Why Does Your Hair Stand Up?

When you rub a balloon on your hair, something invisible is happening — electric charges are moving.

Rubbing the balloon against your hair can transfer tiny negatively charged particles called electrons from your hair to the balloon. The balloon gains extra negative charge, while your hair is left more positively charged. This build-up of charge is called static electricity.

Now something interesting happens.

Many of the hairs on your head have the same type of charge. Charges that are alike repel, which means they push away from each other. Each hair tries to move away from the hairs beside it — making your hair spread out and stand on end.

The charged balloon can also attract your hair. This is why your hair may reach towards the balloon even when the balloon isn't touching it.

Does It Always Work the Same Way?

Not necessarily! Static electricity can be affected by the materials you use and even the air around you.

Try rubbing the balloon for different lengths of time, or compare dry hair, wool, fur or other materials. You may discover that some combinations produce a much stronger effect than others.

That gives you another question to investigate: what conditions create the strongest static charge?