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Summary ✔ Copies of student worksheets , as the makes its orbit Students build a three- around the sun, the tilt produces dimensional model of the variable lengths, and the rotation of the earth to change of . When the appreciate the extremes of Background arctic is tilted away from the sun, at different The Earth’s axis is an imaginary in the months, it gets little months of the year, and make line through its core, connecting or no . The sun appears connections between available the and South poles. The to be at a very low angle on the sunlight and the growth and earth revolves around this axis, , which also means less behavior of of the arctic. one full revolution per day. The intense light reaching the arctic. earth rotates so that during the On the other hand, when the Grade Level arctic is tilted toward the sun, in 5-8; 3-4 day we face the sun, and at the months, it gets more Estimate we face away from the sun. one to two class periods. Because the earth is round, parts intense sunlight almost around the clock. Subjects: of it are closer to the sun than math, physics, geography, others. Parts that are closer Sunlight is critical to photosyn- science (nearer to the , lower lati- thesis, the process by which Skills: tude) experience more intense plants produce their own food. analysis, application, sunlight than parts that are Plants need and sunlight in comparison, problem- further, such as the arctic at high order to photosynthesize. solving . To complicate matters Adequate light and thawed water Learning Objectives further, the Earth’s axis is at a are only available for 3-4 months Students will be able to constant tilted angle of 23.5 ✔ a year in the arctic. The growing Demonstrate how the tilt of degrees. Over the course of a the earth and its rotation affects day length in the arctic (and seasons around the world). ✔ Explain how day length and available solar radiation influ- ence survival strategies of plants native to the arctic. Materials: ✔ Globe, flashlight, modeling clay, scissors, glue, Styrofoam balls and toothpicks—enough for four small and one large ball for each student and five toothpicks for each student, pencils or pens.

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is only about 50-60 days. Because plants are at the bottom of every food chain, sunlight is

critical to all . WATER SUN Plants and of the arctic, where available sunlight is highly variable throughout the year, have adaptations which help them cope with this challenge. Most plants and animals hibernate or become dormant in the winter.

Some animals migrate in the WATER winter to warmer areas south of the . Plants and animals take advantage of the summer with a burst of growth or SUGAR activity during this time. For example, during the summer model showing the position of growth during the short animals can eat throughout the the earth relative to the sun at summer, while they are day and night, helping their four different of the year in dormant in the long winter. young ones grow as quickly as order to understand how this People require sunlight too. possible before winter comes and affects daylight hours and seasons Vitamin D, essential to our the land freezes over again and in the arctic and in other parts of bodily functions, is manufac- becomes dark. This period also the world. tured in the skin when it is helps many animals accumulate exposed to sunlight. blubber, a layer of fat that helps 2. Have students research how keep them warm and provides many growing days there are in them with reserves during Procedure your community. (This infor- the long winter months. 1. Why is sunlight important? mation may be found in a Emphasize to your students, that Have your students think farmer’s almanac.) Compare life all over the world is about why plants and animals, the findings to the number of affected by both the length of including people, need growing days on the arctic light and the strength of light that sunlight. Discuss photosyn- tundra. How does this differ- reaches the earth, wherever they thesis as the way plants make ence affect the plants that grow may be. their own food, and note that in your area vs those that may In this activity, your students will plants need sunlight in order grow in the arctic? Have construct a three-dimensional to photosynthesize. Arctic students brainstorm plants have a burst of rapid hypotheses and conduct

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research to test their earth around the sun. One To be sure this activity is hypotheses. student, or the teacher, should carried out correctly, attach a sit in the center of the circle small stick to the globe at the 3. Look at the climate data holding a flashlight, repre- in line with the provided. How many months of senting the sun (make sure you earth’s axis. Tilt the globe the year is the temperature above have turned off the classroom approximately 23.5 degrees freezing in the arctic? Make lights). The flashlight should and choose a stationary object sure the class understands that be pointed directly at the globe in the room (probably on the this is when snow and ice as it is passed around the circle. ceiling) to which the stick thaw, making water available points. No matter which for plants and animals to use. student is holding the globe, In addition to sunlight, water the stick should always be is also necessary for plants to When the Arctic is pointing to the stationary photosynthesize. tilted away from the object. Students in the four 4. Using the data provided on sun, in the winter seasonal positions can attempt Seasons Around the World rotating the globe, maintaining worksheet and the incomplete months, it gets little a constant tilt, to see where graph provided, have students or no sunlight. sunlight would hit over the label the x and y axis and plot course of one day. the average number of daylight 8. Have students label the appro- hours per day in for 7. The teacher should designate priate seasons on the work- each month of the year. four students equally spaced as sheet. 5. Check your local newspaper or the four seasonal months: search on the internet to find January, April, July and Alternate Method the time of and October. Using a plastic inflat- 1. An alternate activity is to create and the average number of able globe, students hold the a three-dimensional model to daylight hours for your town earth at its 23.5 angle of tilt study the earth’s position rela- or others with a latitude and pass it around the circle, tive to the sun at four times of between you and Alaska. noting where the sun strikes at the year, each of the four What did you discover? What different seasons of the year. seasons. Students will simulate does it mean? If you find infor- where the sun’s rays reach the mation for several places, you earth in January, April, July, can graph the range of daylight and October, taking into hours for comparison. consideration the earth’s tilt. 6. Have students sit in 2. Use small round objects a large circle repre- for the “,” senting the move- such as Styro- ment of the foam balls or

