Why does a rubber balloon that has been rubbed in your hair stick to a wall?

If you have ever installed a circuit board or card into a computer, the product probably was shipped in a “static-free” bag. This bag is designed to keep all excess static charge outside the bag. Many electronic circuits are sensitive to the electrostatic buildup, and can be damaged if such a charge accumulates on sections of the circuit. Therefore, when installing the circuit board, the instructions usually encourage you to neutralize yourself by touching a grounded piece of metal to discharge your body and tools or to wear a grounding strap on your wrist to keep you at ground potential.

The attraction between a charged balloon and a wall is the result of electrostatic forces. When rubber is rubbed on human hair or a wool sweater, electrons transfer easily to the rubber balloon. The balloon is charged by rubbing. The hair or sweater fuzz may stand up as a result of the excess positive charges repelling each other. When the balloon is brought near the wall, it polarizes the wall, moving the positive sources toward it and repelling the negative charges away. The negatively charged balloon is attracted to the many positive charges in the wall. As long as the electrostatic force and frictional force between the balloon and the wall are stronger than the gravitational force pulling the balloon down, the balloon will remain on the wall.


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