Democritus along with Leucippus are the so called greek atomists. They believe that matter is made up of ultimate particles called atoms, according to them, atoms are indivisible, invisible, eternal and impenetrable which is contradictory to what people believe that matter is continuous. Also, according to them, between atoms is just a void(empty space), atoms are in constant motion and substances differ in properties according to nature, arrangement and number of atoms which they are composed.