Which process explains how steam rises from hot water?

Which process explains how steam rises from hot water?

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

Answer: (A)

Rising steam is explained by convection. When water is heated, hot steam becomes less dense than the surrounding cooler air. That buoyancy causes the steam to rise, and the surrounding air moves with it in a convection current. Evaporation explains how steam forms at the surface, but it’s convection that carries the steam upward. Conduction would be heat transfer through direct contact, and radiation is heat transfer by waves, neither of which describes the upward movement of the steam in air.

Rising steam is explained by convection. When water is heated, hot steam becomes less dense than the surrounding cooler air. That buoyancy causes the steam to rise, and the surrounding air moves with it in a convection current. Evaporation explains how steam forms at the surface, but it’s convection that carries the steam upward. Conduction would be heat transfer through direct contact, and radiation is heat transfer by waves, neither of which describes the upward movement of the steam in air.