Construct a Fan - p. 114

Do you want to chill out? Then this experiment will help you keep cool.

This machine uses a belt that works in the same way as a gear. It makes the fan spin faster than the handle that you turn to make it work. Many machines have parts like these that work together at different speeds.

Materials needed:
-A box
-Rubber band, nail, thumb tack, paper fastener
-3 corks
-Thin wooden stick
-Knife
-Scissors
-Stiff plastic
-Jar lid
-Hammer

Let's get started!

1. Ask as adult to make two holes in the front of the box, and a second hole in the back, opposite one of the first holes.



2. Ask the adult to make two holes in the jar lid, using the nail. Make one hole in the middle of the lid and the other near the edge.



3. With help from an adult, use the tack and attach a cork to the jar lid. This is the handle of your fan.



4. Attach the handle to the box with the paper fastener. Push the fastener through the lid and the second hole in the box. The handle should turn easily.



5. Ask an adult to cut four evenly spaced slits in another cork. Now two corks are in use. Make sure to slant the slits.



6. Cut four long strips from the plastic. Make them as wide as the slits in the cork.



7. Push the plastic strips into the slits and push one end of the stick into the cork.



8. Push the stick through the other two holes in the box. The stick should poke out from the back of the box.

9. Push the third cork onto the end of the stick. Loop the rubber band around this cork and the handle. Your fan is now ready!

-The rubber band should fit without much stretching. -The rubber band is a belt that links two wheels: the lid and the cork.

Unfortunately, the rubber band will not stay on the cork and jar lid. But it does work briefly to give you an idea of how the fan works.