What phenomenon is classified as an explosion?

The phenomenon classified as an explosion is best represented by the release of light and heat. When an explosion occurs, it typically involves a rapid and violent release of energy that generates a significant amount of heat and light. This transformation of energy can be the result of a chemical reaction, often involving the combustion of materials, but the defining characteristic of an explosion is the instantaneous nature of the energy release, which is observed in the intense light and heat produced.

While combustion itself can lead to explosions under certain conditions, such as when pressure builds up or in confined spaces, it is not solely definitional of an explosion. Similarly, the release of gas or sound wave transmission may occur during explosive events but do not encapsulate the essence of what constitutes an explosion. Therefore, the release of light and heat serves as the most direct indication and observable consequence of an explosion.