Static and Humidity
What you need:
- a hair drier
- some balloons
- small pieces of paper
- your hair
- a wet cloth or paper towel
First, blow up a balloon and tie it off.
Small, cheap balloon work the best, but any sort
should do the job. Then, tear some tiny bits of
paper and place them on a flat surface. The
pieces should be smaller than your fingernail.
Rub the balloon briskly on your hair and then
bring it near the pieces of paper. If you
generated enough static electricity, then some
of the pieces of paper should jump up to the
balloon. If the paper did not jump to the
balloon, then turn on the hair drier and use it
to dry your hair and the balloon. Be careful not
to get the balloon hot enough for it to pop.
Once the balloon is dry, try it again. This
time, the paper should jump very well for you.
Next, take the wet cloth and rub it gently over
the entire surface of balloon. You want the
balloon to be damp. Then rub the wet cloth
lightly over your hair, to make it damp as well.
Try rubbing the balloon on your hair again and
bring it near the bits of paper. This time, you
will get very little reaction, if any at all.
Once again, dry the balloon and your hair with
the hair drier and the paper will once again
jump up to the balloon.
Why would water cause this? When you rub the
balloon against your hair, you are transferring
electrons (tiny, negatively charged pieces of
atoms) from your hair to the balloon. Because
electricity does not flow easily over rubber,
the electrons are trapped there, building up a
strong, negative static charge. It is this
charge that attracts the bits of paper.
Rubbing the damp balloon against your wet
hair still moved electrons from your hair to the
balloon, but the water formed a conducting
pathway. Instead of remaining trapped on the
balloon, the electrons flowed across its surface
to your skin and then to the ground. You never
built up enough of a static charge to attract
the paper bits. When you used the hair drier to
dry the balloon and your hair, you removed this
pathway, and once again the static charge could
As the weather gets colder, the air is
usually drier. That is why you get a lot more
static shocks in the winter than in the
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