Evolution of Atomic Theory

  • Jan 28, 999


    Who:Democritus (Greek)
    What: He created earliest ideas of atoms, thinking everything was made up of only 4 substances.
    When: 500 BC
    How: He told people his theories.
  • Sep 6, 1010


    Who: Aristotle (Greek)
    When: 2,500 years ago
    What: Aristotle believed that everything was made from natural elements like air, water, fire, and earth.
    How : Told people about his theories.
  • Isaac Newton

    Isaac Newton
    Who: Isaac Newton (English)
    When: Born January 4, 1643
    What: Newton realized that atoms had a neutral electrical charge overall, but could also have their energy levels distorted. Though, this was not accurately proven untill the 1930's
    How: Isaac did his experiments mentally.
  • John Dalton

    John Dalton
    Who: John Dalton (English)
    When: Born on September 6, 1766
    What: Figured out that gases are made out of individual particles
    How: Did different experiments involving air and water mixtures.
  • Max Planck

    Max Planck
    Who: Max Planck (German)
    When: Born April 23, 1858
    What: Originator of Quantum Theory. Used this to explain glowing matter.
    How: Made his point by using mathematics.
  • Hantaro Nagaoka

    Hantaro Nagaoka
    Who: Hantoro Nagaoka (Japanese)
    When: Born August 15, 1865
    What: Had the idea that atoms may have a central nucleus and that electron move like the rings around Saturn.
    How: Saturnian Model (it was an early model, comparing the rings of Saturn to electron movements).
  • Ernest Rutherford

    Ernest Rutherford
    Who:Ernest Rutherford (English)
    When: Born August 30, 1871
    What: Discovered uranium has a positive charge.
    How: He deflected light rays as his experiment. He used a radioactive source and right across put a piece of gold foil. On the outside, he placed a fluorescent screen to see where the light reflected. This provided evidence that atoms have a negative/positive charge.
  • Niels Bohr

    Niels Bohr
    Who: Niels Bohr (Danish)
    When: Born in Denmark on October 7, 1885
    What: A Nobel Physics Prize winner, he figured out electrons can't exsist between energy levels.
    How: Drew a model.
  • Erwin Schrodinger

    Erwin Schrodinger
    Who: Erwin Schrodinger
    When: August 12, 1887
    What: Erwin understood the motions of electrons in atoms.
    How: He did mathmatical equations.
  • Ernest Marsden

    Ernest Marsden
    Who: Ernest Marsden (British)
    When: Born Febuary 19,1889
    What / How: He was the student of Rutherford. They tested out the same experiments and had the same types of theories.
  • James Chadwick

    James Chadwick
    Who: James Chadwick (British)
    When: October 20, 1891
    What: Confirms the exsistence of neutrons.
    How: He hit paricles together, and let the radiation bounce off into pariffin wax. The parts left behind are neutrons.
  • Louis de Broglie

    Louis de Broglie
    Who: Louis de Broglie (French)
    When: Born August 25, 1892
    What: Thought that moving particles have properties of waves.
    How: Did a multitude of experiments.
  • JJ Thomson

    JJ Thomson
    Who: JJ Thomson (British)
    When: On December 11, 1906 Thomson won the Nobel Prize in Physics.
    What: Created the atomic model known as "Plum Pudding". He believed that atoms had a negative and positive charge.
    How: Thomson made a model using electric curent source, metal disks, a sealed tube filled with gas at low pressure, and a glowing beam. When the device is turned on, on disk has a negative current the other a positive, This provided evidence that atoms have a negative/positive charge.