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460
Demorritus
Democritus (460-370 B.C.)
-he was the first person to suggest that matter couldn't be divided
-made up the word "atomos" (atom)
-"atomos couldn't be created, destroyed, or divided"
-couldn't figure out what held them together -
John Dalton
Dalton (1766-1844)
-developed modern atomic theory
-took Demo.'s ideas and rethiught them into his own findings
-brought back the word "atom"
- brining atoms back.. yeah, yeah..
-"Atoms are the smallest particles of matter and are indivisible and indestructible"
-he explained the conservation of mass -
Sir William Crookes
Crookes (1832)
-noticed a green flash of light
-discovered cathode rays
-later led to the creation on tv -
JJ Thompson
Thompson (1856-1940)
- created experiments to find the ration of the particles charge to its mass
-disproved Dalton's theory
-discovered electrons -
Robert Millikan
Millikan (1868-1953)
-ditermined magnitude was 1.602x10^-19
-discovered electron was negative (e^-1)
-discovered mass of electon using the known charge/mass ratio; 9.1x10^-28g -
Ernest Rutherford
Rutherford (1871-1937)
-studied how positvively charged a-particles interacted with solid matter
-created gold foil experiment
-discovered some bounced back at weird angles instead of passing thought the gold foil
-based on that, came to conclusion that the plum pudding model of Thompson was wrong
-discovered basically how the nucleus was set up
-added protons to his model -
James Chadwick
Chadwick (1891-1974)
-discovered neutron (n^0)
-won nodel prize for his discovery -
Aristotle
Aristotle (384- 322 B.C.)
-denied the existance of atoms
-disagreed that they moved through empty space
-people thought his ideas were better than Democritus
