Atom

History of the Atom Timeline by Stacey Clark and Joy'Don Johnson

By stacey.clark2017
  • 450

    Democritus (460)

    stated that all matter is made up of atoms. He also stated that atoms are invisible and so small that they can't be divided and they entirely fill up the space they're in. He wondered how much matter could be used broken down until it could be broken no more. Democritus thought the atom looked like small, hard particles that were all made of the same material, but different shapes and sizes. "History of Atoms." History of Atoms. N.p., n.d. Web. 26 Feb. 2014.
  • 450

    Aristotle (350 BC)

    He discovered that matter must be made of smaller parts. Aristotle had no evidence. His view was accepted for the next 200 years.
    "History of Atoms." History of Atoms. N.p., n.d. Web. 26 Feb. 2014.

  • Dalton

    Dalton
    He discovered that all matter is made of atoms and are indivisible and indestructible. He used the Law of Conservation, Law of Constant Composition, and Law of Multiple Proportions as some supporting evidence of his model. He thought the atom looked like a billiard ball. "History of Atoms." History of Atoms. N.p., n.d. Web. 26 Feb. 2014. "HISTORY OF THE ATOM FROM DEMOCRITUS TO BOHR AND SCHRÖDINGER." HISTORY OF THE ATOM FROM DEMOCRITUS TO BOHR AND SCHRÖDINGER. N.p., n.d. Web. 27 Feb. 2014

  • Thomson

    Thomson
    he discovered the electron and proposed a model for the structue of the atom. He experimented his discovery about the atom using cathode rays. He thought that the atom looked like raisins stuck on the surface of a lump of pudding. He called this model "Raisin in the Pudding" or "Plum Pudding" "History of Atoms." History of Atoms. N.p., n.d. Web. 26 Feb. 2014.

  • Rutherford

    Rutherford
    He discovered that atoms have positively charged particles called protons. He also discovered that there was a large nucleus with an overall positive charge. To make this discovery he made an experiment called the "Gold Foil" experiment where he shot alpha particles at gold foil. The path curved indicating there was a large positive charge. Rutherford thought the atom looked like the solar system, where the planets orbit the sun. "History of Atoms." History of Atoms. N.p., n.d. Web. 26 Feb. 2014

  • Bohr

    Bohr
    he discovered that the electrons do not spiral into the nucleus. ,and protons are in the nucleus and electrons surround it. Bohr based most of his ideas off Rutherford's model. He also added his knowledge of energy levels for electrons. He thought that the atom had a nucleus in the middle with energy levels holding 2 electrons on the first shell and 8 electrons on any levels after. "History of Atoms." History of Atoms. N.p., n.d. Web. 26 Feb. 2014.
    "History of Atoms." History of Atoms. N.p.

  • Heisenberg and Schrodinger ("History of Atoms." History of Atoms. N.p., n.d. Web. 26 Feb. 2014.)

    Heisenberg and Schrodinger ("History of Atoms." History of Atoms. N.p., n.d. Web. 26 Feb. 2014.)
    Heisenberg created the uncertainty principle, stating that you can't know the exact location and energy at the same time. Schrodinger discovered that electrons confined in their own orbits would set up standing waves. Schrodinger did his model based on waves he observed, the famous two-slit experiment. Heisenberg used mathematical quantities called matrices. Schrodinger thought the atom looked like "psi" symbol of wave. He helped create the idea of electron cloud.