History of the Atom

By madisonlevasseur
  • 450 BCE

    Aristotle (384 BC - 322 BC)

    Believed that all matter was made up of air, earth, fire, and water
  • 400 BCE

    Democritus (460 BC- 370 BC)

    In 400 BC he discovered the atom theory
  • 400

    Alchemists

    Studied alchemy, which is known as the forerunner of chemistry
  • 1492

    Columbus arrives in America

  • Robert Boyle (1627 - 1691)

    Discovered the law of gasses

  • American Revolution (1775 - 1783)

  • John Dalton (1766 - 1844)

    Discovered the atomic theory

  • American Civil War (1861 - 1865)

  • Dimitri Mendeleev (1834 - 1907)

    Created the Periodic Table

  • J.J. Thomson

    Discovered the electron and the Plum Pudding Model

  • Ernest Rutherford (1871 - 1937)

    Found that atoms have a positively charged nucleus in the center and that negative electrons are outside the nucleus

  • Hans Geiger (1882 - 1945)

    Co-invented the Geiger counter and the Geiger-Marsden experiment

  • Robert Millikan (1868 - 1953)

    Discovered the value of an electron with the oil drop experiment

  • Neils Bohr (1885 - 1962)

    Contributed the Bohr Model which he found with his Bohr experiment

  • World War 1 (1914 - 1918)

  • James Chadwick (1891 - 1974)

    Discovered the neutron

  • World War 2 (1939 - 1945)

  • Hiroshima