Solar Energy

SOLAR ENERGY

Overview: In this lesson, students investigate energy transfer and photovoltaic (PV) cells through hands-on experiments. Students explore the impact of intensity and angle of light on the power produced by a solar panel and extrapolate information to examine how/where solar panels might be used in their community.

Objectives: The student will: • model the transformation of solar radiation into electricity in a solar cell; • differentiate between voltage, current and watts; • predict and observe the output of a solar panel under variable conditions; • compute and graph the power produced by a solar panel under variable conditions; and • apply knowledge of solar energy to their own community.

Targeted Alaska Grade Level Expectations: [7-8] SA1.1 The student demonstrates an understanding of the processes of science by asking questions, predicting, observing, describing, measuring, classifying, making generalizations, inferring, and communicating. [7] SA1.2 The student demonstrates an understanding of the processes of science by collaborating to design and conduct simple repeatable investigations, in order to record, analyze (i.e., range, mean, median, mode), interpret data, and present findings. [8] SA1.2 The student demonstrates and understanding of the processes of science by collaborating to design and conduct repeatable investigations, in order to record, analyze (i.e., range, mean, median, mode), interpret data, and present findings. [7] SB2.1 The student demonstrates understanding of how energy can be transformed, transferred, and conserved by explaining that energy (i.e. heat, light, chemical, electrical, mechanical) can change form. [8] SB2.1 The student demonstrates an understanding of how energy can be transformed, transferred, and conserved by identifying the initial source and resulting change in forms of energy in common phenomena (e.g., sun to tree to wood to stove to cabin heat).

Vocabulary: active solar design—a design strategy using mechanical systems such as batteries, pumps and fans to transport and store solar energy ammeter—a device used to measure current amperes (amps)—the unit of measure used to express current (rate of flow of electrons) multimeter—an instrument used to measure voltage, current and resistance in an electric system n-layer—the visible layer of a solar cell that is composed of a semiconductor (usually silicon) mixed with another element (usually phosphorus) to create a negative character; this layer usually appears dark blue or black nonrenewable energy source— a mineral energy source that is in limited supply, such as fossil fuels (gas, oil, and coal) and nuclear fuel p-layer—the layer of a solar cell that is composed of a semiconductor (usually silicon) mixed with another element (usually boron) to create a positive character passive solar design—a design strategy where the structure itself functions as the solar collector; solar radiation (heat and light) is transferred by natural energy flow (conduction, convection, radiation) photovoltaic (PV) cell—a device that converts solar radiation into electricity radiant energy—the energy of electromagnetic waves renewable energy source—an energy source that can be replenished in a short period of time (solar, wind, geothermal, tidal)

semiconductor—a substance (such as silicon in a solar cell) that’s electrical conductivity is intermediate between that of a metal and an insulator; its conductivity can be increased with the addition of impurities solar panel—a number of solar cells connected in a frame volts—the unit of measure used to express voltage (the potential for energy to flow) watts—the unit of measure used to express electric power

Whole Picture: From the time of breakup, beginning in March, through the long days of summer, Athhabascan people have long enjoyed the benefits and energy from the sun. (In Ahtna, sun is Saa; Gwich’in, Srii’; and Koyukon, So.) The light and heat from the sun affords more freedom to travel and with access to unfrozen lakes and rivers, the summer fishing season can commence. In his book, “Make Prayers to the Raven,” Richard K. Nelson writes: “Most salmon are caught in the warmth of July and August” and the drying power of the sun helps in the preservation of protein-rich salmon for much-needed food supply during the long winter months in Alaska. In this lesson, students learn how to harness the sun’s energy through the technology of solar cells. Solar cells (also called photovoltaic or PV cells) convert solar energy (radiant energy carried through the sun’s heat and light) into electricity. A solar panel is a group of connected solar cells packaged into a frame. Solar energy is practical in most of Alaska for about nine months of the year. (There is not enough direct sunlight in most parts of the state from November to January to provide adequate electricity.) Solar panels require little maintenance and actually work more efficiently at colder temperatures. As long as you scrape the snow and ice off the surface, they produce more power per daylight hour, as the days grow colder. Since radiant energy from the sun is not available all the time (i.e. at night), solar electric systems require a storage bank of batteries. Solar systems also usually require an inverter which converts the DC (12-volt) current produced by solar cells to the AC (120-volt) current used in most homes, schools and businesses. Solar energy systems are classified as “active” or “passive.” Passive design implies that the building itself functions as the solar collector and thermal energy is transferred by natural energy flow (conduction, convection, radiation). Examples of passive solar design include buildings with south facing windows to maximize sunlight and solar chimneys. The latter serve to ventilate buildings via convection. Active solar energy designs use mechanical systems such as batteries, pumps, and fans to transport and store solar energy for future use.

Materials: • 2-volt (200 mA) solar panel with wires and alligator clips attached (one per group) • Digital ammeter (needs to measure up to 500 mA, one per group) • Small protractor (2 inches in height, one per group) • Lamp with at least 100 watt bulb (one per group) • Meter stick (one per group) • Flashlight • Masking or duct tape • Small, portable electronic device (if available) • STUDENT LAB PACKET: “Solar Energy” • TEACHER INFORMATION SHEET: “Solar Panels 101” • TEACHER INFORMATION SHEET: “Solar Cell Class Demonstration”

Activity Preparation: 1. Review TEACHER INFORMATION SHEET: “Solar Panels 101” to build a deeper understanding of solar energy systems and their applications in Alaska. 2. Check to ensure ammeter(s) have batteries.

3. Read through TEACHER INFORMATION SHEET: “Solar Cell Class Demonstration.” Gather supplies, determine where you will conduct the demonstration and prepare as described.

Activity Procedure: 1. Open with a discussion about energy. Ask students leading questions such as: Where does the electricity that powers our homes and school come from? Students may answer oil or diesel fuel. Follow up with questions about where those resources come from. Bring the discussion around to the fact that almost all Earth’s energy comes from the sun. Small amounts also come from within the Earth (geothermal) and the moon (tidal). Ensure students understand that solar energy is radiant energy carried through the sun’s heat and light and we can transfer this energy into electricity. 2. Use one solar panel to show the class. Pass the panel to a student and ask him/her to share some observations. Pass it to another student or two to share additional observations. Allow time for the class to share what they know about how and where solar panels are used. 3. Conduct the solar cell class demonstration. (See TEACHER INFORMATION SHEET: “Solar Cell Class Demonstration.”) 4. When you return to the classroom, distribute STUDENT LAB PACKET: “Solar Energy” to each student. Divide students into groups of 4-6 and distribute a solar panel, lamp, ammeter, meter stick, protractor and a small piece of tape to each group. 5. Use the student lab packet to review how solar cells transform solar energy into electricity, and how electricity (including that produced by solar panels) is quantified and measured (volts, amps, watts). Use as much detail as is appropriate for your class. See TEACHER INFORMATION SHEET: “Solar Panels 101” for details. 6. Review procedure as a class then allow student groups time to complete STUDENT LAB PACKET: “Solar Energy.” 7. When all groups have finished, discuss the results and review the discussion questions as a class. End with a discussion about the possible advantages and limitations of using solar panels in your community.

Extension Idea: Design reflectors using aluminum foil, magnifying glasses or mirrors to intensify the light hitting the solar panel. Design and experiment to test the efficiency of the panel using these tools. Discuss practical applications for Alaska.

Answers: STUDENT LAB PACKET: “Solar Energy” Data Analysis: 1. Power decreases as distance from the light source increases. 2. less than half the power As you move away from a light source the same amount of light is spread over a larger area so the solar panel only intercepts part of the energy. 3. Power decreases as the angle of the solar panel decreases or increases from 90˚. 4. 90˚ Conclusion: 5. The power produced by solar panels is affected by: angle of light hitting the panels, direction the panels are facing, weather, shade from nearby trees or buildings, season, reflection from snow and more. (Students may have additional ideas.)

6. Answers will vary but should indicate an understanding that panels should be placed to maximize exposure to direct sunlight (usually south facing and at a 90˚ angle to the sunlight). Other considerations might include: locations that use a lot of electricity and accessibility of panels (to clean off snow and ice and to keep them oriented at a 90˚ angle as the sun moves across the sky) as well as the factors listed in number 5 above. Review: 7. Solar 8. solar cell 9. Voltage, current Further Question: 10. Answers will vary but should indicate an understanding that panels should be placed to maximize exposure to direct sunlight (usually south facing and at a 90˚ angle to the sunlight). Other considerations might include: locations that use a lot of electricity and accessibility of panels (to clean off snow and ice and to keep them oriented at a 90˚ angle as the sun moves across the sky) as well as the factors listed in numbers 5 and 6 above.

Solar Photovoltaic Cells Solar photovoltaic cells are made up of two or more very thin layers of semiconductor material. The most commonly used semiconductor is silicon. Silicon is the second most abundant element in Earth’s crust and it has some special chemical qualities. The outermost orbital of electrons in a silicon atom is not full. It is always looking to “share” electrons with neighboring atoms. Sharing electrons with nearby molecules is what forms silicon’s crystalline structure. Solar cells have two layers. The “n-layer” appears dark blue or black. In silicon-based cells, this layer consists of silicon mixed with a small amount of phosphorus. Phosphorus has five electrons in its outer orbital, so even when it bonds with nearby silicon atoms there is still one electron that remains “free” giving this layer a negative “character.” (It does not have a negative charge since there are still equal numbers of protons and electrons at this point.) The “p-layer” is underneath the “n-layer” and is not usually visible. In silicon-based cells, it consists of silicon mixed with a small amount of boron. Boron has only three electrons in its outermost orbital, giving this layer a positive character. When the two layers are placed together at the time of production, electrons flow from the n-layer to the p-layer creating an imbalance in the charge, and an electrical field. (Now the n-layer has a slight positive charge and the p-layer has a slight negative charge.) The point of contact is called the “junction” and the two layers are joined by a connector (a wire) to form a circuit. When radiant energy (sunlight composed of photons) strikes the solar cell, it can be absorbed, reflected or pass through. Photons that are absorbed provide energy to knock electrons loose, allowing them to move. This creates a current (flowing through the wire) as electrons move away from the negative charge in the p-layer, toward the positive charge in the n-layer. The junction acts like a one-way door and does not allow electrons to flow back into the p-layer. A single silicon-phosphorus based solar cell produces about 0.5 volts, regardless of its size. The cell’s voltage varies slightly depending on the type of material that is mixed with the silicon. Cells must be connected in series to get a higher voltage. Voltage can be thought of as water pressure in a hose. The “pressure” or voltage must be high enough to achieve the desired result (i.e. charge a battery or appliances.) Current is measured in amperes (amps). The larger the solar cell, the greater the current will be. If voltage is compared to water pressure in a hose, current is equivalent to the flow (volume) passing through. However, solar panels are usually described and rated in watts. Watts are a measure of total power and are calculated by multiplying volts by amps. Research in solar technology is producing simpler, cheaper and more efficient solar cells all the time. The materials used differ in efficiency and cost. Thin-film solar cells are made from a variety of different materials, including amorphous (non-crystalline) silicon, gallium arsenide, copper indium diselenide and cadmium telluride. These are becoming widely available to charge laptop computers, cell phones, and other portable electrical devices. Another strategy, called multi-junction cells, uses layers of different materials. This increases efficiency by increasing the spectrum of light that can be absorbed. Another field of development includes strategies for boosting the output of photovoltaic systems by concentrating light (with lenses and mirrors) onto highly efficient solar cells.

More on Measuring Solar Output The three basic units in electricity are voltage (V), current (I) and resistance (r). Voltage (V) is the potential for energy to move and is measured in volts. Current (I) is the rate of flow (or amount of electrons) and is measured in amperes, or amps for short. A solar panel that produces two amps sends twice as many electrons as a panel that produces one amp. Resistance (r) is a measure of how strongly a material opposes the flow of electrons and is measured in ohms. Current is equal to the voltage divided by resistance: I = V/r Power (P) in an electric system is the amount of work that can be done with the energy and is equal to the voltage multiplied by the current: P = V x I. Power is measured in watts.

Various devices are used to measure current, voltage and resistance. An ammeter measures electric current; a voltmeter measures voltage; and an ohmmeter measures resistance. A multimeter is a device capable of measuring all three. Returning to the analogy of a garden hose used previously, voltage is equivalent to water pressure, resistance is equivalent to the size of the hose and current is equivalent to the amount of water passing through. If you want to increase the overall power capacity of a system, you should increase the “pressure” (voltage), increase the rate of flow (current) or increase the “hose size” (decrease resistance). A single solar cell produces 0.5 volts, regardless of size. Higher voltages can be achieved by connecting individual cells in series; think of this like steps in a staircase. The cells are connected along a single path so that voltage increases with each cell, but the same current flows through all of them. Solar panels are solar cells connected in series (usually to produce 12 volts.) Current can be increased by increasing the size of individual solar cells or by connecting solar cells in parallel. When cells are connected in parallel there is more than one path for electrons to flow, so current is increased while voltage remains the same. Solar panels do not always operate at full capacity. The total power (watts) produced by a solar panel is significantly affected by the intensity of the sunlight. Solar panels do not need full sun exposure all day to work but they will be most efficient with maximum sun intensity. The intensity of the sun is impacted by atmospheric conditions (cloud cover, smog, shading from nearby structures and trees). Light passing through clouds or smog is scattered and becomes more diffuse. The angle at which sunlight hits the solar panel is also a significant factor in determining the total power output. Maximum intensity is achieved when the sun’s rays hit perpendicular to the panel. The amount by which the sun’s rays differ from this optimum perpendicular arrangement is called the angle of incidence. It is affected by latitude and season, but also by the direction and angle at which the panels are arranged. Changing the angle has the effect of decreasing the cross section of light that is intercepted. In addition, low angle sun on Earth must pass through more atmosphere so some energy is absorbed. Some solar systems incorporate mechanisms to automatically rotate the panels, minimizing the angle of incidence (and maximizing solar output) throughout the day. When the sun is high in the sky (summer) it passes through less atmosphere, is less likely to encounter interference (from trees, chimneys, rooftops, etc.) and is therefore at maximum intensity. Solar panels in Alaska can actually reach peak efficiency in late spring when sunlight abounds, temperatures are cold, skies are often clear and snow on the ground increases reflectivity of light.

Energy Storage Solar energy (photons) is not available 24 hours per day, but our homes and classrooms require energy during the dark hours. Consequently, solar photovoltaic systems are generally designed to incorporate some sort of energy storage such as a battery (or possibly heating water stored in a tank.) Battery storage is limited by the type of battery used. Historically, deep-cycle lead-acid batteries have been used for this purpose, but more modern technologies include lithium and vanadium batteries. Battery technology has not come as far as was expected mainly due to the limitations of the chemicals and the nature of the technology.

Students will demonstrate the movement of electrons in a solar cell. (See diagram on page two.) Activity Preparation: 1. Choose a location to conduct the demonstration. You will need a significant amount of open space. You may choose to move the furniture to the sides of your classroom or reserve space in the school gym. 2. Use tape to mark off two connected boxes on the floor. These will represent the n-layer and the p-layer of the solar cell. The boxes must be big enough to comfortably fit most of your students. The line between the two boxes should be a dotted line. This represents the junction between the layers. 3. Use tape to mark the n-layer with a large “n.“ 4. Use tape to mark the p-layer with a large “p.” 5. Use tape to mark the path of the circuit from the n-layer to the p-layer. The Demonstration: 1. Explain you will be modeling how a solar cell transforms sunlight (radiant energy in the form of heat and light) into kinetic electric energy. Be sure students understand that a solar panel is composed of many connected solar cells. One student will represent the sun and another will represent the electronic device you hope to power. Some students will control the junction (or the flow of electrons within the solar cell) and the remaining students will be electrons. 2. Choose one student to represent the sun. Give them the flashlight and instruct them to stand facing the n-layer. 3. Chose 5 students (or about ¼ of your class) to represent the junction. They should stand on the dotted line between the two layers facing the n-layer. Instruct them to allow electrons to pass from the p-layer to the n-layer but not the other way. For very small classes, desks or folding chairs can be used to represent the junction. 4. Choose one student to represent the electronic device. This student should be willing to act like a radio, television, alarm clock or other common appliance (i.e. sing to represent the radio or beep to represent an alarm clock, etc.) 5. Divide the remaining students almost in half. You will want a couple more students in the p-layer since this layer has a slight negative charge after a solar cell is constructed. 6. Explain the electrons are not equally distributed because of the way solar panels are made. Most panels are made of silicon mixed with other elements that allow electrons to move more easily between the two layers. When the two layers are put together a junction forms that allows electrons to flow in only one direction: from the p-layer to the n-layer. 7. Remind the electrons they do not have enough energy to move on their own. They need the sun’s energy to move from the p-layer to the n-layer and so can only move when the flashlight beam is directly on them. They must stop when it is not on them. 8. When everyone is ready, instruct the sun to turn on the light. The sun should move the flashlight in an arc slowly over the solar cell to represent the sun’s path across the sky. (The sun may need to make multiple trips through the sky for this demonstration.) When light hits the electrons they should begin to move around. Electrons in the p-layer, close to the junction, can pass through into the n-layer. Remind students that they can not pass through the other way! 9. When the n-layer is getting full, instruct students to freeze, and pause the demonstration. Tell students that in order to use the energy in a solar cell, we must create a circuit, or somewhere for the electricity to flow. Identify the dotted path on the floor as the circuit (or wire) through which electrons can flow. As soon as electrons reach the electronic device, it will go on. (Ensure this student understands their role.) Once reaching the electronic device student electrons may return to p-layer to return to the game. 10. Resume the game. Now students in the n-layer may flow through the circuit and the electronic device should go on. Electrons return via the circuit to the p-layer where they must wait to be hit by sunlight again to move towards and through the junction.

student representing sun (with flashlight)

solar cell n student representing electronic device

Key:

the path electrons travel in the circuit

students representing electrons

the path students travel to return to the game the circuit

students representing the junction between layers of the solar cell

PHOTOVOLTAIC CELL KEY A location that can accept an electron Free electron Proton Tightly-held electron

n-layer p-n junction p-layer

A photovoltaic (PV) solar cell is a device that converts the radiant energy (carried by the sun’s heat and light) into electricity. A solar panel is a number of solar cells connected in a frame. Each solar cell consists of two layers. When sunlight hits the solar cell, it provides the energy needed for electrons to flow from the slight negative charge in the p-layer through the p-n junction and towards the n-layer. The p-n junction acts like a one-way door and does not allow electrons to flow back into the p-layer. We can form a circuit by attaching a wire. The electrons flow through the circuit and power electric devices. Power (P) in an electric system (such as a solar panel) is equal to the voltage (V) multipled by the current (I). Voltage (V) is the potential for energy to move. The solar cell you are using creates 2 volts. Current (I) is the rate of flow (the volume of electrons flowing). It is measured in amps. Your ammeter measures milliamps. P = V x I 1 amp = 1000 milliamps

Directions: Work in groups to complete the following experiment.

Testable Question: Does the distance from the light source or the angle of the solar panel affect the power produced by a solar panel?

