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Democritus 440 BCE
Democritus was a Greek philosopher who thought that you would eventually could not be cut, the atom. He also said that atoms were made of a single material that can be formed into many different shapes and sizes. He got the name from the Greek word amtomos meaning "not able to be divided". -
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Aristotle 440 BCE
A Greek philosopher that believed you could never get a particle that could not be cut. People believed him until Democritus proved him wrong. -
John Dalton
Dalton said that all substances are made of atoms. Atoms are small particles that cannot be created, divided, or destroyed. Atoms of the same element are exactly alike, and atoms of different elements are different. Atoms join with other atoms to make new substances. -
JJ Thomson
A British scientist that showed there was a mistake in Dalton's theory. Thomson discovered there was a smaller particle in an atom which were called elctrons which were negatively charged and were in every kind of atom. -
Ernest Rutherford
A formere student of Thomson that dicided to test Thomson's experiment. he aimed a beam of small, positively charged particles at a thin sheet of gold foil. Rutherford put a special coating behind the foil. The coating glowed when it hit by the positively charged particles. Rutherford could then see where the particles went after hitting the gold. When he did this the suprising results came and some of the particles were deflected by the gold. -
Ernest Rutherford
In 1911 Rutherford revised his atomic theory and said that inside of an atom there is a positivley charged part called a nucleus. This was because like charges repelled so even if like charge was coming straight at the nucleus it would be pushed virtually backwards in the direction it came from -
Niels Bohr
A Danish scientist that studied the way that atoms react to light. He showed that they can jump from leevel to level but not in between. -
Erwin Schrodinger and Werner Heisenberg
Austrian and German physists that further explained the nature of electrons in the atom. They stated that electrons do not travel in direct paths.
