Evolution of Atomic Theory and Models

By astr
  • Democritus
    400 BCE

    Democritus

    Period: 460 BCE to 370 BCE
    Democritus was an Ancient Greek pre-Socratic philosopher primarily remembered today for his formulation of an atomic theory of the universe.
  • Democritus atomic model
    340 BCE

    Democritus atomic model

    Democritus’s model stated that matter consists of invisible particles called atoms and a void (empty space). He stated that atoms are indestructible and unchangeable. His atomic model was solid, and stated all atoms differ in size, shape, mass, position and arrangement, with a void exists between them. Aristotle rejected Democritus theory. He didn't think that empty spaces existed. He believed that all matter consisted of four elements. Earth, Air, Water, and Fire.