Gears calculation requires math background. You need to know the diameter of each gears.

## Use math to calculation

**What You Do:**

1. Print out the pattern for the gears and color them however you like. You can cut them out if you want, or just tape the whole paper to the Styrofoam tray.

2. Have an adult cut the Styrofoam around the pattern to make Styrofoam gears. (The easiest way to do this is to cut out a circle along the outside edge of the teeth, then make the cuts around the teeth.)

3. Once you have your gears cut out, use thumbtacks to pin them to a piece of cardboard or another tray. Pin them so that their teeth fit together.

4. If you want to, you can make a small turning handle on the big gear by taping a little piece of Styrofoam so it stands straight up on the gear.

You've just built a

**gear train**. The big gear is the driver. Try turning it slowly. What happens to the little gear? Which way does it turn? Draw a big colorful dot on each gear, and position the gears so that both dots are at the top. As you turn the big gear, have one person count how many times the big gear turns all the way around and another person count how many times the small gear does. Do they turn the same number of times?

**What Happened:**

Gears work to change the direction of motion. When you turned the big gear one way, the little gear turned the other way! Gears also change speed of motion. When you turn the big gear slowly, the smaller gear turns faster. This helps save energy, because you don't have to work as hard to turn the big one slowly as if you had to turn the small one quickly.

gears.pdf | |

File Size: | 125 kb |

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