History of the Atom Timeline by Alexis Howard and Jordan Atkins

By alexisjordan
  • 400

    Aristotle BC

    Aristotle BC
    He dismissed the atomic idea from Democritus as worthless. He believed all matter was made of four fundamental "elements" earth, air, and water. He used the idea of Democritus. He also believed the atom was indivisible.
    Maton, Anthea. "Atoms: Building Block of Matter." Exploring Physical Science. Englewood Cliffs, NJ: Prentice Hall, 1995. N. pag. Print.
  • 460

    Democritus BC

    Democritus BC
    He explained that matter was made up of particles in perpetual motion endowed with ideal qualities. He asked the question, "If you break a piece of matter in half, and then break it in half again, how many breaks will you have to make before you can break it no further."
    Walker, Jim. "ATOMS." Nobeliefs.com. N.p., n.d. Web.

  • Dalton

    Dalton
    He found that the previous theories were correct and that all matter is made of atoms. He performed various experiments with chemicals that showed the matter seemed to consist of elementary lumpy particles(atoms).
    Walker, Jim. "History of Atoms." www.nobeliefs.com. N.p., n.d. Web.

  • Thomson

    Thomson
    He discovered the electron by conducting a series of experiments designed to study the nature of electric discharge in a high vacuum cathode-ray tube.
    "Joseph John Thomson." www.chemheritage.org. Chemical Heritage Foundation, n.d., Web. 25 Feb. 2014.

  • Rutherford

    Rutherford
    His theory was that the atom had a central positive nucleus surrounded by negative orbiting electrons. He came to that conclusion after his "Gold Foil Experiment." It involoved the firing of radio active particles through minutely thin metal foils and detecting them using screens coated with zinc sulfide.
    "Rutherford-Atomic Theory." www.rsc.org. Royal Society of Chemistry, n.d., Web. 26 Feb. 2014.

  • Bohr

    Bohr
    He discovered that electrons travel in seperate orbits around the nucleus and that the number of electrons in the outer orbit determines the properties of an element. He studied Rutherford's model and the quantum theory and soon discovered what happens inside an atom.
    "Niels Bohr: Biography and Atomic Theory." www.livescience.com. TechMedia Network, n.d., Web. 26 Feb. 2014.

  • Heisenberg and Schrodinger

    Heisenberg and Schrodinger
    He said, "The more precisely the position is determined, the less precisely the momentum is known in this instant, and vice versa." Schrodinger was the founder of wave mechanics. Mathematical equations and philosophical implications.
    Cassidy, David. "Heisenberg- Quantum mechanics." www.aip.org. American Institute of Physics, n.d., Web. 26 Feb. 2014.