What is the primary process by which thermal energy is transferred in conduction?

The primary process of thermal energy transfer in conduction occurs through direct contact between solid objects. Conduction involves the transfer of heat through a material without the movement of the material itself. When two solids are in contact, the particles of the hotter object vibrate more quickly due to higher thermal energy. These fast-moving particles collide with the adjacent slower-moving particles of the cooler object, transferring some of their energy in the process. This transfer continues from particle to particle along the material until thermal equilibrium is reached.

In contrast, options related to the movement of liquids, the passing of infrared rays, and air currents pertain to other modes of heat transfer. Liquids can transfer heat via convection, which involves the bulk movement of the liquid. Infrared radiation is associated with the transfer of energy through electromagnetic waves, typically involving gases or vacuums rather than direct contact. Air currents can also lead to heat distribution, but this describes convection, a different mechanism than conduction. Thus, direct contact between solid objects is fundamental to the conduction process specifically.