The movement of fluid due to temperature differences is called?

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

Answer: (A)

When fluids move because of temperature differences, heat is transferred by convection. Warm regions become less dense and rise, while cooler regions are denser and sink, creating a circulating flow called a convection current. This is how heat moves through water in a pot or air in a room heated by a radiator.

Conduction would be heat transfer through direct contact with no large-scale fluid motion. Radiation is heat transfer by electromagnetic waves and doesn’t require a medium. Evaporation involves a surface phase change and isn’t about bulk fluid movement due to temperature-induced density differences.