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democritus
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Democritus: 460 B.C. Democritus began with the idea that everything could be broken down into smaller peices. This is how he came upon his AtomTheory. Aristotle did not believe in this theory. Democritus stated that everything could be broken down into atoms. To Democritus the atom looked like a marble. -
450
aristotle
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Aristotle- 400 B.C.The Atom was introduced by Democritus. Aristotle did not believe in the Atom Theory.Aristotle believed that all matter was made of "The Four Elements" which are Fire, Earth, Air, and Water.He did not have any proof to support his theory. The Atom Theory had no proof as well. People believed Aristotle's theory because aristotle was one of the greatest minds and had many followers. -
dalton
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John Dalton developed the Atomic Theory in 1800. He still believed that the atom was the smallest unit of matter, and that it could not be bvroken down. He believed in Democritus' theory of the atom looking like a marble. He also tried to come up with the atomic stuructures of atoms. -
thompson
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JJ Thompson discovered the electron using the cathode-ray tube. in 1904 Thompson thought the atoms was a sphere of positive force with electrons around it. This is known as the plum pudding model. Thompson also created a mass spectrograph which found isotopes. -
rutherford
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Ernest Rutherford discovered the nucleus. His theory was the atom has a positive nucleus with negative electrons orbiting around it. This changed the atom greatly because it was now known that most of the atoms weight is in the nucleus. His model was known as planetary system model. Ernest rutherford was the student of JJ Thompson. -
bohr
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Niels Bhor proposed a new atom model that would allow the electrons to be outside the nucleus and in orbit around the nucleus. Bhor said the electrons were on a special orbit. His model is knowen as the Bhor Model. -
werner heisenberg
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Heisenberg made the uncertainty priciple. the uncertainty principle says that you cant measure the current position of a particle and measure the position it will be in after it moves. he studied quantam meachanics.
