful. For example, will water quality be monitored, will the drinking water taste less chlorinated or have less odour? •Data needs to be collected at specified intervals. (Students can think back to some of the investigations that they did earlier in the unit. What will be the control? Will residents be surveyed before and after? If so, what types of questions will be on the survey?)
PART 4: GATHER INFORMATION •Help students contact people who may have Indigenous Knowledge of the water systems. Ensure that students consider the following questions while gathering their information: –What is the human impact on the water systems? – What are some of the requirements for maintaining a healthy water system? –What is needed to maintain an adequate supply of safe drinking water? •Students can also research water quality plans on the Internet. Students should look at Bristish Columbia plans, in particular.
PART 5: DEVELOP YOUR PLAN •Students should keep in mind the guidelines for the task when they start to develop their action plan. •Information from all sources needs to be gathered before they start drafting the plan.
NEL Unit C: Performance Task 629 •Have students list the specific steps that need to be taken and when they will work on each step. Students should consider these questions: –Which steps will require getting permission? Who will I need to contact for permission? –What materials will we need at each step, and where will these materials come from? •Be prepared for more than one draft. Time should be built into the schedule so that revisions can be checked before the final draft is done.
PART 6: EVALUATE •Write a checklist of the things that need to be done to satisfy the requirements of the task. •Have students consider these questions: –Did the Performance Task go as planned? Why or why not? –Did the action plan meet your criteria for success? If not, what could have been done differently?
PART 7: COMMUNICATE • The action plan may be communicated in the form of a presentation (live or taped), a letter, or a poster. •If a presentation is used to communicate the action plan, graphics of some kind should be incorporated. If students have access to cameras or video cameras, encourage them to use these tools. •The key points in the action plan must be easily understood by the audience. The procedures for attaining the goal must be clearly explained.
ASSESSMENT FOR LEARNING
What To Look For in Student Work Suggestions for Teaching Students Who Are Having Difficulty Evidence that students can If students have trouble defining criteria for success, check to see whether they Process had trouble defining the task. If they did, help them define the task or the part • understand the problem they would like to work on and list their options. •work together as a team If students are unsuccessful the first time they use criteria, it is often not • develop a realistic plan because they cannot work successfully with criteria but because they need •recognize the importance of consulting with further whole-class direct teaching of how to develop and use criteria. Aboriginal communities Product •evaluate your plan •meet your criteria for success • provide a clear description of the process you followed to develop your plan Communication • prepare and deliver a presentation • use scientific and technical vocabulary correctly •explain your plan clearly
630 Unit C: Water Systems on Earth NEL Review Page 282
UNIT SUMMARY Time •Students’ short stories or stories in Aboriginal oral tradition will vary. 60–90 min See the bulleted list in the student book for the concepts that students Skills and Processes should cover in their stories. The Unit Review provides an •Have students complete BLM UC Unit C Quiz to review the opportunity for students to demonstrate their vocabulary and concepts covered in Unit C. understanding of and their ability to apply the key ideas, Review Key Ideas and Vocabulary—Suggested Answers vocabulary, and skills and processes. 1. (b) condensation Program Resources 2. (b) tides BLM UC Unit C Quiz 3. (c) Salmon farming has more benefits than risks. Nelson Science Probe 8 Web site 4. (e) the number of different types of organisms www.science.nelson.com 5. Fresh water: fog, irrigation pond, iceberg, snow, farm well Water vapour: transpiration Salt water: Arctic Ocean, estuary Solid water: iceberg, snow 6. Slightly weight one end of the pencil. Put the two water samples in graduated cylinders. Float the pencil in each one, weighted end down. More of the pencil’s length will be above the water level in the denser water. 7. (a) T
(b) T (c) F: Air picks up a lot of moisture when it passes over warm water. (d) T (e) F: Chlorine is added to water to kill bacteria. 8. A flood management plan is designed to prevent or to mitigate the negative effects of a flood on human settlements. 9. The risk of flooding is increased when •trees are clear-cut in a watershed •dikes are not properly maintained •urban areas with a lot of blacktop send rain water directly into storm drains rather than allowing it to percolate into the ground Flooding can destroy homes and crops, and take lives.
NEL Unit C Review 631 10. A screen or grate is usually placed over the end of the intake pipe so that large objects (such as logs or branches) and animals are not sucked into the pipe. 11. Icebergs can be dangerous to ships and oil rigs because of their large size. Because icebergs are made of fresh water, they are a potential source of drinking water. 12. The following factors can affect the flow of ocean currents: • differential heating of the oceans by the Sun • differences in density (salt water is denser than fresh water is) • cold water entering the oceans from the icecap and continental glaciers • sea water freezing to become ice, and becoming denser because the salt remains in the water • strong winds blowing across the surface 13. A warm, moist air mass passing over a cold ocean current is more likely to produce fog. Warm air is cooled enough for some of the water vapour to condense into tiny water droplets, or fog.
14. wavelength
crest crest
trough
15. Shallow water Deep water Circular motion of the water is larger at Circular motion of the water is smaller at shallow depths. greater depths. Circular motion becomes distorted as it approaches shallow water.
16. Satellite information is used for weather forecasting, monitoring surface temperatures of water and land, obtaining high-resolution photographs of Earth’s surface, mapping the movements of sea and lake ice, measuring radiant and reflected energy, observing the condition of Earth’s atmosphere (e.g., the ozone layer), and navigating by the global positioning system (GPS). 17. Some of the oil evaporates; some is washed ashore; some sinks to the ocean floor; some is biodegraded by bacteria, fungi, and yeasts; and some is dispersed through a large volume of water.
