This Day in History: 1938-12-17

Nuclear fission discovered On this day in 1938, German scientists Otto Hahn and Lise Meitner performed a crucial experiment that showed it was possible to transform one element (in this case uranium) into another (barium). The experiment, conducted in Sweden (Hahn and Meitner had fled Jewish persecution in Germany) helped focus other work in nuclear chemistry. After WWII, Hahn joined other scientists in demanding controls on nuclear weapons.