1875-1900+(ms)

Plum Pudding Model The plum pudding model was the theory of JJ Thompson. He stated that atoms are like a portion of positive pudding with removable negative electron plums inside. This was the first theory that suggested remoable parts of an atom. However, this theory did not last to long as Rutherford disproved it in his effort to do jsut the opposite. []



Name: J.J. Thomson Life: 18 December 1856 – 30 August 1940 Country of Origin: Britain Year: 1880 Thomson is credited for the discovery of the electron and of isotopes and the invention of the mass spectrometer. He won the Nobel Prize in Physics in 1906 for the discovery of the electron and his work on the conduction of electricity in gases. He conducted a series of experiments with cathode rays and cathode ray tubes leading him to the discovery of electrons and subatomic particles. Thomson imagined the atom as being made up of these corpuscles swarming in a sea of positive charge; this was his plum pudding model.

Name: Wilhelm Rontgen Life: 27 March 1845 – 10 February 1923 Country: Germany Year: 1895 On November 8, 1895 Rontgen produced and detected electromagnetic radiation in a wavelength range today known as x-rays. In 1869, he graduated with a Ph.D. from the University of Zurich. In the two weeks after his discovery, he took the very first picture using x-rays of his wife's hand, Anna Bertha.



Name: Henri Becquerel Life: 15 December 1852 – 25 August 1908 Country: France Year: Henri Becquerel was a French physicist and the discoverer of radioactivity, for which he won the 1903 Nobel Prize in Physics. In 1896, he accidentally discovered radioactivity. “Becquerel wrapped a fluorescent substance, potassium uranyl sulfate, in photographic plates and black material in preparation for an experiment requiring bright sunlight. However, prior to actually performing the experiment, Becquerel found that the photographic plates were already exposed, showing the image of the substance. This discovery led Becquerel to investigate the spontaneous emission of nuclear radiation.”