Atom

Take a piece of something — a stone, some water — and cut it in two. Take one of the pieces and cut it in two. If you could do this many, many times, at the end you have a piece that cannot be cut smaller and be the same thing. This smallest piece is an atom.

Atoms are very, very small. In a very small amount of water, there are more atoms than a person could count in a thousand thousand years — counting one atom at a time, with no sleep.

About one hundred kinds

There are about one hundred kinds of atoms, and all things are made from these kinds, connected in groups. Water is a group of three atoms: two of one kind, and one of another kind. When atoms connect, or stop being connected, things happen: burning, food turning bad, your body using food to live. The word for this is chemical — when you hear it, think about atoms connecting. Burning is atoms connecting very quickly with atoms in the air, and giving out light and hot air.

The centre of the atom

An atom has a very small, very hard center. If you cut the centre of one of the big kinds of atom in two — this is very hard to do — a very, very big amount of light and hot air goes out, from a very small amount of things. People use this to make electricity. People have used it to damage places where very many people live. This happened two times. Most people want the number of times to end at two.

The sun does a different thing: it pushes the centres of two small atoms into each other, and they become one centre. This makes very much light. All the sun's light is made like this.