Blue Planet Full Lesson
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Blue Planet : © Hemera–Thinkstock Photos © Hemera–Thinkstock : Why do we call our planet “Earth” when its surface is mostly water? photo credit photo n Grade Level Part II Pre-K through 2, Upper Elementary, • Whiteboard, chalkboard or flip chart Middle School, High School ▼ Summary • Notepaper and pencil (per group of Students estimate the percentage n Subject Areas three to four) of Earth’s surface that is covered Earth Science, Geography, Math (statis- by water and, by tossing an tics), Health (physical education) Pre-K through 2 Activity inflatable globe, take a simple • Inflatable beach-ball globe that shows n Duration probability sample to check their water and land masses or classroom Preparation time: Part I: 10 minutes; estimates. Part II: 5 minutes; Pre-K through 2: globe 5 minutes • Whiteboard, chalkboard or flip chart Activity time: Part I: 30 minutes; • Copies of Planet Paint (one per Part II: 20 minutes; Pre-K through 2: student) 3 15-30 minutes Objectives Students will: Making Connections n Setting • estimate the percentage of Earth’s sur- Students recognize that the planet is made Indoor or out door face that is covered by water. up of both land and water. However, they • predict what a probability sample will n Skills may not have considered how much of Earth reveal about the relative coverage of Gathering information (calculating); is covered with water, the residence time Organizing (plotting data, graphing, land and water. of water in different places, the amount of estimating); Analyzing; Interpreting; • estimate how long water remains in potable (drinkable) water and the unequal Applying (predicting) locations such as rivers, lakes, ground distribution of water on Earth. Understanding water and the ocean. n Charting the Course these concepts, students should develop a Following “Blue Planet,” “A Drop in Materials greater appreciation for protecting water the Bucket” illustrates the amount of quality and quantity. salt and fresh water on Earth. “The Life Warm Up Box” illustrates the necessity of water • Two sets of colored beads or paper for life. Students simulate the water squares (71 blue beads or squares and 29 Background cycle in “The Incredible Journey.” “Aqua tan) Bodies” demonstrates the amount Dramatic views of Earth from space have of water in our bodies and in other • Large plastic bag confirmed what global mapping has shown animals and plants. “Is There Water on • Four chenille twists for well over a century: the major ity of Earth’s Zork?” investigat es the properties of • Calculator surface is covered by water. Cartographers water. • Copies of Blue Planet—Do the Math! and geographers have mapped and measured 3 n Vocabulary (one per student) the surface of Earth and have determined the approxi mate areas as follows: esti mate, guess, percentage, prob- Part I ability, random sample, residence time, • Inflatable beach-ball globe that shows Land area = 148,429,000 sq. km Water area = permafrost, potable, sample size water and land masses or classroom 361,637,000 sq. km globe Source: National Geographic Atlas of the World • Whiteboard, chalkboard or flip chart • Pencil and notepad • Calculator Blue Planet © 2005, 2008, 2011 Project WET Foundation Project WET Curriculum and Activity Guide, Generation 2.0 © 2011 Project WET Foundation 125 Blue Planet Probability is a powerful tool when we don’t know the expected results. For example, if we didn’t know by scientific measure ment that 71 percent of Earth’s surface is covered by water, probability theory would allow us to take a random sample of points on the globe’s surface and apply our findings to the entire surface of the globe. (See the example in the Warm Up below.) In this activity, students will use the power of probability and a random sample of points on the globe’s surface to determine if their results coincide with what they know, or think they know, about the proportion of land to water on Earth’s surface. Procedure ▼ Warm Up • Show students the beads or paper squares in a clear plastic bag. • Tell students their task is to statistically sample the beads or squares to predict what percentage of them are blue. (Another way of saying this: They will determine the probability of selecting a Our blue planet as seen from space photo credit: © NASA Goddard Space Flight Center Image blue bead or square.) • Shake the beads or squares so they are The total surface area of Earth is the sum of up five times, and tails up five times, even randomly distributed in the bag. the land area and water area (510,066,000 sq. though the actual result may not have these • Have a student, without looking at the km). By dividing the water area by the total exact numbers. The probability remains bag, randomly remove a single bead surface area, we can cal culate the percentage the same. or square. Always have students return of Earth’s surface that is covered by water: the bead or square to the bag after they 361,367,000 ÷ 510,066,000 = 0.7085, which This same concept holds true for water report its color and be sure to shake the we can round to 0.71, or 71 percent. locations on a globe. In theory, a random bag before drawing another bead or sampling of 100 points on an accurate globe square. Since we know by measurement that would yield 71 points on water and 29 points • Using a second supply of beads, have approximately 71 percent of Earth’s surface is on land. Smaller samples should yield similar two stu dents record the results by covered by water, the math ematical concept ratios. For example, a random sampling of 40 placing the beads on chenille twists. of probability allows us to predict what will points on our globe should return approxi- Have one student place only blue beads happen when we randomly select locations mately 28 points that are water, or 70 percent. on a chenille twist; have the other on a globe. The number of samples, or the sample size, is student place tan beads on another Probability is the same concept as selecting important. For our purposes, a sample size of twist. This represents the data in a heads or tails for a coin toss. If you toss a 30 or more is needed to return a reasonably graph-like format. If you are using coin into the air, there is a one in two (or 50 good statistical result. As you might expect, squares, have students create two bar percent) probability the coin will land heads the larger the sample size, the more accurate graphs on the board: blue squares and up. If you toss the coin 10 times, there is the the results obtained. tan squares. same probability the coin will land heads Blue Planet © 2005, 2008, 2011 Project WET Foundation 126 Project WET Curriculum and Activity Guide, Generation 2.0 © 2011 Project WET Foundation Blue Planet • After a total of 30 beads or squares • Why do you think some people call 6. After each catch, the person who have been selected from the bag, Earth the blue planet? (The answer is caught the ball announces whether stop and have students calculate the not that water is blue, but that most the tip of his or her left thumb is on percent age of blue beads or squares of Earth’s surface is covered by water, land or water. If the tip of the thumb selected compared to the other color. which ap pears blue.) is touching both land and water, the To calculate the percentage, divide • What percentage of Earth’s sur face student should choose the one it seems the number of blue beads or squares do you estimate is covered by water? to be touching more. Remember that by the total number of beads selected (Record your answer in a pie chart on the ice cap in the Arctic (at the North (30) and convert the decimal into a the Student Copy Page. Post answers Pole) is all water, while the conti nent percentage (multiply by 100). on the chalkboard or flip chart.) of Antarctica is under much of the ice • Repeat the procedure. After the col- • Are you guessing or do you know the cap at the South Pole. Ask students: If ors of the second 30 beads have been percentage is a fact? If you know it’s a your thumb lands on Antartica, should recorded, divide the total number of fact, how do you know? Did someone you choose land or water? (If the blue beads from both samples by 60 tell you? Did you read it in a book or thumb lands on Antarctica, it should be (the total number of beads sampled) research it on the Internet? counted as land.) and convert your answer to a per- • Is water evenly distributed across 7. Record each catch under head ings centage. Your percentage of blue beads Earth? (No, because it is separated by titled “land” or “water” on a notepad, should be close to 71 percent. If your continents and other landforms. Many chalkboard or flip chart. Another per centage differs slightly from 71 factors contribute to water’s uneven option is to assign two students to percent, it is okay. Statistical sampling distribution on Earth, such as: climate be recorders. Each student holds one allows for a margin of error. However, [related to the latitude of a region], chenille twist. The “land” student places if your sample differs significantly, you landforms, soil, geography, seasonal a tan bead on the chenille twist each may want to continue sampling.