For printable version, click here

KEY QUESTION
Just how far is it from the Earth to the Moon?

POSSIBLE PRECONCEPTIOINS
Most students have no idea how far away the moon is.

KEY CONCEPT
A simple scale model can help students visualize the distance between the Earth and Luna, our moon. 

GENERAL INFORMATION
FOCUS     Distance to the Moon
                Scale models
GRADE LEVEL:    4-12
GROUP SIZE:    Whole class
SETTING:     Indoors
APPROXIMATE TIME REQUIRED: 15 minutes
SCIENCE PROCESSES   Logical thinking
                                     Math skills
                                     Scaling
METHOD     Teacher directed research 

MATERIALS NEEDED

                STANDARD ACTIVITY                                         LOCAL ACTIVITY

*  If a 30 cm globe is not available, you may use other globes but the size of the 'moon' must be adjusted.  The moon should be about ¼ the globe's diameter.  If the globe is 40 cm, your 'moon' should be a ball about 10 cm in diameter.

* This is a common tree all over Micronesia.  It's called Palo Maria, da'ok, biyuch, fotoi, ragish, rakich, rakir and bataches on various islands.  It has round seeds that are ca. 5cm (2 inches) across when green and 3 cm (1 inch) across when dry.

NOTE:  Whatever materials are used, the diameter of the 'Earth' (larger ball) must be four times bigger than the diameter of the 'moon' (smaller ball).  If the da'ok nut you use for the moon is dry and about 3 cm across, use a ball about as wide as the height of a cigarette pack for the 'Earth'.

PROCEDURE
   DOING THE ACTIVITY
Traditional materials are in boldface type.

1.  Tell the students that the Calophylum nut [tennis ball] represents the Moon and the husked coconut [globe] represents the Earth.  Then have them place the Calophylum nut [tennis ball] at the correct distance from the husked coconut [globe] to show the distance from the Earth to the Moon.

2. Ask the students to find the circumference of the Earth and the distance between the Earth and the Moon by consulting a reference book.  *

3. Ask the students to divide the distance to the Moon by the circumference of the Earth.  (The answer is 10.11 or roughly 10.)

4. Wrap the string around the husked coconut [globe] 10 times.  Then hold one end of the string at the surface of the husked coconut [Earth globe] and stretch the measured string across the classroom.  The other end of the string represents the distance from the Earth to the Moon. 

5. Compare the earlier estimate of the distance between the Earth and the Moon with the measured distance based on the Earth's circumference.

* The Earth's circumference is 23,627 miles or about 24,000 miles and the average distance between the Earth and the Moon is 238,900 or about 240,000 miles.  If the students are learning the metric system, the figures are 38,025 km or about 38,000 km for the Earth's circumference and 384,400 km for the average Earth-Luna distance.

EXTENSIONS
1. Create a larger model of the Moon and the Earth with chalk on a sidewalk or playground.  The diameter of the Moon should be 1/4th of the diameter you choose for the Earth.

2. Using any one of several available activities, create a scale model of the Solar System.