Which type of heat transfer involves the movement of fluid?

Convection is the type of heat transfer that specifically involves the movement of fluid. This process occurs when a fluid, such as a liquid or gas, is heated and then circulates, effectively transferring heat from one part of the fluid to another. When parts of the fluid are heated, they tend to rise, while cooler, denser parts sink, creating a continuous circulation pattern. This motion plays a crucial role in heating and cooling processes, such as in boilers, where hot water or steam circulates through a heating system, ensuring even heat distribution.

In contrast, radiation refers to heat transfer through electromagnetic waves and does not require a medium, meaning it can occur even in a vacuum. Conduction describes heat transfer through direct contact between materials without fluid movement, primarily occurring in solids where heat is passed from molecule to molecule. Absorption pertains to the uptake of energy by a material, which may involve the conversion of various forms of energy but is not fundamentally about the movement of fluid. Each of these other forms of heat transfer has its unique mechanisms and applications, but convection is specifically characterized by the movement of fluids.