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460
Democritus
Democritus (460-370b.c)
He first person to suggest that matter can not be divied infitenity.
He created the term "atomos". which decribed the little type of matter. It cant be destroyed or father divied. -
Dalton
Dallton. (1766-1844)
He devolped the modern atomic theory.
He expolred democritus ideas with is own person sciencific research and brought back the term atom.
Dalton theroy was accpted because it had the ablility to explain the conservation of mass.(aoms can be rearrnged,seperated,or combined to form new thing, but cannot be created, destroyed, or divided in the process).
Dalton helped prove scienific research of the atom. -
The Cathode Ray tube
Sir william crookes noticed a green flash of light. Cathode ray tube while working in a dark labitory.
That discovery later helped make tv.
•Came to the conclusion that the ray’s negative particles were found in all forms of matter. These particles are now called electrons. -
The Gold Foil Experiment
Ernest Rutherford (1871 – 1937) studied how positively charged α-particles interacted with solid matter. He designed an experiment to see if α-particles would be deflected as they passed through a thin sheet of gold foil. -
JJ Thompson.
JJ thompson (1856-1940) designed a series of CRT experiments at Cambridge to determine the ratio of the particle’s charge to its mass. He said it has less mass than that of hydrogen atom which disprove dalton theory that atoms were indivisible. Thompson recieved a noble prize.in 1906. he discovery of the electron, the first subatomic particle. The mudding moduel. -
The Mass and Charge of the Electron
American Physicist Robert Millikan (1868 – 1953) designed an oil drop apparatus to determine the charge of the electron.
•Determined that the magnitude of the charge of the electron was 1.602x10-19 coulombs. •This charge was equated to a single unit of negative charge, thus, the electron carries a charge of -1
•Discovered the mass of the electron using the known charge/mass ratio: 9.1x10-28 g -
The Proton and the Neutron
Rutherford refined his concept of the nucleus to include that it contained positively charged particles called protons. Protons are positively charged subatomic particles with a charge equal in magnitude to that of the electron; +1 •English physicist, James Chadwick (1891 – 1974) demonstrated that the nucleus had another neutral subatomic particle, the neutron •Neutrons are subatomic particles that carry no electric charge and weighs just about the same as a proton.
•Chadwick won the 1935 -
Aristotle
Aristotle (384-322b.c)
- He disagreed with democritus idea that atoms move threw empty space
-He completely denied the existence of due to his person experiences
-His idea took us back to square 1
