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Aristotle
Aristotle thought that Democritus's idea of the atom was false. HE believed that different pieces of matter were made of the different elements- fire, earth, and water.
"History of the Atom Video" from Mrs. Harvey's Moodle Page. -
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Democritus
Democritus was a Greek philosopher, and he had the early idea of atoms. He thought that you could cut an object in half over and over again, and eventually you would reach an object that you could not cut anymore. He named these small objects "atomos," which means "uncuttable" in the Greek language. Democritus also thought that these "atomos" came in different shapes and sizes, depending on the object that the atoms were a part of.
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John Dalton
John Dalton was an English scientist, and he believed Democritus's idea that all matter was made of tiny particles called atoms. He also believed that they could not be split in half any further. He believed that atoms were arranged in different combinations for different compunds.
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J. J. Thomson
J. J. Thomson was a British physicist, and he discovered that atoms have electrons, which have a negative charge. He also discovered that these electrons were smaller than the atoms. Thomson thought that the nucleus, the center of an atom, was positively charged, that the atom was electrically neutral, because the negative charge of the electrons and the positive charge of the nucleus cancelled each other out. He created a model called the "Plum Pudding Model."
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Ernest Rutherford
Ernest Rutherford was a British physicist, and he discovered that atoms had a nucleus. He set up the Gold Foil Experiment. He also discovered that the nucleus, which was in the center of the atom, was positively charged, and the electrons were floating around the empty space surrounding the nucleus. His model of the atom is called the "Nuclear Model," nuclear referring to the nucleus of the atom.
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Niels Bohr
Niels Bohr was a Danish physicist, and he believed that the electrons did not float around the nucleus. He believed that the electrons spun around the nucleus on orbitals, like the planets in the solar system do. He also thought that Rutherford's theory of the nucleus was true. He created the Bohr Diagram to show that the electrons orbited the nucleus in a circluar motion.
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Erwin Schrodinger
Erwin Schrodinger was a German scientist, and he thought that the electrons travelled very fast in different designs and patterns. He did not believe Bohr's idea of electrons orbiting around the nucleus in a circluar motion was false. He used mathematical equations and models, and he created the Quantum Mechanical Model in the 1920s.
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Werner Heisenberg
Werner Heisenbeg was a German scientist, and he created the Uncertianty Principle. This principle stated that a person can either know the location or the speed of an electron. They can not know both at the same time.
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