|Name of Activity
||Orbits of the Earth, Moon, and Sun
||Michael Hart, Usula Deelstra
||earth, moon, sun, models, rotation, tilt, relative size, seasons, stars, size, motion
||K, 1, 2, 3, 4, 5, 6
||1 Hour Total
||The class will explore the relation between the Earth, moon, and sun using classroom models.
||The Purpose of this activity is to discuss how the Earth, moon, and sun move relative to each other. And to discuss rotation, tilt, and relative size. In regards to relative size, a physical activity is introduced to help enhance the concept of the relation of the Earth, moon, and sun to each other.
- Tape Measure.
||This activity deals with the orbit of the earth around the sun and the orbit of the moon around the earth. It takes the earth one year (365 days) to orbit the sun. At the same time, the earth is rotating about its own axis. The earth makes one complete rotation once a day. The combination of the rotation of the earth, its orbit about the sun, and the earth’s natural tilt cause seasons on the earth. For a more detailed description see http://www.windows.ucar.edu/tour/link=/the_universe/uts/earth3.html. This website contains information about the earth’s orbit, its rotation, and the seasons. Similar to the earth, the moon has an orbit and rotation also. A description of the moon can be found at http://www.windows.ucar.edu/tour/link=/the_universe/uts/moon1.html.
- Begin the activity by discussing facts relating to the Earth, moon and sun.
- Talk about how the three move relative to each other.
- Select three students to imitate the motion of the sun, Earth, and moon.
- Have the Earth stand in place and turn around, talk about how one turn is one day.
- Have the Earth walk one lap around the sun, imitating the passing of one year on Earth.
- Have the student carefully do both movements together.
- Next add the moon. Have the moon orbit the Earth, it takes 28 days for the moon to orbit the Earth. During this time we see all the stages of the moon.
- Finally, put all the movements together.
- Discus the tilt of the Earth, and how it produces seasons.
- Turn out the lights. Using the globe and flashlight have one student hold the flashlight representing the sun.
- Have a second student walk around the flashlight with the globe.
- Show students that as the globe moves around the sun, the northern or southern hemispheres will be tilted towards the sun, these are the different seasons.
- Discuss the relative sizes of the sun, moon, and Earth.
- The sun is the largest, but to us it appears about the same size as the moon because it is so much farther away.
- Have students break into groups of two.
- One student will get a small balloon and the other a larger balloon.
- The student with the small balloon will tell the student with the large balloon to walk backwards until the balloons appear to be the same size
- Finally, ask students to discuss the relationship between the size that an object appears and the distance from you that it is. Finally, explain that we “built” our own models today to explore the motion of the planets, engineers use models to understand systems like the solar system that are too big to make life-sized models to study.