Static: the spark you can make yourself

Have you ever pulled off a jersey in the dark and seen tiny sparks, or touched a door handle and felt a zap? That is static electricity, and you made it yourself.

Tiny charged particles

Everything is made of atoms, and atoms contain even smaller particles. Some of these, called electrons, carry a negative charge. Others, in the middle of the atom, carry a positive charge. Usually the positives and negatives balance, so an object has no overall charge.

When you rub two different materials together, like a balloon and your hair, some electrons get knocked off one and stick to the other. The balloon ends up with extra electrons, so it is negatively charged. Your hair has lost some, so it is positively charged.

Push and pull

The space around a charged object where it can push or pull other charges, without touching them, is called an electric field.

Why static stays put

In materials like plastic, rubber and glass, electrons cannot move easily. These materials are insulators, so any charge they pick up stays where it is: static means 'not moving'. In metals, electrons move freely, so a charge spreads away quickly. That is why you feel a zap when you touch a metal door handle: the extra charge suddenly jumps from you to the metal.

Static on a giant scale

Lightning is static electricity in a storm cloud. Ice and water particles bump into each other as they swirl, charges build up, and eventually a huge spark leaps between the cloud and the ground. It is thousands of times hotter than a kitchen oven. When thunder rolls, go indoors and stay away from tall trees and water.