jan 1, 400 BC - Democritus 400 BC
Democritus theorized that matter is made up of tiny particles that can not be broken down smaller. He called these particles atoms. Different elements are made up of different atoms. 
He tried simple experiments to test his theory.
Description:
 Democritus theorized that matter is made up of tiny particles that can not be broken down smaller. He called these particles atoms. Different elements are made up of different atoms. 
He tried simple experiments to test his theory. 
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