Which method of heat transfer relies on the movement of fluids?

Convection is the method of heat transfer that specifically relies on the movement of fluids, which can be either liquids or gases. In convection, heat is transferred as the fluid moves, carrying energy with it. This process can occur in natural forms, such as warm air rising and cooler air descending in the atmosphere, or in forced convection, such as when a fan circulates air in a room.

In contrast, conduction is the transfer of heat through direct contact between materials without any movement of the materials themselves; it occurs in solids where heat is passed from one particle to another through collisions. Radiation involves the transfer of heat in the form of electromagnetic waves, such as infrared radiation, and does not require any medium for the heat to travel, unlike convection which specifically involves the movement of fluid to transfer heat. The option that combines conduction and convection lacks specificity since it suggests a method that incorporates varied principles, while convection distinctly focuses on fluid movement.