Cereal Magic - Likes repel.

Materials Required

• A piece of Cereal
• A plastic comb
• Feet long thread (12 inches)

Procedure

Tie one end of the thread to the cereal piece. Hang the thread freely from the other end so that the cereal can swing freely. Run the comb through hair several times or rub in a silk cloth (comb and hair should be oil free).
Now, take the comb closer to the cereal slowly. Observe. Then again take the comb closer to the hanging cereal slowly. Observe the difference.
You should have noticed that the first time you brought the comb closer to the cereal, the cereal got stuck to the comb. When you did the same the second time, the cereal repelled from the comb.

Why?

When you ran the comb through the hair, the negative charge in the hair got transferred to the comb.

Now, the cereal is not charged it is neutral. So when you brought the comb to the cereal the first time, the negative charged comb attracted the chargeless cereal piece.

Now, when the cereal touched the comb, some negative charge in the comb got transferred to the cereal piece. When you brought the comb near the cereal the second time they repel because both contain negative charge. Like charges repel.