Around 1800, the English chemist John Dalton reintroduced the idea of the atom, which was first introduced by the ancient Greek philosopher named Democritus.
Dalton did many experiments with gases and compounds that provided evidence for the existence of atoms.
Dalton developed an atomic theory that is still mostly accepted today. It is one of the most important theories in all of science.
Dalton thought individual atoms were solid, hard spheres, so he modeled them with wooden balls.
