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400
B.C. ARISTOTLE
- He believed that all matter was made of The Four Elements . Being Fire, Eart, Air, and Water. *his theory was never adopted. even though both the Atom Theory and his had no proof. the public supported Aristotle's theory because he was one of the greatest minds and had also many followers.
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460
B.C. DEMOCRITUS
Believed in the idea that everything could be broken down into smaller peicesand thats how he came to the idea of the atomic theory. Stating that everything could be broken down into atoms. similer to a marble. -
ANTONIE LAVOISIER
The founder of the two elements that make up water. He named one Oxygen because of the acid in it and the other Hydrogen. -
JOPHN DALTON
John Dalton developed the atomic theoryin the 1800. He still believed that the atom was the smallest unit of matter, Also he believed in Democritus' theory of the atom looking like a marble, tried to calculate the atomic weight of compounds, and tried to come up with the atomic stuructures of atoms. -
HENRI BECQUEREL
Henri Becquerel discovered uranium produced x-ray radiation. Leading him to discover radioactivity when he was studying phosphorescence. All this came to the fact that atoms were able to change shape. -
J.J THOMSON
JJ Thompson discovered the electron using the cathode-ray tube. before in 1904 Thompson thought the atoms was a sphere of positive force with electrons around it. He also created a mass spectrograph which found isotopes. his modle was known as the plum pudding model. -
MAX PLANCK
ounded the Quantum Theory, States that "In 1900 Max Planck made a profound discovery in modern physics . He showed that light must be emitted and absorbed in discrete amounts if it was to correctly describe observed phenomena Prior to then light had been considered as a continuous electromagnetic wave, thus the discrete nature of light was completely unexpected." -
MARIE AND PIERRE CURIE
Curie_small_square 28th Jan, 1900 Marie and Pierre Curie Marie and Pierre Curie were a married couple. After their marriage they continued to work together in science. The couple discovered two elements: the first is poloium the sceond is radium their discovery did dnot chage the model of teh atom it just added to the known elements during that time. -
ROBERT MILLIKAN
Robert%20millikan_small_square 1st Jan, 1908 Robert Millikan Robert Millikan was responsible for finding the charge of a single electron. He did this using his oil drop expirement. He proved that subatomic particles do exsist. Millikan is also credited with proving einstein. he did this by using the Photoelectric effect. http://en.wikipedia.org/wiki/Robert_Andrews_Millikan#Charge_of_the_electron -
ERNEST RUTHERFORD
Rutherford_small_square 1st Jan, 1911 Ernest Rutherford Ernest Rutherford discovered the nucleus. His theory was the atom has a positive nucleus with negative electrons orbiting around it. This changed the atom greatly because it was now known that most of the atoms weight is in the nucleus. His model was known as planetary system model. Ernest rutherford was the student of JJ Thompson.http://www.rsc.org/chemsoc/timeline/pages/1911.html -
NIELA BOHR
Proposed a new atom model that allowed the electrons to be outside the nucleus and in orbit around the nucleus. BHis model is knowen as the Bhor -
ERWIN SCHROBINGER
The equation for quantum wave mechanics was the second reason electrons move in waves about an atom. H -
WERNER HEISENBERG
Came up with the uncertainty priciple saying that you cant measure the current position of a particle and also measure the position it will be in after it. -
JAMES CHADWICK
Proved the exsistence of neutrons. Another subatomic particle was found in the atom. Changing the way the atom was viewed.