632 Unit C: Water Systems on Earth NEL Use What You’ve Learned—Suggested Answers 18. People generally like to settle in areas where there is a plentiful water supply. Some groups of people, however, have chosen to live in arid and desert environments or in flood-prone locations. Modern technology has made it easier to locate local water supplies in order to supply their needs. Dikes and dams have been built to keep people who live on flood plains safe. 19. 1 E; 2 H; 3 C; 4 J; 5 A; 6 B; 7 K; 8 L; 9 F; 10 D 20. Pollutants are more highly concentrated in lakes, oceans, and seas because all water must at one point enter these bodies of water. 21. Students’ answers will vary. Some students may recount their own experiences of government and organizations (e.g., Red Cross, Armed Forces) working together during a flood. The government can mobilize the organizations, which can provide people to help with sandbagging or running refuge centres, as well as money. Between floods, the government can seek and pay for ways to prevent floods in the future. 22.
Average Monthly Temperature (°C) in Average Monthly Precipitation (mm) in St. John’s and Vancouver St. John’s and Vancouver 25.0 200.0
20.0 175.0
15.0 150.0 C) ° 10.0 125.0 5.0 100.0 0.0 75.0 mperature ( –5.0 Te –10.0 Precipitation (mm) 50.0 –15.0 25.0 –20.0 0.0 JFMAMJJASOND JFMAMJJASOND Month Month St. John’s Vancouver St. John’s Vancouver The warm Gulf Stream passes St. John’s, in Newfoundland and Labrador, and the warm Kuroshio/Alaska current passes off the coast of British Columbia. Because both of these currents are warm, they add a lot of moisture to the air above them. This moisture is released over land as rain in British Columbia and rain and snow in Newfoundland and Labrador. The warm moist air can also moderate the air temperature to a certain extent.
NEL Unit C Review 633 23. Physical and/or chemical condition Effect on aquatic organisms increase in temperature diminishes the reproduction and survivability of fish
too much phosphate promotes the growth of green algae, which can lead to oxygen depletion and the suffocation of some aquatic organisms, such as insects and fish too much human waste poisons organisms, makes the water unfit for drinking, and depletes the oxygen as the waste decomposes, which can kill fish
too much water removed for irrigation causes the water body to dry up, which affects all the aquatic organisms.
increased salinity could kill many of the organisms
Think Critically—Suggested Answers 24. With selective logging practices, some of the soil higher up the slope can be retained, allowing rainwater to soak in rather than running off. Keeping a section of forest on both banks of a stream or river will prevent soil from washing into them. Proper construction of logging roads and maintenance of culverts (keeping them free from debris) will prevent flooding and debris flows. These are standard practices for many areas in British Columbia that experience high rainfall. 25. Concerns about a landfill include air pollution from the production of methane gas and the possibility of chemicals leaching from the garbage into the ground water supply. 26. Livestock should be kept away from the drinking water supply. Sanitary waste disposal (i.e., proper outhouses) is required. A well should be drilled to access ground water (instead of using a surface water supply for drinking water). 27. Students’ drawings will vary. The new home owner should locate the position of the drinking water well and the septic system, complying with local government and public health regulations on the allowable distance between them. The topography of the site should also be taken into account. On a sloped property, the well should be higher up the hill, and the septic system should be below it. Local well drillers and septic system installers understand these systems and often know where the ground water is, how deep it is, and which way it tends to flow. 28. The Mariana Trench is extremely deep. Few submersibles or ROVs are capable of operating at such depths because of the very high pressure at the bottom. 29. To prevent erosion of beaches by waves and storms, build berms on the beach and breakwaters that run perpendicular to the shore.
634 Unit C: Water Systems on Earth NEL 30. Forests: Reforestation and selective cutting help to reduce harm by preventing erosion. Clear-cutting causes erosion into nearby streams and rivers. The pulp and paper manufacturing process can produce pollution that can harm local waterways. Minerals: There are few positive effects on the water system. Mining produces waste materials—waste rock and slag—that must be disposed of. Often, salts leach from these materials and enter local water systems. Open-pit mining can lower the surrounding water table as water is pumped out of the pit. Oil: There are few positive effects on the water system. Oil spills and leaks are harmful. Water: Treatment facilities, bank protection, and preventing erosion are activities that may benefit the water system. The use of chemicals, the release of waste products, and air pollution that causes acid precipitation harm it. Protection of wetlands helps to maintain the ability of the land to regulate water levels and provides habitat for many species. Preventing development on flood plains reduces the risk to humans during flooding and also reduces potential damage to the water system during construction. Negative effects include wetlands being filled in; leakage of chemicals into ground water from landfill sites, storage tanks, and agricultural practices; and development that affects the water table by diverting water directly into storm sewers instead of allowing it to soak into the ground. 31. Students’ answers will vary. Some students will argue for selling water because of the economic benefits to the country and may say that a lot of the water is “wasted” because it flows out to one of the oceans. Other students will argue against selling, because moving the water permanently from one place to another may put the water system out of balance, may change weather patterns (because water carries a lot of heat), and may have a major impact on wildlife.
Reflect on Your Learning—Suggested Answers 32. This question is likely to produce a variety of responses, depending on the outlook of students. Hopefully, most students will say that they know more about what to do, they understand better how to do it, and they are motivated to do it. Students will probably indicate that it is often difficult to do the right thing. Most people find this difficult simply because they are reluctant to change their lifestyle, especially activities that affect the aquatic environment, (e.g., using as much water as we want without consideration of shortages; using large vehicles that are not fuel efficient, thus contributing to air pollution and acid precipitation).
NEL Unit C Review 635