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Science and Technology of France

French Scientists
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Edme Mariotte(1620-84) - Mariotte was a French physicist who "wrote on percussion, air and its pressure, the movements of fluid bodies and of pendulums, colours, etc."

André Marie Ampère (1775-1836) - Ampère, a teacher at Paris, has his permanent place in the history of science because it was his name that was given to the unit by which we measure electrical current. He had, of course, an interest in electricity; in addition, Ampère made similar investigations as did Avogadro into the nature of matter in its gaseous state.

Jacques Alexander César Charles (1746-1823) - The French scientist after which is named the Charles's Law which made the connection that a rise in temperature expanded the volume of gas. Charles was to become one of first balloonists.

Kirsten Byrn

Henri Becquerel Some of our acts seem to be of very little importance. But, eventually, they might bring a major revolution, one of those strong movements which change the world. A world in which a hundred years later, its effect are still felt. Henri Antoine Becquerel did one such act at the end of last century by forgetting some photographic plates in his drawer for a few days. He discovered by pure chance that radiation ionises the air. It is not caused by the Sun and its intensity does not decrease with the passage of time. This is the beginning of nuclear age. In his laboratory in the Natural History Museum, he multiplied his trials. He tried to induce fluorescence in some chemical compounds by exposing them to sun rays with the mepe that they will form an impression on the pmeto plates later. Calcium sulphide seemed to produced some results. But, they could not be reproduced. On the other hand, uranium sulphate seemed to veil pmetographic emulsions when exposed to sunlight. But the results were still misleading.

Georges Charpak 1992 Nobel Prize laureate, is well known in Canada. Invited in October 1994 by the Scientific Service, he gave a sparkling lecture and was given a tour of Ottawa's premier laboratories and met with its leading scientists. When he returned in 1995, he was made an honorary doctor of the University of Ottawa. For the occasion, he sponsored a Canada-Israel research grant put together by the French embassy. The originality of the different machines stems from the proportional multi-wire chamber or "Charpak detector", whose design and construction earned the French physicist the Nobel Prize in 1992. The proportional multi-wire chamber is a gas (a mix of xenon and CO2) particle detector. From the outside the detector is a 50 cm wide aluminium box with a small manometer on top, which serves to maintain xenon pressure at 3 bars. When the box is opened, an alignment of wires can be seen inside. They are made of copper. Measuring 10 microns in diameter, they are pulled tight like the weft of fabric on a loom. The axis of each wire faces the x-ray source, 1.30 m away; the wires measure 5 cm and are separated from one another by a distance of 1.2 mm. Cathodes are set up on each side of the wire layout. The connections to the first electronic level are under the chamber. Each wire is connected to an amplifier, a selection component and a counter. All the components are on 32 cards inserted into a built-in hood on the chamber. The chamber-electronic counting unit is supported by an arm with x-ray tube fitted onto its other end.

Marie Curie In her pioneering way, Marie Curie decided, in 1897, to take a physics doctorate. Henri Becquerel, who was studying X-rays, had recently observed that uranium salt left an impression on a photographic plate in spite of its protective envelope. What better subject could there have been for Marie than to try and understand the effect, the energy of these uranic rays ? Pierre consented. And so his frail wife set about her work, handling tons of minerals; she noted that another substance, thorium, was « radioactive », a term she herself had coined. Together, they demonstrated in a major discovery that radioactivity was not the result of a chemical reaction but a property of the element or, more specifically, of the atom. Marie then studied pitchblende, a uranic mineral in which she measured a much more intense activity than is present in uranium alone. She deduced that there were other substances besides uranium that were very radioactive, such as polonium and radium, which she discovered in 1898. In their experiments, Pierre observed the properties of the radiation while Marie, for her part, purified the radioactive elements. Both shared the same, uncanny tenacity, which was all the more admirable given their deplorable living conditions. Their laboratory was nothing more than a miserable hangar, where in winter the temperature dropped to around six degrees. One chemist commented that &171; it looked more like a stable or a potato cellar ». And yet, Marie admitted that &171; one of our pleasures was to enter our workshop at night; then, all around us, we would see the luminous silhouettes of the beakers and capsules that contained our products. &187; Despite their difficulty at obtaining any advances or loans, Marie and Pierre Curie refused to file a patent application that would have secured them financially; in their eyes, enabling any scientist, French or foreign, to find applications for radioactivity took priority. Pierre tested radium on his skin. It caused a burn, and then a wound : its effect on man was thus proven. Soon radium was being used to treat malign tumours: Curietherapy was born. In 1903, Marie defended her thesis. Together with Becquerel, the Curies were awarded the Nobel Prize for Physics for their discovery of natural radioactivity. Their happiness was short lived. In 1906, Pierre, weakened by radiation and overworked, was run over by a car. Marie was forced to continue alone. She took charge of educating her two children; she took up the position which her husband had finally obtained at the Sorbonne, and thus became the first woman to be appointed professor there. She also had to fight the prejudices of her day: hatred of foreigners and sexism which, in 1911, prevented her from entering the Academy of Science. And yet, soon after, she was honoured with a Nobel Prize for Chemistry for determining the atomic weight of radium. But her real joy was « easing human suffering. » The founding of the Radium Institute by the University of Paris and the Pasteur Institute in 1914 would enable her to fulfil her humanitarian wish.

Louis Pasteur was born on December 27, 1822 in Dole, in the region of Jura, France. His discovery that most infectious diseases are caused by germs, known as the "germ theory of disease", is one of the most important in medical history. His work became the foundation for the science of microbiology, and a cornerstone of modern medicine. Pasteur's phenomenal contributions to microbiology and medicine can be summarized as follows. First, he championed changes in hospital practices to minimize the spread of disease by microbes. Second, he discovered that weakened forms of a microbe could be used as an immunization against more virulent forms of the microbe. Third, Pasteur found that rabies was transmitted by agents so small they could not be seen under a microscope, thus revealing the world of viruses. As a result he developed techniques to vaccinate dogs against rabies, and to treat humans bitten by rabid dogs. And fourth, Pasteur developed "pasteurization", a process by which harmful microbes in perishable food products are destroyed using heat, without destroying the food. Each discovery in the body of Pasteur's work represents a link in an uninterrupted chain, beginning with molecular asymmetry and ending with his rabies prophylaxis, by way of his research in fermentation, silkworm, wine and beer diseases, asepsis and vaccines.

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Marie Curie

French II 4th Period Danielle Montalvo