Which method of heat transfer occurs through direct contact between objects?

• A. Radiation
• B. Conduction
• C. Convection
• D. Evaporation

Answer: (B)

Conduction is the heat transfer that happens through direct contact between objects. When a hotter object touches a cooler one, its faster-moving particles collide with the cooler object's particles, transferring some of their energy. This transfer continues until both objects reach similar temperatures. That’s why a metal spoon left in hot soup gets warm all the way to the handle—the heat travels through the spoon by direct contact. Metals are especially good at conducting heat because their particles and free electrons move energy efficiently.

In contrast, radiation transfers heat without touching—energy moves as waves from the hot object to the cooler one. Convection involves the movement of fluids carrying heat with the flow, not direct contact. Evaporation is a phase-change process that uses energy to change a liquid to vapor, rather than a direct contact mechanism for moving heat between objects.