Define radiation.The transfer of heat:through a solidby the flow of a liquid or gasfrom hot objects but not cold objectsby the movement of waves, not particles

Radiation is a method of heat transfer that does not require a medium (like solid, liquid, or gas) to occur, unlike conduction and convection. It involves the emission and absorption of electromagnetic waves, primarily in the infrared spectrum. This means that heat can be transferred through the vacuum of space, as is the case with energy received from the Sun.

In contrast to conduction, where heat moves from one molecule to another through direct contact, and convection, where heat is transferred by the movement of fluid, radiation can occur even in the absence of matter. In the context of heat transfer, radiation is characterized by the emission of energy in the form of electromagnetic waves, which can be absorbed by other bodies, increasing their thermal energy.

The nature of radiation allows it to heat objects at a distance and to play a significant role in energy exchanges in various environmental contexts, such as in the warming of the Earth by solar radiation.