Introduction:

For a long time, people thought that the Sun and the moon were the same size and that they both travelled around the Earth. This was called the geocentric theory. The Sun's diameter is really over 865,000 miles across; which is more than 400 times the size of the moon and 100 times the diameter of earth. If you put 109 Earth's side by side you would have the distance across the center of the Sun.

Materials:

• a clear sidewalk, or large yard
• 3 wooden stakes or a piece of chalk
• 109 Cheerios or other small cereal
• a pencil
• a large sheet of brown paper
• 2 yards of string
1. Mark the spot where you are beginning with a stake or chalk mark and put you heel against the mark. Place a mark in front of your toe. Now walk 108 more steps from that point, putting one foot directly in front of the other. Mark where you stop. You have just made a model of the diameter of the Sun.

2. Lay 109 Cheerios in a row on brown paper. Tie one end of the string around the pencil. Hold the other end on the fifty-fifth Cheerio so that the pencil point touches the outside of the last Cheerio. Have another student draw a circle on the paper around the pencil. You have just made a model of the Earth.

3. Compare the model of the Sun to the model of the Earth. Quite a large difference isn't it?