What is the process of heat transfer through direct contact called?

The process of heat transfer through direct contact is known as conduction. This occurs when molecules in a substance collide with one another, transferring thermal energy from the hotter areas to the cooler areas. For example, when a metal spoon is placed in a hot pot of soup, the heat from the soup is transferred directly to the spoon through conduction, making the spoon feel warm to the touch.

In conduction, the energy transfer takes place between solids, liquids, or gases when they are in direct contact. Unlike convection, which involves the movement of fluids and the transfer of heat through the mass movement of the fluid itself, and radiation, which involves the transfer of heat in the form of electromagnetic waves through space without requiring a medium, conduction is strictly about physical contact. Diffusion, on the other hand, describes the spread of particles from areas of higher concentration to areas of lower concentration, which is distinct from heat transfer processes. Understanding conduction is essential in fire inspection and safety as it plays a significant role in the behavior of materials under heat and fire conditions.