Democritus 2

History of the Atom Timeline

  • 400

    Democritus

    Democritus
    In 400BC Democritus came up with the concept of the atom. Which he based his theory on observations and natural curiosity.
  • Dalton

    Dalton
    He made his mind up that there is many different kinds of atoms. He based his theory by spending a lot of time in labs and watching reactions.
  • Thompson

    Thompson
    That atoms have positive and negative charges and that they can be divided, He based his theory on using a cathode ray. Called his atom model " Plum Pudding".
  • Rutherford

    Rutherford
    He discovered that atoms had a nucleus and discovered that there was protons. He shot high velocity alpha particles to spread out the atom. Used the beam to go through a gold plate.
  • Bohr

    Bohr
    He said that electrons orbited around the nucleus. He did work on Rutherfords model and came up with several different theories. He thought the particles orbited in a neat rotation.
  • Heisenberg and Schrodinger

    Heisenberg and Schrodinger
    Both said that electrons did not orbit the nulceus in complete neat orbit. He said they were in a very unpredictable manor and didn't go in a complete circle. He worked closely on theoretical investigations into the quantim theory.