Becquerel, Henri

From New World Encyclopedia
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Henri Becquerel was born in [[Paris]], France to a family which, including himself and his son, produced four generations of scientists. Henri's grandfather, Antoine Cesar Becquerel, invented a method of extracting metals from ores using electrolysis.  His father, Alexander Edmond Becquerel, was a physicist who researched solar phenomena and phosphorescence.  
 
Henri Becquerel was born in [[Paris]], France to a family which, including himself and his son, produced four generations of scientists. Henri's grandfather, Antoine Cesar Becquerel, invented a method of extracting metals from ores using electrolysis.  His father, Alexander Edmond Becquerel, was a physicist who researched solar phenomena and phosphorescence.  
  
As child, young Henri loved to visit his father's laboratory and delighted in the equipment used to set up experiments.  Written accounts of that period of his life point to a close relationship between father and son in the passing on of the experimental scientific tradition.  The phrase coined by Newton, ..."standing on the shoulders of giants" takes on tangible meaning in the case of the Becquerel family's scientific legacy. The Becquerel legacy led successive generations to walk in the shoes of their predecessors on the path of discovery of scientific truths.
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As child, young Henri loved to visit his father's laboratory and took great delight in examining the various tools he found there.  Written accounts of that period of his life suggest there was a close relationship between father and son in the passing on of the scientific tradition.  The Becquerel scientific legacy ultimately led young Henri to a pivotal redefinition of the nature and structure of the atom and consequently opened a new era of atomic physics.  Along with other scientists such as Roentgen and the Curies, Henri Becquerel entered the world of subatomic phenomena at the close of the 19th century and thus opened the atomic age of the 20th century.
  
His father , A.E. Becquerel, was a pioneer in the field of fluorescence. Henri Becquerel's grandfather and his father were successive directors of the Museum of Natural History in Paris.  Henri attainted the same post in 1891 and while there he built upon the foundation laid by his father and seemingly by accident stumbled upon a revolutionary discovery which changed forever our understanding of atomic structure.
+
His father , A.E. Becquerel, was a pioneer in the field of fluorescence. Henri Becquerel's grandfather and his father were successive directors of the Museum of Natural History in Paris.  Henri attainted the same post in 1891 and in those well equipped laboratories he conducted research in photoluminescence, continuing the explorations done by his father.
 +
 +
It was in those laboratories where, while studying fluorescence, he found evidence of invisible rays of energy released by a crystaline substance - potassium uranyl sulfate.
  
Early in his career as a research physicist, Henri developed his laws of radiation of light from phosphorescent substances. Then in one of the most famous cases of "accidental scientific discovery, he stumbled upon the phenomenon of radioactivity.  Wilhem Roentgen's discovery of "X-rays" had already captured the interest of Becquerel and he began to explore the notion that flourescence might contain some of the mysterious "X-rays".  Becquerel had been working with crystals of chemicals which when exposed to sunlight, later emitted fluorescent light.  
+
Early in his career as a research physicist, Henri developed his laws of radiation of light from phosphorescent substances. Then in one of the most famous cases of "accidental scientific discovery", he stumbled upon the phenomenon of radioactivity.  Wilhem Roentgen's discovery of "X-rays" had already captured the interest of Becquerel while attending a lecture on the phenomenon.  Shortly afterward he began a study of X-rays, reproducing Roentgen's experiments. Soon he began to explore the notion that flourescence might contain some of the mysterious "X-rays".  Becquerel had been working with crystals of a compound containing uranium which, after being exposed to sunlight, later had emitted fluorescent light. He intended to prove radiation would be emitted by using a photographic plate and then prepared a sample of the uranium salt for exposure to the sun. A cloudy period ensued and  no sunlight was availabe, which left Becquerel at an impasse.  He wrapped the crystals and a copper cross in a black cloth with the photosensitive plate and put them in a drawer. Quite a number of rainy days followed with no sunlight. Becquerel finally removed the plate from the drawer and developed it expecting he might see some faint evidence of emission. To his immense surprise the photo plate revealed a distince image of the copper cross,evidence of strong radiation which must have come from the uranium compound itself.  He began to research these energetic emissions which were then called "Becquerel rays."  Becquerel published a half dozen papers exploring this phenomenon but then left it for other interests. 
  
 +
News of experiments on radiation by the husband and wife team of Marie and Pierre Curie attracted Becquerel's interest and he did assist in obtaining two Academy of Science grants for Marie Curie's work.  With Becquerel's support the Curies published their findings on radium in the journal of the Academy of Science in France.
  
