What does conduction refer to?

Conduction refers to the transfer of heat through direct contact between materials. This process occurs at the molecular level, where kinetic energy is passed from one molecule to another when they are in contact. For instance, when one end of a metal rod is heated, the molecules at that end begin to vibrate more rapidly. These vibrations are transmitted through the rod as neighboring molecules collide with each other, effectively transferring heat along the length of the rod.

This mechanism is distinct from other forms of heat transfer. Convection, for example, involves the movement of fluids (liquids or gases) and does not occur via direct contact, as it relies on the bulk movement of the fluid itself to distribute heat. Radiation, meanwhile, is the transfer of energy in the form of electromagnetic waves and does not require a medium, allowing heat to be transferred through the vacuum of space. The concept of heat retention in solids speaks to the ability of a material to hold or store thermal energy, but it does not define the process of conduction itself. Understanding conduction is essential in various applications, from cooking to materials science, where heat transfer plays a critical role.