Wednesday, December 08, 2004

Pierre curie

Pierre was educated at home by his father, and in his early teens showed a strong aptitude for mathematics and geometry. By the age of 18 he had completed the equivalent of a higher degree, but did not proceed immediately to a doctorate due to lack of money. Instead he worked as a laboratory instructor.
In 1880, Pierre and his older brother Jacques demonstrated that an electric potential was generated when crystals were compressed. Shortly afterwards, in 1881, they demonstrated the reverse effect: that crystals could be made to deform when subject to an electric field. Almost all digital electronic circuits now rely on this phenomenon in the form of crystal oscillators.
Prior to his famous doctoral studies on magnetism he designed and perfected an extremely sensitive torsion balance for measuring magnetic coefficients. Variations on this equipment were commonly used by future workers in that area. Pierre Curie studied ferromagnetism, paramagnetism, and diamagnetism for his doctoral thesis, and discovered the effect of temperature on paramagnetism which is now known as Curie's law. The material constant in Curie's law is known as the Curie constant. He also discovered that ferromagnetic substances exhibited a critical temperature transition, above which the substances lost their ferromagnetic behaviour. This is now known as the Curie point.
Pierre worked with his wife Marie Curie in isolating polonium and radium. They were the first to use the term 'radioactivity', and were pioneers in its study. Their work, including Marie's celebrated doctoral work, made use of a sensitive piezoelectric electrometer constructed by Pierre and his brother Jacques.


marie curie

Born desperately poor in Warsaw, Poland, her first years were sorrowful ones, marked by the death of her sister and, four years later, her mother. She was notable for her diligent work ethic, neglecting even food and sleep to study. After graduating from high school, she suffered a mental breakdown for a year. Due to her gender, she was not allowed admission into any Russian or Polish universities so she worked as a governess for several years. Eventually, with the monetary assistance of her elder sister, she moved to Paris and studied chemistry and physics at the Sorbonne, where she became the first woman to teach.
At the Sorbonne she met and married another instructor, Pierre Curie. Together they studied radioactive materials, particularly the uranium ore pitchblende, which had the curious property of being more radioactive than the uranium extracted from it. By 1898 they deduced a logical explanation: that the pitchblende contained traces of some unknown radioactive component which was far more radioactive than uranium; thus on December 26th Marie Curie announced the existence of this new substance.
Over several years of unceasing labour they refined several tons of pitchblende, progressively concentrating the radioactive components, and eventually isolated initially the chloride salts (refining radium chloride on April 20, 1902) and then two new chemical elements. The first they named polonium after Marie's native country, and the other was named radium from its intense radioactivity.

Wednesday, November 24, 2004

101 dalmations

One Hundred and One Dalmatians is an animated film released by Walt Disney Productions on January 25, 1961, based on the novel The Hundred and One Dalmatians by Dodie Smith. It also appeared in 1961 as a Walt Disney comic book based on the animated film.One Hundred and One Dalmatians features Rod Taylor as the voice of Pongo, the first of the dalmatians, and Betty Lou Gerson as the voice of the villainous Cruella De Vil. The plot centers around the fate of the kidnapped puppies of Pongo and Perdita.One Hundred and One Dalmatians was remade in 1996 as 101 Dalmatians, a live-action film starring Glenn Close as Cruella De Vil (none of the animals talked in this version).