Few processes of nature have had so great an impact on the course of history in the twentieth century as nuclear fission. Its discovery led almost immediately to bomb projects in several countries.
Uranium is a hard, dense, malleable, ductile, silver-white, radioactive metal of the actinide series in Group 3 of the periodic table. Uranium has three distinct forms (see allotropy); the orthorhombic crystalline structure occurs at room temperature.
Or A-bomb, weapon deriving its explosive force from the release of atomic energy through the fission (splitting) of heavy nuclei (see nuclear energy). The first atomic bomb was produced at the Los Alamos, N.Mex., laboratory and successfully tested on July 16, 1945.
The wartime effort to design and build the first nuclear weapons (atomic bombs). With the discovery of fission in 1939, it became clear to scientists that certain radioactive materials could be used to make a bomb of unprecedented power.
The energy stored in the nucleus of an atom and released through fission, fusion, or radioactivity. In these processes a small amount of mass is converted to energy according to the relationship E = mc2, where E is energy, m is mass, and c is the speed of light.
