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There are other ways that we survey the Earth, which Aristophanes never dreamed of.

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NASA scientists use airplanes and satellites.

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But what if we wanted to survey other planets, like Mars?

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NASA scientists are doing that right now.

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But first, let's head to Central Middle School in Charlotte Courthouse, Virginia.

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There, students are following in the footsteps of Aristophanes.

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Hi! We're from Central Middle School in Charlotte Courthouse, Virginia.

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NASA Connect asked us to show you how to do the student activity for this show.

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In this lesson, you will work in small groups to take accurate measurements of shadows

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using geometry to determine the size of an angle.

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Here are the materials you'll need for each group.

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A straight stick approximately 91 centimeters long.

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A meter stick or tape measure.

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A piece of string approximately 91 centimeters and a rocker weight.

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A scientific calculator.

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Index card.

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Compass.

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Copies of the student data chart for each student.

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Let's begin.

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Divide the class in research groups of three to five members.

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Set your measurement station by first placing the gnomon perpendicular to the ground.

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For your measurement to be accurate, it is critical that the gnomon is vertical.

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To check the vertical position, tie the rock or weight to the string

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and dangle it above the ground in front of the gnomon.

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Next, measure the height of the gnomon.

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Place an index card under the station to mark where the shadow ends.

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Take measurements every two minutes, beginning at least ten minutes before local noon,

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which is the time that the sun is highest in the sky.

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This will most likely not be noon, as indicated on your time measuring device.

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Students should note that when the sun is highest in the sky, the shadow length is the shortest.

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Since the edge of the shadow is fuzzy and the shadow is moving from east to west in the northern hemisphere,

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be careful in deciding where to place your mark.

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Record your data on data chart one.

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Now, back in your classroom, locate the latitude and longitude of your school location

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and record it on data chart number one.

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Identify your best shadow length.

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This is the best shadow length at local noon time.

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Next, calculate the tangent by dividing the length of the shadow by the height of the gnomon.

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Locate this number, or the nearest rounded number, on the tangent table.

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The measure of the tangent can also be found by dividing the length of a shadow

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by the height of an object on the scientific calculator.

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Record tangent on student data chart.

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Make a scale drawing of your gnomon and shadow.

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Complete the triangle and measure the tangent with a protractor to verify your calculations.

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What's next, Jennifer?

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Let's analyze the data by reviewing the results of this activity and by responding to the following questions.

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Did the weather conditions affect the results of this activity?

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If so, how?

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As the shadow lengthens over time, how will the angle be affected?

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If each group uses a gnomon with a different length, how will that affect the results of this activity?

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For more activities like this, check out our website at edu.larc.nasa.gov forward slash connect.

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NASA Connect would like to give a special thanks to the mentors from the AIAA chapter at Howard University in Washington, D.C.

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We appreciate all your help with the student activity.