6.3 Heat Transfer and Thermal Equilibrium

Explain the relationship between the transfer of thermal energy and molecular collisions.

• The particles in a warmer body have a greater average kinetic energy than those in a cooler body.
• Collisions between particles in thermal contact can result in the transfer of energy. This process is called “heat transfer,” “heat exchange,” or “transfer of energy as heat.”
• Eventually, thermal equilibrium is reached as the particles continue to collide. At thermal equilibrium, the average kinetic energy of both bodies is the same, and hence, their temperatures are the same.