What process involves the transfer of heat through direct contact in solids?

The process of heat transfer through direct contact in solids is known as conduction. In conduction, heat moves from the hotter part of a solid to the cooler part through molecular collisions. When one part of a solid is heated, its molecules vibrate more rapidly and collide with adjacent molecules, transferring kinetic energy and thus heat to them. This transfer continues along the material until thermal equilibrium is reached, meaning all parts of the solid are at the same temperature.

For example, if a metal rod is heated at one end, the heat will travel through the rod to the cooler end by conduction. This process is fundamentally different from convection, which involves the movement of fluid (like air or water) that transports heat, or radiation, which involves the transfer of heat through electromagnetic waves without the need for a medium. Evaporation pertains to the process of a liquid turning into vapor and does not relate to heat transfer in solids.