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500
Democritus
He was the first person to suggest that matter could be infinitley divided. Has the famous quote "Atoms could not be created, destroyed, or divided". -
John Dalton
started the beginning of modern technology. took ideas and started to revise them. atoms are the smallest particles of matter. -
sir william crookes
He notcied a green light. He later found out the light was cathode rays. This led to the invention of televiison and things in that area . He cme to the concusion that the raysnegative particles were all forms of matter. These are now called electrons. -
JJ Thomson
he found out the true mass of the atom. which made dalton ideas wrong. he was awarded for this with a noble prize. JJ Thompson also came up with the Plum Putting Model. The bready part of the pudding represented the plums and the pudding part was the negatively and positivley charges. -
Robert Milikan
He desigend an oil drop apparatus to determine the charge of the electron. He determined the charge of the elctron was 1.602x10^-19 coulombs. This means the charge of the electron would be -1. -
Ernest Rutherford
He designed an experiment to see if a-particles would be deflected as they pass through a thin sheet of gold foil. He found that a few a-particles bounced back at odd angles. This was the Gold Foil Experiment. Based on his experiment he came to the conclusion that Thompsom's experment was wrong. He discovered the nucelus and protons. -
James Chadwick
Discovered that the nucleus has another neutral subatomic particle named neutrons. They carry no electric charge and weigh the same as a proton.He then won the Nobel Prize in 1935 for his discovery. -
aristotle
he disagreed with democritus ideas said that atom cannot move through space.
