Becquerel, Henri

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{{epname|Becquerel, Henri}}
 
{{epname|Becquerel, Henri}}
{{For|the SI unit of radioactivity|Becquerel}}
 
'''<<Please add a "Legacy" section that summarizes his main accomplishments and the influence of his work on society at large. Place the Legacy section toward the end, just before the "See also" section.>>'''
 
  
 
{{Infobox_Scientist
 
{{Infobox_Scientist
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[[Antoine César Becquerel]].
 
[[Antoine César Becquerel]].
 
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'''Antoine Henri Becquerel''' (December 15, 1852 &ndash; August 25, 1908) was a [[France|French]] [[physicist]], [[Nobel laureate]], and one of the discoverers of [[radioactivity]]. He inherited a tradition of research from his grandfather, [[Antoine Cesar Becquerel]], who developed the field of electrolysis, and his father, [[A.E. Becquerel]], who invented a new method for [[spectroscopic analysis]]. Henri's gifts included his ability to conduct extensive research and develop a summarizing theory which was written as a mathematical formula. He is known for the laws of radiation associated with [[phosphorescence]].
 +
{{Toc}}
 
[[Image:Becquerel plate.jpg|thumb|right|Image of Becquerel's photographic plate that was fogged by exposure to radiation from uranium salts. The shadow of a metal [[Maltese Cross (symbol)|Maltese Cross]] placed between the plate and the uranium salts is clearly visible.]]
 
[[Image:Becquerel plate.jpg|thumb|right|Image of Becquerel's photographic plate that was fogged by exposure to radiation from uranium salts. The shadow of a metal [[Maltese Cross (symbol)|Maltese Cross]] placed between the plate and the uranium salts is clearly visible.]]
  
'''Antoine Henri Becquerel''' (December 15, 1852 &ndash; August 25, 1908) was a [[France|French]] [[physicist]], [[Nobel laureate]], and one of the discoverers of [[radioactivity]].
+
Becquerel's investigations were conducted during a period of new discoveries about energy, including the newly recognized [[X-ray]]s of [[Wilhelm Conrad Röntgen]]. Duplicating Röntgen's experiments led Becquerel to intuitively compare the types of radiation and led him to accept the notion that some radiation comes from within the substance itself rather than by external stimulation, such as in the case of phosphorescence. His discovery of  radiation from a [[uranium]] salt eventually contributed to a change in the paradigm of classical physics and helped begin the era of atomic physics. His work led to a more detailed understanding of the structure of matter and its relationship to energy.
  
==Early days and family==
+
== 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.
  
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 electrolysisHis 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 experimental set-ups 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.  Two preceding generations of scientists gave Henri Becquerel the impetus to further illuminate the truth through scientific research.   
  
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 physicsAlong 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.
+
In 1890, Becquerel married Louise Désirée Lorieux. Their son, [[Jean Becquerel|Jean]], became a physicist and studied the optical and magnetic properties of [[crystal]]s.
 +
   
 +
== Education in engineering and physics ==
  
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 attained the same post in 1891 and in those well equipped laboratories he conducted research in photoluminescence, continuing the explorations done by his father.
+
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 always been focused 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. In 1878, he accepted a teaching position in physics at the Conservatoire des Arts et Metiers. Within ten years, he had earned his doctorate with a [[dissertation]] on the absorption of light by crystals.
 
It was in those laboratories where, while studying fluorescence, he found evidence of invisible rays of energy released by a crystalline 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. Wilhelm 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 fluorescence might contain some of the mysterious "X-rays".
+
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.
  
Becquerel had been working with crystals of a compound containing uranium that, 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 available, 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 distinct 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.
+
==Research and discovery of radioactivity==
  
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.
+
Early in his career as a research physicist, Henri Becquerel developed laws of radiation of light from phosphorescent substances. While attending a lecture on the discovery of "X-rays," Becquerel's attention was captured by the mention of a [[fluoroscope]], a device his father had invented. Shortly afterward, he began his own study of X-rays, reproducing [[Wilhelm Röntgen]]'s experiments. He became intrigued by a suspicion that [[fluorescence|fluorescent]] materials just might emit some of these mysterious X-rays.
  
Becquerel conducted his own research on the phenomena of radiation and in 1899 declared that the rays could be deflected by a magnetic 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.
+
In 1896, he began working with crystals of a uranium compound ([[potassium uranyl sulfate]]), which, after exposure to sunlight, emitted fluorescent light. To determine whether X-rays were being emitted by the compound, he prepared a photographic plate for use after exposing a sample of the uranium salt to the Sun. As it turned out, a cloudy period ensued, during which no sunlight was available. Becquerel was 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, intending to retrieve them later. Quite a number of rainy days followed, with no sunlight.
  
