In regards to heat transfer, which method works through direct contact?

Conduction is the method of heat transfer that occurs through direct contact between materials. When objects or substances are in direct physical contact, heat energy is transferred from the hotter area to the cooler area until thermal equilibrium is reached. This process happens at the molecular level, where faster-moving (hotter) particles collide with slower-moving (cooler) particles, transferring energy in the process.

Understanding conduction is crucial because it’s the primary means by which heat is transferred in solids. For instance, when you touch a metal rod that has been heated at one end, the heat travels through the rod by conduction as the molecules vibrate and pass on their kinetic energy to adjacent molecules.

In contrast, convection relies on fluid motion (liquids and gases) to transfer heat and is not based on direct contact; radiation allows heat transfer through electromagnetic waves and does not require any medium. Thermodynamics refers to the broader study of heat and energy transfer but does not specify a method of heat transfer. Thus, conduction is distinguished as the method that operates through direct contact between objects.