what is fission

Fission is a nuclear reaction in which the nucleus of an atom splits into two or more smaller nuclei. This process often produces gamma photons and releases a large amount of energy. Fission is a form of nuclear transmutation because the resulting fragments are not the same element as the original parent atom. The two or more nuclei produced are most often of comparable but slightly different sizes, typically with a mass ratio of products of about 3 to 2, for common fissile isotopes. Fission produces energy for nuclear power and drives the explosion of nuclear weapons. Uranium and plutonium are most commonly used for fission reactions in nuclear power reactors because they are easy to initiate and control. When each atom splits, a tremendous amount of energy is released, which heats water into steam. The steam is used to spin a turbine to produce carbon-free electricity.