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.  
+
He finally removed the plate from the drawer and developed it, expecting to see some faint evidence of emission of radiation. To his immense surprise, the photographic plate revealed a distinct image of the copper cross, evidence that strong radiation must have come from the uranium compound itself. In this manner, he accidentally discovered the phenomenon that came to be known as "[[radioactivity]]."
  
* Spouse: Louise Désirée Lorieux (m. 1890)
+
Describing his method to the [[French Academy of Sciences]] on January 24, 1896, he said,
* Children: [[Jean Becquerel|Jean]]
+
<blockquote>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.<ref>Henri Becquerel,  [http://gallica.bnf.fr/ark:/12148/bpt6k30780/f422.chemindefer Sur les radiations émises par phosphorescence] ''Comptes Rendus'' 122(1896):420-421. Retrieved November 7, 2007.</ref></blockquote>
  
==Rise in natural sciences, discoveries and major works==
+
Becquerel was [[Marie Curie]]'s doctoral adviser and collaborated with Pierre and Marie Curie in their studies of radioactivity. He assisted them in obtaining two Academy of Science grants for their work. With Becquerel's support, the Curies published their findings on [[radium]] in the journal of the Academy of Science in France. Marie Curie used the term "Becquerel rays" when referring to the radiation discovered by Becquerel. In addition, she was the first to use the term "radioactivity" to describe both Becquerel rays and the radiation that she and Pierre discovered emanating from radium.
  
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.
+
Meanwhile, based on his research on radiation phenomena, Becquerel declared, in 1899, that the rays could be deflected by a magnetic field. This observation suggested that at least some of the radiation was composed of electrically charged particles. In 1900, he was clearly committed to the idea that the radiation had to include particles of negative charge—just like the cathode rays discovered by [[J.J. Thompson]].
  
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 1901, Becquerel identified [[uranium]] as the component of his experimental compound that emitted the radiation. He published a half dozen papers exploring the phenomenon of radioactivity before turning his attention to other interests.
  
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 plate]]s 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]].
+
== Nobel prize ==
  
Describing his method to the [[French Academy of Sciences]] on January 24, 1896, he said,
+
In 1903, Becquerel shared the [[Nobel Prize in Physics]] with [[Pierre Curie|Pierre]] and [[Marie Curie]], "in recognition of the extraordinary services he has rendered by his discovery of spontaneous radioactivity."
<blockquote>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.<ref>{{cite journal|author=Henri Becquerel|title =Sur les radiations émises par phosphorescence|journal=Comptes Rendus |volume = 122| pages = 420-421|year=1896|url=http://gallica.bnf.fr/ark:/12148/bpt6k30780/f422.chemindefer}}</ref><ref>''Comptes Rendus'' 122, 420 (1896), [http://web.lemoyne.edu/~giunta/becquerel.html translated by Carmen Giunta]. Accessed September 10, 2006.</ref></blockquote>
 
  
In 1903, he shared the [[Nobel Prize in Physics]] with [[Pierre Curie|Pierre]] and [[Marie Curie]] "in recognition of the extraordinary services he has rendered by his discovery of spontaneous radioactivity."
+
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 the Curies each deserved recognition for their unique contributions to the understanding the newly discovered phenomenon called "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]].
 
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]].
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== Honors ==
 
== Honors ==
  
 +
'''Awards'''
 
*[[Rumford Medal]] (1900)
 
*[[Rumford Medal]] (1900)
 
*[[Helmholtz Medal]] (1901)
 
*[[Helmholtz Medal]] (1901)
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*[[Barnard Medal]] (1905)
 
*[[Barnard Medal]] (1905)
  
== Named after him ==
+
'''Named after him'''
 
+
* The [[SI]] unit for radioactivity is called the [[becquerel]] (Bq).
* The [[SI]] unit for radioactivity, the [[becquerel]] (Bq), is named after him.
 
 
* A crater on the [[Moon]] and another on [[Mars]] have been named [[Becquerel (crater)|Becquerel craters]].
 
* A crater on the [[Moon]] and another on [[Mars]] have been named [[Becquerel (crater)|Becquerel craters]].
  
