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KS3 Science - Atomic History Timeline: Democritus

How ideas about the atom developed - evolution of the atomic model

The Laughing Philosopher

was an ancient Greek philosopher. (460 BCE 370 BCE) 

Democritus was born at Abdera, about 460 BCE, although according to some 490. His father was from a noble family and of great more

Is the Atom a fundamental particle? Read more to find out

Click on above image to learn more....

Shortcomings of Democritus theory

  • It is only a conceptual definition 
  • No talk about sub-atomic particles

Democritus' Theory

Main Points 

** Atom is the smallest particle 

** Atom is indivisible

Democritus held that nothing could come from nothing, that everything is already in the world and it is merely a matter of combination and re-combination of eternal bits of immutable stuff called atoms that remain indivisible in and of themselves. Read more HERE


Democritus expanded the atomic theory of Leucippus. He maintained the impossibility of dividing things ad infinitum...

He explained the origin of the universe as follows : The original motion of the atoms was in all directions—it was a sort of “vibration” hence there resulted collisions and, in particular, a whirling movement, whereby similar atoms were brought together and united to form larger bodies and worlds.

Read more from Britannica Encyclopedia HERE