The Co-Discoverer of Radiation
Henri Becquerel was born in Paris, France on December 15, 1852 into an illustrious scientific family, which produced four generations of scientists. He studied history at the École Polytechnique and engineering at 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 1896, while investigating the work of Wilhelm Conrad Röntgen and phosphorescence in uranium salts, Becquerel accidentally discovered radioactivity. Becquerel wrapped a fluorescent substance potassium uranyl sulfate in photographic plates and black material in preparation for an experiment requiring bright sunlight. Prior to actually performing the experiment, however, Becquerel found that the photographic plates were already exposed, showing an image of the substance. This discovery led Becquerel to investigate the spontaneous emission of nuclear radiation. In 1903 he shared the Nobel Prize in Physics with Marie and Pierre Curie for his pioneering work on radiation. It was Madame Marie Curie who is credited with coining the word radiation.
Today the becquerel (symbol Bq) (pronounced: ‘be-kə-rel) is the SI-derived unit of radioactivity. One Bq is defined as the activity of a quantity of radioactive material in which one nucleus decays per second. Bonne Anniversaire, Henri!
Image of Henri Becquerel by Paul Nadar, image in the public domain.
