French physicist who was the son of physicist Edmond Becquerel, and father of physicist Jean Becquerel. In 1896, while investigating fluorescence Eric Weisstein's World of Physics in uranium salts, he accidentally discovered radioactivity Eric Weisstein's World of Physics in uranium-containing pitchblende by noting that the photographic plate upon which the pitchblende had been resting was fogged. Although he initially believed this to be a luminescence Eric Weisstein's World of Physics effect, his subsequent dissolving of the salt and recrystallization in total darkness showed that the luminescence Eric Weisstein's World of Physics was not involved. He also discovered that all uranium compounds (not just specific salts) fogged the plates, unlike luminescence Eric Weisstein's World of Physics which was confined to particular salts. The full impact of Becquerel's discovery was not appreciated, however, until the work of Marie and Pierre Curie, with whom he shared the 1903 Nobel Prize in physics.