Atomic Model Timeline

  • 430 BCE


    A philosopher in ancient Greece, suggests that matter is made of atoms, but he can't prove it. Atom is Greek for "unbreakable".
  • 400 BCE


    A famous Greek philosopher who came up with the word "element"
  • 335 BCE


    Aristotle teaches that the world is not made of atoms but of four elements - earth, air, water and fire
  • 700

    The Alchemists

    The Alchemists
    A type of scientist who lived during the Middle Ages who believed they could turn other substances to gold. (This is impossible).
  • Robert Boyle

    Robert Boyle
    Boyle reports that elements can't be broken down and that compounds are combinations of elements.
  • John Dalton

    John Dalton
    Dalton proves that atoms exist. He determines a compound's element breakdown, then calculates the weight of each atom. However, he only thinks a compound has only one atom of an element, so water is HO. His model of the atom is called the "billiard ball".
  • The Curies

    The Curies
    Worked with radium to learn more about radioactive elements. Discovered that radioactive elements lose their electrons over time.
  • J.J. Thompson

    J.J. Thompson
  • Niels Bohr

    Niels Bohr
    Bohr discovered