Henri Becquerel mentored Marie Curie and later shared a Nobel Prize with Pierre and Marie Curie for their combined contribution to the understanding of radioactivity. Much to his credit he refused to accept the Nobel prize unless it was shared among himself and the Curies.
+
Becquerel conducted his own research on the phenomena of radiation and in 1899 declared that the rays could be deflected by a mangnetic field which suggested they were at least partially particles.  In 1900 he was clearly committed to the idea that the radiations had to include particles of negative charge- just like the cathode rays discovered by J.J. Thompson.
 +
 
 +
Although Becquerel was the only one of the three present at the awarding of the Nobel Prize for Physics in 1903, it was clear that he and Pierre and Marie Curie deserved recognition for unique contributions to understanding the newly discovered phenomenon of radioactivity.  
  
Throughout his youth and young adulthood, Henri Becquerel was known as a man of high moral standards.  He studied science at the ''[[École Polytechnique]]'' and engineering at the ''[[École Nationale des Ponts et Chaussées|École des Ponts et Chaussées]]''. He published his first work at the age of 22 and continued to produce writings on science throughout his life.
 
 
* Spouse: Louise Désirée Lorieux (m. 1890)
 
* Spouse: Louise Désirée Lorieux (m. 1890)
 
* Children: [[Jean Becquerel|Jean]]
 
* Children: [[Jean Becquerel|Jean]]
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== References ==
 
== References ==
<<We need at least 3 reliable references here, properly formatted.>>
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Asimov's Biographical Encyclopedia of Science and Technology. by  Isaac Asimov, Second Revised Edition, Doubleday & Co. Inc, Garden City, New York, 1982
 +
 
 +
Obsessive Genius, The Inner World of Marie Curie, by Barbara Goldsmith published by W.W. Norton & Company, Inc, New York, c. 2005,  ISBN 0-393-05137-4
 +
 
 +
100 Scientists who shaped world history., by John Hudson Tiner, San Mateo, California, Bluewood Books. ISBN 0912517395
 +
 
 +
12 Pioneers of Science, Harry Sootin, New York, Vanguard Press, 1960 
  
  

Revision as of 23:54, 3 November 2007


Antoine Henri Becquerel

Henri Becquerel.jpg
Antoine Becquerel, French physicist
Born

December 15, 1852
Paris, France

Died August 25, 1908

Le Croisic, Brittany, France

Residence Flag of France (bordered).svg France
Nationality Flag of France (bordered).svg French
Field Physicist
Institutions Conservatoire des Arts et Metiers
École Polytechnique
Paris Museum
Alma mater École Polytechnique
École des Ponts et Chaussées
Known for Radioactivity
Notable prizes Nobel.svg Nobel Prize for Physics (1903)
Note that he is the father of Jean Becquerel, the son of A. E. Becquerel, and the grandson of

Antoine César Becquerel.

Image of Becquerel's photographic plate that was fogged by exposure to radiation from uranium salts. The shadow of a metal Maltese Cross placed between the plate and the uranium salts is clearly visible.

Antoine Henri Becquerel (December 15, 1852 – August 25, 1908) was a French physicist, Nobel laureate, and one of the discoverers of radioactivity.

Early days and family

Henri Becquerel was born in Paris, France to a family which, including himself and his son, produced four generations of scientists. Henri's grandfather, Antoine Cesar Becquerel, invented a method of extracting metals from ores using electrolysis. His father, Alexander Edmond Becquerel, was a physicist who researched solar phenomena and phosphorescence.

As child, young Henri loved to visit his father's laboratory and took great delight in examining the various tools he found there. Written accounts of that period of his life suggest there was a close relationship between father and son in the passing on of the scientific tradition. The Becquerel scientific legacy ultimately led young Henri to a pivotal redefinition of the nature and structure of the atom and consequently opened a new era of atomic physics. Along with other scientists such as Roentgen and the Curies, Henri Becquerel entered the world of subatomic phenomena at the close of the 19th century and thus opened the atomic age of the 20th century.

His father , A.E. Becquerel, was a pioneer in the field of fluorescence. Henri Becquerel's grandfather and his father were successive directors of the Museum of Natural History in Paris. Henri attainted the same post in 1891 and in those well equipped laboratories he conducted research in photoluminescence, continuing the explorations done by his father.

It was in those laboratories where, while studying fluorescence, he found evidence of invisible rays of energy released by a crystaline substance - potassium uranyl sulfate.

Early in his career as a research physicist, Henri developed his laws of radiation of light from phosphorescent substances. Then in one of the most famous cases of "accidental scientific discovery", he stumbled upon the phenomenon of radioactivity. Wilhem Roentgen's discovery of "X-rays" had already captured the interest of Becquerel while attending a lecture on the phenomenon. Shortly afterward he began a study of X-rays, reproducing Roentgen's experiments. Soon he began to explore the notion that flourescence might contain some of the mysterious "X-rays". Becquerel had been working with crystals of a compound containing uranium which, after being exposed to sunlight, later had emitted fluorescent light. He intended to prove radiation would be emitted by using a photographic plate and then prepared a sample of the uranium salt for exposure to the sun. A cloudy period ensued and no sunlight was availabe, which left Becquerel at an impasse. He wrapped the crystals and a copper cross in a black cloth with the photosensitive plate and put them in a drawer. Quite a number of rainy days followed with no sunlight. Becquerel finally removed the plate from the drawer and developed it expecting he might see some faint evidence of emission. To his immense surprise the photo plate revealed a distince image of the copper cross,evidence of strong radiation which must have come from the uranium compound itself. He began to research these energetic emissions which were then called "Becquerel rays." Becquerel published a half dozen papers exploring this phenomenon but then left it for other interests.

