In this short seminal article, Lise Meitner and Otto Frisch propose nuclear fission to explain the experimental results of neutron bombardment of uranium conducted by Otto Hahn and Fritz Straussmann. The authors use a liquid drop model of the nucleus to explain how uranium splits into the barium observed by Hahn and Straussmann. They further calculate the energy released in that process as about 200 Mev, the energy difference expected from the difference in mass between the uranium atom and the elements in the middle of the periodic table produced by the fission reaction.