Hypothesis: If the distance from the light source or the angle of the solar panel changes, then the power produced by a solar panel will change. Based on this hypothesis make a prediction about how the power produced by a solar panel will change as the angle of the panel and distance from the light source changes. Check one statement from each section. Prediction 1: If the distance from the light source increases then power (watts) will: ____ increase. ____ decrease. ____ stay the same.

Prediction 2: The greatest power (watts) will be produced when the panel is placed at: ____ a 90 degree angle. ____ angles greater than 90 degrees. ____ angles less than 90 degrees.

Experiment: Materials: • 2-volt solar panel • Ammeter • Protractor • Lamp (with at least 100 watt bulb) • Meter stick • Tape Procedure: 1. Set up the lamp as directed by your teacher. 2. Measure with the meter stick and use a small piece of tape to mark the following distances from the heat lamp: 15 cm, 30 cm, 45 cm, 60 cm, 75 cm and 90 cm. 3. Turn on the ammeter and ensure it is set to measure DC current in mA (milliamps). 4. Use the alligator clips to attach the solar cell to ammeter. Attach the black (negative) wires together and the red (positive) wires together. Part I: Angle of Solar Panel 5. Hold the solar cell upright facing the light on the 30 cm mark. 6. Place the flat part of the protractor flat on the table. Align the solar cell with the 90˚ mark. 7. Read and record the current (in milliamps) displayed on the ammeter. 8. Repeat for the other angles. Record the data in the chart. 9. Convert the values in milliamps to amps and record. 10. Calculate the watts produced by the panel at each angle. Record.

Part II: Distance from Light Source 11. Hold the solar cell at 90˚ on the 15 cm mark. 12. Read and record the current (in milliamps) displayed on the ammeter. 13. Repeat at each distance, keeping the solar panel at 90˚. Record the data in the chart. 14. Convert the values in milliamps to amps and record. 15. Calculate the watts produced by the panel at distance. Record.

Data: Part I: Angle of Solar Panel (measured at 30 cm) Angle of Solar Current Current Voltage Watts Panel (milliamps) (amps) (volts) (amps x volts) 90˚ 2

60˚ 2

30˚ 2

15˚ 2

120˚ 2

150˚ 2

Part II: Distance from Light Source (measured at 90˚) Distance from Current Current Voltage Watts Lamp (milliamps) (amps) (volts) (amps x volts) 15 centimeters 2

30 centimeters 2

45 centimeters 2

60 centimeters 2

75 centimeters 2

90 centimeters 2

Directions: Choose a graph for each data set. Be sure to give each graph a title and to label each axis.

0.30

0.25

0.20

0.15

0.10

0.05

0˚ 20˚ 40˚ 60˚ 80˚ 100˚ 120˚ 140˚ 160˚ 180˚

0.30

0.25

0.20

0.15

0.10

0.05

0 10 20 30 40 50 60 70 80 90

Data Analysis: 1. Describe what the graph shows about the relationship between power produced by the solar panel and distance from the light source. ______

2. If the solar panel is moved twice the distance away it produced: _____ more than half the power. _____ less than half the power. _____ about half the power. Explain why you think this happens. ______

3. Describe what the graph shows about the relationship between power produced by the solar panel and the angle of the panel. ______

4. At what angle is the power (watts) produced by the panel the greatest? ______

Conclusion: 5. In this experiment you changed the distance between the solar panel and the light source, however, Earth’s distance from the sun does not change. What factors might influence the power produced by a solar panel on your school or home? ______

6. Describe where you would place solar panels on your school and how you would arrange them. Why? ______

Review: 7. ______energy is radiant energy carried through the sun’s heat and light. 8. A ______is a device the converts the sun’s radiant energy into electricity. 9. ______is the potential for energy to move, and ______is the rate of flow (the volume of electrons flowing).

Further Question: 10. You have solar panels to place around your village. You want them to produce the most power possible where it is needed most. Where in your village would be a good place to put solar panels? Why? What angle would you place them at? Why? ______

Overview: In this lesson students design, construct and test a simple, passive water heater then record and graph the results of testing their design. Students investigate and discuss the practical applications of this concept in their own communities.

Objectives: The student will: • design and construct a simple passive solar heating system; • record and graph results of testing the system; • revise their design to make the system more effective; and • propose ways to utilize solar water heating in their own community.

Targeted Alaska Grade Level Expectations: [7-8] SA1.1 The student demonstrates an understanding of the processes of science by asking questions, predicting, observing, describing, measuring, classifying, making generalizations, inferring, and communicating. [7-8] SA1.2 The student demonstrates an understanding of the processes of science by collaborating to design and conduct simple repeatable investigations, in order to record, analyze (i.e., range, mean, median, mode), interpret data, and present findings. [7] SB2.1 The student demonstrates an understanding of how energy can be transformed, transferred, and conserved by explaining that energy (i.e., heat, light, chemical, electrical, mechanical) can change form. [8] SB2.1 The student demonstrates an understanding of how energy can be transformed, transferred, and conserved by identifying the initial source and resulting change in forms of energy in common phenomena (e.g., sun to tree to wood to stove to cabin heat). [7-8] SE2.1 The student demonstrates an understanding that solving problems involves different ways of thinking by indentifying, designing, testing, and revising solutions to a local problem.

Vocabulary: active solar design – a design strategy using mechanical systems such as batteries, pumps and fans to transport and store solar energy mean – a number or quantity having a value that is intermediate between other numbers of quantities median – the middle value in a sequence of numbers (or the average of the two middle numbers when a sequence has an even number of values) mode – the value that occurs most frequently in a data set nonrenewable energy source – a mineral energy source that is in limited supply, such as fossil (gas, oil, and coal) and nuclear fuels passive solar design – a design strategy where the structure itself functions as the solar collector; solar radiation (heat and light) is transferred by natural energy flow (conduction, convection, radiation) renewable energy source – an energy source that can be replenished in a short period of time (solar, wind, geothermal, tidal)

Whole Picture: In a traditional Koyukon story it is said the sun was once a beautiful young woman who flew off into the sky. Jules Jette, in 1913, quotes a Koyukon saying, “We do not look at the sun because it would shame a young woman.” But the sun is not mentioned much in traditional stories because it is such a dependable natural phenomenon. And nowhere is it said to be a taboo subject.

This dependable source of energy can be harnessed to produce electricity as well as to heat both air and water. Solar energy heating systems are classified as active or passive. Passive design implies that the structure itself functions as the solar collector. Thermal energy is transferred to air and water by natural energy flow (conduction, convection, radiation). Examples of passive solar design include buildings with south facing windows (to maximize sunlight), greenhouses and solar chimneys. Solar chimneys serve to ventilate buildings via convection. Active solar energy designs use mechanical systems such as batteries, pumps and fans to transport and store solar energy for future use. Both active and passive solar energy systems can be used to heat water. The main components of an active system are the collectors, the storage tank and the distribution system (often including pumps and circulation pipes). Solar water heating systems often also include an auxiliary heater for times when the solar collector does not get water hot enough to use as a stand alone system. Even in those cases, solar water heaters can still result in significant energy savings by preheating water. Active solar water heating is a useful and practical application of solar energy for much of Alaska, especially regions where fuel prices are high. Our demand for hot water remains high in the summer months when solar energy abounds. It is estimated that solar energy can provide 40-60% of the annual hot water demand for most locations. However, Alaskan systems do require special considerations including a circulation loop of antifreeze that will flow through the solar collector outdoors. This loop then passes through a heat exchanger where it transfers its heat to water that can be stored in a tank. In milder climates, water can travel directly outdoors and through the solar collectors.

Materials: • Black aquarium tubing (one piece per group, approximately 36 inches long) • 9” x 13” disposable aluminum cake pan (one per group) • Scissors (one pair per group) • Heat lamp (one per group) • Digital thermometer (one per group) • Sturdy foam or paper cups (two per group, not plastic!) • 100-mL graduated cylinder (one per group) • Caulk (one tube) • Books, notebooks, and other classroom items to create different level platforms • Duct tape • Cool water (at least 100 mL per group) • STUDENT LAB: “Solar Water Heaters”

Activity Preparation: 1. Review STUDENT LAB: Solar Water Heaters. Gather supplies. Determine what preparation you will do and what students can do. (You may need to cut aquarium tubing, poke holes in disposable cups, gather books, etc.) 2. If you feel it is necessary, construct a solar water heater as described to use as an example.

NOTE: After designing and assembling the solar water heaters, you will need to allow at least two hours for the caulk to dry before testing them. Check the tube of caulk for specifications.

Activity Procedure: 1. Ask students if they have ever heard of or experienced a solar water heater. Most students may initially say no, but encourage them to think a little deeper. Have they ever turned on a hose or another outdoor water source in the summer and then felt warm water? Have they ever left a cup or bucket of water on a window sill on a sunny spring or summer day and noticed that it warmed up? This is solar water heating! Solar radiation (heat and light) from the sun is transferred to the water. Solar water heating is nothing new. People, including Native Alaskans, have been using the sun to heat water for thousands of years.

2. Explain that this lesson will explore how we can harness the sun’s solar energy to heat water for use in our homes and schools. The systems mentioned above (hoses in the sun or cups on a window sill) are called passive systems because they have no mechanical parts. Active systems use devices such as pumps and fans to transport water and other substances throughout the system. In today’s lab, students will work in groups to design, build and test a passive water heating system. 3. Divide students into groups. Distribute STUDENT LAB: “Solar Water Heaters” and associated supplies. 4. Instruct students to follow the instructions to complete the lab. 5. When all students have finished, pool their data on the white board. Calculate the mean, median and mode of each run and of the total temperature gain. Allow time for each group to share their design, results and revision ideas. 6. Review answers to remaining discussion questions. Lead a discussion about how and where solar water heating could be of use in your community.

Extension Ideas: 1. The shape of a solar collector can affect its efficiency. A parabolic collector is the most powerful type of collector because it concentrates light toward a single point, the focal point. Ask students to design a more efficient parabolic collector using aluminum foil. Repeat the experiment. 2. Calculate the focal point (f) of the parabolic collectors using the following equation: f = x2/4a. Measure the longest diameter (width) of the parabola at its rim. Divide by two to determine the radius (x). Measure the depth of the parabola at its vertex (a). The vertex is the bottom of the “U”. The focul point is the distance f from the vertex of the parabola.

Answers to STUDENT LAB: “Solar Water Heaters” Data: Hypotheses will vary. Graphs will vary but should reflect an increase in water temperature with each run. Be sure that students label each axis and include a title. Review: 1. Solar 2. Passive 3. Active 4. 40-60 Conclusion: 5. Students should observe and record an increase of 3-5 degrees Fahrenheit per run. 6. Answers will vary, but students should suggest ways to keep the water in the tubing under the heat lamp as long as possible. Possibilities include decreasing the angle of the collector and increasing the length of the tubing (more loops and curves). 7. Benefits of a solar water heating system in Alaska: saves money on fuel; does not require much maintenance; uses solar energy when it is plentiful (summer months) Challenges/drawbacks of solar water heating in Alaska: can only provide 40-60% of hot water needs, so still need a back up water heater; can not provide much hot water in winter months 8. Answers will vary. 9. Answers will vary.

Antifreeze

Water to Bathrooms and Kitchen

Heat Storage Exchanger Tank

Pump Pump

Water from Main (40º)

Solar Water Heating Solar energy is radiant energy carried in the sun’s heat and light. It can be used to produce electricity as well as to heat air and water. Solar heating systems can be active or passive. Passive design means that the structure itself is the solar collector. One example is a greenhouse. Active solar designs use mechanical systems such as batteries, pumps, and fans to transport and store heat energy for future use. Active solar water heaters in cold climates include a solar collector, storage tank and pumps. In cold climates like Alaska, they also require a heat exchanger. A fluid such as antifreeze flows through pipes in a solar collector where it is warmed by the sun. The antifreeze flows through a heat exchanger where it transfers its heat to water. The warm water is stored in an insulated tank until it is used. Active solar water heating is a useful and practical way to use solar energy in Alaska, especially in communities where fuel prices are high. People use hot water throughout the year, so solar water heating works especially well in summer when solar energy abounds. It is estimated that solar energy can provide 40-60% of the annual hot water demand for most locations in Alaska.

Directions: In this lab you will work as a team to design, build and test a solar water heater. You will use a heat lamp to represent the sun. Follow the directions carefully in each section and be creative!

Materials:

• Black aquarium tubing (36 COOL WATER RESERVOIR inches) • Aluminum cake pan (9” x 13”)

• Scissors AQUARIUM • Heat lamp TUBING • Sturdy disposable cups (2) • Caulk • Books and notebooks (different sizes to create different levels) • Duct tape • Digital thermometer • Cool water

• 100-mL graduated cylinder WARM WATER COLLECTOR

Procedure: 1. Build the collector: • Gently stretch the piece of black tubing to get it as straight as possible. • Use very small pieces of tape to attach the black tubing to the cake pan. The tubing must start at one end of the pan and end at the other. You want the water to stay in the tubing as long as possible, so add loops and curves. Be careful not to kink the tubing and block the water off.

2. Build the storage containers: • Carefully poke a hole in one cup, just above the bottom. This is the cool water reservoir. The other cup will be the warm water collector. Label each cup. • Insert one end of the black tubing into the hole in the cool water reservoir. • Caulk around the hole to seal it.

3. STOP! Allow time for caulk to dry (at least two hours or as directed on the tube of caulk). 4. Assemble a platform with at least three levels: the cool water reservoir should be highest, the collector should be in the middle and the warm water collector should be lowest. You want gravity to make the water flow, but you want it to flow as slowly as possible. 5. Set up the heat lamp as directed by your teacher. It should be pointed directly at the black tubing. 6. Measure 100 mL of water in the graduated cylinder. Record the temperature. This is “run 0.” 7. Make a prediction about how much heat your water will gain in the solar heater. 8. Carefully pour the water into the cool water container. Adjust the collector and containers as needed to ensure the water will flow into the warm water collector.

9. As soon as all the water is in the warm water collector, take the final temperature and record. This is “run 1.” 10. Run the same water sample through the heater two more times and record each temperature. These are “run 2” and “run 3.” 11. Create a bar graph to show your results. Do not forget to include a title for your graph and to label each axis.

Data: Prediction: ______

Run Water Temperature

Total heat gained in solar heater:______

80°

70°

60°

50°

40° 0 1 2 3

Review: 1. ______energy is radiant energy carried in the sun’s heat and light.

2. ______solar design means that the structure itself is the solar collector.

3. ______solar designs use mechanical systems such as batteries, pumps, and fans to transport and store energy for future use.

4. It is estimated that solar energy can provide ______% of the annual hot water demand for most locations in Alaska.

Conclusion: 5. Describe the results of each test of your water heater. How close was your prediction?

______

6. Using only the materials provided, suggest one way you could make your water heater more efficient. Explain what evidence supports your conclusion. Use complete sentences.

______

7. List at least one benefit and one drawback of using a solar water heating system in Alaska.

______

8. Do you think a solar water heater would work at your home or school? Why or why not? Draw one location where you think it could work. Be sure to show the location of the sun and where you would place the solar collector.

______

9. Do you think Native Alaskan people used solar water heating hundreds of years ago? How?

______

Overview: The United States of America follows the Western/Gregorian calendar but each individual, family, community and culture has its own set events, celebrations and ceremonies that define its seasons. In this lesson, students will discuss seasons as they are recognized in their family and community.

Objectives: The student will construct a calendar that depicts a personal, cultural representation of seasons.

Targeted Alaska Grade Level Expectations: [7]SF1.1-SF3.1 The student demonstrates an understanding of the dynamic relationships among scientific, cultural, social, and personal perspectives by investigating the basis of local knowledge (e.g., describing and predicting weather) and sharing that information.

Vocabulary: calendar – a system of organizing the days it takes for Earth to orbit the sun; the simplest calendar system just counts periods of time from a reference date; more complex calendars have cycles such as weeks and months Gregorian calendar – also called the Western calendar; introduced by Pope Gregory XIII by decree on February 24, 1582; the Gregorian calendar was a reformation of the older Julian calendar, which had errors; groups days into years of 365 or 366, divides the year into 12 months and contains a seven-day week season – a division of the year marked by changes in weather, ecology and hours of daylight

Whole Picture: The Tanana Chiefs Conference website (http://www.tananachiefs.org/logo_detail.shtml) describes traditional seasons as such: Athabascans led a nomadic lifestyle. They traveled in small family groups or clans, following the seasons in search of food. In late fall and early winter they hunted the migrating caribou. The caribou were most important for their flesh and hides, which provided food, clothing and shelter. Winter days and nights were spent surviving the cold and darkness. During this time of confinement, the history of the people was passed from generation to generation through stories and legends. In early spring the people traveled to spring camps as the winter’s supply of food was depleted. They hunted ducks, geese, muskrats and beaver on the lakes. The fresh food was a welcome change of diet. After long winters of separation and hardships the tribes gathered to celebrate and discuss mutual concerns. Summers were busy in the fish camps along the rivers. Once the salmon runs began, fish were caught, smoked and stored for winter. The rivers were the lifeblood of the Athabascans, providing food and transportation. Each fall the tribes gathered berries and hunted waterfowl. After the snow had fallen, the men hunted hibernating bears. As it was with the first Athabascans, the cycle was complete and began again. Such were the old ways and such are the new. From season to season, from camp to camp, life is a never-ending cycle. The integrity of life is in this understanding. To an Athabascan, the only things that change are the ways of survival. The Gregorian calendar, more commonly known as the Western calendar, is an internationally accepted time-keeping tool. It was put in place in 1582 by Pope Gregory XIII and follows the rotation of Earth around the sun, which takes approximately 365.25 days. The calendar takes into account that each 365.25-day year (each

with 24 hours) is actually 11 minutes short, which would skew the calendar after many years if not addressed. To solve this, the Gregorian calendar includes a cycle of leap years to set things back on track. Every year that is exactly divisible by four is a leap year, except for years exactly divisible by 100. The centurial years divisible by 400 are still leap years.

Language Links: Alaska Native people have always been careful observers of the seasons. Ask a local Native language speaker to provide the words in the local dialect for the words listed in the chart below. The local dialect for these words may differ from the examples provided. Share the words with students to build fluency in local terms related to weather. Include local words in songs, stories and games when possible.

English Gwich’in Denaakk’e Deg Xinag Lower Tanana Your Language sun drin oozhrii so no’oy sro early: sonot spring shreenyaa xulegg ding’ sronot late: hulookk’ut summer shin saanh sanh sanh fall/autumn khaiints’a huyts’en’ xiyts’in’ xwyhts’en winter khaii huyh xiyh xwyh

Materials: • Blank paper, such as copy paper (multicolored, four or more sheets per student) • Scissors • Glue • Colored pencils • Overhead transparency marker • Transparency sheets (three) • VISUAL AID: “ ‘Seasons’ by Catherine Attla” • VISUAL AID: “These Are My Seasons” • STUDENT INFORMATION SHEET: “ ‘Seasons’ by Catherine Attla” • STUDENT WORKSHEET: “These Are My Seasons”

Activity Preparation: 1. Copy VISUAL AID: “ ‘Seasons’ by Catherine Attla” and VISUAL AID: “These Are My Seasons” pages 1-3 to transparencies. 2. Copy extra triangle template sheets from STUDENT WORKSHEET: “These Are My Seasons.” Consider using colored copy paper in a variety of colors to give students options.

