How to Make a Windmill With a Paper Clip and a Cork

Wind-powered generators use the same principles as this windmill to convert wind power to electricity.

You can build a working model windmill with your kids at home as an educational craft project or help your middle schooler build one for a school assignment or science fair. The windmill transfers wind energy into rotational force, demonstrated in this model by its ability to wind up a string to lift a paper clip using only the force of a person's breath.

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Empty half-gallon paper milk carton
Sand
Sharp pencil
Drinking straw
Cork
Push pin
Paper pinwheel
Paper clip
Thread

Instructions

- 1
  
  Rinse out the milk carton thoroughly and allow it to dry. Pour about 2 inches of sand into the bottom of the milk carton to weight it down.
- 2
  
  Poke a hoke in one side of the milk carton 6 to 10 inches above the bottom using the sharp pencil, then push the pencil straight through to poke a hole in the opposite side of the carton as well.
- 3
  
  Poke a hole in one end of the cork using the point of the pencil, then stick one end of the straw into the hole in the cork.
- 4
  
  Thread the straw through the two holes in the milk carton. Attach the pinwheel to the uncorked end of the straw with a pushpin so that the pinwheel will turn the straw when it spins.
- 5
  
  Tie a paper clip to one end of a 36-inch length of thread. Tie the other end of the thread around the cork.
- 6
  
  Blow on the windmill to make it spin. As it spins, it should wind up the thread and lift the paper clip up off the ground.