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250
Democritus
He existed in 500 b.c. and he though that all matter consisted of extremely small particles that could not be divided. He discussing it with other philosiphers -
250
Aristotle
He existed in 500 b.c. and he didn't think that there was a limit to the number of times matter could be divided he disscused this with other philosiphers -
John Dalton
He discovered that all matter is made up of individual particles called atoms, which cannot be divided. He did this by making wooden spheres to repreesent the atoms of different elements. -
joseph Proust
He discovered that a given compound always has the same elements in the same proportion by mass. -
J.J Thomson
His real name is Joseph John Thomas. His discovered that a beamwas a stream of charged particles that interacted with the air in the tube and caused it to glow. His student did this by placing a pair of charged metal plates on either side of the glass tube. -
Hantaro Nagaoka
Suggest that an atom has a central nucleus.His model was based around an analogy of the stability of the rings around Saturn. -
Ernest Mardsen
He agreed with Ernest Ruthford. He did this by aiming a narrow beam of alpha particles at a piece of gold surrounded by mirrors. -
Ernest Ruthford
He theorized that the mass and charge ata ny location in the gold would be too small to change the path of an alpha particle. His student did the expirement to prove it -
Niels Bohr
He agreed with Rutherford's model but focused on the electrons. In niels Bohr's model, the electrons move in spherical orbits at fixed distances form the nucleus. -
Louis de Broglie
He discovered that moving produts like elctrons having some properties of waves. He did this by working out math problems. -
Werner Heisenberg
Heisenberg worked out that particles had a lot more energy over short distances than expected. He realized that a particle can borrow energy as long as it is paid back in a short time. -
Erwin Schrodinger
He used mathmatical equations to describe the motion of atoms inside a cell. -
James Chadwick
He confirms the existence of neutrons which have no charge. He did this bybombarded the alpha rays on Beryllium atom and observed that Beryllium artificially became radioactive for a short time