Activity Procedure: 1. Display VISUAL AID: “ ‘Seasons’ by Catherine Attla.” Hand out STUDENT INFORMATION SHEET: “ ‘Seasons’ by Catherine Attla” so students have their own copy as they discuss. Explain Attla documented traditional seasons and how they compare to and differ from the Western calendar. Review Attla’s calendar and discuss how it differs from the Western calendar (eight divisions instead of 12 months, differing lengths instead of uniform lengths, and names describe what’s happening in the environment).

2. Hand out STUDENT WORKSHEET: “These Are My Seasons.” Explain students will create their own seasonal calendar based on things that are important to them. 3. Display VISUAL AID: “These Are My Seasons,” page 1 on an overhead. Remind students the Western calendar places the first day of spring on March 21, the first day of summer on June 21, the first day of fall as September 21 and the first day of winter as December 21, but Alaska tends to follow its own calendar. What months do you think of as spring? Summer? Fall? Winter? Using an overhead marker, demonstrate to students how you might divide your seasons to model how you want them to decide where their spring, summer, winter and fall should be. (See example at right.) What reminds you of each season? Maybe summer is fishing, fall is moose hunting, winter is snow machining and spring is mud! Add a sketch depicting something that reminds you of each season in the space provided. 4. On the board, brainstorm ideas for the seasonal calendar. What things are important during the year? Ask students to think about family activities, holidays, hunting, berry picking, seasonal sports (school, professional), vacations, conferences (like Alaska Federation of Natives), etc. Some things happen on one day or just a few days. Some things span weeks to months. The shorter items, like birthdays, Christmas, etc., will be written on the lines. Things that span a longer period of time will be put on the triangles around the outside. For example, basketball, football, hockey and other sports span many months. Hunting seasons usually span a week or two. Gardening season may run June through August. The fair (such as the Tanana Valley Fair or the state fair in Palmer) is just a little over a week, but it may be a highlight! 5. Ask students to begin working on STUDENT "& 253 WORKSHEET: “These Are My Seasons.” Once they "$% /5&6 !"# have completed the first page, display VISUAL AID: "& % :" $ % " &/ “These Are My Seasons,” page 2. This is the graphic ) 5 ( &6 artist’s depiction. Display page 3. This is Elder Robert ' Charlie’s depiction of seasons. Explain students will

4 & write holidays and events with a small range on the " 5 % & # ( 9 +

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that span weeks to months, such as hunting season, ,

sports seasons, etc. using triangles cut from the

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6 8 / triangle can be glued to the back of the circle. This 2 may require teacher guidance until students get the hang of it. 6. Once students have completed their seasonal calendar, consider having them glue it to a piece of construction paper. Display student calendars so students can look at each other’s seasons.

NOTE: Consider leaving the calendars on display and adding new events throughout the year. In addition, tie in other UNITE US lessons by adding information related to alternative energy, such as the appropriate time of year for using solar panels, wind turbines, in-river hydropower, biomass, etc.

Extension Ideas: 1. Go to the Tanana Chiefs Conference website (http://www.tananachiefs.org/logo_detail.shtml) and view the logo, “The Athabascan Circle” by Athabascan artist James Grant. This is another depiction of a seasonal cycle. Discuss this alternative way of viewing the seasons.

Explore other types of calendars such as the Islamic calendar, which is a lunar calendar, the Iranian calendar, which begins on the vernal equinox, and the Hebrew calendar, which is a luni-solar calendar based on twelve months of 29 or 39 days. Investigate Leap Year, a year containing one extra day in order to keep the calendar system synchronized with the seasons.

Answers: STUDENT WORKSHEET: “These Are My Seasons” Answers will vary.

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"& % :" $ % " &/ ) 5 ( &6 '

4 & " 5

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5 1

6 /

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Seasons according to Elder Robert Charlie of Minto

Directions: Following the lead of Elder Catherine Attla, create your own calendar of seasons. Draw lines to divide the year into four seasons (spring, summer, winter, fall) as you experience them. Add a sketch depicting something that reminds you of each season. Add important events. When you are ready, cut out the circle along the outside line.

er Jan emb uary Dec Winter er b Fe m b e ru v a o ry N

Spring

M r e a r b c

o h t

m l

Fall

a s

y u

Summer

y l u J

Use these templates to add seasonal events to your calendar.

NAME: ______THESE ARE MY SEASONS

Use these templates to add seasonal events to your calendar.

Overview: In this supplementary lesson, students build a working windmill generator that demonstrates the use of wind as an alternative energy source.

Objectives: The student will: • build and test a windmill generator; and • speculate on conditions necessary for successful use of wind power as an alternative energy source

Vocabulary: LED unit – light emitting diode interlock – to fit into each other, as parts of machinery, so that parts work together armature – the pivoted part of an electric device, as a buzzer or relay that is activated by a magnetic field housing – a fully enclosed case and support for a mechanism rotor – a rotating part of a machine

Whole Picture: In the old days, Athabascan people would sing songs to the wind spirit to bring about favorable conditions for hunting and traveling. Even today, understanding the complexity of wind patterns is an important skill for subsistence hunters. One old way of forecasting wind was to observe the stars. When the stars twinkle intensely it meant strong winds were coming. The people would say, “Wind makes the stars sway.”

Wind energy is an alternative energy source used in many parts of the world. The largest wind farm in the world is located in Texas at the Horse Hollow Wind Energy Center. Scientists and engineers are working on ways to capture wind power at sea and above Earth. Wind generators are a clean, renewable way of producing energy, but they only work when the wind is blowing. In this activity, students will be able to see how a wind turbine generator works. After building and testing their wind turbine generators, students will be able to develop an informed prediction about the likelihood of adding wind power to their community’s energy sources.

Materials: • Green Science™ “Windmill Generator” Kit (one for each team) • Small hex head screwdriver (one for each team) • Empty plastic two-liter bottle (one for each team) • Box fans (at least one-preferably one for each team) • STUDENT WORKSHEET: “Wind Power” (Note: Green Science Windmill Generator Kits can be purchased online.)

Activity Preparation: 1. Several days before the activity begins collect enough empty two-liter plastic bottles so that each team has one. Fill each bottle half full with sand/dirt or fill each half full with water and freeze. Water in its liquid state is not recommended, as the LED will not work if it gets wet.

2. At least one day before the activity, build a generator from one of the Green Science Windmill Generator kits to use as a demonstration model for students. Set up a box fan and determine if it has sufficient power to turn the rotor blades fast enough to light the LED unit.

Activity Procedure: 1. On the day of the activity, group students into teams of two. Explain each team will build a wind-powered generator. The purpose of the construction is to demonstrate how wind energy is transformed to electric energy. Explain that after each team completes a generator the product will be field tested to see if it works.

2. Distribute the Green Science Windmill Generator Kits. Instruct students to take out the instructions in each kit and look them over. Each team should check that their kit is complete.

3. Distribute the hex head screwdrivers. Tell students to follow the instructions contained in the kit to build their wind-powered generators. Assist as necessary.

4. Set up one or more box fans as students work on windmill generators.

5. When each team completes the windmill generator give each a plastic bottle filled with sand/dirt or ice. Have the students attach the generator to the bottle as described in the instructions.

6. As each team completes their windmill generator with the bottle/base attached, give each student a copy of STUDENT WORKSHEET: “Wind Power,” and ask each student on the team to complete the two hypotheses on the worksheet.

7. Have each team field test the windmill generator using one of the box fans. Ask them to record their observations on the worksheet.

8. Once observations are completed, ask students to return to their seats and complete the rest of the student worksheet.

9. After all students have field tested their windmill generators and completed their student worksheets discuss observations and conclusions of the teams. Discuss responses to prompts regarding land and climate features necessary for successful implementation of wind power as an alternative energy source. Collect student worksheets.

Answers: Answers will vary. Data and Wind Direction sections should indicate that consistent and strong wind create the most efficient circumstances for energy generation. The direction section should show that 45-degree angle direction provides optimal results. In the Analysis section students should conclude that a source of wind that is strong and consistent is needed for efficient use of wind power as an alternative energy source.

Testable Question: What geographic and/or climate features are necessary for efficient use of wind as an alternative energy source?

Background Information: Wind power is an alternative energy source used in many places in the world. Scientists are looking at new ways to harness the energy of the wind. However, not all communities or areas are good candidates for the use of wind power. The activity in this lesson involves testing a miniature generator to discover the circumstances under which it operates most efficiently, then predicting land and/or climate features that would be necessary to use wind efficiently as an alternative energy source.

Hypothesis: A hypothesis is an “educated guess” about the outcome of an experiment. A hypothesis is the scientist’s “educated guess” about WHY something he/she observes is happening. A hypothesis is often stated as an “if-then” statement. Sometimes a hypothesis is supported; sometimes it is not. Either outcome gives a scientist important information. Before you begin the field tests of your windmill generator make a hypothesis about the relationship of the intensity of the wind and the power generated by the windmill generator. Make another hypothesis about the relationship of the wind direction and the power generated by the windmill generator. Here is a sample hypothesis: If wind speed increases, then the brightness of the LED light will stay the same.

Wind Intensity Hypothesis: Make a hypothesis about the relationship of the wind’s intensity and the power created by the windmill generator. ______

Wind Direction Hypothesis: Make a hypothesis about the relationship of the wind’s direction and the power created by the windmill generator.

______

Investigation: Materials: • Two - liter bottle half filled with ice • Green Science™ Windmill Generator Kit • Hex head screwdriver • Box fan

Procedure: 1. Follow the instructions in the Green Science Windmill Generator Kit to build the generator. Use the hex head screwdriver provided to put the windmill generator together.

2. Attach the completed windmill generator to the top of two-liter bottle half filled with ice by the screw cap at the bottom. The LED light is now inside the bottle.

3. Take the completed windmill generator to the nearest box fan. Set the windmill generator on the tape mark in front of the fan.

Data: Wind Intensity: Set the bottle containing the windmill generator directly in front of the fan. Note what happens at each fan setting.

Low Setting: Did the rotor blades turn? Yes____ No____ Did the LED light? Yes____ No____ Note brightness of LED unit

Medium Setting: Did the rotor blades turn? Yes____ No____ Did the LED light? Yes____ No____ Note brightness of LED unit (brighter or less bright as compared to previous test?)

High Setting: Did the rotor blades turn? Yes____ No____ Did the LED light? Yes____ No____ Note brightness of LED unit (brighter or less bright as compared to previous test?)

Wind Direction: Set the bottle containing the windmill generator directly in front of the fan. Turn the setting to “High.”

Did the rotor blades turn? Yes____ No____ Did the LED light? Yes____ No____ Note brightness of LED unit

Turn the windmill generator at a 45-degree angle to the fan. Turn the setting to “High.”

Did the rotor blades turn? Yes____ No____ Did the LED light? Yes____ No____ Note brightness of LED unit (brighter or less bright as compared to previous test?)

Turn the windmill generator at a 90-degree angle to the fan. Turn the setting to “High.”

Did the rotor blades turn? Yes____ No____ Did the LED light? Yes____ No____ Note brightness of LED unit (brighter or less bright as compared to previous test?)

Turn the windmill generator at a 180-degree angle to the fan. Turn the setting to “High.”

Did the rotor blades turn? Yes____ No____ Did the LED light? Yes____ No____ Note brightness of LED unit (brighter or less bright as compared to previous test?)

Data Analysis: 1. What happened to the brightness of the LED unit as wind speed increased?

______

2. What happened to the brightness of the LED unit as the angle of the windmill to the box fan increased? ______

Conclusions: 3. Does the intensity of the wind make a difference in the performance of the windmill generator? Yes_____ No______

Based on your observations explain how you reached your conclusion. Use complete sentences. ______

4. Does the direction of the wind make a difference in the performance of the windmill generator? Yes_____ No______

Based on your observations explain how you reached your conclusion. Use complete sentences. ______

Further Questions: 5. Based on your observations of the small wind powered generator, what land and climate features need to be present in order for wind to be considered as a source of alternative energy for a whole community? List at least two. ______

Write the name of your community on the following line. ______

Does your community have the land and climate features necessary to consider wind as a source of alternative energy? Yes______No______

6. In the space below, explain your answer. Use complete sentences. ______

Overview: In this lesson students will learn about contour lines and how to identify features on a topographic map, then work with Elders to learn local place names.

Objectives: The student will: • identify features found on a topographic map by examining a U.S. Geological Survey contour map; • create a 3-dimensional model from a simple topographic map template; and • interview Elders to learn local place names.

Vocabulary: contour line – line on a map connecting points of the same elevation contour map – map that shows elevations and surface features of the land by means of contour lines elevation – the vertical distance between a standard reference point, such as sea level, and the top of an object or point on Earth, such as a mountain; the summit of Mount Everest is the highest elevation on Earth feature – a prominent or conspicuous part or characteristic glacier – a slowly moving mass or river of ice formed by the accumulation and compaction of snow on mountains or near the poles gradient – the degree to which something inclines; a slope island – a piece of land completely surrounded by water lake – a large inland body of standing fresh or salt water mountain – generally massive, usually steep-sided, raised portion of Earth’s surface; can occur as single peaks or as part of a long chain; can form through volcanic activity, by erosion, or by the collision of tectonic plates river – a large, natural stream of fresh water that flows into an ocean, a lake or other body of water, usually fed by smaller streams that flow into it slope – to have or take an inclined or oblique direction or angle considered with reference to a vertical or horizontal plane; slant topographic map – a map showing topographic features, usually by means of contour lines topography – the shape, height, and depth of the land surface in a place or region; physical features that make up the topography of an area include mountains, valleys, plains, and bodies of water; man-made features such as roads, railroads, and landfills are also often considered part of a region’s topography; detailed description or drawing of the physical features of a place or region valley – a low area of land between hills or mountains, typically with a river or stream flowing through it

Whole Picture:

Knowledge of the land and its topography is interwoven in the language of the Athabascan people. Gaa’al tajj njik means “where-game-usually-passes-along-a-trail,” and Jak ddhaa means “blueberries mountain” known for abundant blueberries. Kihtr’uu choh means “big bare-topped mountain,” and Vineeteiidii van means, “it-floods- over-lake,” a lake known to overflow in the winter.

Richard Nelson, in his book “Make Prayers to the Raven,” says it best. To most outsiders, the vast expanse of forest, tundra, and mountains in the Koyukon homeland constitutes a wilderness in the absolute sense of the word. For the Western mind, it is wilderness because it is essentially unaltered and lacks visible signs of human activity, and it must therefore be unutilized. But in fact the Koyukon homeland is not a wilderness, nor has it been for millennia. This apparently untrodden forest and tundra country is thoroughly known by a people whose entire lives and cultural ancestry are inextricably associated with it. The lakes, the hills, river bends, sloughs, and creeks are named and imbued with personal or cultural meanings. Indeed, to the Koyukon these lands are no more a wilderness than are farmlands to a farmer or streets to a city dweller. At best we can call them wildland. (246) Modern topographic maps differ from other maps in that they have lines that connect points of equal elevations. These lines are called contour lines and show the height above sea level. Topography is one of several factors that influence climate. The primary ways in which topography influences climate are temperature and precipitation.

Materials: • Sticky note flags • Topographic map of Alaska, Tyonek Quadrant (one per group) • Craft foam, approx. 9”x6”, as thick as possible (three+ sheets per group) • Scissors • Glue • Modeling clay (optional) • TEACHER INFORMATION SHEET: “USGS Topographic Map Symbols” • STUDENT INFORMATION SHEET: “Topographic Examples” • STUDENT WORKSHEET: “Topo Map Checklist” • STUDENT WORKSHEET: “Mapping Routes”

Activity Preparation: 1. Review TEACHER INFORMATION SHEET: “USGS Topographic Map Symbols” for information about how to read a topographic map. 2. Make extra copies of STUDENT INFORMATION SHEET: “Topographic Examples” for Activity Procedure 4. 3. The topographic map used in the lesson was chosen because it highlights such a wide variety of features. If possible, obtain a topographic map of your area for Activity Procedure 8. Invite an Elder to visit and talk about the local place names, including the reasons people chose to settle in the area.

Activity Procedure: 1. Divide students into groups. Hand out a copy of the topographic map of Alaska, Tyonek Quadrant. Allow students to explore the map for a few minutes then ask students to make some observations about the lines and symbols on the map. How many different kinds of features can they see? 2. Hand out STUDENT WORKSHEET: “Topo Map Checklist.” Ask students to complete the worksheet. Students should use sticky note flags to mark found items and should not mark on the maps. 3. Discuss the worksheet with students. “If there were no labels on the map, how would you be able to tell where there was a mountain? A lake? A glacier? A river?” Introduce related vocabulary words: contour line, elevation, topography, etc. Ask students to point to the highest elevation on a mountain. Circulate to check for understanding. 4. Divide students into groups. Distribute STUDENT INFORMATION SHEET: “Topographic Examples,” craft foam, scissors and glue. Ask each group to pick one of the maps to model. Ask students to cut out one piece of foam for each contour level. Next, ask students to glue their contour levels together to make the feature shown on the original map.

NOTE: Students can use extra copies of the map sheets to cut along contour lines and trace around them on the foam.

5. If time allows, hand out modeling clay and ask students to smooth the edges between the contour lines. 6. Allow students to compare models with classmates. Ask the following questions: a. What is a contour line? b. What does a river, lake, mountain, valley, island, etc. look like on a topographic map? c. How would you construct the contour lines on a topographic map to show a cliff? d. What would it feel like to walk in an area where the contour lines are far apart? Close together? 7. Hand out STUDENT WORKSHEET: “Mapping Routes.” Explain the directions and tell students to be prepared to explain their reasoning regarding the route they chose. Allow students time to complete. 8. Invite an Elder to visit and talk about the local place names. If available, label a map of your area (topographic or other map type) with Athabascan place names. Do a profile of the region. Find out why the Native people chose this spot to settle. What were the appealing topographic features?

Language Links: Ask a local Native language speaker to provide the words in the local dialect for the topography words listed in the chart below. The local dialect for these words may differ from the examples provided. Share the words with students to build fluency in local terms related to the land. Include local words in songs, stories and games when possible.

English Gwich’in Denaakk’e Lower Tanana Deg Xinag Your Language Land Nan Nen’ Nen’ Ngan River Han No’ Nik’a Xin Valley Nihtak Taayee Tok’a Hill Taih Teyh Teyh Mountain Ddhah Dle¬ Ddhe¬ Deloy Lake Van Benh Ben Vinq’it Glacier Git Loo Òu Ocean Chuu choo Daagheyukk kk’e Tth’itu’bogha

Answers: STUDENT WORKSHEET: “Topo Map Checklist” Part One Answers will be flagged on student maps.

Part Two 1. airplane 2. U.S. Geological Survey (USGS) 3. 200 feet 4. Hayes River 5. The person at point B

STUDENT WORKSHEET: “Mapping Routes” Answers will vary.

