Briefly distinguish between nuclear fission and nuclear fusion.

Nuclear Fission is the splitting of an atom such as Uranium-238 by bombarding it with neutrons. Two or more smaller nuclei and additional neutrons are produced during fission. The neutrons set off a chain reaction which results in the emission of enormous amounts of energy. These reactions have been used in nuclear reactors and in atom bombs.
Nuclear fusion is the combination of two lighter nuclei to produce a heavier nucleus. Nuclear fusion results in the production of enormous amounts of energy. These reactions have been used in hydrogen bombs. However, scientists have not been able to successfully harness nuclear fusion to produce electrical energy.