News of experiments on radiation by the husband and wife team of Marie and Pierre Curie attracted Becquerel's interest and he did assist in obtaining two Academy of Science grants for Marie Curie's work. With Becquerel's support the Curies published their findings on radium in the journal of the Academy of Science in France.

Becquerel conducted his own research on the phenomena of radiation and in 1899 declared that the rays could be deflected by a mangnetic field which suggested they were at least partially particles. In 1900 he was clearly committed to the idea that the radiations had to include particles of negative charge- just like the cathode rays discovered by J.J. Thompson.

Although Becquerel was the only one of the three present at the awarding of the Nobel Prize for Physics in 1903, it was clear that he and Pierre and Marie Curie deserved recognition for unique contributions to understanding the newly discovered phenomenon of radioactivity.

  • Spouse: Louise Désirée Lorieux (m. 1890)
  • Children: Jean

Rise in natural sciences, discoveries and major works

Antoine Henri Becquerel was educated at Lycee Louis-le-Grand during his early years. He moved on to the Ecole Poytechnique and finally the Ecole des Ponts et Chaussees. His direction in life seems to have been always focussed on science. He won his engineering degree in 1877 and served with the National Administration of Bridges and Highways while maintaining an interest in problems of a scientific and theoretical nature. He later accepted a teaching position in physics at the Conservatoire des Arts et Metiers in 1878. Within ten years he had earned his doctorate with a dissertation on the absorption of light by crystals.

In 1892, he became the third in his family to occupy the physics chair at the Muséum National d'Histoire Naturelle. In 1894 he became chief engineer in the Department of Bridges and Highways.

In 1896, while investigating phosphorescence in uranium salts, Becquerel discovered radioactivity accidentally. Investigating the work of Wilhelm Conrad Röntgen, Becquerel wrapped a fluorescent mineral, 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 fully exposed. This discovery led Becquerel to investigate the spontaneous emission of nuclear radiation.

Describing his method to the French Academy of Sciences on January 24, 1896, he said,

One wraps a Lumière photographic plate with a bromide emulsion in two sheets of very thick black paper, such that the plate does not become clouded upon being exposed to the sun for a day. One places on the sheet of paper, on the outside, a slab of the phosphorescent substance, and one exposes the whole to the sun for several hours. When one then develops the photographic plate, one recognizes that the silhouette of the phosphorescent substance appears in black on the negative. If one places between the phosphorescent substance and the paper a piece of money or a metal screen pierced with a cut-out design, one sees the image of these objects appear on the negative. … One must conclude from these experiments that the phosphorescent substance in question emits rays which pass through the opaque paper and reduces silver salts.[1][2]

In 1903 he shared the Nobel Prize in Physics with Pierre and Marie Curie "in recognition of the extraordinary services he has rendered by his discovery of spontaneous radioactivity."

In 1908, Becquerel was elected permanent secretary of the Académie des Sciences. He died the same year, at the age of 55, in Le Croisic.

Honors

The SI unit for radioactivity, the becquerel (Bq), is named after him, and there are Becquerel craters on the Moon and Mars.

  • Rumford Medal (1900)
  • Helmholtz Medal (1901)
  • Nobel Prize for Physics (1903)
  • Barnard Medal (1905)

See also

Notes

  1. Henri Becquerel (1896). Sur les radiations émises par phosphorescence. Comptes Rendus 122: 420-421.
  2. Comptes Rendus 122, 420 (1896), translated by Carmen Giunta. Accessed September 10, 2006.

References
ISBN links support NWE through referral fees

Asimov's Biographical Encyclopedia of Science and Technology. by Isaac Asimov, Second Revised Edition, Doubleday & Co. Inc, Garden City, New York, 1982

Obsessive Genius, The Inner World of Marie Curie, by Barbara Goldsmith published by W.W. Norton & Company, Inc, New York, c. 2005, ISBN 0-393-05137-4

100 Scientists who shaped world history., by John Hudson Tiner, San Mateo, California, Bluewood Books. ISBN 0912517395

12 Pioneers of Science, Harry Sootin, New York, Vanguard Press, 1960


Jones, Bessie Zaban, ed.The Golden Age of Science, Thirty Portraits of the Giants of 19th - Century Science by Their Scientific Contemporaries; Simon and Schuster, New York with the Smithsonian Institution, Washington, D.C. 1966 in particular, the article entitled: Antoine Henri Becquerel, by Andre Broca - from Revue general des sciences pures et appliquees

External links

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