Balloon Sticking to Wall
Name: Isaac T.
Why can a charged balloon stick to a neutral wall?
When the charged balloon approaches the wall, it repels charges in the wall that are the same
as those on the balloon as it simultaneously attracts charges in the wall that are opposite
to the balloon charges. Thus, the opposite charge between balloon and wall holds the balloon
on the wall.
The wall is not grounded, or at least not well grounded. Dry wall,
plaster, and paint are pretty good insulators. It picks up the opposite charge on the balloon.
A neutral object actually has both positive and negative charges: protons and electrons.
When a charged object comes near a neutral surface, the charges of the surface rearrange
themselves. The attractive charges that are opposite the balloon's charge are pulled a
little toward the balloon. The repulsive charges that are the same as the balloon are
pushed a little away. This makes the closest wall charges attractive, giving a little
attraction to the balloon. Because the balloon is so light, this is enough to support
Dr. Ken Mellendorf
Illinois Central College
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Update: June 2012