In thermal conduction, heat transfer occurs between which of the following?

• A. Two solid materials that are touching each other
• B. Liquids in different containers
• C. Gases in different pressure zones
• D. Water and air

Answer: (A)

In thermal conduction, heat transfer occurs specifically between materials that are in direct contact with each other. When two solid materials come into contact, molecules in the hotter object vibrate more rapidly due to higher thermal energy and collide with neighboring molecules in the cooler object. This transfer of kinetic energy ultimately causes the cooler object to increase in temperature as it absorbs heat from the hotter material.

While heat transfer can occur through other methods, such as convection in liquids and gases or radiation across distances, thermal conduction is distinct in that it relies on direct contact between solids. Thus, the interaction between the two solid materials that are touching directly facilitates the transfer of heat energy through their molecules.