What is a Topographic Map? A map is a representation of the Earth, Reading Topographic Maps or part of it. The distinctive character- Interpreting the colored lines, areas, and other symbols is the fi rst istic of a topographic map is that the step in using topographic maps. Features are shown as points, lines, shape of the Earth’s surface is shown or areas, depending on their size and extent. For example, individual by contour lines. Contours are imag- houses may be shown as small black squares. For larger buildings, inary lines that join points of equal the actual shapes are mapped. In densely built-up areas, most indi- elevation on the surface of the land vidual buildings are omitted and an area tint is shown. On some above or below a reference surface, maps, post offi ces, churches, city halls, and other landmark buildings such as mean sea level. Contours are shown within the tinted area. make it possible to measure the The fi rst features usually noticed on a topographic map are the height of mountains, depths of area features, such as vegetation (green), water (blue), and densely the ocean bottom, and steep- built-up areas (gray or red). ness of slopes. Many features are shown by lines that may be straight, curved, A topographic map shows solid, dashed, dotted, or in any combination. The colors of the lines more than contours. The usually indicate similar classes of information: topographic contours map includes symbols (brown); lakes, streams, irrigation ditches, and other hydrographic that represent such fea- features (blue); land grids and important roads (red); and other roads tures as streets, buildings, and trails, railroads, boundaries, and other cultural features (black). At one time, purple was used as a revision color to show all feature streams, and vegetation. changes. Currently, purple is not used in our revision program, but These symbols are con- purple features are still present on many existing maps. stantly refi ned to better relate to the features they Various point symbols are used to depict features such as buildings, represent, improve the campgrounds, springs, water tanks, mines, survey control points, appearance or readability of and wells. Names of places and features are shown in a color cor- the map, or reduce production responding to the type of feature. Many features are identifi ed by cost. labels, such as “Substation” or “Golf Course.”

Topographic contours are shown in brown by lines of different Consequently, within the same widths. Each contour is a line of equal elevation; therefore, contours series, maps may have slightly dif- never cross. They show the general shape of the terrain. To help ferent symbols for the same feature. the user determine elevations, index contours are wider. Elevation Examples of symbols that have values are printed in several places along these lines. The narrower changed include built-up areas, roads, intermediate and supplementary contours found between the index intermittent drainage, and some letter- contours help to show more details of the land surface shape. Con- ing styles. On one type of large-scale tours that are very close together represent steep slopes. Widely topographic map, called provisional, spaced contours or an absence of contours means that the ground some symbols and lettering are hand- slope is relatively level. The elevation difference between adjacent contour lines, called the contour interval, is selected to best show drawn. the general shape of the terrain. A map of a relatively ﬂ at area may have a contour interval of 10 feet or less. Maps in mountainous areas may have contour intervals of 100 feet or more. The contour interval is printed in the margin of each U.S. Geological Survey (USGS) map.

Bathymetric contours are shown in blue or black, depending on their location. They show the shape and slope of the ocean bottom surface. The bathymetric contour interval may vary on each map and is explained in the map margin. U.S. Department of the Interior U.S. Geological Survey

Hill

1000’

750’ Contour Interval = 100 ft

Two Hills with Valley Dome

2100’

2350’

2316’

2400’

2200’

2000’ 2300’ Contour Interval = 100 ft

Ridge

1100’ 1000’ 900’ 800’ 700’

1000’ 900’

1100’

Contour Interval = 100 ft

PART ONE Directions: Find the following on the USGS topographic map and mark each one with a sticky note flag.

_____ Beluga Mountain _____ Tyonek _____ Chakachamna Lake _____ Susitna Flats _____ Shamrock Glacier _____ Neacola Mountains _____ Cook Inlet _____ Porcupine Butte _____ Mount Susitna _____ Skwentna River _____ Fire Island _____ Parks Highway _____ The Iditarod Trail _____ Border for Lake Clark National Park _____ Border separating the Matanuska-Sustina Borough and the Kenai Peninsula Borough

PART TWO Directions: Refer to the USGS topographic map to answer the following questions.

1. What is the symbol for a landing strip? ______

2. Who published the map? ______

3. How far apart are the contour intervals? ______

4. What river is fed by Hayes Glacier? ______

5. Refer to the figure below. One person is standing at point A, another at point B. Which person is standing at a higher elevation? ______

B A

Directions: Draw a route between point A and point B on the topographic map below. Your route should be the one that makes the most sense to travel. There is no single correct route, however, you should use the features of the map to help make your choice.

Overview: In this lesson, students review cloud types, cloud cover and basic weather vocabulary through multimedia, hands-on activities and written work. Students then work as a class to collect long-term weather data at their school, supplementing the data they collect with data retrieved from the Alaska Climate Research Center.

Objectives: The student will: • review basic weather terminology and phenomenon; • collect long-term weather data at their school; • retrieve weather data from the Internet; and • practice using basic weather symbols.

Vocabulary: atmosphere – the mixture of gases that surrounds Earth barometer – an instrument for measuring atmospheric pressure climate – the average weather conditions of a region over time (30 years or more) condensation – the change of a gas or vapor into a liquid, either by cooling or increased pressure dew point – the temperature at which air becomes saturated with water vapor and dew forms evaporation – the change of a liquid into a vapor at a temperature at or below the boiling point precipitation – a form of water, such as rain, snow or sleet, that condenses from the atmosphere and falls to Earth’s surface relative humidity – the ratio of the actual amount of water vapor present in the air at a given temperature to the maximum amount of water vapor the air could hold at that temperature weather – the state of the atmosphere at a particular time and place wind chill – a measure of the effect of wind on air temperature; the felt temperature on exposed skin due to wind

Whole Picture: Many people, including Alaska Native Elders and scientists, note patterns in weather to share with others and prepare for future conditions. Earth’s changing climate has made it even more important to keep long-term weather data and to monitor these data for changes and trends, especially in places like Alaska where change is happening most rapidly. Weather is different from climate. Weather describes atmospheric conditions over a short period of time, whereas climate describes atmospheric conditions over relatively long periods of time (at least 30 years.) Examples of climatic conditions measured over time include sea level rise and permafrost thaw.

Knowledge of weather phenomena is an integral part of Alaska Native culture. Native Elders have long been able to predict weather based on observations. These observations and predictions are crucial to subsistence activities and safety. Weather words, including many different descriptors for clouds, are present in all Alaska Native languages.

Materials: • Binder • NOAA/NASA Skywatchers chart • Glue stick • Scissors • White construction paper (one sheet per group) • Blue construction paper (one sheet per group) • Min/max outdoor thermometer • TEMPLATE: “Weather Data” • TEACHER INFORMATION SHEET: “Introductory Activities: Weather” • TEACHER INFORMATION SHEET: “Weather Symbols” • STUDENT WORKSHEET: “Weather Words” • STUDENT WORKSHEET: “Weather Symbols” • TEMPLATE: “Weather Symbols”

Activity Preparation: 1. Make copies of TEMPLATE: “Weather Data” and insert into binder. 2. Choose a location for the outdoor thermometer. 3. Devise a strategy for how and where your class will collect weather data. [Note: Stick to a standard time and process (i.e. at the start of the day or class period). Data collection should not take more than 10 minutes.] Students will need access to the Internet to record information from the Alaska Climate Research Center as well as time to check the conditions outdoors. You may choose to make collecting weather data the responsibility of one or more students for a day or week at a time and rotate. Students can report back to the class. 4. Two reliable websites for retrieving weather data from the Internet are: the Alaska Climate Research Center and Weather Underground. Check them both to determine which you will use with your class. a. Weather Underground (http://www.wunderground.com/)—Visit. Enter your community’s zip code. Bookmark this website. b. Alaska Climate Research Center (http://climate.gi.alaska.edu/)—Bookmark the main website as well as a link for sunrise/sunset information for your village. Bookmark the main page, then click on the menu for “External Weather Links.” Select “sunrise/sunset” from the drop down menu. When you reach the “Heavens Above” website, select the link for “Home.” Click “edit manually” under the heading “Configuration.” Enter the latitude, longitude and name of your village, then click “submit.” This should bring you back to the “Home” page. Now click on the link for “Sun” data for today and you should see sunrise/sunset information for your village. Bookmark this page. 5. Review TEACHER INFORMATION SHEET: “Introductory Activities: Weather.” Decide which (if any) are appropriate for your class. 6. Review STUDENT WORKSHEET: “Weather Symbols” and TEACHER INFORMATION SHEET: “Weather Symbols.” Print TEACHER INFORMATION SHEET: “Weather symbols.” Cut the daily weather reports on the dotted lines so that you have six strips of paper.

NOTE: This lesson requires data collection over a period of weeks or even months. The duration of data collection is flexible and up to your discretion. You may choose to make it a daily or weekly task for a small group of students and rotate the responsibility over time. You may choose to collect weather data for a few weeks or throughout the entire school year.

Activity Procedure: 1. Ask students why people observe, record and study weather. The ensuing discussion should include an understanding that weather and climate affect almost all aspects of our lives, including how we supply our basic needs and the renewable energy options that are feasible for our communities. Ask students to list aspects of their lives that are impacted by weather and climate. Include a discussion of the difference between weather and climate. 2. Conduct any activities from TEACHER INFORMATION SHEET: “Introductory Activities: Weather” that are appropriate for your class. 3. Explain that the class will be working together to collect long-term weather data in a class weather journal. Data will be collected via observations at your school and via weather data available from the Alaska Climate Research Center. Explain your strategy for data collection (what time of day, location, who will collect data, etc.). 4. Review the process of retrieving weather data from the Internet. If using the Alaska Climate Research Center website, visit http://climate.gi.alaska.edu. Click on the link “Current conditions and weather forecasts” found under the Alaska Weather heading on the menu to the left of the screen. Click on “Current weather conditions around Alaska (Pop-Up Map)” found under CURRENT CONDITONS. Choose your village and record the current weather conditions, date and time. 5. Review the process of retrieving sunrise/sunset information for your village. Show students how to access the “Heavens Above” website bookmarked on your computer. Sunrise and sunset appear in bold. Students will need to calculate the length of day. 6. Pass out STUDENT WORKSHEET: “Weather Symbols.” Review the symbols and how to fill in the boxes found on the weather data sheets. 7. Practice interpreting weather symbols. Pass out the six daily weather descriptions to six students. Instruct them to read each aloud, one at a time, pausing at the end of each sentence. Students should raise their hand as soon as they have identified which number matches this description. When the class has identified it correctly, students should fill in the date on the line provided. 8. Use TEMPLATE: “Weather Symbols” if you would like students to draw some weather symbols for further practice.

Extension Ideas: 1 E 1. Calculate the mean, median, mode, and range of V 2 3 temperatures for given month or season. Graph C O N D E N S A T I O N the results. E P 2. Calculate the percentage of sunny days (cloud W O cover less than 50%) each month. Calculate the P R 4 5 number of calm versus windy days. Discuss what P R E C I P I T A T I O N A R this means for alternative energy strategies for I T E 6 7 the community. W I N D C H I L L E T L O A 3. Compare each day’s high and low to the normal A I N T 8 and/or record temperatures for that date. B A R O M E T E R M I 4. Calculate the heating degree days for each daily H A V 9 temperature. (See the lesson Community Energy A T M O S P H E R E T E Use for more on heating degree days.) R E H U Answers to STUDENT WORKSHEET: “Weather Words” M I See figure at right. D I T Y

Answers to STUDENT WORKSHEET: “Weather Symbols” 1. April 3 2. November 2 3. August 11 4. October 1 5. January 31 6. July 16

Directions: The following activities are provided as optional introductory activities to the weather journal lesson. Choose the activities best suited to students’ experience and knowledge base. 1. Review MULTIMEDIA: “Earth’s Weather Scavenger Hunt.” Decide which pieces (if any) you will use to supplement learning in this lesson. Suggestions include: “weather observation” and “sundogs” for cultural integration, “cloud game” to review cloud types, and “air pressure” to review wind and the Beaufort scale.

2. Estimating Cloud Cover: In this activity, students practice visually estimating cloud cover. Each student group will need one piece of blue construction paper, one piece of white construction paper and a glue stick. Work with students to fold the white piece of construction paper into 10 roughly equal squares. (Make one fold down the center the long way, and four folds the short way, approximately 2¾ inches apart.) Each group should choose the percent cloud cover they would like to represent (in intervals of 10) and use the appropriate number of squares to make clouds. (Each square represents 10%.) Students should use the entire square, but may tear or cut it into cloud shapes. Students should glue their clouds to the blue piece of paper (without overlapping) and write their percentage on the back of the page. Allow each group time to show their sky while other groups estimate the cloud cover represented. Facilitate a discussion about which ones were easiest to estimate and why. This activity is part of the GLOBE (Global Learning and Observations to Benefit the Environment) lesson Estimating Cloud Cover: A Simulation (http:// www.globe.gov/tctg/atla-cloudcover.pdf?sectionId=20&lang=EN).

3. Assign STUDENT WORKSHEET: “Weather Words” as a review in class or as homework.

January 31: Clear skies and calm wind. Temperature is –37.1 °F. Barometric pressure is 29.52 inches Hg. ______

July 16: Low visibility. Sky is obscured with significant smoke. Temperature is 74.4 °F. Barometric pressure is 30.11 inches Hg. ______

August 11: Rain and overcast skies. Wind from the north at 3 – 7 knots. Temperature is 44.2 °F. Barometric pressure is 29.91 inches Hg. ______

October 1: Cloud cover more than 80% (7/8). Snow. Light wind from the east at 1–2 knots. Temperature is 21.1 °F. Barometric pressure is 29.81 inches Hg. ______

April 3: Overcast skies. Significant fog. No wind.Temperature is 30.9 °F and barometric pressure is 29.07. ______

November 12: Cloud cover over 10% (1/8). Winds from the south at 13 – 17 knots. Temperature is –12.6 °F and barometric pressure is 30.04. ______

Directions: Complete the crossword puzzle using the clues provided and the vocabulary words from the Word Box below. Word Box climate Across barometer 2. the change of a gas or vapor into a liquid, either by cooling or increased pressure atmosphere 4. a form of water, such as rain, snow or sleet, that condenses from the atmosphere and precipitation falls to Earth’s surface condensation 6. a measure of the effect of wind on air temperature; the felt temperature on exposed relative humidity skin due to wind weather 8. an instrument for measuring atmospheric pressure wind chill dew point 9. the mixture of gases that surrounds Earth

Down 1. the change of a liquid into a vapor at a temperature 1 below the boiling point

3. the temperature at which air becomes saturated with 2 3 water vapor and dew forms 5. the ratio of the actual amount of water vapor present in the air at a given temperature to the maximum amount that the air could hold at that temperature 6. the state of the 4 5 atmosphere at a particular time and place 6 7 7. the average weather conditions of a region over time

Directions: Meteorologists (scientists who study weather and climate) have developed Sky Cover a system of symbols to help them communicate weather conditions quickly clear and efficiently. Information is recorded in each corner of the box. The circle in the center indicates sky 1/8 cover. A line coming from Temperature Pressure the center circle shows (°F) (inches Hg) scattered the direction the wind is ) and D ots ire 3/8 coming from. (Imagine the n ct (k io center circle is a compass.) d n e e 4/8 The line is branched to p S

indicate wind speed (in d Sky

n 5/8

knots). Look at the boxes i Cover W on the next page and broken listen to the six weather descriptions. Decide which 7/8 box matches each date and write the date on the line overcast Weather provided. Condition obscured

Weather Conditions Wind Speed Rain Speed Symbol Beaufort Scale in miles per Shaft shows direction in knots (kn) Description hour (mph) wind is coming from Rain Shower Calm Calm smoke rises vertically Thunderstorm

Drizzle 1 – 2 kn 1 – 2 mph smoke drifts slightly

Snow 3 – 7 kn 3 – 8 mph leaves rustle

Snow Shower 8 – 12 kn 9 – 14 mph leaves in constant motion

Freezing Rain 13 – 17 kn 15 – 20 mph raises dust; branches stir Freezing Drizzle 18 – 22 kn 21 – 25 mph small trees sway Fog 23 – 27 kn 26 – 31 mph large branches move Haze whole trees in motion; twigs break 48 – 52 kn 55 – 60 mph Smoke off trees; slight structure damage trees uprooted; 73 – 77 kn 84 – 89 mph Dust or Sand severe structural damage

Blowing Snow 103 – 107 kn 119 – 123 mph devastation

1. 30.9 29.07 2. –12.6 30.04

3. 44.2 29.91 4. 21.1 29.81

5. –37.1 29.52 6. 74.4 30.11

Date: ______Temperature Pressure Time: ______(°F) (inches Hg) Location: ______

Current temperature: ______Minimum temperature for last 24 hours: ______Maximum temperature for last 24 hours: ______

Sunrise: ______Sunset: ______Length of Day: ______

Weather Wind Speed (Knots) Wind Speed & Direction: ______Condition and Direction

Cloud Type: ______Cloud Cover: ______

Notes:

RETRIEVING WEATHER DATA FROM THE ALASKA CLIMATE RESEARCH CENTER: 1. Go to the Alaska Climate Research Center website at: http://climate.gi.alaska.edu 2. Click on the link “Current conditions and weather forecasts” found under the Alaska Weather heading on the menu to the left of the screen. 3. Click on “Current weather conditions around Alaska (Pop-Up Map)” found under CURRENT CONDITONS. 4. Choose your village and record wind conditions and atmospheric pressure.

Overview: Students investigate cloud types with a focus on noctilucent clouds, a rare cloud type scientists think could be a climate-change indicator, then interview Elders about cloud knowledge as a weather predictor.

Objectives: The student will: • view visual aids, online multimedia and a classroom demonstration to review basic information about cloud formation and types; • read and answer questions about a series of science articles that trace scientific knowledge of noctilucent clouds; and • build a model that represents the conditions necessary to view noctilucent clouds.

