Atom

History of the Atom Timeline by Katheyrn Young and Kaytie Olinde

By kaytie.olinde2018
  • 400

    Democritus

    Democritus
    D. was the first scientist to theorize atoms.Taught by Leucippus he theorized the idea himself as a guess with no research.He thought atoms were solid ball shape pieces of matter that could not be divided anymore. He thought that they looked basically how they seemed such as; solids- hooks liquids- wet, & gases- "whirling." DeWitt, Tyler. "Models of the Atom Timeline." YouTube. YouTube, 6 Dec. 2012.
    Coffey, Jerry. "Democritus Atom." Universe Today. N.p., 22 Mar. 2010. Web. 19 Feb. 2015.

  • Dalton (Dalton's Atomic Theory)

    Dalton (Dalton's Atomic Theory)
    Williams, Matt. "John Dalton's Atomic Model." Universe Today. N.p., 01 Dec. 2014. Web. 20 Feb. 2015. He theorized that atoms are indivisible making up matter& different things have different atom arrangements..
    Researching gases, he found out some gases only combine with specific "proportions" and the same goes for different compounds with the same element(s).
    1.atoms are indivisible 2.all atoms are the same 3.diff. elements have diff. weights and c.p 4.when combining diff. elements the atoms form compounds 5.atoms can not be created or destroyed.

  • Thomson

    Thomson
    DeWitt, Tyler. "Discovery of the Electron: Cathode Ray Tube Experiment." YouTube. YouTube, 27 Nov. 2012. Web. 24 Feb. 2015. Thomson said atoms are made of electrons (some positive and some negative) to hold together the atom.
    He used a cathode raytube. He put metal in the side andwhen he connected it to a power source the beam of lightshot through and it went straight but later bent away from the positive charge. (electrons=negative)
    JJ thought atoms were ball shaped but inside there were smaller balls that were neg. & pos. charged that held together to make up the atom. (Plum Pudding atom)

  • Rutherford

    Rutherford
    Rutherfird changed Thompson's model by saying that the protons and electrons are not mixed but that the electrons orbit the protons like planets orbit the sun.
    Rutherford used the gold foil experiment to test Thompson's theory. The gold foil experiment consists of a gold piece of foil and an alpha source. For the experiment to work the particles should go straight through the gold foil.
    DeLeon, N. "Rutherford Model of the Atom." Rutherford Model of the Atom. N.p., n.d. Web. 19 Feb. 2015.

  • Bohr

    Bohr
    Bohr discovered that electrons could only travel in certain orbits around the nucleus.
    Bohr observed Rutherford's experiment and model and and realized that the atoms wouldn't be stable according to Planck's quantum theory which explains atom stability.
    Allain, Rhett. "The Development of the Atomic Model." Dot Physics. N.p., 4 Sept. 2009. Web. 19 Feb. 2015.

  • Heisenberg and Schrodinger

    Heisenberg and Schrodinger
    Heinsenber and Schodinger discovered that you cannot know the momentum and position of a particle at the same time which disproved Bohr's theory.
    They used the Heisenberg uncertainty principle which states that you cannot know th eposition and momentum and position of a particle simultaneously.
    Saffman, Mark. "World Book Online Reference Center | Online Reference Book| Online Encyclopedia." World Book. N.p., n.d. Web. 23 Feb. 2015.