Rutherford+and+Chadwick

=Rutherford and Chadwick=

Rutherford's experiment was studying the angles at which alpha particles as they passed through gold foil. It was discoverd that nearly all of the alpha particles went throught the foil without any disturbance. Under Rutherford's direction, an undergraduate student looked for evidence of the aplha particles scattering at large angles. A few of the particles did scatter at large angles, some were even reflected back. This was inconsistent with the plum-pudding model of Thompson. A year later, Rutherford proposed that most of the mass of an atom and its positive charge are present in a very small dense part od the atom called the nucleus. Electrons move around the nucleus through the empty space in the atom. Most of the alpha particles passed through the gold foil because they went through the empty space, the ones that were reflected at large angles were the ones that came within close proximity of the positive nucleus. In further studies he found that in the nucleus, protons, or positively charded materials in the atom, were present. Therefore Rutherford disproved Thompson's plum pudding atom model.  Chadwick recieved the nobel prize for discovering the nucleus of an atom. Chadwicks discovery made it possible to make elements heavier than uranium in the laboratory. This was revolutionary in that it allowed even the largest atoms to be penetrated and split their nuclei. This led the way for fission of Uranium 235 and Nuclear Fission. His discovery helped inspire Enrico Fermi to discover nuclear reactions brought by slowed neutrons, and led Otto Hahn and Fritz Strassmann to the discovery of nuclear fission. He later helped the United States develope the Nuclear bombs to drop on Japan.

Sources:
http://en.wikipedia.org/wiki/Image:Rutherford_gold_foil_experiment_results.svg http://en.wikipedia.org/wiki/Image:Ernest_Rutherford2.jpg http://upload.wikimedia.org/wikipedia/commons/c/c2/Chadwick.jpg http://library.thinkquest.org/19662/images/eng/pages/exp-rutherford-1.jpg http://en.wikipedia.org/wiki/Image:Rutherford_gold_foil_experiment_results.svg