Vocabulary: altostratus – middle clouds, light gray and uniform in appearance, generally covering most of the sky; indicate the likelihood of precipitation altocumulus – middle clouds with puffy, patchy appearance cirrus – a cloud formation made up of feathery white patches, bands, or streamers of ice crystals; cirrus clouds form at upper levels of the atmosphere cirrocumulus – high clouds with puffy, patchy appearance, often with wave-like patterns, the clouds indicate rain, thunder, lightning, and wind, never produce rain or snow cirrostratus – high clouds, light gray or white, often thin with light seen through them; usually covers much of the sky; never produce rain or snow cloud – a visible mass of condensed water droplets or ice particles floating in the atmosphere; clouds take various shapes depending on the conditions under which they form and their height in the atmosphere, ranging from ground level or sea level to several miles above Earth condensation – the change of a gas or vapor to a liquid, either by cooling or by being subject to increased pressure; when water vapor condenses in the atmosphere, it condenses into tiny drops of water, which form clouds cumulonimbus – large clouds with dark bases and tall billowing towers, can have sharp well defined edges or anvil shape at the top, can be accompanied by thunder, usually are seen when there is a storm or storm coming cumulus – a white, fluffy cloud often having a flat base; cumulus clouds form at lower levels of the atmosphere and are generally associated with fair weather, however large cumulus clouds that billow to higher levels can produce rain showers ice – water frozen solid, normally at or below a temperature of 32° nimbostratus – low and middle dark gray clouds with precipitation falling from them precipitation – a form of water, such as rain, snow, or sleet, that condenses from the atmosphere and falls to Earth’s surface

stratus – a low-lying, grayish cloud layer that sometimes produces drizzle; a stratus cloud that is close to the ground or water is called fog stratocumulus – low clouds with irregular masses, rolling or puffy in appearance, sometimes with space between clouds; often form after a rainstorm water cycle – the continuous process by which water is distributed throughout Earth and its atmosphere; energy from the sun causes water to evaporate from oceans and other bodies of water and from soil surfaces; plants and animals also add water vapor to the air by transpiration; as it rises into the atmosphere, the water vapor condenses to form clouds; rain and other forms of precipitation return water to Earth, where it flows into bodies of water and into the ground, beginning the cycle over again water vapor – water in its gaseous state, especially in the atmosphere and at a temperature below the boiling point

Materials: • Small, clear plastic container w/clear lid (or use clear plastic wrap), big enough for tin can lid to fit inside • Salt (a pinch) • Lid from juice concentrate or cut lid from canned good • Soda bottle lid • Warm water • Styrofoam™ ball, approximately 6” (one per group) • Flashlight, small (one per group) • Batting (small pinch per group) • Toothpicks (5 per group) • Round head sewing pin (1 per group) • Oil pastels (1 set per group) • Clay or tacky putty (one lump per group) • NOAA/NASA Cloud Chart (one per pair) • MULTIMEDIA: “Cloud Game” • MULTIMEDIA: “Noctilucent Cloud Song” • VISUAL AID: “Clouds” • VISUAL AID: “Noctilucent Clouds” • VISUAL AID: “Noctilucent Clouds in Perspective” • VISUAL AID: “Studying Noctilucent Clouds” • STUDENT INFORMATION SHEET: “Scientists Learn About Night-Shining Clouds” • STUDENT INFORMATION SHEET: “Noctilucent Cloud Song Lyrics” • STUDENT WORKSHEET: “Cloud Review” • STUDENT WORKSHEET: “Understanding Night-Shining Clouds” • STUDENT LAB: “Understanding Night-Shining Clouds” • STUDENT WORKSHEET: “Elder Interview”

Whole Picture: Alaska Native people have always been careful observers of the weather. Native languages are rich in words describing weather. Knowing how to interpret the weather, including the cloud types, is important cultural knowledge. It affects all aspects of daily and yearly cultural activities, especially subsistence hunting and food gathering. By middle school, students likely have knowledge of how clouds form. In case review is needed: Clouds are formed when water on Earth evaporates and forms water vapor held in the air. As warm are rises, cooling occurs. The cooler the air, the smaller the amount of water vapor it can hold, therefore some of the water vapor is forced to condense onto tiny particles (dust, pollution, etc.) floating in the atmosphere. A small drop of water forms around each particle. A cloud is a visible mass of such water in the form droplets of water

or ice crystals small enough to stay suspended in the atmosphere. Noctilucent clouds are clouds on the edge of space that are visible in Alaska and similar latitudes in late summer. They occur in the extreme conditions of the cold summer mesosphere. The appearance of the clouds appears to be sensitive to environmental conditions. The sky must be relatively free of tropospheric clouds. The 82- kilometer altitude region must be in

sunlight – this condition is fulfilled Illustration courtesy of NASA when sun is less than 16 degrees below the observer’s horizon. The sky background must be dark enough for the clouds to stand out – this requires that the sun is at least 6 degrees below the horizon. In the last few decades scientists, such as those with NASA’s AIM (Aeronomy of Ice in the Mesosphere) have learned a lot about how the clouds form. At temperatures around minus 230 degrees Fahrenheit, dust from space that finds its way to the atmosphere provides a resting spot for water vapor to condense and freeze. The clouds form every day and are widespread, though can only be see under certain environmental conditions. During the northern hemisphere’s summer, the atmosphere is heating up and expanding. At the outside edge of the atmosphere, that actually means that it’s getting colder because it’s pushed farther out into space.

Activity Preparation: Gather the materials needed for the lesson and review the information and related articles.

Activity Procedure: 1. Gauge student knowledge and review the basics of cloud formation with students as needed. As a motivational activity, perform the following demonstration: a. Fill a soda bottle cap with water and place it on the bottom of the clear container.

b. Place a few salt grains onto the metal lid (removed from the can). c. Set on top of the soda bottle cap.

d. Carefully add warm water to the dish so that the bottom is covered. Do not wet the lid.

e. Cover the container with a lid or plastic wrap. Make sure it is tightly covered.

f. Wait 20 minutes. While waiting, continue with the lesson. g. After 20 minutes, you should see water gathered around the salt. The water evaporated from the bottom of the container, but instead of escaping into the air, it attached itself to the salt, just like it does to dust and other microscopic particles in the air.

2. Show VISUAL AID: “Clouds” and review the three basic cloud types. 3. Hand out STUDENT WORKSHEET: “Cloud Review.” Explain students will use the information in the worksheet along with MULTIMEDIA: “Cloud Game,” found at www.uniteusforclimate.org, to complete the worksheet. If students are having trouble finding answers to the crossword puzzle, allow them to ask peers for assistance. Students should not give peers the answer, but instead show them where to find it.

NOTE: Have you checked the demonstration? Reiterate that dust and other pollutants form the nucleus for water droplets. Ask: What kinds of things are atmospheric pollutants? (exhaust, smoke, volcanic ash, factory pollution, etc.)

4. Write the word “noctilucent” on the board. Ask students if they have heard the word. Remind them of the word “nocturnal”. What part of the word is similar? (noct meaning night) What about “lucent” – what does it mean? (Means softly bright or radiant, shining) Write the word “clouds” after noctilucent. “Knowing what you do about the word, what kind of clouds do you think these are?” (night-shining, or night-glowing clouds) 5. Explain students are going to study about notilucent clouds, which are a very rare kind of cloud found only in Alaska and other areas with similar latitude. Noctilucent clouds can only be seen under very specific circumstances: The sun must be below the horizon but still casting light into the upper atmosphere, the sky must be free of other cloud types (which could obstruct the view) and it must be late summer. Tell students they will hear more about these things in the lesson. 6. Show VISUAL AID: “Noctilucent Clouds.” Explain noctilucent clouds are found in an area of the atmosphere much higher than more common clouds. Show VISUAL AID: “Noctilucent Clouds in Perspective.” Point out the highest common clouds (associated with weather patterns) are found up to about 10 miles above Earth’s surface. Noctilucent clouds are found about 50 miles above the surface. They are not associated with weather, but are thought to be a climate indicator.

7. Hand out STUDENT INFORMATION SHEET: “Scientists Learn About Night-Shining Clouds” and STUDENT WORKSHEET: “Understanding Night-Shining Clouds.” The reading level in each article included is high school level, so choose a reading strategy best suited for the class. Consider reading aloud to students, one article at a time, then discussing each set of related questions. When you reach the Critical Thinking section, consider doing a Think-Pair-Share activity. Ask students to pair up and talk about the questions. Once they have explored the question, ask them to share their ideas with one other pair then write the answer they think is best on their own worksheet. 8. Divide students into small groups. Hand out STUDENT LAB: “Understanding Night-Shining Clouds.” Ask each group to select a member to collect materials listed on the lab sheet. Read through the directions then allow students to explore on their own. Circulate to check for understanding. 9. Hand out STUDENT WORKSHEET: “Elder Interview.” Explain students will interview Elders and culture bearers to find out Native language terms for different cloud types and weather associated with such clouds. Assist students in identifying Elders to visit. Students may visit individually or in small groups. 10. After Elder visits are complete, ask each student to share what they learned from their Elder interview with the class. Help students identify similarities and differences among information learned from different Elders. Create a class list of Native language terms for clouds and cloud types..

Language Links: Ask a local Native language speaker to provide the words in the local dialect for the weather phenomenon listed in the chart below. The local dialect for these words may differ from the examples provided. Share the words with students to build fluency in local terms related to weather. Include local words in songs, stories and games when possible.

English Gwich’in Denaakk’e Lower Tanana Deg Xinag Your Language Rain / It’s Kohn / yo¬ee raining Tsin / ahtsin hødelaatlghaanh Chonh Chonh Wind / It’s windy Ahtr’aii Ts’ehy Eltr’eyh Xidetr’iyh Snow / It’s snowing Zhah Tseetl Yeth Yith Zhee k’oh / Clouds / It’s Kk’ul / yokk’u¬ K’wth / k’wth cloudy gwit’eh goo’aii hoolaanh xulanh Q’uth Sun / It’s sunny Drin oozhrii So / Sole¬ Sro No’oy Freeze / It’s freezing Datan Ggaats Gats Ice Òuu Ten Tenh Tinh

Extension Ideas: 1. Visit NASA’s AIM (Aeronomy of Ice in the Mesosphere) Project website to learn more about the latest discoveries involving noctilucent clouds. (http://aim.hamptonu.edu/mission/index.html) 2. Consider studying other rare cloud formations and the cause behind them. Look for rare cloud types such as nacreous clouds, mammatus clouds, altocumulus castelanus, mushroom clouds, cirrus Kelvin-Helmholtz, lenticular clouds, roll clouds, shelf clouds, Morning Glory clouds, pileus cloud, and diamond dust. Visit the cloud appreciation society website for tips. (http://cloudappreciationsociety.org/) 3. Perform the “cloud in a bottle” demonstration. Pour two inches of very hot tap water into a clear, empty 2-liter soda bottle that has the label removed. Place your mouth over the opening and blow into it to ensure

the bottle is fully expanded. Immediately seal the bottle tightly. Shake the bottle vigorously for one minute. This will distribute water molecules in the air. Light a match and let it burn for two seconds then drop it into the bottle. Quickly recap the bottle. Lay the bottle on its side with black paper behind it. Press hard on the bottle for ten seconds. The bottle is strong, so don’t be afraid to really push hard. Release, observe and repeat until a cloud forms. When the cloud forms, unscrew the cap. You should see the cloud escape from the bottle. If not, give the bottle a light squeeze. The cloud in a bottle activity simulates the conditions necessary for cloud formation: water vapor in the air, smoke particles for water to collect on, and cooling of the air by lowering the air pressure within the bottle.

Answers: STUDENT WORKSHEET: “Cloud Review” 1.-3. Answers will vary. Drawing should resemble C U M U L U S C description and VISUAL AID. I O 4. See crossword puzzle answers at right. R N R D STUDENT WORKSHEET: “Understanding Night U L E Shining Clouds” S T R A T U S N 1. 1885 Y T S 2. No, they thought it was ice-coated dust E R A particles from the dust of meteors. F A I R A T 3. C. 50 Miles T L I G H T N I N G 4. B. An electron microscope found that nickel F O G O was in the clouds, an element in meteors. C N 5. A Nike-Cajun rocket N I M B O S U S 6. No M 7. Any one of the following: Why are the clouds A L T I T U D E only seen in the summer? Why are the displays L localized? Why do the clouds behave the way C I R R O C U M U L U S they do? S 8. lasers 9. They pop before they reach high enough. 10. C. During the warm summer months. 11. D. All of the above. 12. Yes 13. Answers will vary but student should indicate an understanding of at least one of the following concepts: In the last three decades (1979 – 2007 or current) understanding of the cause of noctilucent clouds has increased. A variety of different scientific instruments have been used to study the clouds so scientists have much more data. The theory that meteor dust helps form the clouds is now widely accepted. 14. Answers will vary but students should indicate that the sighting of noctilucent cloud is a new phenomenon; scientists wonder if the sightings began around the same time that the climate began to warm. Many scientists attribute the recent trend toward a warmer climate to human activity, such as an increase in carbon dioxide in the atmosphere. Carbon dioxide is a greenhouse gas.

STUDENT WORKSHEET: “Elder Interview” Answers will vary depending on the Elder interviewed.

Cirrus clouds Cirrus clouds occur high up in the sky. These thin, wispy clouds are often stretched out by high winds.

Cumulus clouds Cumulus clouds are white, puffy clouds that look like floating cotton balls. When they grow larger and taller, they can develop into thunderstorm clouds.

Stratus clouds Stratus clouds are thick gray clouds that occur lower and often cover the entire sky. Light rain or drizzle often falls from these clouds.

Noctilucent clouds look like their wispy cousin the cirrus, but they occur at a much higher altitude.

Cirrus clouds are found in the troposphere – about 10 miles up (6 to 12 kilometers).

Noctilucent clouds are much higher. They occur in the mesosphere – about 50 miles up (82 kilometers).

The conditions under which they occur are slightly different than other cloud types too. • They are only seen in the Arctic. • They are only seen in late summer. • They are only seen at dusk or dawn. • Reported sightings are new to recorded history. The clouds may be a climate change indicator.

Noctilucent cloud photos by Patrick Cobb.

UAF, in partnership with NASA and several other agencies, operates a rocket range that also serves as a clustered observatory for rocket-borne and ground-based studies of the atmosphere. These images, taken at Poker Flat Research Range were provided by the University of Alaska Fairbanks Geophysical Institute.

NOTE: The following articles, Noctilucent Clouds, Clouds that Glow at Night and Exploring the Heavens with Laser Light, are excerpts from the Alaska Science Forum. The full article for each can be found at the Geophysical Institute website: http://www.gi.alaska.edu/ScienceForum/.

Noctilucent Clouds by T. Neil Davis September 28, 1979, Article #346

This column is provided as a public service by the Geophysical Institute, University of Alaska Fairbanks, in cooperation with the UAF research community. T. Neil Davis is a seismologist at the institute. Like blue-white spider webs laced across the twilight sky, noctilucent clouds form a wispy filigree in the heavens. Truly a polar phenomenon, noctilucent clouds are never seen at latitudes below 45°. Thus, in North America, noctilucent clouds are pretty much the property of Alaska and Canada. Nor are noctilucent clouds an everyday occurrence. In 1885, they were first recognized as something strange in the sky. Since then more than a thousand sightings have been recorded in the world. Several displays occurred over central Alaska in the summer of 1979. The characteristic that distinguishes noctilucent clouds from all others is their remarkably high altitude, 82 (plus or minus a few) kilometers (about 50 miles). Rarely do normal clouds extend as high as 15 kilometers. Noctilucent clouds are seen only in deep twilight, when the sun is 6° to 16° below the horizon. Then the sky is dark enough for the thin noctilucent clouds to be seen and yet the sun is still in position to reflect enough light from the clouds to make them visible to an observer. Though noctilucent clouds have been recognized for nearly a century, no one quite knows why they occur. Almost certainly, the clouds consist of ice-coated dust particles, the dust presumably coming from meteors striking the atmosphere. Beyond that, not much is known.

Clouds that Glow at Night by Larry Gedney July 30, 1982, Article #556

This article is provided as a public service by the Geophysical Institute, University of Alaska Fairbanks, in cooperation with the UAF research community. Larry Gedney is a seismologist at the Institute. As we move into August, the opportunity to observe noctilucent clouds is at its best. Many people who have lived in the northern latitudes for years have probably noticed them before without having a proper appreciation for what they really are. Noctilucent (night-shining) clouds ride in the sky above 99.9 percent of the atmosphere and over 40 miles above the highest clouds associated with weather. At an average altitude of 50 miles (80 km), they actually skirt the lowest fringes of the aurora, and are above the height at which meteors are observed. For reasons which are not well understood, they occur only at higher latitudes and almost exclusively during the summer months. What are they made of and why are they there? Some rocketborne observations have provided clues. The first of these studies was made in Sweden in 1962. A Nike-Cajun rocket with a payload designed to trap particles of a cloud and return them to earth was fired into a noctilucent display and successfully recovered. Under an electron microscope, the surfaces on which the particles were captured revealed millions of minute motes of dust as small as 0.05 microns in diameter (a micron is one-thousandth of a millimeter, a millimeter is about half the thickness of pencil lead). Electron bombardment indicated that the particles contained nickle. Nickle is an element quite rare on earth, but common in meteorites.

The picture which therefore emerges is that noctilucent clouds are meteor dust particles covered with ice. Knowing what they are, however, in no way explains why they behave as they do. It would be expected that meteoritic particles would be evenly distributed in the earth’s upper atmosphere. Why, then, are noctilucent displays localized; why do they occur only occasionally; why only during the summer months; and, why only at the higher latitudes? These questions about the rare and beautiful spectacle remain to be answered.

Exploring the Heavens with Laser Light by Ned Rozell February 17, 1998, Article #1376

This column is provided as a public service by the Geophysical Institute, University of Alaska Fairbanks, in cooperation with the UAF research community. Ned Rozell is a science writer at the institute. Imagine a glowing green pencil that reaches so far into the night sky it seems to pierce the Big Dipper. Such is the sight on a hillside above the Chatanika River valley, where scientists at Poker Flat Research Range aim lasers skyward. With lasers, they hope to learn more about the upper tiers of Earth’s atmosphere. Laser light is the primary tool of Richard Collins, a researcher at the Geophysical Institute of the University of Alaska Fairbanks. Unlike a standard light bulb that emits light in all directions, a laser’s energy is focused in one direction. Collins is able to send pulses of laser light high enough to reach the part of the atmosphere he studies—the mesosphere, a region from thirty to fifty miles above sea level, just below where the bottom of the aurora forms. The laser also allows Collins to see noctilucent, or “luminous night” clouds. Collins is funded to study the mesosphere because scientists think this area will cool as Earth’s surface warms, and they want to find out why. Because the mesosphere is a tough place to study—balloons carrying sensors pop before they get that high, and satellites can’t orbit that low—scientists know little about the region. The mesosphere is the home of shooting stars, where meteors flame out as they hurdle toward Earth at speeds as fast as 30 miles per second. Meteors, pebble-size fragments left over from the birth of the solar system, glow with the heat of friction as they collide with gas molecules in the mesosphere. When a meteor burns, it leaves a trail of smoke and atoms of metal. Oddly, temperatures in the mesosphere are coldest when it is warmest on the ground. This leads to the formation of noctilucent clouds above Alaska in August. Because the clouds have only been reported since the 1870s, scientists wonder if perhaps human activity causes or intensifies the clouds, which may be the result of pollution and a fingerprint of global change. Measurements taken throughout the year, through the waxing and waning of the seasons, are important in understanding how the entire atmosphere might evolve over the long haul. Collins gathers information from the mesosphere with an incredibly simple tool—a column of colored light that reaches where more complicated machines fail.

Polar Ice Clouds May Be Climate Change Symptom

ScienceDaily (Aug. 21, 2007) — As the late summer sun sets in the Arctic, bands of wispy, luminescent clouds shine against the deep blue of the northern sky. To the casual observer, they may simply be a curiosity, dismissed as the waning light of the midnight sun. But to scientists, these noctilucent ice clouds could be an upper-atmospheric symptom of a changing climate. “The question which everyone in Alaska is dealing with is what are the symptoms of climate change and, as in medicine, how do these symptoms reflect the underlying processes,” said Richard Collins, a researcher at the Geophysical Institute at the University of Alaska Fairbanks. “It is believed that [these clouds] are an indicator of climate change.”

