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150
Democritus
(is really 400 B.C.) Democritus came up with the idea of the atoms saying that they were so small that no one could see them and that is why no one has. -
350
Aristotle
(Is really 350 B.C.) Aristotle came up with his four elements earth, air, fire, and water. His physics said that everything was determined by the weight and there was a fifth element that the heavens wee made of. -
Aug 3, 1492
Columbus discovers new world
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Virginia Colony Founded
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Pennsylvania Colony Founded
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War for Independence starts
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Joseph Proust
Proust formed his law that states all elements in a compound are in a fixed proportion by weight, regardless of how they are made. -
John Dalton
John Dalton came out with the first periodic table that is very similar to the one we know today just missing many elements. His system was based on the weight of hydrogen atoms most measurements were wrong but just barley. -
Civil war starts
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President Lincoln assinated
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Henri Becquerel
Becquerel discovered radioactivity by mistake when he but uranium on a piece of metal in a dark room, came back a few days later and discovered that it had turn the metal black. After more work he won the noble prize for his discovery. -
Ernest Rutherford
Rutherford says with radiation is made up of, Alpha, Beta, and Gamma rays. He also converted nitrogen atoms to helium by bombarding them with alpha particles (helped along nuclear fission later). -
Rutherford Model
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Max Planck
Max Plank came up with his law that says that that the energy of each quantum is equal to the frequency of the radiation multiplied by the universal constant. -
J.J. Thomson
J.J. Thomson is credited with the discovery of the electron by passing electricity through a gas. Thomson also created the Thomson model or the pudding model was all the electrons and protons are mixed together. -
Thomson Model created
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Neils Bohr
Neils Bohr came out with his model of the atom that had a nucleus and the atoms circling around it in levels or quantum. -
Bohr model
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Louis de Broglie
Louis de Broglie won a noble prize for describing how a electron behaves known as the parallel concept that wave and particlilike behave similar. -
Robert Millikan
Millikan won the 1923 noble prize for his "oil drop" experiments, in which he measured that charge of an electron. This was the first time that it was confirmed that electrons had a charge. -
Great Deperesion
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James Chadwick
James Chadwick is best known for his discovery of the neutron in 1932. This discovery led to the ability to make atomic weapons, which Chadwick assisted in at the Los Alamos facility in New, Mexico. -
Werner Heisenberg
Heisenberg won the noble prize this year for developming quantim mechanics and predicting that there are two types of hydrogen atoms. -
World War II
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First Atomic Bomb Test
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Regan Elected President
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Quantum Mechanical Model
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Obama Elected President
