Which term refers to the transfer of heat from one molecule to another or through one substance to another?

The term that refers to the transfer of heat from one molecule to another or through one substance to another is conduction. This process occurs when heat is transferred through direct contact between materials or within a single material. When molecules of a substance are heated, they vibrate more vigorously and pass their kinetic energy to neighboring molecules. This direct transfer occurs best in solids, where the closely packed molecules facilitate the efficient conduction of heat.

In contrast, radiation involves the transfer of heat through electromagnetic waves, which can happen in a vacuum and does not require a physical medium. Convection refers to the transfer of heat by the movement of fluids (liquids and gases), where hot fluid rises and cooler fluid sinks, creating a circulation pattern. Thermal diffusion generally refers to the broader process of heat spreading through materials or systems and can involve a combination of conduction, convection, and radiation, but it is not as specific as conduction when discussing heat transfer directly between molecules.