Which is an example of convection?

Which is an example of convection?

• A. Direct contact with a hot object
• B. Heat transfer by electromagnetic waves
• C. Evaporation caused by a spray
• D. A turbulent whirlpool; or fluidotherapy

Answer: (D)

Convection is heat transfer by the bulk movement of a fluid. In a turbulent whirlpool or fluidotherapy, warm water or air is circulating around the body part, so the moving fluid carries heat to or from the tissue. The turbulence enhances mixing and heat transfer, which is the hallmark of convection. The other mechanisms operate differently: direct contact with a hot object transfers heat by conduction through molecular contact, heat transfer by electromagnetic waves is radiation, and evaporation involves a phase change at the surface (often with spray). So the turbulent whirlpool or fluidotherapy best illustrates convection because it relies on the moving fluid to transport thermal energy.

Convection is heat transfer by the bulk movement of a fluid. In a turbulent whirlpool or fluidotherapy, warm water or air is circulating around the body part, so the moving fluid carries heat to or from the tissue. The turbulence enhances mixing and heat transfer, which is the hallmark of convection. The other mechanisms operate differently: direct contact with a hot object transfers heat by conduction through molecular contact, heat transfer by electromagnetic waves is radiation, and evaporation involves a phase change at the surface (often with spray). So the turbulent whirlpool or fluidotherapy best illustrates convection because it relies on the moving fluid to transport thermal energy.