History of the Atom Timeline by Fallon Ledoux

By fallon.ledoux2017
  • 450

    Aristotle (350B.C.)

    Aristotle (350B.C.)
    Aristotle did not discover anything about the atom. He did not believe in Democritus' theory about the atom. Many people at that time believed Aristotle's opinion was important.He thought that atoms were made up of Earth, water, air, and ether. All things were just different mixtures of those elements. He did not believe in the atomic model.
  • 450

    Dem. Citations

    "A Brief History of Modern Atomic Theory." Chemistry Tutorial : History of Atomic Theory. AUS-e-TUTE N.d., n.d. Web. 25 Feb. 2014. "Chemistry Project : The History Of The Atom." Chemistry Project : The History Of The Atom. N.p., n.d. Web. 26 Feb. 2014. DeWitt, Tyler. "Models of the Atom Timeline." YouTube. YouTube, 06 Dec. 2012. Web. 26 Feb. 2014.
  • 450

    Aristotle Citations

    DeWitt, Tyler. "Models of the Atom Timeline." YouTube. YouTube, 06 Dec. 2012. Web. 26 Feb. 2014. "Chemistry Project : The History Of The Atom." Chemistry Project : The History Of The Atom. N.p., n.d. Web. 26 Feb. 2014. "A Brief History of Modern Atomic Theory." Chemistry Tutorial : History of Atomic Theory. AUS-e-TUTE N.d., n.d. Web. 25 Feb. 2014.
  • 450

    Democritus (460B.C.)

    Democritus (460B.C.)
    He wondered how much a piece of matter could be cut until it was as tiny as it could get, and he called this piece an atom. He stated that everything is made up of atoms. They are small and invisible. He came up with the first atomic molecule. Leucippus, one of his mentors, taught him his idea of the atomic theory. His methods were based on his beliefs and ideas. He believed the atom looked like a solid sphere of different shapes and sizes. The model is called the Democritus' atomic model.

  • Dalton (1808)

    Dalton (1808)
    After Aristotle, it took 2,000 years for Democritus' idea to resurface. He believed chemical reactions were caused by the arrangement of atoms. He stated that atoms could not be created or destroyed. The first to develope an experiment to prove that atoms arranged in different configurations to create different compounds. He thought there were atoms grouped together in different combinations. His model was called the Billard Ball.

  • dalton citations

    Noels, I. "HISTORY OF THE ATOM FROM DEMOCRITUS TO BOHR AND SCHRÖDINGER." HISTORY OF THE ATOM FROM DEMOCRITUS TO BOHR AND SCHRÖDINGER. N.p., 2003-2012. Web. 25 Feb. 2014. Hawley, John F. "2: Cosmology Becomes a Science." 2: Cosmology Becomes a Science. EDU, 2005. Web. 26 Feb. 2014.

  • Thomson (1897)

    Thomson (1897)
    He believed atoms are spheres of positive material with small negatively charged particles inside. He created the idea that the positive charges and negative charges were equal inside the sphere. He gathered his evidence by conducting experiments with cathode ray tubes. He thought negatively charged electrons were embedded in a sphere that had a positive charge. His model was called the Plum Pudding Model.

  • Thomson citations

    DeWitt, Tyler. "Models of the Atom Timeline." YouTube. YouTube, 06 Dec. 2012. Web. 26 Feb. 2014.

  • Rutherford (1910)

    Rutherford (1910)
    He discovered that the positive charge of an atom was located at the center and was the source of the atom's mass. He used the gold foil experiment to gather his evidence. From this he learned that matter is mostly empty space because most atoms could pass though gold foil. The atom model was known as the planetary model because the elements orbit the nucleus just like the planets orbit the sun.

  • Rutherford citations

    A Brief History of Modern Atomic Theory." Chemistry Tutorial : History of Atomic Theory. AUS-e-TUTE N.d., n.d. DeWitt, Tyler. "Models of the Atom Timeline." YouTube. YouTube, 06 Dec. 2012. Web. 26 Feb. 2014.

  • Bohr (1913)

    Bohr (1913)
    He added to Rutherford's model by proposing that electrons never lose energy. Those with lower energy were farther away than those with a higher energy. The electrons were on a specific orbit route. Bohr used theories from observations he saw from Rutherford's model to make his discoveries. He composed a visible way to watch electrons energy levels. The rings were at an equal distance from one another, and only some electrons could fit on each ring. They called it the Bohr Model of the atom.

  • Bohr citations

    DeWitt, Tyler. "Models of the Atom Timeline." YouTube. YouTube, 06 Dec. 2012. Web. 26 Feb. 2014. "A Brief History of Modern Atomic Theory." Chemistry Tutorial : History of Atomic Theory. AUS-e-TUTE N.d., n.d. Web. 25 Feb. 2014.

  • Heisenberg and Schrodinger (1926)

    Heisenberg and Schrodinger (1926)
    Schrodinger discovered electrons were not spinning in orbits, but were actually moving around the nulceus making different outlines. Heisenburg came up with the uncertainty principle, which is when a wavelegth of light is beamed on an electron, it will absorb the energy causing it to change position. Schrodenger used a set of equations to find probability waves which decides particles motion. Heisenburg used theories from previous scientists. The model is called the Quantum Mechanical Model.

  • Heisenburg and Schrodinger Citeation

    Gabby R. & Iridian C. & Chris H. "Quantum Mechanical Model - History of the Atom." History of the Atom. N.p., 2012-2013. Web. 27 Feb. 2014.