Does anyone else remember rubbing your school shoes on the industrial school carpet until you’d built up enough charge to zap people? We spent many wet winter days stuck in a classroom doing this to each other! This is static electricity, and there are other ways to experience it, which are much better with the kids.
Static electricity is caused by friction between two surfaces. Some surfaces are better at building and maintaining a charge than others. We used a balloon for our experiments because it is easy to create the charge and to witness its effects. The friction causes the surface to gain a charge (negative or positive), and when another surface has the opposite charge, they become attracted. Static electricity can cause a ‘zap’ if you touch someone or something after building up some static on yourself. You can find a good explanation of static electricity at Science Made Simple.
Rubbing the balloon on the rug.
Raising L’s hair.
Stuck to L’s head.
We used balloons to demonstrate and play with static electricity. I blew up a couple of balloons and gave one to each of the kids. First they rubbed their balloons against their hair to build up the charge. When they raised the balloon away from their heads their hair was attracted back to the balloon, looking like it was standing on end. They also tried rubbing the balloons on the carpet, and on their clothes, but it didn’t provide enough charge to lift their hair.
Stuck to the wall.
They discovered that after rubbing the balloons on their hair, there was enough charge to hold the balloon to the wall. They were amazed by this, and spent quite a lot of time trying this over and over.
I emptied the hole punch onto the carpet (this can make a big mess, so be prepared to vacuum after, and ask a parent first!). All the little bits of paper from the hole punch scattered on the floor. The kids charged up their balloons and then attempted to pick up these bits of paper. They tried picking up the paper from different heights to see how far away the balloon could be before it lost its attraction. They marveled as they watched the paper fly up to stick to the balloon.
Lifting paper off the floor.
Paper stuck to the balloon.
They discovered that they could get the best reaction by rubbing the balloons on their head, though this did cause their hair to become rather knotty after a while. We had to carefully brush their hair out at the end, but they had a brilliant time playing with the balloons.
We also discussed some other places that we might encounter static electricity zaps, such as on the trampoline and the slide.
Today We Did 