What process involves the direct transfer of heat between objects in contact?

Conduction is the process that describes the direct transfer of heat between objects that are in physical contact with each other. In conduction, heat energy moves from the hotter object to the cooler object until thermal equilibrium is reached. This occurs at the molecular level as the high-energy molecules in the hotter substance collide with the lower-energy molecules in the cooler substance, transferring kinetic energy in the process.

Understanding conduction is vital in fire investigations because it plays a significant role in how fires spread, especially in solid materials. For example, when a fire starts in a room, the heat could be conducted through walls or furniture, causing subsequent materials to ignite even if they are not directly exposed to open flames.

The other processes, such as convection and radiation, involve different mechanisms of heat transfer. Convection involves the movement of fluid (liquid or gas) and the carrying of heat with it, while radiation refers to the transfer of heat through electromagnetic waves without the need for a medium. Distillation, on the other hand, is a separation process based on differences in boiling points and is not related to the transfer of heat between physical objects.