Atomic Model Time Line

  • 400 BCE

    Discovery of Atoms

    Democritus, born 460 BCE, died 370 BCE, thought that atoms exist. He also thought that they were very small.
  • 410

    Battle of Cyzicus

    A battle Faught in 410 BC by the Roman forces against the Mithridates VI's forces. This battle allowed Athens to recover control over a number of
    cities in the Hellespont over the year.
  • Atomic Theory

    Atomic Theory
    John Dalton, known as "Father of Modern Chemistry", born 1766, died 1844 created the atomic theory. It was a careful experimentation showing that matter reacted in whole number ratios. This led him to publishing the Atomic Theory, his model called "marble".
  • Mexican War of Independence

    A war in 1810 Faught by the people of Mexico and the Spanish colonial government, with an outcome of Mexico "won".
  • Electromagnetic Induction

    Michael Faraday, born 1791, died 1867 discovered Electromagnetic Induction. The Induction is a generation of electricity in a wire by means of the electromagnetic effect of a current in another wire”.
  • Kanalstrahlen (Canal Rays)

    Eugen Goldstein, born 1850, died 1930 discovered what he termed Kanalstrahlen, or canal rays, also called positive rays. Canal rays are positively charged radiations that consist of particles having charges equal in magnitude.
  • The electron

    The electron
    JJ Thompson, born 1856, died 1940 discovered the electron. He found evidence of electrons while playing with a cathode ray tube. The electron then went on to propose a model for the structure of the atom. JJ Thompson created the "plum pudding" model.
  • San Francisco earthquake

    In 1906 a major earthquake with a magnitude of 7.9 that occurred on April 18, 1906, at 5:12 am off the northern California coast.
  • Elementary Charge

    Robert Millikan, born 1868, died 1953 discovered the value of elementary charge. He did this by using the famous oil drop experiment.
  • Alpha and Beta Rays

    Alpha and Beta Rays
    Ernest Rutherford, born 1871, died 1937 discovered Alpha and Beta Rays. Rutherford shot alpha particles at the foil, and some of the alpha particles bounced off the foil and came back. This is how the nucleus was discovered.
  • Model of the Atom

    Model of the Atom
    Neils Bohr, born 1885, died 1962 proposed a model of the atom. Neils did a bunch of math to say that electrons are on orbits around the nucleus. He created the "solar system" model.
  • The British steamship Lusitania

    1915 the British steamship Lusitania is sunk without warning off the coast of Ireland by a German submarine killing 1,195 people.
  • Quantum Mechanics

    Werner Heisenberg, born 1901, died 1976 formulated a type of quantum mechanics based on matrices.
  • Energy Levels of Electrons in Atoms

    Energy Levels of Electrons in Atoms
    Erwin Schrodinger, born 1887, died 1961 figured out that the electrons are in clouds around the nucleus, and not on set tracks. He allowed us to figure this out with probility equations. He made a model called, "quantum mechanical"
  • The Great Depression

    A period of severe global economic downturn that occurred from 1929 -1939
  • Existence of the Neutron

    Existence of the Neutron
    James Chadwick, born 1891, died 1974 found the neutron (no change) He then created the “electron cloud” model with neutrons added.
  • The Holocaust

    The Holocaust era began in January 1933 when Adolf Hitler and the Nazi Party came to power in Germany. It ended in May 1945, when the Allied Powers defeated Nazi Germany in World War II. 6 million Jews were killed.