Electricity is a stream of electrons that gives off energy as light and heat. In lightning, electrons flash between clouds or from a cloud to the ground. But you don’t have to be struck by lightning to get zapped. When you scuff your feet on a rug, electrons from the rug rub off onto you. If you touch a metal doorknob, which conducts electrons well, the electrons will leap into the metal. The energy transfer gives you a tiny electric shock. Electricity that builds up in this way is called static electricity.

Rub a comb against fur, silk, nylon, or wool; the comb will collect electrons and become negatively charged. That causes it to attract objects that are positively charged. Hold the comb near a trickle of water from a faucet, salt and pepper, threads, a table-tennis ball, scraps of paper, your hair, or anything else that strikes your fancy. Watch what happens.

Illustration by Loel Barr
Text adapted from Fun With Physics (National Geographic Society, 1986)