Steam rising from a teapot demonstrates which heat transfer mode?

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

Answer: (B)

Heat is moving through the air by convection in this scene. The hot steam that forms at the teapot spills upward, and because the steam is hotter and less dense than the surrounding air, it rises and carries energy with it. As the steam moves, it heats the surrounding air, creating a visible plume and ongoing air currents—that’s convection. Conduction would require heat transfer through direct contact with a solid, which isn’t what’s driving the rising plume. Radiation is heat transfer without a medium (like warmth felt from a hot surface), whereas the characteristic movement of hot gas here shows the bulk motion of fluid carrying energy, i.e., convection. Evaporation is the phase change that produces steam, not the mechanism that transports heat through the air.