History of the Atom Timeline by Fallon Kidd and Laci Felker

By Fallon Rene
  • 340

    Aristotle (340B.C.)

    Aristotle (340B.C.)
    -dismissed Democritus's atom idea
    - thought you could keep cutting down and there would be no stopping point
    - methods he used is theories from observations
    - thought the atom wasn't an atom but combination of 4 elements and are made up of small matter
    "History of Atoms." History of Atoms. N.p., n.d. Web. 21 Feb. 2014. http://nobeliefs.com/atom.htm.
  • 450

    Democritus (450 B.C)

    Democritus (450 B.C)
    http://www.glogster.com/jhaephae/atomic-theory/g-6m1uvdbteeuhmcjkfrkp6a0.' >"Glogster Home Page." Glogster. N.p., n.d. Web. 21 Feb. 2014.</a>-
    -discovered/developed the idea of the atom
    - how many breaks can you or do you have to do to break it no further?
    -he used theories from observations to make his discoveries.
    -thought the atom looked like around sphere
    "HISTORY OF THE ATOM FROM DEMOCRITUS TO BOHR AND SCHRÖDINGER." HISTORY OF THE ATOM FROM DEMOCRITUS TO BOHR AND SCHRÖDINGER. N.p., n.d.

  • Dalton (early 1800's)

    Dalton (early 1800's)
    • figured it out by performing experiments with various chemicals, found that matter had lumpy particles -said that matter is composed of tiny invisible indestructible particles called atoms
    • all different elements have different atom -atoms cant be created or destroyed -figured it out by experimental observations
    • "Billard Ball" - model of atom HISTORY OF THE ATOM FROM DEMOCRITUS TO BOHR AND SCHRÖDINGER. N.p., n.d. Web. 21 Feb. 2014. http://profmokeur.ca/chemistry/history_of_the_atom.htm.

  • Thompson (late 1800's, early 1900's)

    Thompson (late 1800's, early 1900's)
    -discovered the electron and they had negative charge so matter must have positive charge
    -"Plum Pudding" Model-total positive charge equals total neagtive charge

    -used experiments with cathode ray tubes

    "History of Atoms." History of Atoms. N.p., n.d. Web. 23 Feb. 2014. http://www.nobeliefs.com/atom.htm
    "A Brief History of Modern Atomic Theory." Chemistry Tutorial : History of Atomic Theory. N.p., n.d. Web. 23 Feb. 2014. http://www.ausetute.com.au/atomichist.html

  • Rutherford

    Rutherford
    -used gold foil experiment with alpha rays to explore the inside of an atom
    -thought that the electrons must exist somewhere in the empty space around the positive centers that contain most mass
    -model looked like plantes around sun
    -number of protons equal number of electrons
    "History of Atoms." History of Atoms. N.p., n.d. Web. 23 Feb. 2014. http://www.nobeliefs.com/atom.htm
    "A Brief History of Modern Atomic Theory." Chemistry Tutorial : History of Atomic Theory.http://www.ausetute.com.

  • Bohr (early 1900's)

    Bohr (early 1900's)
    -can only orbit certain distances from nucleus
    -Atoms radiate energy when electrons go from higher to lower orbit,absorbs when it does opposite
    -said orbits have different shapes
    -"Planetary"/"Quantam Model
    -ultraviolet,visible,and infrared waves to figure it out
    "A Brief History of Modern Atomic Theory." Chemistry Tutorial : History of Atomic Theory. http://www.ausetute.com.au/atomichist.html
    "History of Atoms." History of Atoms http://www.nobeliefs.com/atom.htm

  • Heisenburg (1927) and Schrodinger (1925)

    Heisenburg (1927) and Schrodinger (1925)
    -had an idea about why not go all the way with particle waves and try to form a model based off that ~ Electron Cloud (surrounds nucleus)
    -used mathematical quantities
    -Heisenberg uncertainty principle~no experiment can measure the position and momentum of a quantum particle simultaneously.
    "History of Atoms." History of Atoms. N.p., n.d. Web. 23 Feb. 2014. http://www.nobeliefs.com/atom.htm
    (i uploaded a picture twice but i'm not sure if its showing up,it is but not on timeline)