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small fruit. Students should 23.5° angle and not moving day at that time of year. insert a toothpick through the the paper at all, students Students should notice their center of each of their four should begin an orbit around arctic tundra being at different earths, from “pole to pole.” the sun, being sure not to locations relative to the sun Using a pencil or pen, draw a rotate their earth or change the throughout the year. circle around the North Pole to angle in any way. Secure the 6. Have students refer to their represent the Arctic Circle. second earth to the paper. Do graph of daylight hours and Make another mark on the the same for the third and think about which angle of circle to represent the location fourth earths, again being sure rotational tilt the earth would of the arctic tundra. Use a not to move the paper, rotate be in during each of the four larger Styrofoam ball to repre- the earths, or change the tilt in seasons. Students can label the sent the sun. Insert a tooth- any way. When the model is seasons on their model. pick into the “sun” just far complete, students should Conduct a class discussion enough to secure the ball to check their work by verifying about what their models mean. the toothpick. that the angled toothpicks are Where are the longest days in parallel to one another, all 3. Press five pieces of modeling June? In December? Why does pointing in the same direction. clay onto a piece of cardboard, the arctic have such long days Students can very carefully one in the center for the sun, and short and vice versa? rotate each earth without and the remaining four at Why does it have such a short removing them from the clay, equal distances away from the growing season? What do you to see how much sunlight sun, and from each other, think these events mean for might reach their tundra in a approximating a circle. Provide a template on which students can attach the modeling clay. 4. Position the sun onto the paper by inserting the tooth- pick into the clay in the middle of the paper. 5. The earth maintains a steady angle representing the 23.5° tilt. Students should angle one of their earths approximately 23.5 degrees away from the sun, and secure it into the clay at that angle, noticing the loca- tion of their arctic tundra. Holding a second earth at a

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arctic plants? Animals? How the winter position (December have they adapted to this kind of is a winter month in the situation? What kinds of adap- ). Select tations do they have to help a point on that earth appearing them survive in habitats with to get the most sunlight in one these extremes? day. Notice the location of that point relative to the loca- tion of the tundra on that earth. Now go to a globe and Modifications for attempt to find that same Younger Students point, and the country it falls (3-4) in. The student should come ✔ Have students do steps 6 and up with a country in the 7, with your assistance. How . LICHEN MOTH Students can then complete are the seasons and lengths of hardi- the table on the student days determined by the earth’s ness zones found in the North activity sheet. angle and rotation? What does American arctic? Are their differ- this tell you about the tempera- ences and similarities in their tures you should expect at structures? What are they? ✔ Alternatively, have students different times of the year? propose and demonstrate a way of explaining this material to younger students, such as Extension Assessment using a poster, sharing their own models from this activity, ✔ Have students investigate plant ✔ Have students consider: How or doing a life-size demonstra- hardiness zones for the North does day length and the rotation tion of the earth’s movement. American arctic and your of the earth impact seasons in community. What does “plant other parts of the world? Where hardiness” mean? Which zone is in the world is it summer in your community in? What native December? Determine this by plant species are adapted to your considering the earth that the plant hardiness zone? To the student has labeled as being in

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WORKSHEET

Seasons around the world

Graph the following data for average monthly daylight hours for the Alaskan tundra: Y January 1 ; February 7 hours; March 12 hours; April 16 hours; May 3 hours; June 24 hours; July 24 hours; August 19 hours; September 14 hours; October 9 hours; November 3 hours; December 0 hours. X Graph the data for your region: Y January February March April May June July August September October November December . X

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WORKSHEET

Seasons Around the World Using your model, world map, or globe, fill in the following chart to indicate what season it is in different parts of the world during the given months

Month/Season January April July October

Alaska

Florida

Australia

Sweden

Argentina

Ecuador

Your state:______

(include a graph of average monthly temperature for several Arctic locations). Data for graph of Alaskan tundra average monthly temperatures: (degrees F) January:-14; February:-20; March:-16;April-2; May 19; June 33; July; 39;August: 38; September: 31; october:-14; November:-1 December-13.

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