==See also==
+
== Legacy ==
  
* [[Marie Curie]]
+
Henri Becquerel can be seen as a pioneer in a new world of subatomic phenomena at the close of the nineteenth century. He possessed the ability to formalize  experimental results into precise mathematical statements. His exploration of invisible but detectable emanations coming from within the atom itself led to a pivotal redefinition of the nature and structure of the [[atom]] and helped introduce a revolutionary era of atomic physics. In addition, it led to new ideas about the relationship between [[matter]] and [[energy]]. Becquerel was willing to risk his health by allowing himself to be burned by the radiation he was researching in order to better understand its effects. Along with the Curies, he was a pioneer of the study of radiation a phenomena which changed not only the field of physics but certainly affected modern medical science.  He was [[Marie Curie]]'s doctoral supervisor and shared the Nobel Prize in Physics with Pierre and Marie Curie.
* [[Radioactive decay]]
 
* [[Uranium]]
 
* [[X-ray]]
 
  
 
== Notes ==
 
== Notes ==
Line 88: Line 86:
  
 
== References ==
 
== References ==
'''<<Please format each reference according to our guidelines. I have formatted the first one.>>'''
 
  
* Asimov, Isaac. 1982. ''Asimov's Biographical Encyclopedia of Science and Technology''. 2nd ed. Garden City, New York: Doubleday.
+
* Asimov, Isaac. 1982. ''Asimov's Biographical Encyclopedia of Science and Technology,'' 2nd ed. Garden City, NY: Doubleday. ISBN 0385177712
 +
* Goldsmith, Barbara. 2005. ''Obsessive Genius: The Inner World of Marie Curie.'' New York: W.W. Norton & Co. ISBN 0393327485
 +
* Jones, Bessie Zaban, ed. 1966. ''The Golden Age of Science: Thirty Portraits of the Giants of 19th - Century Science by Their Scientific Contemporaries''. New York: Simon and Schuster, in cooperation with the Smithsonian Institution, Washington.
 +
* Sootin, Harry. 1960. ''12 Pioneers of Science''.  New York: Vanguard Press.
 +
* Tiner, John Hudson. 2000. ''100 Scientists Who Shaped World History''. San Mateo, California: Bluewood Books. ISBN 0912517395
  
* 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.
+
----
 
+
{{Nobel Prize in Physics Laureates 1901-1925}}
* 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==
 
 
 
'''<<Please check each Web link to ensure that it's still active and relevant to this article. Then add a "Retrieved" date to each valid link. (The Retrieved date is the date YOU checked the link, and it should read like: "Retrieved November 7, 2007.)>>'''
 
 
 
* [http://www.nobelprize.org/physics/laureates/1903/becquerel-bio.html Henri Becquerel - Biography]
 
* [http://www1.bipm.org/en/si/history-si/radioactivity/becquerel.html Becquerel short biography] and the use of his name as an unit of measure in the [[SI]]
 
* [http://alsos.wlu.edu/qsearch.aspx?browse=people/Becquerel,+Henri Annotated bibliography for Henri Becquerel from the Alsos Digital Library for Nuclear Issues]
 
  
{{Nobel Prize in Physics Laureates 1901-1925}}
 
  
{{Persondata
 
|NAME=Becquerel, Antoine Henri
 
|ALTERNATIVE NAMES=
 
|SHORT DESCRIPTION=[[France|French]] [[physicist]]
 
|DATE OF BIRTH=December 15, 1852
 
|PLACE OF BIRTH=[[Paris]], [[France]]
 
|DATE OF DEATH=August 25, 1908
 
|PLACE OF DEATH=[[Le Croisic]], [[Brittany]], [[France]]
 
}}
 
  
 
[[Category:Physical sciences]]
 
[[Category:Physical sciences]]
 
[[Category:Biography]]
 
[[Category:Biography]]
[[Category:Biographies of Scientists and Mathematicians]]
+
[[Category:Physicists]]
[[Category:Biography]]
 
  
 
{{credit|118215257}}
 
{{credit|118215257}}

Latest revision as of 15:20, 25 January 2023


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.

Antoine Henri Becquerel (December 15, 1852 – August 25, 1908) was a French physicist, Nobel laureate, and one of the discoverers of radioactivity. He inherited a tradition of research from his grandfather, Antoine Cesar Becquerel, who developed the field of electrolysis, and his father, A.E. Becquerel, who invented a new method for spectroscopic analysis. Henri's gifts included his ability to conduct extensive research and develop a summarizing theory which was written as a mathematical formula. He is known for the laws of radiation associated with phosphorescence.

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.

Becquerel's investigations were conducted during a period of new discoveries about energy, including the newly recognized X-rays of Wilhelm Conrad Röntgen. Duplicating Röntgen's experiments led Becquerel to intuitively compare the types of radiation and led him to accept the notion that some radiation comes from within the substance itself rather than by external stimulation, such as in the case of phosphorescence. His discovery of radiation from a uranium salt eventually contributed to a change in the paradigm of classical physics and helped begin the era of atomic physics. His work led to a more detailed understanding of the structure of matter and its relationship to energy.

