Swinging Cereal

Try this simple experiment from HomeRoomTeacher.com ( http://www.homeroomteacher.com/infoeasyscienceexp eriments.html) to explore static electricity. This experiment works best on a day when the weather is dry.

You will need a rubber or plastic comb, thread, and small dry pieces of O-shaped cereal. Tie a piece of cereal to one end of a 12-inch piece of thread. Attach the other end of the cereal to the end of something so that the cereal does not hang close to anything else (a table edge is a good place for this).

Use a brand-new comb or, if using a "pre-owned" comb, wash it first to remove any oils and dry it well. After it has dried, charge it by running it through long, dry hair several times or vigorously rub it against a wool sweater. Slowly bring the comb near the cereal. It will swing to touch the comb and then jump away by itself. Try to touch the comb to the cereal again- the cereal will jump away as the comb approaches!

What happened: combing the hair (or rubbing the comb against a wool sweater) moved electrons from the hair/sweater to the comb. The comb had a negative charge. The neutral cereal was attracted to it. When they touched, electrons slowly moved from the comb to the cereal. Now both objects had the same negative charge, and the cereal was repelled.