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340
Aristotle
Aristotle belived that all atoms came from the four elements, air, earth, water, and fire. He also believed that atoms could not be constantly moving if they were in a void. -
440
Democritus
Democritus belived that if you continualy cut an attom, you would end up with an "uncuttable" piece. He named these "uncuttable" pieces particles, which means uncattable in Greek. He thought that these particles were made of one sublace only and were one particular shape. He also thought that they were constantly moving. -
John Dalton
Dalton claimed that elements were able to combined wiht other elements because all elements are made of atoms. He came up with a three-part atomic theory:
1. All particles are made of atoms, they cant be divided or destroyed. 2.Atoms of the same elements are identical diferent element's atoms are different. 3. atoms join with other substances to create new and different substances. -
J.J. Thomson
In and experiment using a cathode ray, Thomson disproved Dalton's atomic theory. he discovered that atoms can be divided. He used his results to create the Plum-Pudding model. -
Rutherford
In his expirement, Rutherford shot a beam of positively charged particles through a sheet of gold foil. What he got from the results disproved Thompsons theory that the paticles were soft (shown in his plum pudding model). Rutherfords results showed that not all of the particles allow the beam to go through. Some light particles were bounced back while most went through. This led Rutherford to creat a new and more accurate model.
