Which of the following methods involves the transfer of heat by direct molecular contact?

The correct answer is conduction. This method of heat transfer occurs when heat moves through a material as molecules collide with one another. In conduction, the kinetic energy from the hotter region is transmitted to the cooler region through direct contact of particles. For example, if you place a metal spoon in a hot cup of coffee, the heat from the coffee transfers to the spoon through conduction, warming the spoon at the molecular level.

In contrast, convection refers to the transfer of heat through the motion of fluids, where warmer areas of a liquid or gas rise while cooler areas sink, creating circulation. Radiation involves the transfer of heat through electromagnetic waves and does not require any medium, allowing heat to travel through a vacuum, such as the warmth of the sun reaching Earth. A convection current specifically describes the flow patterns created by the convection process, rather than detailing the direct molecular contact seen in conduction. Thus, conduction is unique in its reliance on direct molecular contact for heat transfer.