Nuclear reactions change the nuclei of atoms. There are many different types of Nuclear reactions.
- Radioactive decay is when a radioactive atom spontaneously changes, releases one or more radioactive particles and/or photons and becomes a different type of atom which may be stable or radioactive.
- Neutron capture is when an atom absorbs a neutron and may become radioactive.
- Nuclear fission is when an atom splits into two smaller atoms and energy is released. The best known cases of nuclear fission are when Uranium or Plutonium split releasing energy to power nuclear power stations or Nuclear weapons.
- Nuclear fusion is when more than one atom, almost certainly two at a time combine to form a heavier atom. All atoms heavier than hydrogen have come into being through nuclear fusion. If the combining atoms are lighter than iron nuclear fusion releases energy. Nuclear fusion powers the sun and other stars, nuclear fusion also powers the hydrogen bomb.