Electrostatic Charges

For this experiment, I thought we would do a simple one, but one that always entertains people. As with many other science experiments, it is simple to do, but the more observant you are, the more you will learn about static electricity.

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To try this, you will need:

  • a balloon
  • a sheet of paper
  • (maybe) a hair drier

First, tear some of the paper into small bits, about half the size of the nail on your little finger. Put the pieces of paper onto a flat surface. Blow up the balloon and tie it off. Rub it briskly against your hair or a piece of cloth. Then see if it will stick to the side off your head. If it does, then bring it near the bits of paper. You should notice that the bits of paper jump up and stick to the balloon. If it does not stick, dry the balloon and your hair with the hair drier and try again.

When you rubbed the balloon against your hair, you transferred electrons (negatively charged bits of atoms) from your hair, to the balloon. The balloon wound up with extra electrons, giving it a negative charge. Your hair wound up missing some electrons, leaving it with a positive charge. Am I sure your hair lost electrons? Yes, positive.

Opposite charges attract, so the negatively charged balloon sticks to your positively charged hair. But why did the bits of paper stick to the balloon? You didn't rub the balloon against them, so they should not have an electrostatic charge.

Well, they didn't have a charge until you brought the balloon near them. As the charged balloon came near, the negative charge of the balloon pulled on the positively charged protons and pushed away (repelled) the negatively charged electrons. Opposite charges attract and like charges repel. Some of the electrons were pushed to the far side of the paper, giving the paper poles, almost like a magnet. One end of the paper was positive, and the other end was negative.

If you watch, you should notice that the bits of paper tend to stick out from the balloon, with one end (the positive one) sticking to the balloon, and the negative end sticking out away from the balloon. You may even notice bits of paper forming chains, with the positive end of one bit sticking to the negative end of another.

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