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500
Democritus
In 500 B.C.E, Democritus pondered what would happen if they broke everything down. He decided that the last thing that couldn't be broken down was atoms. At the time every one agreed with the idea until Aristole turned it down.
https://sites.google.com/site/historyofanatom/lecippus-democritus -
500
Aristotle
Around the time when Democritus was talking about his views on the world and atoms, Aristotle was also alive but not accepting on this. He thought that the world was made up of the four elements, Earth, fire, land and water.
https://the-history-of-the-atom.wikispaces.com/Aristotle -
First Colonies in America
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Beginning of American Revolutionary War
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America declares her independence
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Joseph Proust
He published Laws of Definitie Proportions or Law of Constant Composition in 1794, which states that a compound is made up of same proportions of elements by mass regardless of how the compound was created.
http://staff.concord.org/~ddamelin/chemsite/c_AtomicTheory/Proust.html -
John Dalton
Dalton found that that oxygen and carbon combined to make 2 compounds. With this knowledge, it led him to propose the Law of Simple Multiple Proportions.
http://dl.clackamas.cc.or.us/ch104-04/dalton's.htm -
Henri Becquerel
In around 1880 to 1890's, Becquerel did detailed studies of the physical properties of cobalt, nickel, and ozone, and studied how crystals absorb light by doing experiments with uranium salts.
http://www.famousscientists.org/henri-becquerel/ -
J.J. Thomson
Thomson discovered that an atom was made up of little particles, called Electrons. He bought up the idea that th negatively charged electrons equalled out the postively charged protons and neutrons were neutral.
http://www.tutorvista.com/science/jj-thomson-atomic-theory-0 -
Max Planck
In the 1900's, Planck came up with an equation to answer questions ones before him asked when they got their results. His equation was E=Nhf, with E=energy, N=integer, h=constant, f=frequency.
http://history1900s.about.com/od/1900s/qt/quantumtheory.htm -
First movie Theatre
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Albert Einstein
In 1905, Albert Einstein mathmatically proved the existence of atoms. Einstien also realized that even though obseravle particles are much larger, they still generate pressure the same way as the invisible molecules in which they are immersed. He also found e=mc^2
http://ansnuclearcafe.org/2012/03/20/albert-einstein-and-the-most-elemental-atomic-theory/ -
Robert Millikan
In 1909, Millikan began some experiments to find the charge of a electron. He recieved more precise results in 1910 with his oil-drop experiment where he replaced water which he used in his first experiment. http://en.wikipedia.org/wiki/Robert_Andrews_Millikan -
Ernest Rutherford
In 1911, Rutherford proposed a new model that described the atom as a tiny, dense, positively charged core called a nucleus. Then the electons circulate like the atom is the sun and electrons are planets.
http://www.britannica.com/EBchecked/topic/514258/Rutherford-atomic-model -
The day the Titanic sank
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Neils Bohr
In 1913, Bohl proposed a model that explains how electons orbit around the nucleus.
http://abyss.uoregon.edu/~js/glossary/bohr_atom.html -
The start of World War 1
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The end of World War 1
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Werner Heisenberg
Using some background knowledge, he created the first quantum mechanics. He also discovered the electrons do no travel in neat little orbits around the nucleus due to the fact that they contain photons that cause them to change momentum and physics.
https://the-history-of-the-atom.wikispaces.com/Werner+Heisenberg -
Erwin Schrodinger
Schrodinger combined the equations for the behavior of waves and de Broglie to make a model for the distribution of electrons in an atom. Unlike the Bohr model, Schrodinger's model is 3 dimensional.
http://chemed.chem.purdue.edu/genchem/history/schrodinger.html -
First TV made
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Louis de Broglie
In the 1920's. Louis de Broglie came up with the wave mechanics theory, since he believed electons acted as waves and particles. He found that the waves produced by electrons that were in the orbit around the nucleus, set up awave of energy, frequency, and wavelength. https://the-history-of-the-atom.wikispaces.com/Louis+de+Broglie -
James Chadwick
Chadwick discovered the neutron using evidence that another scientist collected. He found that they had the same mass as protons and were neutral with their charge.
https://sites.google.com/site/historyofanatom/james-chadwick -
The beginning of World War 2
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Pearl harbor
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The end of World War 2
