The transfer of heat by the movement of a fluid is called what?

The transfer of heat by the movement of a fluid is called what?

• A. Evaporation
• B. Radiation
• C. Conduction
• D. Convection

Answer: (D)

Convection is heat transfer by the movement of a fluid. When a fluid is heated, it becomes less dense and rises, while cooler fluid sinks, setting up a circulating flow that carries thermal energy from hotter to cooler regions. This can happen naturally, like warm air rising above a heater, or be forced by a fan or pump. In contrast, conduction transfers heat through direct contact without bulk fluid motion, and radiation moves heat through electromagnetic waves independent of the fluid. An everyday example of convection is boiling water, where heat from the bottom creates currents that move warmer water upward and cooler water downward, spreading heat through the liquid.

Convection is heat transfer by the movement of a fluid. When a fluid is heated, it becomes less dense and rises, while cooler fluid sinks, setting up a circulating flow that carries thermal energy from hotter to cooler regions. This can happen naturally, like warm air rising above a heater, or be forced by a fan or pump. In contrast, conduction transfers heat through direct contact without bulk fluid motion, and radiation moves heat through electromagnetic waves independent of the fluid. An everyday example of convection is boiling water, where heat from the bottom creates currents that move warmer water upward and cooler water downward, spreading heat through the liquid.