Wheels with teeth
Why should a wheel have teeth? Wheels don’t eat! But some wheels use
teeth to get a lot of work done—and they can do things that other
wheels can’t do.
A wheel with teeth is called a gear. It’s a wheel that makes other
wheels move. If you look at an eggbeater, you can see three gears. The
big one with the handle is the gear you turn. The teeth on this gear
fit into the spaces between the teeth on the two small gears. When you
turn the handle, the teeth on the big gear push the teeth of the small
gears and make these gears turn.
