What form of energy is involved in the processes of fusion and fission?

Fusion and fission are nuclear processes that involve significant transformations of atomic nuclei, which is the source of nuclear energy. In fusion, lighter atomic nuclei combine under extreme temperature and pressure to form a heavier nucleus, releasing energy in the process. This is the principle that powers stars, including our sun. In fission, a heavier nucleus splits into lighter nuclei, accompanied by the release of energy. This process is harnessed in nuclear reactors and atomic bombs.

Both of these processes fundamentally alter the structure of atomic particles, leading to energy release that is quantified and harnessed as nuclear energy. This type of energy is vastly greater than chemical energy, which involves electron arrangements rather than nuclear transformations. Gravitational potential energy and mechanical energy pertain to different types of physical interactions and movements, which do not directly contribute to the energy changes that fusion and fission experience.