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 experimental set-ups 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. Two preceding generations of scientists gave Henri Becquerel the impetus to further illuminate the truth through scientific research.

In 1890, Becquerel married Louise Désirée Lorieux. Their son, Jean, became a physicist and studied the optical and magnetic properties of crystals.

Education in engineering and physics

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 always been focused 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. In 1878, he accepted a teaching position in physics at the Conservatoire des Arts et Metiers. 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.

Research and discovery of radioactivity

Early in his career as a research physicist, Henri Becquerel developed laws of radiation of light from phosphorescent substances. While attending a lecture on the discovery of "X-rays," Becquerel's attention was captured by the mention of a fluoroscope, a device his father had invented. Shortly afterward, he began his own study of X-rays, reproducing Wilhelm Röntgen's experiments. He became intrigued by a suspicion that fluorescent materials just might emit some of these mysterious X-rays.

In 1896, he began working with crystals of a uranium compound (potassium uranyl sulfate), which, after exposure to sunlight, emitted fluorescent light. To determine whether X-rays were being emitted by the compound, he prepared a photographic plate for use after exposing a sample of the uranium salt to the Sun. As it turned out, a cloudy period ensued, during which no sunlight was available. Becquerel was 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, intending to retrieve them later. Quite a number of rainy days followed, with no sunlight.

He finally removed the plate from the drawer and developed it, expecting to see some faint evidence of emission of radiation. To his immense surprise, the photographic plate revealed a distinct image of the copper cross, evidence that strong radiation must have come from the uranium compound itself. In this manner, he accidentally discovered the phenomenon that came to be known as "radioactivity."

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]

Becquerel was Marie Curie's doctoral adviser and collaborated with Pierre and Marie Curie in their studies of radioactivity. He assisted them in obtaining two Academy of Science grants for their work. With Becquerel's support, the Curies published their findings on radium in the journal of the Academy of Science in France. Marie Curie used the term "Becquerel rays" when referring to the radiation discovered by Becquerel. In addition, she was the first to use the term "radioactivity" to describe both Becquerel rays and the radiation that she and Pierre discovered emanating from radium.

Meanwhile, based on his research on radiation phenomena, Becquerel declared, in 1899, that the rays could be deflected by a magnetic field. This observation suggested that at least some of the radiation was composed of electrically charged particles. In 1900, he was clearly committed to the idea that the radiation had to include particles of negative charge—just like the cathode rays discovered by J.J. Thompson.

In 1901, Becquerel identified uranium as the component of his experimental compound that emitted the radiation. He published a half dozen papers exploring the phenomenon of radioactivity before turning his attention to other interests.

Nobel prize

In 1903, Becquerel 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."

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 the Curies each deserved recognition for their unique contributions to the understanding the newly discovered phenomenon called "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

Awards

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

Named after him

  • The SI unit for radioactivity is called the becquerel (Bq).
  • A crater on the Moon and another on Mars have been named Becquerel craters.

Legacy

Henri Becquerel can be seen as a pioneer in a new world of subatomic phenomena at the close of the nineteenth century. He possessed the ability to formalize experimental results into precise mathematical statements. His exploration of invisible but detectable emanations coming from within the atom itself led to a pivotal redefinition of the nature and structure of the atom and helped introduce a revolutionary era of atomic physics. In addition, it led to new ideas about the relationship between matter and energy. Becquerel was willing to risk his health by allowing himself to be burned by the radiation he was researching in order to better understand its effects. Along with the Curies, he was a pioneer of the study of radiation a phenomena which changed not only the field of physics but certainly affected modern medical science. He was Marie Curie's doctoral supervisor and shared the Nobel Prize in Physics with Pierre and Marie Curie.

Notes

  1. Henri Becquerel, Sur les radiations émises par phosphorescence Comptes Rendus 122(1896):420-421. Retrieved November 7, 2007.

References
ISBN links support NWE through referral fees

  • Asimov, Isaac. 1982. Asimov's Biographical Encyclopedia of Science and Technology, 2nd ed. Garden City, NY: Doubleday. ISBN 0385177712
  • Goldsmith, Barbara. 2005. Obsessive Genius: The Inner World of Marie Curie. New York: W.W. Norton & Co. ISBN 0393327485
  • Jones, Bessie Zaban, ed. 1966. The Golden Age of Science: Thirty Portraits of the Giants of 19th - Century Science by Their Scientific Contemporaries. New York: Simon and Schuster, in cooperation with the Smithsonian Institution, Washington.
  • Sootin, Harry. 1960. 12 Pioneers of Science. New York: Vanguard Press.
  • Tiner, John Hudson. 2000. 100 Scientists Who Shaped World History. San Mateo, California: Bluewood Books. ISBN 0912517395



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