Duration of Activity:
40 minutes.

Student Prerequisites:
From previous discussion and reading, students should have a basic understanding of the Earth and Sun’s rotation (spin) and revolution (orbit). This lesson is best taught after completing the two “Motion of the Sun and Earth” lessons in this unit.

Materials:

• Chalk (blue, red, white and yellow)
• Work sheets

Teacher Background Information:

• The Earth’s diameter is about 7,926 miles and the diameter of the Moon is about 2,160 miles. The scale of the Moon to the Earth is approximately 4 to 1.
• The distance between the Earth and the Moon is approximately 238,906 miles.
• The Earth and Moon spin counterclockwise with North being “up.”
• The Earth and Moon are in synchronous rotation. The Moon rotates slowly in comparison to the Earth. The Moon rotates in the same amount of time that it takes to revolve around the Earth—27 days, 7 hours, 43 minutes and 11.47 seconds! We always see the same side of the Moon facing us.
• The time between two consecutive full moons is 29.5 days. This longer period of time is due to the fact that the Earth is also moving along its orbit as it revolves around the Sun.
• See the following Internet resource for more compete information on the Moon:
  The Moon

Teacher Preparation:
Allow time to locate chalk and copy work sheets.

"Adding the Moon" Work Sheets
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View Completed Student Work Sheets

1. The Moon rotates or spins on its axis.
2. The Moon revolves or orbits around the Earth.
3. The Moon and the Earth revolve around the Sun.
4. The motion of the Sun, Earth, and Moon are cyclical.
   
   

Grade Level:
Grades 1-3

Procedure:

1. Return to the playground area where students drew the Sun and Earth from previous lesson to reuse your drawing.
2. Divide students into small groups.
3. Review that the Earth revolves around the Sun. Ask students, "What revolves around the Earth? What do you see in the sky almost every night and also during the day?"
4. If you cannot use the previous playground drawing of the Earth, ask one group to draw the Earth (a 10-inch circle filled with blue chalk), and another group to draw the sun (2-foot circle filled with orange or red chalk). Ask students to draw the orbit of the Earth around the Sun.
5. Ask another group to draw the Moon (3-inch circle filled with white chalk). The Moon should be about 3 feet away from the Earth so that students can move about easily. Note: Orbit sizes not to scale for this activity. Remind students that distances in space are vast and that this is a model to help understand motion.
6. Ask another group to draw a line indicating the Moon’s orbit around the Earth.
7. Pick one student to act as the Earth and one to act as the Moon.
8. Ask student how long it takes for the Earth to spin around—24 hours.
9. Explain that the Moon rotates much slower—it takes a little more than 27 days for the Moon to rotate all the way around. Ask students, "Which spins faster, the Earth or the Moon?"
10. Explain that the Moon rotates and orbits around the Earth at the same time. Ask the “Moon” how he or she should move. The Moon character will spin and revolve in a counterclockwise direction as seen from above (North is up). Reminder: This is not a race and the rate of speed is constant and steady.
11. Ask the “Earth” how he or she should move. The Earth, like the Moon, is spinning counterclockwise as seen from above (North is up).
12. Get your Earth and Moon characters moving in rotation/revolution.
13. Finally, select a student to act as the Sun and have students move again—so that students can see the Sun, Earth, and Moon all moving together.
14. At the conclusion ask students, “Which role was the hardest to play?” Take a vote.
15. If time allows, ask for a second set of students to play the Sun, Earth and Moon
    and model the motion again.

Assessment:
Distribute the "Adding the Moon" work sheet to assess what students have learned from this activity.

Bibliography:
See related books and websites.