What You Need:
- Hard rubber or plastic comb
- Small pieces of dry cereals like puffed rice or cornflakes
- Tie a piece of the cereal to one end of a 12-inch piece of thread. Find a place to attach the other end so that the cereal does not hang close to anything else (You can tape the thread to the edge of a table).
- Wash the comb and dry it well.
- Charge the comb by running it through long, dry hair several times or rubbing it vigorously on a wool sweater.
- Slowly bring the comb near the cereal. The cereal will swing to touch the comb and if you hold it for long enough, the cereal will jump away by itself.
- Now try to touch the comb to the cereal again. The cereal will move away as the comb approaches.
Combing your hair moves electrons from your hair to the comb, giving the comb a negative static charge. The neutral cereal is thus attracted to the comb. When the two touch, electrons slowly move from the comb to the cereal. This causes both the objects to have the same negative charge and the cereal is repelled.