What is convection?

Convection is the transfer of heat through the movement of fluids, which can be either liquids or gases. This process occurs when warmer, less dense portions of a fluid rise while cooler, denser portions sink, creating a cycle of movement that distributes heat throughout the fluid.

This is different from conduction, which involves heat transfer through direct contact between materials, where energy moves from one object to another without the movement of the material itself. Additionally, convection can involve the circulation of air based on temperature differences, but it is a broader concept that specifically focuses on the movement of fluids as a method for heat transfer. Lastly, the transfer of energy through electromagnetic waves refers to radiation, which does not involve the movement of matter in the same way as convection does.

Therefore, the definition that encompasses the essential characteristics of convection is indeed the transfer of heat through the movement of fluids.