Dozens of scientists from several countries will gather at the University of Alaska Fairbanks Aug. 20-23 to discuss the latest findings on noctilucent clouds and other phenomena of the earth’s upper atmosphere during the Eighth International Workshop on Layered Phenomena in the Mesopause Region. Sessions will include information on the latest ground-based and satellite data on the mesopause region, an area of the atmosphere 50 miles above Earth’s surface and the site of the coldest atmospheric temperatures. Noctilucent clouds form under conditions that counter common logic. They only form in the summer, when solar radiation is most intense, Collins said. That solar heating, rather than warming the mesopause, causes cooling, he said. “The mesopause region is colder in summer under perpetual daylight than it is in winter under perpetual darkness.” The reason lies in the movement of air within the atmosphere, Collins said. Solar radiation heats the lower atmosphere, causing a rising cell of air over the summer pole, he said. “As the air rises it cools and that beats out the radiative heating.” Those cold temperatures allow the ice clouds to form in the mesopause. The clouds could serve as an indicator of climate change because an increase in carbon dioxide, which causes heating in the lower atmosphere, causes cooling in the upper atmosphere. Collins said the noctilucent clouds are a relatively new phenomenon. History indicates that humans first recorded their presence in the 19th century, he said. Satellite and ground-based data has been limited, he said, but it appears that the clouds have become more prevalent over time. A new satellite, Aeronomy of Ice in the Mesosphere, or AIM, was launched in April 2007 to observe clouds and their environment in the mesopause, Collins said scientists are looking forward to having more reliable data, which could contribute to a broader understanding of the upper atmosphere, noctilucent clouds and how both fit into the climate system. University of Alaska Fairbanks (2007, August 21). Polar Ice Clouds May Be Climate Change Symptom. ScienceDaily. Retrieved November 15, 2010, from http://www.sciencedaily.com¬ /releases/2007/08/070820145343.htm

High oh high way up above the ozone Shining over a darkened sky High oh high in regions near the poles In mesospheric zones so high Set against the arctic cold twilight How and why can you be? Casting off an irridescent light Are you tied to our destiny Known for only the last century Our global climate history We don’t know how you have come to be An atmospheric mystery Noctilucent!

Noctilucent Cloud That ghostly shining polar shroud Every year you number more and more We didn’t think you’d be allowed And with time you’re brighter than before At latitudes so low (but there you go) Forming in a most unlikely place At the edge of space

Shining over a darkened sky Noctilucent Cloud In mesospheric zones so high That ghostly irridescent shroud How and why can you be? We didn’t think you’d be allowed At latitudes so low (we need to know)

You’re a cloudy mystery (mystery...) For the twenty-first century Glowing over the polar sky Noctilucent Cloud! In mesospheric zones so high How and why can you be? Are you tied to our destiny High oh high on wings above the ocean Our global climate history On a Pegasus, AIM launches into space You’re still a cloudy mystery Measuring the temperature so cold Noctilucent Noctilucent Noctilucent Cloud! Sizing up the cosmic dust so old How much water vapor lies within Your layer so thin?

Noctilucent Cloud That ghostly irridescent shroud We didn’t think you’d be allowed At latitudes so low (how can we know?)

Directions: Below you will find descriptions for the three main types of clouds. In the box to the right of each description draw a sketch of what the cloud type looks like.

1. Cirrus Cirrus clouds are described as thin, wispy strands that appear high in the sky, generally between 20,000 and 40,000 feet (6 to 12 kilometers) but can be higher. High winds blow the clouds into long streamers thin enough for sunlight and moonlight to pass through. Airplanes traveling at such heights leave condensation trails that can turn into cirrus clouds. In Latin cirrus means, “curl of hair.” The presence of cirrus clouds can mean a weather front is approaching.

2. Cumulus Cumulus cloud are usually puffy, billowing towers of white that can extend for thousands of feet, usually beginning with flat bases ranging from 4,000 to 8,000 feet (1.2 to 2.5 kilometers) in altitude. Such clouds are formed when warm, moist air rises. As it rises, air cools and condensation occurs. The size of a cumulus cloud depends on the force of the upward movement of the air and the amount of moisture in the air. In Latin cumulus means, “heap.” The presence of cumulus clouds usually means fair weather, however when such clouds continue to grow larger and taller, forming cumulonimbus clouds, they can produce heavy rain, lightning, wind, hail and even tornadoes.

3. Stratus Status clouds blanket the sky with white and grey. Such clouds are often formed when a layer of warm, moist air passes over a layer of cool air. As the two layers meet, the warm air cools to the point of condensation, forming a blanket-like cloud. These flat, featureless clouds are low in altitude (usually 2,000 to 7,000 feet) and block out the sun. Stratus clouds can reach all the way to the ground, too. When this happens it is called fog. In Latin stratus means, “layer.” The presence of stratus clouds can mean light mist, drizzle or light snow.

Directions: Complete the following crossword puzzle using information from the previous page and the MULTIMEDIA FILE: “Cloud Game” found at www.uniteusforclimate.org.

1 2

4 5

ACROSS DOWN 1. Means “heap” in Latin. 1. Occur at heights of 20,000 to 40,000 feet. 4. Presence can mean light drizzle or light snow. 2. Trail left by airplanes. 6. Cumulus clouds usually mean this kind of weather. 3. Latin meaning for stratus. 7. Produced by cumulonimbus. 4. A combination of cumulus and stratus. 8. A very low stratus layer. 9. Latin for rainy or stormy. 10. Word meaning how high. 11. Sailors called this ‘mackerel sky.’

Directions: Use STUDENT INFORMATION SHEET: “Scientists Learn about Night-Shining Clouds” to answer questions 1 - 14.

Article One: Noctilucent Clouds by T. Neil Davis, 1979

1. Around what year was the first recorded sighting of noctilucent clouds?______

2. In 1979, did scientists know what caused the phenomenon? What was their guess? ______

3. Circle one. About how high above Earth’s surface are noctilucent clouds found? A. 82 miles B. 15 miles C. 50 miles D. 16 degrees

Article Two: Clouds That Glow at Night by Larry Gedney, 1982 Illustration courtesy of NASA

4. Circle the best answer. How can scientists guess that meteors are involved with the presence of noctilucent clouds? A. Scientists have watched meteors fly through noctilucent clouds. B. An electron microscope found nickel in cloud residue, an element in meteors. C. Meteors also glow in the night sky, so they are likely related.

5. What instrument was used to reach and study the clouds? ______

6. In 1982, did scientists know why noctilucent clouds are found only in certain latitudes? ______

7. Write one other thing scientists were wondering in 1982 about noctilucent clouds. ______

Article Three: Exploring the Heavens with Laser Light by Ned Rozell, 1998

8. What instrument are scientists like Dr. Richard Collins currently using to study noctilucent clouds? ______

9. Why can’t scientists use a weather balloon to study noctilucent clouds? ______

10. Circle one. Temperatures in the mesosphere, where these clouds are found, are coldest when? A. During the Ice Age. B. During the coldest part of the winter. C. During the warm summer months.

Article Four: Polar Clouds May Be Climate Change Symptom by ScienceDaily, 2007

11. Circle one. What are scientists hoping to learn in current studies of the mesosphere? A. Is human activity contributing to an increase in noctilucent cloud sightings? B. Are noctilucent clouds a climate-change indicator? C. Is an increase in the amount of carbon dioxide contributing to more noctilucent clouds? D. All of the above.

12. Are scientists still learning about the mesosphere and noclilucent clouds?______

Critical Thinking

13. How do these four articles show progress in the scientific study of noctilucent clouds? ______

14. Why do scientist think the increase in sightings of noctilucent clouds could be related to human activity? ______

Directions: Using the materials listed, follow the steps below to create noctilucent clouds above Earth. Materials • Styrofoam™ ball, approximately 6” (one) • Batting (small pinch) STEP 1: Using oil pastels, color • Round head sewing pin (one) the Styrofoam™ ball to • Clay or tacky putty (one small lump) resemble planet Earth. • Flashlight, small (one) Sketch in Alaska in the • Toothpicks (five) Northern hemisphere. • Oil pastels (one set per group)

STEP 2: Place a piece of clay or tacky putty about the size of a half-dollar coin on your working surface. Place your foam Earth on the tacky surface and gently press until it stays in place. Make sure Alaska is tiltedß upward. (*Remember: Earth is tilted on its axis at an angle of about 23.5°.)

STEP 3: Place a round head pin where your community lies in Alaska. Press it until the round head sits at the surface. Place three or four toothpicks around the pin.

STEP 4: Take a small piece of batting material and pull it thin so that it looks like wispy clouds. Gently place the “clouds” over the toothpicks. The toothpicks support the “clouds.”

STEP 5: Use your small flashlight to imitate the sun. Light up the clouds but leave Earth’s surface, where your community is marked, in the dark.

HINTS: • Noctilucent clouds are seen at dawn and dusk. Where is the sun in relation to Alaska during those times of day? • The sun is most directly overhead in the region of the equator. Where is the equator on your model Earth?

STEP 6: In the space below, draw your lab set up. Include the flashlight/sun. Use labels.

STEP 7: Write a sentence or two that explains how the surface of Earth can be dark, but the noctilucent clouds are illuminated by the sun. ______

Directions: Visit an Elder or culture bearer, taking along the NOAA/NASA Cloud Chart given to you by your teacher. Ask the Elder, “Do any of these pictures look like clouds you would expect to see overhead this time of year?” “Are there Native words for different clouds types?” “What can clouds tell us about the weather?” “Can you use clouds to predict weather?”

Elder Name: ______Date of Interview: ______

Summarize what the Elder said below: ______

Overview: Students apply knowledge about albedo by making observations in the environment, working through energy ratio data, and designing an experiment to prove or disprove a hypothesis about snow melt.

Objectives: The student will: • identify the initial source and resulting change in forms of energy; • describe an experiment and make inferences to explain the results; and • organize and display data into a histogram.

Targeted Alaska Grade Level Expectations: Science [7-8] SA1.1 The student demonstrates an understanding of the processes of science by asking questions, predicting, observing, describing, measuring, classifying, making generalizations, inferring and communicating. [7] SA1.2 The student demonstrates an understanding of the processes of science by collaborating to design and conduct simple repeatable investigations, in order to record, analyze (i.e., range, mean, median, mode), interpret data, and present findings. [7]SB2.1 The student demonstrates an understanding of how energy can be transformed, transferred, and conserved by explaining that energy (i.e., heat, light, chemical, electrical, mechanical) can change form. [8] SB2.1 The student demonstrates an understanding of how energy can be transformed, transferred, and conserved by identifying the initial source and resulting change in forms of energy in common phenomena (e.g., sun to tree to wood to stove to cabin heat). Math [8] S&P-1 The student demonstrates an ability to classify and organize data by [designing, collecting (L)], organizing, displaying, or explaining the classification of data in real-world problems (e.g., science or humanities, peers or community), using histograms, scatter plots, or box and whisker plots with appropriate scale [or with technology (L)].

Vocabulary: absorption – the taking up and storing of energy (such as radiation, light or sound) without it being reflected or transmitted albedo – the proportion of the incident light or radiation that is reflected by a surface heat – thermal energy that flows from an object or substance at a higher temperature toward an object or substance at a lower temperature radiation – the emission or movement of electromagnetic energy through space or a medium, such as air reflection – the turning back of a wave (such as a light or sound wave) when it encounters a boundary; reflected waves return immediately to their original medium instead of entering the medium they encounter

Whole Picture: The light that reflects off snow can be blinding. Before Western-style sunglasses were introduced, the Athabascan people used the technology of the snow goggle to limit the amount of light that reached the eyes. Cutting and shaping a piece of cottonwood bark to fit over the nose and across the eyes, then placing narrow slits over the eyes, reduced the amount of reflected light and prevented snow blindness for subsistence hunters. Elder Robert Charlie remembers using snow goggles. “I had to use it when I used to be out doing my subsistence way of life. Let’s say, March, when it snows, it’s much brighter than other times and you are out walking, taking

care of your trapping activity and the sun is shining very bright on the fresh snow—that’s when you have a good chance of having snow blindness.” In Western science, the amount of energy that snow is reflecting is a topic of study. The reflectivity is called Albedo. It is common knowledge dark-colored clothing is warmer than light-colored clothing. The scientific property behind this difference is called albedo. When the sun shines on a surface, solar radiation, or solar energy, is either absorbed into or reflected off that surface. Materials that are lighter in color have a higher albedo than the same materials with a darker color. Black jeans have a low albedo; they reflect very little solar energy. White jeans have a high albedo; they reflect a large amount of solar energy. Albedo affects Earth’s environment. Soil, water, and snow also have albedo measurements. Fresh snow reflects 90 percent of the solar energy striking its surface, so its albedo measurement is 0.90. This means that only 10 percent (100-90) of the solar energy that reaches the snow is absorbed. The albedo of a water surface depends on the angle at which the sunlight strikes it and whether the surface is smooth or rough. The average albedo of Earth as a whole is 30 percent. As snow ages and becomes discolored, its albedo changes. The climate system is characterized by strong positive and negative feedback loops between processes that affect the state of the atmosphere, ocean, and land. A simple example is the ice-albedo positive feedback loop whereby melting snow exposes more dark ground (of lower albedo), which in turn absorbs heat and causes more snow to melt. A feedback effect, also known as a feedback loop, is a cycle within a system that continually increases (“positive feedback”) or decreases (“negative feedback”) the effects of the system. The climate system is characterized by strong positive and negative feedback loops between processes that affect the state of the atmosphere, ocean, and land. A simple example is the ice-albedo positive feedback loop whereby melting snow exposes more dark ground (of lower albedo), which in turn absorbs heat and causes more snow to melt. In the northern oceans melting sea ice exposes more dark water (of lower albedo), which in turn absorbs heat and causes more ice to melt. In the Arctic, where snow and ice are present for long periods each year, a change in the albedo of the surface can cause rapid climate changes. Climate models predict far more warming in the polar regions than in the tropics. In the past few decades, temperatures have risen about twice as fast in the Arctic as in the rest of the world. This is largely because of the high albedo of snow and ice. As snow and ice melt, the exposed darker surfaces absorb more heat. This sensitivity to climate makes it more difficult to model climate responses at the poles.i

Materials: • Pennies, preferably 1982 or later to ensure all have the same metallic composition (nine per group) • Snow or blocks of ice • Containers that are at least 4 inches x 4 inches x 4 inches to hold snow or blocks of ice (one per group) • Heat lamps (one per group) • Timer (one per group) • Ruler • Black permanent marker • White correction fluid or non-water-soluble paint • MULTIMEDIA: “Albedo” (on the UNITE US website: http://www.uniteusforclimate.org) • STUDENT WORKSHEET: “Albedo” • STUDENT LAB SHEET: “Snow Pennies”

Activity Preparation: (NOTE: This activity may take a substantial amount of time. Once students design their experiment you may want to have them make observations at regular intervals throughout the day, rather than continuously observing the snow.) 1. Blacken one third of the pennies with black magic marker, cover one third of the pennies with white correction fluid, and leave one third as they are. Make enough so that each group of three students will have a least three of each type.

2. Scout for an area to conduct Activity Procedure steps one and two. Look for items that have landed and melted small holes into the snow or ice. 3. Write the vocabulary words with definitions on the board or on chart paper.

Activity Procedure: 1. Take students outside to observe how small objects that are on snow or ice, like spruce cones, small branches, gravel, sand, dog feces, pieces of bark, etc., eventually end up below the surface of the snow where they first landed (or were placed). (NOTE: This observation will be easiest to make when there has not been a fresh snowfall for at least a few days, the temperature has been fluctuating between the 10°F and 30°F, and there is plenty of daylight.) 2. Ask students to explain why they think objects on the snow seem to tunnel into the snow. If they think the objects melted their way into the snow/ice ask them how this could be when the temperature has been below freezing. If they say the sun heated up the objects ask why the sun did not heat up the snow around the tunnel too. Some students may state or imply that no melting has occurred, but the objects weight compacted the snow. Ask the class how they might test this idea. Return to the classroom. 3. Review the vocabulary words written on the board or chart paper. Use examples from around the classroom to illustrate. The overhead lights are radiating light, objects in the room reflect and absorb that light, etc. Explain the word albedo is used by scientists to talk about reflectivity in the environment. For example, fresh snow has the highest reflectivity of all Earth’s natural surfaces. It reflects up to 90 percent of sunlight. Dirt reflects only about 5 percent of sunlight. The rest is absorbed. Albedo is an important factor when studying climate and climate change. As Earth warms, snow cover decreases. Less snow means less energy is reflected and more energy is absorbed. When Earth’s surface absorbs more energy, temperature increases. Warmer temperatures mean less snow and the cycle is set in motion. 4. Show students the multimedia component, “Albedo.” Start with Global Energy Balance, then move on to Snow Reflects Energy and Snow-Albedo Feedback. Pass out STUDENT WORKSHEET: “Albedo,” and ask students to complete. 5. Divide students into small groups. Hand out STUDENT LAB SHEET: “Snow Pennies.” Explain each group will design an experiment, with a testable question and a hypothesis, about albedo using a block of ice or container of snow, a set of nine pennies, a timer, a ruler and a heat lamp. Each experiment must have: • a testable question • a hypothesis • one variable (experimental group), and a control group • a way to measure and keep track of results Possible testable questions include: a. How does the color of the penny affect how much ice/snow it can melt? b. How does the distance between the objects affect how fast the ice/snow melts? 6. Draw an example of a bar graph on the board. Instruct groups to use the data collected from their group’s experiment to graph their results, and then determine if the data does or does not support their hypothesis. Students should have their hypothesis and plan/procedure approved before collecting materials to begin. Tell students: • The heat lamp must be at least 12 inches away from the surface of the ice or snow. • The heat lamp and its bulb will be hot and should not be touched. • They can use the ruler and timer in any way they need in their experiment. • They will have ______(determined by teacher) amount of time to design and implement their experiment. • They will have ______(determined by teacher) amount of time to complete their graph and worksheet. They can put the graph on the back of their lab packet or use a fresh piece of paper. • Time permitting, students can share results with the rest of the class at the end.

Critical Thinking Questions: 1. What type of energy did the heat lamp emit, and what type of energy was this turned into when it hit a penny or the ice/snow? How did the color of the penny affect this process? 2. How could you use what you learned during this activity to help you pick a color of house paint if you lived in a cold area that did not get hot in the summer? How about if you lived in a desert that was sunny and hot the whole year?

Extension Idea: Allow students to design a similar experiment using materials other than pennies.

Answers: STUDENT WORKSHEET: “Albedo” 1. a. Vegetation; b. White Concrete; c. Black Asphalt; d. Bare Soil 2. Highest reflectivity: snow Highest absorption: black asphalt 3. (50% + 78% + 30% + 3%)/4 = 40.25% 4. The reflectivity = 100%, so 300 watts/ 1000 watt) x 100% = 30%. According to the table the surface is likely bare soil. 5. Answers will vary. 6. The crossword puzzle answers are: 1: reflection; 2: albedo; 3: absorption; 4: radiation; 5: heat

STUDENT LAB SHEET: “Snow Pennies” Answers will vary.

