Aristotle said that atoms were composed of the four elements: fire, water, earth, and air. Each of these atoms had certain properties depending on what they were made of: hotness, dryness, wetness, or coldness. This contradicted the work of Democritus and put a second theory in use for almost 2000 years (before it was disproved). He also originated a method of gathering scientific facts and recording them methodically.
Aristotle admired Democritus as a role model.