sentence: Fusion is the source of heat in the sun.
sentences_before: Nuclear fusion is the combining of two atoms into one and nuclear fission is the splitting of an atom. Both ways make big amounts of energy. They sometimes take place in nature.
sentences_after: Fission is also used in nuclear power plants to make electricity. Both fusion and fission can be used in nuclear weapons.
concept_name: fusion
headings: Nuclear energy
categories: Nuclear energy