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Benjamín
Utorok, 31. marca 2020
Piezoelectric Effect (Marie Curie, Pierre Curie)
Dátum pridania: 29.08.2003 Oznámkuj: 12345
Autor referátu: Stromek
 
Jazyk: Angličtina Počet slov: 768
Referát vhodný pre: Stredná odborná škola Počet A4: 2.7
Priemerná známka: 2.97 Rýchle čítanie: 4m 30s
Pomalé čítanie: 6m 45s
 
Curie, Marie (1867-1934) or Curie, Pierre (1859-1906), French physicists and Nobel laureates, who were wife and husband; together, they discovered the chemical elements radium and polonium. The Curies' study of radioactive elements contributed to the understanding of atoms on which modern nuclear physics is based.
Pierre Curie was born in Paris on May 15, 1859, and studied science at the Sorbonne. In 1880 he and his brother Jacques observed that an electric potential is produced when pressure is exerted on a quartz crystal. The brothers named the phenomenon piezoelectricity. In the course of later studies of magnetism, Pierre Curie discovered a certain temperature (the Curie point) at which magnetic substances lose their magnetism. In 1895 he was named professor in the School of Physics and Chemistry in Paris.
Originally named Marja Sklodowska, Marie Curie was born in Warsaw on November 7, 1867. Her father taught high school physics. In 1891 she went to Paris (where she changed her name to Marie) and enrolled in the Sorbonne. Two years later she passed the examination for her degree in physics, ranking in first place. She met Pierre Curie in 1894, and they married in 1895.
Marie Curie was interested in the recent discoveries of radiation. Wilhelm Roentgen had discovered X rays in 1895, and in 1896 Antoine Henri Becquerel had discovered that the element uranium gives off similar invisible radiations. Curie thus began studying uranium radiations, and, using piezoelectric techniques devised by her husband, carefully measured the radiations in pitchblende, an ore containing uranium. When she found that the radiations from the ore were more intense than those from uranium itself, she realized that unknown elements, even more radioactive than uranium, must be present. Marie Curie was the first to use the term radioactive to describe elements that give off radiations as their nuclei break down.
Pierre Curie ended his own work on magnetism to join his wife's research, and in 1898 the Curies announced their discovery of two new elements: polonium (named by Marie in honour of Poland) and radium. During the next four years the Curies, working in a leaky wooden shed, processed a ton of pitchblende, laboriously isolating from it a fraction of a gram of radium. They shared the 1903 Nobel Prize in physics with Becquerel for the discovery of radioactive elements.
 
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