The History of the Atom

By Fadumo
  • 450 BCE

    Democritus

    Democritus
    Experiments: The idea of cutting an apple intol small pieces until it can't be cut anymore.
    Contributions: name atomos - where modern word atom comes from. Future Scientists will revive his ideas and advance it.

  • John Dalton

    John Dalton
    Experiment: Studied pressures of gasses and researched the properties of compounds.
    Contributions: Developed three ideas: Dalton's Atomic Theory. Was the 1st scientist to explain the behavior of atoms in terms of weight.

  • J.J Thomson

    J.J Thomson
    Experiments: Putting currents of electricity inside emplty glass tubes.
    Contributions: Made the discovery of the electrons which was the first subatomic particle to be identified. Thomson discovered the electron using cathode rays.

  • Ernest Rutherford

    Ernest Rutherford
    Experiments: Rutherford aimed a beam of alpha particles at a very thin sheet of gold foil. Outside the foil he placed a screen of material that glowed when alpha particles stuck on it.
    Contributions: Discovered the nucleus and protons.

  • Niels Bohr

    Niels Bohr
    Experiments: Bohr obtained an accurate formula for the energy levels of the hydrogen atom. He postulated that the angular momentum of the electron is quantized.
    Contributions: Created the Bohr model which was an improvement to the Rutherford model. The model shows the atom as a small, positively charged nucleus, surrounded by the electrons that travel in circular orbits around the nucleus. This attraction's provided by electrostatic forces.