Duration of Activity:
40 minutes.

Student Prerequisites:
From previous discussions and reading, students should have a basic understanding of the concepts of rotation (spin) and revolution (orbit).

Materials:

• Chalk for playground drawing (blue, yellow, orange, red)
• Work sheets
• Wrap-around map (optional)

Teacher Background Information:

• The Earth’s diameter is about 7,926 miles and the diameter of the Sun is about 865,400 miles.
• The scale of the Earth to the Sun (in diameter) is approximately 109 to 1.
• Sun is 93,000,000 miles from the Earth.
• Not all parts of the Sun rotate at the same speed. At its equator it takes 27 days for the Sun to complete one rotation. Near its poles, the rotation period is as much as 31 days.
• The Earth rotates once every 24 hours (one day) and it takes 365 days (one year) for the Earth to revolve around the Sun.
• The direction of rotation and revolution as seen from above with North up is counterclockwise.
• See the following Internet solar resource:
  The Sun

Teacher Preparation:

Allow 15 minutes to locate materials and print out wraparound map and work sheets.

Work Sheets:

"Motion Playground Model" Work Sheet
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1. The Earth rotates or spins on its axis.
2. The Sun rotates or spins on its axis.
3. The Earth revolves or orbits around the Sun.
4. The motion of the Sun and Earth are cyclical.

Grade Level:
Grades 1-3

Procedure:
In the classroom

1. Locate an area where students can draw on the playground surface and divide students into small groups.
2. Ask one group to draw a large Sun on the blacktop (a circle, 2 feet in diameter, filled with yellow, orange or red chalk).
3. Ask a second group to draw the Earth (a circle, 10-inches in diameter, filled with blue chalk). Note: Sizes are not to scale.
4. Have another group draw the Earth’s orbit around the Sun with blue chalk (orbit should be at least 10 feet in diameter). Note: Sizes do not represent the actual scale of the Earth-Sun system.
5. Select one student to act as the Earth and one student to act as the Sun. If you are using the wraparound world map, tape it around the “Earth” student.
6. Explain that the Sun is at the center of the solar system and that it rotates approximately once every 27 days. Explain that it is a cycle. Ask the “Sun” how he or she should move. Ask, “Is this fast or slow?”
7. Slowly turn the “Sun” to demonstrate rotation. The Sun should spin slowly in a counterclockwise direction while standing in one spot.
8. Explain that the Earth also rotates in a cycle. The rotation is completed once every 24 hours. Ask, “Is the Earth faster or slower than the Sun?” They should answer, “faster than the Sun.” Ask the “Earth” how he or she should move.
9. Turn the “Earth” as it moves along the lined orbit to demonstrate rotation and revolution. Note that the Earth should rotate and revolve in a counterclockwise direction.
10. Reminder: This is not a race and the rate of speed is constant and steady.
11. Explain that it takes an entire year for the Earth to complete its orbit around the Sun. Ask students, "How many times has the Earth revolved around the Sun since you were born?"
12. Get your “characters” moving in rotation/revolution.
13. Assign the “Sun” and “Earth” roles to another set of students and repeat the rotation/revolution.
14. At the conclusion ask students, “Which role was the hardest to play, and why?" Take a vote. Generally, students will respond “the Earth” since it rotates and revolves!
15. Return to the classroom and distribute the work sheets for students to complete.

Assessment:
Use the "Motion Playground Model" work sheet to assess what students have learned from this activity.

Bibliography:
See related books and websites.