Try This at Home: Charged Balloons
Illustrated Concepts
Opposite charges attract each other and like charges repel each other.
What You Need
- 2 rubber balloons
- Marker
- Masking tape
- 2 lengths of string or ribbon, about 1 meter (1 yard) each
- Plastic wrap
- Hair
What To Do
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Make sure you have an adult with you to supervise this experiment.
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Blow up both balloons and tie their ends. Label one balloon "A" and the other "B".
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Tie each string to the end of a balloon. Tape the other ends of the strings to the ceiling. The balloons should hang approximately half a foot apart.
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Make a hypothesis! The balloons should be hanging still now. What do you think will happen if you rub the plastic wrap on balloon A? What will happen when you rub balloon B on your hair?
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Rub some plastic wrap briskly against balloon A and then release it so that it hangs freely. What happens?
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Now rub both balloons A and B on your hair. What happens now? Was your hypothesis correct? Can you explain what is happening here in terms of the charges on the balloons?
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Clean up.
What's Happening
Both balloons started out with equal amounts of positive and negative charge; they were neutral. By rubbing the plastic wrap against balloon A, negatively-charged electrons moved from the balloon to the plastic wrap, leaving behind more positive charge than negative on balloon A. Balloon B remains neutral, but the negatively-charged electrons in B are attracted by the positive charge of balloon A, so some electrons move to the side of balloon B that is closest to A. Opposite charges attract; the negative electrons in balloon B attract the positive charge of balloon A so the two balloons move closer together.
Rubbing the balloons on your hair causes electrons to move from your hair to the balloon. Now, both balloons A and B are negatively charged. Like charges repel; the electrons in balloons A repel the electrons in balloon B so the two balloons move farther apart from each other.
Fun Fact
Every second, 50 to 100 lightning bolts strike the ground worldwide.

