What we know about atoms goes back to the Greek philosopher Democritus. Around 530 B.C., he wrote that atoms moved around in empty space. They bounced off each another or joined in clusters.
He thought all changes in the world were due to atoms. Everything was affected by changes in how atoms moved or were packed together.
Democritus’s ideas were accepted until the nineteenth century. That was when people began making amazing discoveries about the atom. And the discoveries continue to this day.
