Atomism

Atomism is an idea that dates all the way back to ancient Greece. It says that all matter is made up of tiny, unbreakable parts called atoms. Atoms can not be seen by your eyes, but they make up everything--from rocks, to plants, to people. Atoms are too small for us to see, but scientists are able to use things like microscopes and special chemicals to study them. They have learned that atoms come in different shapes and sizes, and each thing is made up of a different kind of atom.