What does "conduction" refer to in heat transfer?

In the context of heat transfer, conduction specifically refers to the transfer of heat through solid materials without the movement of the material itself. This process occurs at the molecular level, where energetic particles collide with their neighboring, less energetic particles, transferring kinetic energy and thus heat. For example, when one end of a metal rod is heated, the heat travels to the cooler end through direct contact between the particles in the metal.

The key aspect of conduction is that it relies on the physical contact of particles within a solid substance. Unlike other forms of heat transfer, such as convection (which involves fluid movement) or radiation (which does not require a medium), conduction happens entirely within solid materials. Understanding conduction is crucial for those working in fields like power engineering since it impacts material selection and thermal management in equipment and systems.