What does conduction refer to in the context of heat transfer?

In the context of heat transfer, conduction specifically refers to the process of heat transfer through direct contact between materials. When two objects at different temperatures come into contact, heat flows from the hotter object to the cooler one until thermal equilibrium is reached. This transfer occurs at the molecular level, where faster-moving particles in the hotter object collide with slower-moving particles in the cooler object, thereby transferring energy.

This mode of heat transfer is significant in various practical applications, such as cooking (e.g., a pot on a stove), heating systems, and materials science. Conductive heat transfer is affected by the thermal conductivity of the materials involved; for instance, metals are good conductors of heat, while insulators like rubber or wood are not.

The other options describe different methods of heat transfer. Heating through the movement of air refers to convection, where heat is transferred via the movement of fluids such as air or water. Heating through radiation involves the transfer of energy as electromagnetic waves, like sunlight warming the Earth. Heating via atmospheric pressure does not accurately describe a method of heat transfer and is not relevant in this context. Thus, conduction is best defined as heating by direct contact.