G2 Gas Fitter Practice Exam

Conduction is the process of heat transfer that occurs through the direct contact between materials. In this context, it specifically refers to how heat moves from particle to particle within a solid or between adjacent solid surfaces that are in direct contact. When one part of a material is heated, the particles in that area begin to vibrate more vigorously. These energetic particles collide with neighboring, cooler particles, transferring some of their energy, which results in the propagation of heat throughout the material.

This explanation highlights the essential mechanism of conduction—energy transfer at the microscopic level through collisions between particles—making option B the right choice. The concept of conduction involves the solid phase primarily, as fluids, such as gases and liquids, typically facilitate heat transfer through convection, while radiation involves the transfer of heat in the form of electromagnetic waves. Thus, while conduction is one mode of heat transfer, it is distinct from these other processes.