Separation

Materials:

paper towel
spoon
wool sweater
1 tsp. salt
balloon
1 tsp. pepper

Directions:

1) Place the paper towel on a table. Place the salt and pepper on the towel.
2) Mix the salt and pepper thoroughly with the spoon.
3) Ask one girl to come up and try to separate the salt from the pepper.
4) After she has given up, have them sit down. Blow up the balloon. Tie a knot in the end. Rub the balloon with the sweater.
5) Hold the balloon near the salt-and-pepper mixture.

Explanation: When you rub the balloon with the sweater, you give the balloon a negative charge. The pepper is attracted to the balloon because the electrons in the pepper move to the side of the pepper that opposite the balloon. The side near the balloon develops a negative charge, and the positive is attracted to the negative charge of the balloon. The electrons in the salt don't move, so they stay where they are, without a charge. This is a good example of static electricity.


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