An immersion therapy that relies on heat transfer by circulating water is an example of which method?

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

Answer: (B)

Convection is heat transfer through a moving fluid. In immersion therapy with circulating water, a pump moves the water around the limb, creating currents that carry thermal energy with the flow. This movement speeds up heat transfer between the water and the tissues, which is why circulating water baths are described as convection—specifically forced convection due to the pump.

Conduction would require heat transfer through direct contact with a solid or a stationary fluid, which isn’t the mechanism here. Radiation transfers heat via electromagnetic waves without a medium, which also isn’t the method in a circulating water bath. Conversion isn’t the standard way we categorize heat transfer in this context.