What defines conduction in heat transfer?

Conduction in heat transfer is defined as the transfer of energy through direct contact between materials. This process occurs at the microscopic level, where faster-moving particles in a hotter region collide with slower-moving particles in a cooler region, transferring kinetic energy in the form of heat. This mode of heat transfer is highly efficient in solids, particularly metals, where particles are closely packed together, allowing for effective energy transfer.

In contrast, the movement of fluids relates to convection, where heat is transferred through the movement of a fluid (liquid or gas) caused by differences in temperature and density. Thermal radiation involves the transfer of energy through electromagnetic waves and does not require a medium, making it distinct from conduction. The generation of sound waves has no relation to heat transfer mechanisms, as sound is associated with pressure waves traveling through a medium rather than the transfer of thermal energy. This understanding solidifies conduction as solely reliant on physical contact between materials.