Final answer:
Atoms release energy when they smash together either through chemical reactions, where energy is released as heat from the formation of new bonds, or through nuclear reactions, where energy is released from nuclear binding energy in the form of heat, light, and radiation.
Step-by-step explanation:
When atoms smash together, they release energy through processes known as chemical reactions and nuclear reactions. In a chemical reaction, energy is usually released as vibrations we recognize as heat, due to the breaking of old bonds and the formation of new, stronger bonds between atoms. On the other hand, nuclear reactions, such as fission or fusion, involve the release of energy from the nuclear binding energy of the atoms, which can manifest in the form of heat, light, and radiation and is typically much more intense than chemical reactions.