Related Terms. Ratio of the density of a substance at 20Â°C or 68Â°F to the density of water at 4Â°C or 39.2Â°F.
Nuclear fission. NUCLEAR FISSION. Nuclear fission is a reaction in which an atom's nucleus is broken apart, releasing a tremendous amount of energy. Nuclear fission is used in many power plants on Earth (and is used in atomic weapons). nuclear fission: Reaction that splits nuclei into less massive fragments.nuclear fusion: Reaction that joins the nuclei of atoms to form more massive nuclei. - (n.). The splitting of an atomic nucleus into two large fragments. nuclear fusion - (n.) ... ~ reactors naturally produce free neutron s; their role is to sustain the energy-producing chain reaction.
During induced nuclear fission, the heavy nucleus (as uranium-235 and/or plutonium-239) is split through bombardment with a neutron into two (or less frequently three) fragments plus emitting 2-3 neutrons.n nuclear physics and nuclear chemistry, nuclear fission is a nuclear reaction in which the nucleus of an atom splits into smaller parts, often producing free neutrons and lighter nuclei, which may eventually produce photons (in the form of gamma rays).