What you need to know absorption – the taking up and storing of energy (such as radiation, light, or sound) without it being reflected or transmitted albedo – the proportion of the incident light or radiation that is reflected by a surface; reflectivity heat – thermal energy that flows from an object or substance at a higher temperature toward an object or substance at a lower temperature radiation – the emission or movement of electromagnetic energy through space or a medium, such as air reflection – the turning back of a wave (such as a light or sound wave) when it encounters a boundary; reflected waves return immediately to their original medium instead of entering the medium they encounter When sunlight reaches Earth’s surface, some of the light energy is absorbed and some is reflected. The energy that is absorbed contributes to heating things on the surface. The reflected light is what we use to actually see what is around us. Scientists measure the reflectivity and absorption in terms of percentage of energy that falls on the body. The combination must add up to 100 percent. For example, if 100 watts of light energy falls on a snowy surface, 80 watts will be reflected and 20 watts will be absorbed. The term “albedo” is a scientific term used to talk about how energy is reflected by an object. Albedo is given a range from 0 to 1. An object that reflects no light whatsoever would have an albedo of 0. Most land areas are in the albedo range of 0.1 to 0.4.

Figure A - Reflectivity Map Table 1 - Reflectivity Chart

Material Reflectivity A. B. Snow 80% White Concrete 78% 50% 78% Bare Aluminum 74% Vegetation 50% Wood Shingle 17% C. D. Water 5% 3% 30% Black Asphalt 3% Bare Soil 30%

1. Look at the Reflectivity Map (Figure A) and the Reflectivity Chart (Table 1). What are the likely compositions of the areas in the map?

A. ______C. ______

B. ______D. ______

2. What material (on the chart) has the highest reflectivity?______What material (on the chart) has the highest absorption?______

3. Using Figure A, what is the average area of these four equal-area regions combined? Use the back of this page to work out the math, then write your answer below. ______

4. You are doing some measurements near the school. You note that 1000 watts of light energy hit the surface; 300 watts are reflected and the rest are absorbed. What is the reflectivity of the surface? Looking at Table 1, what is the surface likely to be? ______

Critical Thinking

5. There is a thermometer near the community center in your town/village. That temperature is recorded each day at noon and at midnight and the temperature readings are put into the town records. The parking lot is currently bare soil. Next summer there is a plan to pave the parking lot with black asphalt. Do you think the change will affect the temperature readings? Why or why not? ______

Vocabulary Review Using the vocabulary words on page one, please complete the crossword puzzle below. Across: 1. turning back of light 4. movement of energy through a 5 3 medium 5. flows from an object with higher temperature to one with lower temperature

2 4

1 Down: 2. reflectivity with a range of 0 to 1 3. the storing of energy

Testable Question: ______Be careful! ______The heat lamp is hot! Hypothesis: ______Materials: ______• Container with ice or snow ______• Set of nine pennies: three plain, three painted black, three painted white • Timer Directions: Design an experiment that has one variable • Heat lamp (experimental group), and a control group. Include a way to measure and keep track of your results. Your teacher must approve your hypothesis and plan before you begin. NOTE: Your heat lamp must stay 12 inches from your ice or snow.

Variable: ______

Control: ______

Method of data collection: ______

Plan: (Use this area to make notes, write your plan and draw a diagram.)

Data Collection: (Use this area to record your data as you collect it. Refer to your plan. Remember that you will be using your data to make a graph.) Be careful! The heat lamp is hot!

Variable Control

Conclusion: Was your hypothesis proved or disproved? Use complete sentences to explain. ______

Overview: In this lesson, students build a calorimeter, test the energy content in various edible nuts and investigate biomass as an alternative energy source for Alaska communities through three case studies.

Objectives: The student will: • build a simple calorimeter and test the energy content of various edible nuts; • calculate the calories, per gram, released during the combustion of various nuts and graph the results; • consider the feasibility of biomass as an energy source; and • examine three case studies featuring Alaska communities using biomass energy.

Targeted Alaska Grade Level Expectations: [7-8] SA1.1 The student demonstrates an understanding of the processes of science by asking questions, predicting, observing, describing, measuring, classifying, making generalizations, inferring, and communicating. [7] SA1.2 The student demonstrates an understanding of the processes of science by collaborating to design and conduct simple repeatable investigations, in order to record, analyze (i.e. range, mean, median, mode), interpret data, and present findings. [8] SA1.2 The student demonstrates an understanding of the processes of science by collaborating to design and conduct repeatable investigations, in order to record, analyze (i.e. range, mean, median, mode), interpret data, and present findings. [8] SB2.1 The student demonstrates an understanding of how energy can be transformed, transferred, and conserved by identifying the initial source and resulting change in forms of energy in common phenomena (e.g. sun to tree to wood to stove to cabin heat).

Vocabulary: biomass – all living and recently living things calorie – the amount of heat required to raise the temperature of one gram of water by 1°C calorimeter – a device used to measure energy content by calculating the heat required for a chemical reaction joule – a unit of energy equal to 1/3,600 watt hour (equal to burning a 1 watt light bulb for one second) nonrenewable energy source – a mineral energy source that is in limited supply, such as fossil fuels (gas, oil, and coal) and nuclear fuel renewable energy source – an energy source that can be replenished in a short period of time (solar, wind, geothermal, tidal) watt – a unit of power; equivalent to one joule per second watt hour – a measure of electrical energy equivalent to consuming one watt for one hour

Whole Picture: Biomass is a renewable energy source that includes all living and recently living things. Biomass energy is created by the combustion of carbon-based matter. The energy in biomass comes from the sun. Plants convert radiant energy into chemical energy through photosynthesis and store this energy as glucose. When we burn biomass, we use this stored energy to produce heat. Alaska Native people have been using biomass fuels for heat and light for thousands of years; the most common source is wood. Other forms of biomass energy include biofuels made from fermented plant material (such as ethanol made from corn), solid waste (garbage and animal waste), and landfill gas (capturing the methane released during decomposition).

Interior Alaska has extensive biomass resources including wood, sawmill waste, fish byproducts and municipal waste (garbage, especially paper and wood products). Conventional timber as well as fast growing shrubs like willows and alders can be cultivated and harvested for power generation and/or heating. On average, 1.5 million acres of forested land in Alaska is adversely affected by wildfires and beetles each year. Some of this wood is salvageable as biomass fuel. Biomass is currently being used in Alaska communities to generate electricity and heat. It may become a more feasible energy option as the cost of oil and gas continues to rise, especially in rural communities. We use a variety of units of measure for power and energy such as calories, joules, watts and BTUs. Many people are familiar with calories as a unit of food energy. A calorie is actually a unit of heat. It approximates the energy needed to increase the temperature of one gram of water by 1°C. Its use is largely archaic, having been replaced by the joule. However, it remains in use as a unit of food energy. The calories seen on food labels are actually “large calories,” “kilogram calories” or simply “food calories.” One large calorie is 1,000 calories. It approximates the energy needed to raise the temperature of one kilogram of water by 1°C. A joule is a unit of power in the International System of Units. It is equivalent to the work required to produce one watt of power for one second. Watts are a unit of power that is equivalent to one joule/second. A calorie is equal to 4.19 joules. Watts are a unit of power per unit time. One watt equals one joule per second. Power output and consumption (of engines, motors, heaters, etc.) is often expressed in kilowatts (1,000 watts). Electric companies often bill consumers in kilowatt hours. One kilowatt hour is equivalent to 1,000 watt hours or 3,600 joules. Using a 60 watt light bulb for one hour uses 60 watt hours or 0.06 kilowatt hours of electricity. BTUs (British Thermal Units) are often used to rate heating and cooling systems like wood stoves, grills and air conditioners. Like the calorie, the BTU is a traditional unit of measure that is largely archaic in scientific contexts. One BTU is approximately equal to the heat energy needed to raise the temperature of one pound of water by one degree Fahrenheit. One pound of dry wood contains about 7,000 BTUs.

Materials: • 12-ounce soda pop cans (two per group) • Safety glasses (one pair per student) • Digital scale (one per group) • Oven mitt (one per group) • Scissors (one pair per group) • Shelled pecans, almonds, cashews, walnuts, peanuts or other edible nuts (enough for each group to have a variety of types) • Paper fasteners (at least 1.5 inches long, 5-10 per group) • Thermometer (with probes or small enough to fit in the opening of a soda can, one per group) • 100 mL graduated cylinder (one per group) • Thumbtack (one per group) • Water (room temperature, 100 mL per group) • Long tweezers (at least 6 inches, one per group) • Aluminum foil (3-inch square, per group) • Hot pad to protect desk/table (one per group) • Grill lighter • Needle-nose pliers (for optional class demonstration) • STUDENT LAB: “Biomass Energy” • STUDENT WORKSHEET: “Biomass: Three Alaskan Case Studies”

Activity Preparation: 1. Carefully review procedure.

NOTE: This experiment involves cutting up an aluminum can and burning nuts. The nuts will produce a significant amount of heat and some smoke. Use discretion to determine if it is better to conduct the lab as a class demonstration or in small groups. Teachers may want to choose a location with some ventilation (at least a window that can be opened.) Each nut will take approximately five minutes to burn. Large nuts like Brazil nuts can take up to 10-15 minutes. If time is limited, each group could test one kind of nut and then the class can share data. 2. Be prepared to clearly review safety precautions. Calorimeters need to be placed on a stable surface. While in use, the bottom will become hot. Use discretion to determine whether students are allowed to use the lighter, or whether you will light the nuts for them. Consider safety and the time available and decide if you will precut the windows in the soda cans. Do not discard the squares of aluminum! 3. Decide if/how you will use the STUDENT WORKSHEET: “Biomass: Three Alaska Case Studies.” You may choose to use them along with the student lab, as homework or as a follow-up later on.

Activity Procedure: 1. Ask students how they think their ancestors stayed warm during long Alaska winters. (People have been burning organic fuels like wood and animal fat for thousands of years.) 2. Introduce students to the terms “biomass” and “biofuels.” What does the prefix “bio” mean? (The root word bio means “life,” and so biomass means a total mass of living or once living material; biofuel refers to a fuel made directly from living matter.) Although wood is still the most common biomass resource in Alaska, we have many other resources. Ask students to brainstorm Alaska’s biomass resources. Keep a list on the white board and provide hints as needed. (Students may mention fish oil, burning garbage, wood scraps and sawdust, fast-growing shrubs, capturing landfill gases, biodiesel made from used vegetable oil, etc.) 3. Explain more Alaska communities are again looking to biomass as an energy source. Ask students why they think this is? (The cost of oil and gas continues to rise making energy costs in rural Alaska among the highest in the nation.) 4. Explain today’s lab will focus on biomass as an energy source. Students will measure the energy available through combustion of a plant product (nuts). Remind students that energy comes in many forms and can change form. Ask students where the energy in the nuts came from. It is originally from the sun. This radiant energy was captured via photosynthesis by the plants that grew the nuts and is stored as potential chemical energy in the cells of the plant. This energy is released as light (radiant) and heat (thermal) energy when we burn the nut. OPTIONAL CLASS DEMONSTRATION (to accompany this discussion): Hold a cracker, potato chip or other available snack food with the needle nose pliers. Light with the grill lighter and allow to burn as you discuss the energy available through the combustion of plant products. If time allows, compare various snack foods. Be aware that oily foods like potato chips will produce smoke. Choose a location with appropriate ventilation. 5. Distribute STUDENT LAB SHEET: “Biomass Energy” and provide instructions for completing the lab in small groups or as a class demonstration. Allow time to carefully review the safety considerations mentioned in the Activity Preparation section. 6. When all groups are finished, share data on the white board (if necessary), review results and answers to questions. 7. If applicable, distribute STUDENT WORKSHEET: “Biomass: Three Alaska Case Studies.”

Extension Ideas: 1. Try burning other food items in the calorimeter (including snack foods and leftovers from student lunches!) Oily foods work particularly well. How do these compare to nuts? Graph results. 2. Contact one of the communities featured in STUDENT WORKSHEET: “Biomass: Three Alaska Case Studies.” Find out more about the project’s successes and challenges.

Answers to STUDENT LAB SHEET: “Biomass Energy” 1. Answers will vary. 2. Answers will vary. 3. Answers will vary. 4. Answers will vary. 5. the size (mass) of the sample and the oil content of the nut 6. the oil content of the nut 7. Responses will vary, but students should recognize the energy released from nuts is very small compared to the energy we use each day. Alaska communities would need to import a very large quantity of nuts, which is not economical. 8. Responses may vary but may include timber, shrubs (such as alder and willow), animal waste (from dog yards or farm animals), paper/cardboard, wood byproducts (sawdust, saw mill scraps), food scraps, fish oil, fish scraps, etc. 9. D 10. energy content (by calculating the heat required for a chemical reaction) 11. calorie 12. You would need spruce poles measuring 14.4 feet in length.

diameter = 2r 24 feet = 2r r = 12 feet

s = √(r2 + h2) s = √(122 + 82) s = √208 s = 14.4 feet

13. You would need 542.6 ft2 of birch bark to cover the structure.

surface area = π · r · s surface area = 3.14 · 12 feet · 14.4 feet = 542.6 ft2

Answers to STUDENT WORKSHEET: “Biomass: Three Alaska Case Studies” 1. Answers will vary but may include: creating local jobs, reducing the risk of wildfire close to the community, using a renewable energy source, reducing the cost of fuel used, decreasing carbon emissions and reducing dependence on imported fuel. 2. Answers will vary but may include: high initial investment (very expensive to buy), may require special expertise to maintain equipment, could deplete nearby forests. 3. Answers will vary.

Directions: A calorimeter is a device used to measure energy content by calculating the heat required for a chemical reaction. Follow the directions below to build a calorimeter and use it to measure the biomass energy available through the combustion of different nuts. (Do not eat the nuts!)

Testable Question: What kinds of nuts contain the most stored heat energy?

Prediction: Predict which nuts will produce the greatest and smallest change in water temperature when burned in the calorimeter.

Greatest change in water temperature (most energy released):______

Smallest change in water temperature (least energy released):______

Materials: • 12-ounce soda pop can (2) • Digital scale • Safety glasses • Scissors • A variety of shelled nuts • Paper fasteners (5-10) • Thermometer • 100 mL graduated cylinder • Thumbtack • Water (room temperature) • Oven mitt • Tweezers • Aluminum foil (3-inch square) • Hot pad

Experiment: Build the calorimeter: 1. Measure 100 mL of water in the graduated cylinder and carefully pour it into one can. 2. Carefully cut a window (approximately 3.5 inches tall by 2 inches wide) out of the side of the second can (close to the bottom), if your teacher has not already done this for you. 3. On the opposite side of the window, use a thumbtack to poke a small hole approximately 1-2 inches from the bottom. Insert a paper fastener into the hole and spread the arms slightly. This will be the platform for the nuts to sit on. 4. Place the can with the water on top of the can with the window. Be sure to place your calorimeter on the hot pad in a safe place where it will not be bumped or knocked over.

Test the nuts: 5. Determine the mass of the first nut with the digital scale. Record the type of nut and its mass in the data table. 6. Use the thermometer to take the start temperature of the water in the top can. Record it in the data table. 7. Place the square of aluminum foil over the hole in the top soda can (to act as a lid). 8. Carefully place the nut on the paper fastener in the lower can. 9. As directed by your teacher, you or your teacher will light the nut. Allow it to burn. 10. Do not touch the calorimeter as the nut is burning! It will be hot. If the nut falls off the fastener, use the tweezers to carefully put it back on. 11. When the nut has been consumed (and the fire goes out) take the end temperature. Record it in the data table. CAUTION: The bottom will be hot! 12. Calculate the temperature change in ° Celsius. If necessary, convert both the start and end temperature to Celsius before calculating the temperature change. (Do not simply convert the temperature change!) Round to the nearest whole number. 13. Use the formula provided to calculate the calories released. Record in the data table. 14. Divide the calories released by the original mass of the nut to get the calories released per gram. Record in the data table. 15. Repeat the process for each nut.

Graph your results: 16. Create a bar graph of your results: • Put the type of nut on the x-axis. Label the axis. • Put the calories per gram on the y-axis. Label the axis and be sure to include the units in your label. • Give your graph a title on the line provided.

Data

Mass of Volume Mass of Start End Temp. Calories Type of Nut of Water Water Temp. Temp. Change Calories per Gram Nut (g) (mL) (g) (°C) (°C) (°C) (cal) (cal/g)

Use the following formulas in your calculations: • The formula for converting temperatures from Fahrenheit to Celsius is:

5 ° Celsius = ⁄9 × (° Fahrenheit – 32)

• The formula for converting volume of water to mass is:

1 milliliter (mL) water = 1 gram (g) of water.

• A calorie is the amount of heat required to raise one gram of water by 1° Celsius, so:

calories = mass of water (g) × temperature change (°C).

• The formula for calculating calories per gram is:

calories per gram = calories / mass of nut

Data Analysis: 1. Which type of nut produced the most heat (measured in calories)?______

2. Which type of nut produced the least heat (measured in calories)? ______

3. Which type of nut produced the most heat per gram?______

4. Which type of nut produced the least heat per gram? ______

5. What factors do you think contributed to the nut that produced the most heat?

______

6. What factors do you think contributed to the nut that produced the most heat per gram?

______

Conclusion: 7. Do you think burning nuts would be a good source of energy for your community? Why or why not?

______

8. What biomass energy resources are available in your community?

______

Review: 9. Biomass can be:

A) trees B) food scraps C) paper D) A, B, and C

10. A calorimeter measures______.

11. A ______is the amount of heat required to raise one gram of water by 1° Celsius.

Biomass and Alaska Native Culture: Alaska Native people have used biomass as a source of heat and light for thousands of years. Athabascan people built sod shelters with a central fire pit. The houses were usually constructed of spruce poles fastened with willow. The willow also provided a place to insert moss for insulation. The structure was covered with birch bark for weatherproofing. Finally, they added about two feet of dirt around the base of the structure to keep out drafts and covered the doorway with a bear hide with full fur. Families maintained the fire in the center of the sod house to provide heat, light and a means of cooking food. Wood and small animal bones were burned. Smoke escaped through the vent in the top. —Information provided by Chief Robert Charlie. Using the formulas provided below, complete the following word problems. Round to the nearest tenth and show your work.

diameter = 2r

s s = √(r2 + h2) h surface area of a cone = π·r·s

π = 3.14 r

12. You would like to build an Athabascan sod house that is 24 feet in diameter and 8 feet tall at the center. What size spruce poles do you need to cut?

13. How much birch bark would you need to collect in order to weatherproof your sod house?

CASE STUDY ONE: The Tanana Washeteria Adapted from the Alaska Center for Energy & Power

The washeteria in Tanana is more than a place where local residents can do laundry and take a shower. It is an example of using local, sustainable resources to save energy and money.

In 2007, the Interior Alaska community installed two wood-fired Garn® Boilers to heat the washeteria and other buildings nearby. [A wood- fired Garn® Boiler is a wood stove located inside a water tank. The water absorbs and then stores the heat. This type of system can be used to heat multiple buildings by piping the heated water through a system of pipes in the floor.]

By stoking each boiler with wood just a few times during the day, the system produces enough BTUs to heat the buildings and the 280,000-gallon water storage tank. Use of heating oil has dropped by 30%, saving the community tens of thousands of dollars each year. Solar panels were also installed on the roof of the washeteria to help reduce electricity costs.

The city obtains wood for the boilers by paying local woodcutters $250 per cord. The community used to buy diesel fuel and that money would leave the village. Now it has created an economic opportunity for residents that keeps the money local. There are plans to expand the system with three larger wood-fired boilers to heat tribal buildings and the senior citizen center.

