Breaking apart of a body into smaller fragments. In nuclear physics, fission refers to splitting of a heavy atomic Core of an atom, where nearly the entire mass and all positive charge is concentrated. It consists of protons and neutrons. into two or more lighter nuclei with an associated release of energy. The mass of the nucleus before fission is greater than the combined masses of the resulting fragments; the mass difference (Δm) is released as energy:
E = Dmc2
Some or all content above used with permission from J. H. Wittke.