The Atom

By mrollins
  • 350 BCE

    Democritus

    Democritus
    Democritus developed the concept of the atom. He believed everything in the universe was made up of atoms.
  • 330 BCE

    Aristotle

    Aristotle
    Aristotle believed that all substances were made of fire, water, air and earth.
  • 1492

    Christopher Columbus

    Christopher Columbus
    Sails and discovers America

  • Robert Boyle

    Robert Boyle
    Robert Boyle came up with a theory that stated the absolute pressure put out by a set mass of gas is opposite to the volume it holds.

  • American Revolution (1765-1783)

    American Revolution (1765-1783)
    A colonial revolt against England

  • John Dalton

    John Dalton
    John proposed the modern atomic theory.

  • American Civil War (1861-1865)

    American Civil War (1861-1865)
    The war between the North and South

  • Dmirtri Medeleev

    Dmirtri Medeleev
    Mendeleev formulated the periodic law also known as the periodic table.

  • J.J. Thomson

    J.J. Thomson
    Thomson created the "Plum Pudding" model of the atom. He also discovered the identification of the electron and the first subatomic particle. J.J. Thomson also designed a study to find the nature of electric discharge in a high vacuum cathode ray tube. He discovered the electric discharge.

  • Hans Geiger

    Hans Geiger
    Hans Geiger is known for the Geiger Counter and finding of the atomic nucleus.

  • Ernest Rutherford

    Ernest Rutherford
    Rutherford is known for his "Rutherford Model", finding the atomic nucleus, the proton, radon, creating the beta particle, alpha particle, artificial disintegration and the Rutherford Backscattering Spectrometry.

  • Robert Millikan

    Robert Millikan
    Robert Millikan is known for measuring the charge of an electron. Millikan also ran an experiment using the "Crooks Tube". He added a atomizer and two metal plates, then he added oil droplets to see how they would fall. When there was no charge they all fell at the same rate, but when there was a charge the oil drops fell at different rates. If they were negatively charged they would fall slower of even rise.

  • Neils Bohr

    Neils Bohr
    Neils Bohr proposed the theory of the Hydrogen Atom based on the quantum theory of energy transferring only in well defined quantities.

  • World War I (1914-1918)

    World War I (1914-1918)

  • James Chadwick

    James Chadwick
    James Chadwick discovered the neutron.

  • Wold War II (1939-1945)

    Wold War II (1939-1945)

  • Hiroshima

    Hiroshima