During which process does heat transfer occur because of density differences in water or air?
A. Conduction
B. Pollution
C. Radiation
D. Convection
2. Explain your answer.
Explanation: As water's temperature increases in the presence of a heat source, it will become less dense and rise. As it moves up and away from the heat source, it cools and becomes denser and sinks.
Convection occurs due to the differences in density, and only happens in gases or liquids. The heat is transferred by the movement of a heated fluid, which is air or water.
