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He thought that all the materials on Earth were not made of atoms. He thought that they were made out of the four elements, fire, earth, water, and air. He believed that all matter was made up of one of the elements. But, later on all of Aristotle's theory was proven wrong.
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In the year of 384 BC, Aristotle was born
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In, around, the year of 450 BC, Aristotle thought of the 4 elements which are fire, earth, air, and water.
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He proposed that all matter, including space and time, was made up of small units called atoms. He had little evidence and did no experiments, though Lucretius kept his idea.
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Democritus was born. He was a Greek Philosper who was born in Greece.
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In this year, Democritus's hypothesis was craeted. He thought that there are an infinite number of atoms.
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On September 6, 1766, John Dalton was born.
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He agreed that all matter is made of atoms, which he thought were indestructible. He also said that compounds were created by combining two atoms, and that atoms of given elements have identical mass and properties.
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On December 18, 1856, J.J Thomson was born.
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On March 22, 1868, Robert Millikan was born.
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On August 17, 1871, Ernest Rutherford was born.
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On August 7, 1885, Neils Bohr was born.
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On October 20, 1891, Sir James Chadwick was born.
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In the year of 1897, J.J Thomson discovered the electron. He also conducted the Cathode Ray Tube experiment. He experimented by testing and studying the nature of electric discharge in a high vacuum Cathode Ray Tube. Thomson mad a Plum Pudding Model, too. It displays eectrons scattered in a sphere of positively charged material.
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Robert Millikan conducted te oil drop experiment by measuring the effect of an electric field on very small oil droplets. He used this experiment to determine the charge of a single electron.
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Ernest Rutherford conducted the Gold Foil Experiment. From that he made two major conclusions that were: The atom is made up of mostly central charge and the atom contains a nucleus. The experimental evidence that led to Rutherford's conclusion is that the majority if the alpha particles passed straight through the gold foil.
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Neils Bohr was a Danish physicist. He proposed a model of the atom that is similar to the model of the solar system. The electrons go aroud the nucleus like planets orbit around the sun. He said that an electron is founf only in specific circular paths, or orbits around the nucleus. He gave birth to the idea that the electrons emit light by jumping orbits.
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Sir James Chadwick discovered the neutron in the center part of the atom. Chadwick believed that what he discovere, the neutron, was just complex particle consisting of a proton and a electron.
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In 1935, James Chadwick was awarded the Nobel Peace Prize in Physics for discovering the neutron.