CASE STUDY TWO: The Craig Schools & Swimming Pool Adapted from the Alaska Center for Energy & Power

Craig is a fishing village of 1,400 people located in southeast Alaska. In 2004 they looked at the heating bills for the local schools and swimming pool, and knew they needed to make a change. The boilers used 20,000 gallons of diesel and 40,000 gallons of propane annually. The monthly fuel bill for the three buildings was over $10,000.

Craig is located in a forested area, so woody biomass is a plentiful resource and a local sawmill is able to supply tons of wood chips. In 2008, with support from the U.S. Department of Agriculture and Alaska Energy Authority, Craig installed a wood-fired heating system they hoped would save them money and reduce the amount of fossil fuels they needed.

It is too early to know the exact economic impact of the wood-fired system, but so far it has displaced 85% of the diesel and propane. With a price tag of $1.5 million, the system will pay for itself in twelve years by using a resource that grows in the town’s backyard.

A BTU (British Thermal Unit) is a unit of measure used to describe the amount of energy a fuel contains (similar to how an inch or a mile is used to express distance). BTUs are also used to rate heat-generating devices like wood stoves. One BTU is equal to the heat energy needed to raise the temperature of one pound of water by one degree Fahrenheit. One pound of dry wood contains about 7,000 BTUs. Propane contains about 15,000 BTUs per pound, while charcoal contains about 9,000 BTUs per pound.

CASE STUDY THREE: The Tok School Adapted from the Alaska Department of Natural Resources Division of Forestry

The Alaska Division of Forestry (DOF) is working on two problems at the same time in the community of Tok: protecting the town from wild fires and high energy costs. The DOF Tok-area staff, U.S. Fish & Wildlife Service and a local contractor are working together to thin dense stands of trees around the school. The wood chips will be used in a wood-fired (biomass) boiler system that is being planned to heat the school. It will replace the current oil-fired boiler and should reduce heating fuel costs for the building. The thinning project around the school will generate enough biomass to heat the Tok School for at least 1.5 years. The cooperators hope that this project will serve as a model for other small communities in Interior Alaska that are similarly threatened by wildlife and share the burden of high fuel costs.

Thinking Deeper: 1. Based on these stories, identify at least three benefits of using biomass energy.

______

2. Based on these stories, identify at least three drawbacks of using biomass energy.

______

3. Think about what biomass energy resources are available in your area and describe a building in your community that you think could use this energy. Why did you choose this resource and this location?

______

Overview: Students observe a demonstration of the role of thermal conductivity in heat transfer, and design and conduct an experiment to compare the thermal conductivity of four substances. (NOTE: This lesson may require two class periods.)

Objectives: The student will: • observe a demonstration of the role of thermal conductivity in heat transfer; • design and conduct an experiment to compare the thermal conductivity of various substances; and • compare the types of insulation used in traditional Athabascan homes to modern-day construction techniques.

Targeted Alaska Grade Level Expectations: Science [7-8] SA1.1 The student demonstrates an understanding of the processes of science by asking questions, predicting, observing, describing, measuring, classifying, making generalizations, inferring and communicating. [7-8] SA1.2 The student demonstrates an understanding of the processes of science by collaborating to design and conduct repeatable investigations, in order to record, analyze (i.e., range, mean, median, mode), interpret data, and present findings. [7] SB1.1 The student demonstrates an understanding of the structure and properties of matter by using physical properties (i.e., density, boiling point, freezing point, conductivity, flammability) to differentiate among and/or separate materials (i.e., elements, compounds, and mixtures). [8] SB1.1 The student demonstrates an understanding of the structure and properties of matter by using physical and chemical properties (i.e., density, boiling point, freezing point, conductivity, flammability) to differentiate among materials (i.e., elements, compounds, and mixtures). [8] SD3.2 The student demonstrates understanding of cycles influenced by energy from the sun and by Earth’s position and motion in our solar system by recognizing types of energy transfer (convection, conduction, and radiation) and how they affect weather.

Vocabulary: catalyst – a substance that starts or speeds up a chemical reaction between other substances conduction – the flow of energy, such as heat or an electric charge, through a substance; in heat conduction the energy flows by direct contact of the substance’s molecules with each other convection – the transfer of heat energy through liquids and gases by the movement of molecules; when molecules of liquid or gas come in contact with a source of heat, they move apart and away from the source of heat, and cooler molecules take their place; eventually, as the cooler molecules are heated, they move as well, and a convection current forms, transferring the heat energy – the capacity or power to do work; energy can exist in a variety of forms, such as electrical, mechanical, chemical, thermal, or nuclear energy transfer – any form of energy can be transformed into another form; different forms of energy include kinetic, potential, thermal, gravitational, sound, light, elastic and electromagnetic heat – a form of energy produced by the motion of molecules; the heat of a substance is the total energy produced by the motion of its molecules insulator – a material that blocks or slows down the passage of sound, heat, or electricity radiation – the emission or movement of energy through space or a medium, such as air

temperature – a measure of the average kinetic energy of atoms or molecules in a system; a numerical measure of hotness or coldness on a standard scale such as Fahrenheit, Celsius and Kelvin thermal – relating to heat

Whole Picture: Traditional Athabascan homes used materials readily available in the environment to create a warm and cozy winter home heated by a central fire pit and by body heat. Construction techniques used in dwellings, such as the sod house, showed an understanding of the insulating qualities of the building materials and of snow. Modern home construction techniques seek to reduce the amount of heat transfer. In the winter, insulation keeps heat inside from escaping and keeps outside cold from entering. In summer it may be the opposite! In home insulation, the “R-value” indicates how well a material insulates. For example, one inch of high-density fiberglass has an R-value of five (R-5), an inch of polyurethane panel can obtain an R-value as high as eight (R- 8), and one inch of brick has an R-value of one point eight (R-1.8). One inch of snow has an R-value of one (R-1). Heat is transferred in three ways: conduction, convection and radiation. Conduction is the flow of energy, such as heat, through a substance. Heat energy flows by direct contact of the materials. In other words, when things are touching, the heat passes from the hotter to the cooler. If you touch a hot surface, your fingers get burned because of the heat transfer. Convection is the transfer of heat energy through liquids and gases (fluid) by the movement of molecules. Temperature difference is the catalyst that begins the convection process. There may be a difference in temperature within the fluid, between the fluid and its boundary, or from the application of an external heat source. The basic premise behind convection is that when material cools, it becomes more dense so it sinks, while heated matter becomes more buoyant and rises. Convection plays a role in the movement of air in Earth’s atmosphere. When air close to Earth’s surface is heated by solar energy, it becomes less dense and rises. Cooler, more dense air sinks, rushing in to fill the space. The cooler air then heats, rises and the process continues. The American Meteorological Society defines convection as this: “Vertical air circulation in which cool air sinks and forces warm air to rise.” The process is visible in a pot of water on a hot stovetop. The heated water expands (becoming lighter or more buoyant) and rises to the top. The cooler water sinks. The process repeats and a circulation cycle is visible. Fluid trapped in such a cycle is called a convection cell, a common weather phenomenon. Radiation is the emission or movement of energy through space or a medium, such as air. It is energy transmitted in a wave motion (like electromagnetic waves). The sun’s energy (light and heat) reaches Earth through the process of radiation. It travels through space, then through Earth’s atmosphere. When radiant energy reaches a surface it is either reflected or absorbed. Think of a greenhouse. The radiant energy enters through the glass and the heat energy is absorbed by things inside (soil, water, etc.) which “trap” the heat and slow it from leaving the greenhouse.

Materials: • Glass beaker • Styrofoam™ cup • 2 thermometers • Hot water • Bucket • Snow or ice • Small sheet of aluminum foil (one per group) • Stopwatch • Cotton balls (1 cup per group) • Rice (1 cup per group) • Play dough (2 ounces per group)

• Cups, 3 ounces (four per group) • Half-pint wide-mouth canning jars (four per group) • Ice cubes (four per group) • Aluminum dish, 9” x 9” or larger (one per group) • STUDENT LAB: “Is it Hot or Not?” • TEACHER INFORMATION SHEET: “Alternative Experiment” • STUDENT INFORMATION SHEET: “Traditional Housing” • STUDENT WORKSHEET: “Comparing Houses”

Activity Preparation: 1. Prepare a bucket of ice or snow. Store in the freezer or outside if it is cold enough. If weather permits, this activity can be done outside using the snow on the ground instead. 2. Prepare a chart on the board Time in Temperature: Temperature: or on chart paper. It should minutes Styrofoam cup Glass beaker have three columns and 0:00 12 rows. One column will 0:30 have the heading, “Time,” 1:00 the next “Styrofoam™ cup,” and the last, “Glass beaker”. 1:30 The remaining rows will 2:00 allow for the recording 2:30 of temperature every 30 3:00 seconds over a five-minute 3:30 period. See example at right: 4:00 4:30 5:00 Activity Procedure: 1. Hold up one glass beaker and one Styrofoam™ cup. Ask students what they think will happen to the temperature of hot water in the containers if they are placed in snow or ice. Ask students to predict which container will lose heat faster and write student predictions on the board. (NOTE: For the demonstration to be a “fair test” the beaker and the Styrofoam™ cup should be a similar size and shape so each has the same surface area touching the snow and ice. The amount of surface area has a big impact on conduction.) 2. Assign one student to be a timekeeper. Assign two other students to be temperature trackers, one for each container. Explain that when signaled, the timekeeper should begin the stopwatch and announce the time every 30 seconds for 5 minutes. The temperature trackers will note the temperature in their assigned container at each 30-second interval. 3. Pour 1 cup of hot water into a glass beaker and 1 cup into a Styrofoam™ cup. Place a thermometer inside each cup. Cover each with aluminum foil. (This will reduce the influence of cooling from evaporation and exposure to ambient air temperature.) Place the cup and beaker in the snow and signal the timekeeper to start the stopwatch and begin announcing the time for the temerature trackers. When five minutes are up, write the times and temperatures on the pre-prepared chart (see Activity Preparation) for all students to see. 4. Ask students to use the information on the chart to make a graph showing the water temperatures over time in both the Styrofoam™ cup and the glass beaker. Each graph must have the “X” and “Y” axes labeled and a key. Students should create a line graph. Give students five minutes to complete their graphs.

5. Discuss the results of the activity. Ask the following questions: a. Which container kept the water hot for a longer period of time? b. Did the results surprise you? c. What difference in the materials of each container might have contributed to the loss of heat? d. If you wanted to keep your hot chocolate warm for as long as possible, which container would you choose? 6. Remind students that heat can also be called thermal energy. It is transferred by conduction, convection, and radiation. Review the definitions. Ask students which type of energy transfer occurred in the demonstration (conduction). (NOTE: Radiation and convection also occur, but only the transfer of heat to the surrounding medium is considered in this demonstration.) Make sure students understand that the water is cooled because heat is being transferred from the hot water through the container to the ice or snow around the cups, not because the ice or snow transfers cold. 7. Refer students back to the chart and to their graphs. Discuss why the water in the glass beaker lost heat faster than the Styrofoam™ cup. Explain that the Styrofoam™ cup has a lower thermal conductivity than the glass beaker. Thermal conductivity is a measure of the rate at which heat travels through a substance and is a physical property of matter. A material with a high thermal conductivity, like glass, transfers heat quickly. A material with a low thermal conductivity, like Styrofoam™, transfers heat slowly. Things that have a low thermal conductivity are also called insulators, because they insulate or slow down the loss or gain of heat. 8. Ask students why they might want to know the thermal conductivity of a substance. When is thermal conductivity important? (Insulating walls, roofs; in jackets, coats; coffee mugs, thermoses, etc.) 9. Show students the materials list for the STUDENT LAB: “Is it Hot or Not?” (air, cotton balls, play dough, rice). Ask, “Which do you think has the highest thermal conductivity?” Explain that students will conduct an experiment to determine which material has the highest thermal conductivity. Divide students into small groups and distribute the STUDENT LAB: “Is it Hot or Not?” 10. Assist students throughout the process of writing a hypothesis and designing their experiment as needed. Check student experimental procedures for practicality and experimental validity before providing them with the necessary materials. Student experiments should have a control group and a single variable. (NOTE: If students are unable to design an appropriate experiment, or if time or materials are unavailable, use the procedure in the TEACHER INFORMATION SHEET: “Alternative Experiment.”) 11. Allow students time to perform their experiments and complete their worksheets. 12. Ask each group to share their experiment with the class, including their hypothesis, process, data and conclusion. Discuss how student results differed and why. (Differing experimental procedure, etc.) (NOTE: While the thermal conductivity of air is very low, heat is transported effectively through the process of convection. This may happen in the experiment, but should not substantially influence the results. It is, however, important to a more in-depth understanding of density and heat transfer. In low- density materials with high air volumes and large empty spaces, heat can be transferred quickly through convection, as opposed to more slowly through conduction.) 13. Ask the following critical thinking questions: a. Based on the results of this experiment, what can be inferred about insulating a home? b. How does a thermos keep things cold? (Remember, a thermos is often made of metal and glass, which seems counter intuitive. The reason it works is the vacuum between those materials. The heat cannot be transferred because there are no molecules present in the vacuum.) c. How about bunny boots (extreme cold vapor-barrier boots) developed by the United States armed forces? (These boots have an area of dead air space and a layered sole.) 14. Hand out STUDENT INFORMATION SHEET: “Traditional Housing.” Read the information with the class. Ask students to complete STUDENT WORKSHEET: “Comparing Houses.”

Extension Ideas: 1. If you have access to different kinds of furs, such as caribou, moose, rabbit, etc., do a similar test as in the lesson. Wrap the fur around jars of hot water and do a “before and after” temperature measurement to see which fur is the best insulator. 2. Test man-made materials, such as socks or mittens, to see which is the best insulator.

Answers to STUDENT LAB: “Is it Hot or Not?” 1. Styrofoam™ cup. 2. 2-14 Answers will vary

Answers to STUDENT WORKSHEET: “Comparing Houses” 1. Modern 2. Traditional 3. Traditional 4. Modern 5. Traditional 6. Answers will vary

Testable Question Which material has the highest thermal conductivity: air, cotton balls, rice, or play dough?

Observations 1. In the classroom demonstration, which material had the higher thermal conductivity: glass beaker or Styrofoam? ______2. Based on the classroom demonstration and your own personal experience, which material do you believe has the highest thermal conductivity? Explain your reasoning. ______

Background Information Thermal conductivity is the measure of how much heat is transferred through a substance. The higher the thermal conductivity, the faster heat is transferred through the substance. Air has a very low thermal conductivity. In the case of snow, the more dense it is, the higher its thermal conductivity.

Hypothesis 3. Use the background information in this worksheet to write a hypothesis about which material has the highest thermal conductivity: air, cotton balls, rice, or play dough.

If______then______because______.

Experiment Materials: 4. List the materials required for the experiment:

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Procedure: 5. Write the procedure for the experiment, step by step. If more steps are needed, continue on the back of this sheet, or attach a separate sheet of paper.

STEP 1 ______

STEP 2 ______

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STEP 3 ______

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STEP 4 ______

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STEP 5 ______

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STEP 6 ______

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STEP 7 ______

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STEP 8 ______

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STEP 9 ______

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STEP 10 ______

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Data: 6. Use the grid below to chart experimental data.

Analysis: 7. Use the grid below to graph the data.

8. What patterns do you see in the data? ______

9. How would you explain the patterns in the data? ______

Conclusion: 10. Was your hypothesis proved or disproved?______

11. What data proved or disproved your hypothesis? ______

Questions: 12. If your hypothesis was disproved, how would you revise your hypothesis? Explain your reasoning. ______

13. If you were to repeat the experiment, how would you change the procedure? Why? ______

14. What new questions do you have? ______

Materials • 3-ounce cups (4) • Half-pint wide-mouth canning jars (4) • Cotton balls (1 cup) • Play dough (2 ounces) • Rice (1 cup) • Ice cubes (4) • Hot water, not boiling • Aluminum or glass baking dish (9" x 9" or bigger)

Procedure

STEP 1. Place cotton balls in one of the canning jars to the cover the bottom. Fill the bottom of the other two jars with play dough and rice. Leave one cup empty; this is the control, filled with air.

STEP 2. Place a 3-ounce cup inside each of the jars.

STEP 3. Fill the space in-between the cup and the jar with rice, play dough, and/or cotton balls. You may need to remove the cup to fill the sides and then replace the cup. [Illustration]

STEP 4. Place the jars inside the baking dish so that they are evenly spaced. Fill the dish with hot water.

STEP 5. Place an ice cube in each 3-ounce cup. Check cups and make observations every 5 minutes for 30 minutes.

Traditionally among Athabascans, housing was built to suit the season and tasks of the people. During the spring and summer, many families traveled to fish camps like this one along the Tanana River (right). Summer camps consisted of tents or other semi-permanent dwellings. Winter camps, however, were set up during the coldest months of the year and interiors had to be warm. Winter camp was made up of several households, and although the exact house plan and building materials varied from area to area, the winter houses of many Athabascan groups were similar. They were semi-subterranean structures made of a wood frame covered by birch or spruce bark, which was then covered by moss, and topped with soil. All that was visible of the houses from ground level were mounds of snow with smoke curling out of the centers. The semi-subterranean house plan used by most Alaskan Native groups in winter is excellent for retaining heat, because there is little surface area through which heat can escape and cold winds cannot penetrate the structure. In addition, the many layers of insulation used on Interior Athabascan winter houses kept the inside quite warm.

Chief Robert Charlie Talks About Building a Sod House “Let us go back to the ancestral times of Athabascan People when there was no such building material as is available nowadays. To build a sod house, say a 15’ by 15’ round structure, you must first gather your materials. Athabascans always carried hand-made tools with them when moving in small groups, for cutting and digging. In this case tools were made of bones or obsidian.” “Laying the foundation is digging dirt two or three feet deep for a 15’ x 15’ family-sized house. The wall frame is spruce or willow 10 feet long and three inches in diameter at the trunk. The poles would be four to six inches apart all the way around. The house is built like a tepee, seven to eight feet high with a hole in the upper center so the smoke can go out. Around the frame they wrap birch bark or dried and oiled caribou hide. Once the hide is up they would put soil and moss on the outer part of the walls. They put extra soil around the skirt of the sod house. The door would be of bear hide with full fur.” “Once the sod house is completed, there is no draft coming in and it makes it very comfortable. The fire in the center makes for a bright light and is used for cooking.”

Think about the traditional housing described in STUDENT INFORMATION SHEET: “Traditional Housing” and compare it to modern construction techniques used in homes.

Label each sentence “Traditional” or “Modern.”

1. ______homes use materials like fiberglass and foam to insulate walls and roofs.

2. ______homes use materials commonly found in the environment, such as moss, to insulate walls.

3. ______homes ventilate using a hole in the center of the roof to let the smoke escape.

4. ______homes have a heating system, such as a furnace or wood-burning stove.

5. ______homes have a fire pit for heat. Having lots of people in the home also provides heat.

Critical Thinking

6. Why is it important to know the thermal conductivity (how much heat will transfer through) of materials used in building a home? ______

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______in Delta, Inc. courtesy Progress Photo for of Partners