Which process involves the transfer of heat through direct contact?

The process of heat transfer through direct contact is known as conduction. This occurs when two materials at different temperatures come into contact with each other, allowing thermal energy to flow from the hotter object to the cooler one. Conduction is fundamentally dependent on the physical contact between the materials; heat moves through the material as particles collide and transfer kinetic energy.

For example, when a metal rod is heated at one end, the heat travels through the rod to the cooler end via conduction, as the atoms in the metal vibrate and collide with neighboring atoms, passing energy along the rod.

In contrast, radiation refers to the transfer of heat in the form of electromagnetic waves (like infrared radiation) and does not require a medium. Convection involves the movement of fluids (liquids or gases) where warmer areas of a liquid or gas rise and cooler areas sink, creating a circulation pattern. Sublimation is a phase transition where a substance changes from a solid to a gas without passing through the liquid phase and is not related to heat transfer mechanisms like conduction does.

Understanding these distinctions clarifies why conduction is the appropriate term for heat transfer through direct contact.