Henri Becquerel – biography bio wiki atomic theory
(1852 – 1908) Antoine-Henri Becquerel
Facts about Henri Becquerel
He was born :
December 15, 1852 | France
He passed away :
August 25, 1908
Sign of the zodiac :
Biography of Henri Becquerel
Antoine-Henri Becquerel , was born on December 15, 1852 in Paris. Becquerel was the French physicist who discovered radioactivity through his research on uranium and other substances. In 1903 he shared the Nobel Prize in Physics with Pierre Curie and Marie Curie .
He was born into a family of several generations of scientists, the most notable being his grandfather Antoine-César Becquerel (1788-1878), but also his father, Alexandre-Edmond Becquerel (1820-91), and his son Jean Becquerel (1878-1953). ).
After his first studies at the Lycée Louis-le-Grand, Henri received his formal scientific education at the École Polytechnique (1872-74) and his engineering training at the École des Ponts et Chaussées (School of Bridges and Highways; 77). In addition to his posts of teaching and research, Becquerel was for many years an engineer in the Department of Bridges and Roads, being appointed chief engineer in 1894.
His first academic position was in 1876 as assistant professor in the Polytechnic School, where in 1895 he acceded to the chair of physics. At the same time, he was naturalist assistant to his father at the museum, where he also assumed the chair of physics after his death.
Electricity, magnetism, optical phenomena and energy were important areas of research in physics during the nineteenth century. For several years, the young man’s research focused on the rotation of plane-polarized light by magnetic fields, a theme opened by Michael Faraday to which Henri’s father had also contributed.
Henri then became concerned about infrared radiation, examining, among other things, the spectra of different phosphorescent crystals under infrared stimulation. Of particular importance, he extended his father’s work by studying the relationship between the absorption of light and the emission of phosphorescence in some uranium compounds.
By 1896, Henri was an accomplished and respected physicist, a member of the Académie des Sciences since 1889, but more important than his research, was his experience with phosphorescent materials, his familiarity with uranium compounds and his general skill in laboratory techniques, including photography. All these elements together put the discovery of radioactivity at your fingertips.
At the end of 1895, Wilhelm Röntgen discovered X-rays. Becquerel learned that X-rays emitted from the area of a vacuum glass tube became fluorescent when struck by a beam of cathode rays. He undertook to investigate if there was any fundamental connection between this invisible radiation and visible light, so that all luminescent materials, even if stimulated, would also produce X-rays.
To test this hypothesis, he placed phosphorescent crystals on a photographic plate that had been wrapped in opaque paper so that only a penetrating radiation could reach the emulsion. He exposed his experimental arrangement to sunlight for several hours, stimulating the crystals in the usual way. As it developed, the photographic plate revealed silhouettes of the mineral samples and, in later experiments, the image of a coin or metal cut interposed between the glass and the paper envelope.
Becquerel reported this discovery to the Académie des Sciences in its session of February 24, 1896, noting that certain uranium salts were particularly active.
Therefore, he confirmed his opinion that this luminescent substance emitted something very similar to X-rays while eliminating visible radiation.
henri becquerel atomic theory
But the following week, Becquerel learned that his uranium salts continued to expel penetrating radiation even when they were not made to phosphoresce by ultraviolet in sunlight. To explain this novelty, he postulated a lasting form of invisible phosphorescence; When he briefly described the activity in the metallic uranium, he interpreted it as a unique case of metallic phosphorescence.
During 1896, Becquerel published seven articles on radioactivity, as Marie Curie later named the phenomenon; in 1897, only two and in 1898, none. This was an index of his interest and the interest of the scientific world in the subject; During the period, numerous radiations were studied (eg, cathode rays, X-rays, Becquerel rays or “discharge rays”, radio waves, the visible spectrum, and other luminescent materials); Becquerel’s rays did not seem particularly significant.
X-rays, much more popular, could take pictures of sharper and faster shadows. The extension of radioactivity to another known element was required, thorium in 1898, and the discovery of new radioactive materials, such as polonium and radi, to make the world and Becquerel aware of the importance of its discovery.
Returning to the field he had created, Becquerel made three more important contributions. One was to measure, in 1899 and 1900, the deflection of beta particles, which are a component of radiation in electric and magnetic fields.
From loading to the mass value thus obtained, it showed that the beta particle was the same as the recently identified electron of Joseph John Thomson. Another discovery was the fact that the supposedly active substance in uranium, uranium X, lost its radiation capacity over time, while uranium, although inactive when freshly prepared, finally recovered the lost radioactivity.
When Ernest Rutherford and Frederick Soddy found similar degradation and regeneration in thorium X and thorium, they were led to the theory of the transformation of radioactivity, which explained the phenomenon as a subatomic chemical change in which one element spontaneously transmutes into another .
The last great achievement of Becquerel was the physiological effect of radiation. Others may have noticed this before him, but his report in 1901 about the burn caused by carrying an active sample of Curie’s radio in his pocket, inspired the doctors’ research, which eventually led to its medical use.
For his discovery of radioactivity, Becquerel shared the Nobel Prize in Physics of 1903 with the Curies; He was also honored with other medals and memberships in foreign companies. His own Academy of Sciences elected him president and one of his permanent secretaries.