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

Becquerel was born in Paris into a scientific family which, including him and his son, produced four generations of scientists. He studied science at the École Polytechnique and engineering the École des Ponts et Chaussées. 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. Henri was very interested in Roentgen’s work and wondered if fluorescing minerals would produce the same results. He wrapped a fluorescent mineral, potassium uranyl sulfate, in photographic plates and black material and put them in a drawer because it was cloudy. Instead of seeing what he expected – little to no picture on the plates- we was astounded to see an a fully exposed plate. The minerals had fluoresced without being first exposed to radiant energy! Becquerel had discovered radioactivity – or the spontaneous emission of nuclear radiation, he just didn’t realize it yet! In 1896, Becquerel accidentally discovered radioactivity while investigating phosphorescence in uranium salts. 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, the year of his death, he was elected permanent secretary of the Académie des Sciences. He died at the age of 55 in Le Croisic.

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

External links

• Henri Becquerel - Biography
• About Henri Becquerel
• Becquerel short biography and the use of his name as an unit of measure in the SI