Final answer:
In convection, warmer material rises and colder material sinks, transferring energy. Hot air is less dense than cold air, causing it to rise and creating buoyancy.
Step-by-step explanation:
In convection, warmer material rises and colder material sinks, transferring energy. Hot air is less dense than cold air, which causes it to rise and creates buoyancy. This movement of mass is driven by buoyant forces and is responsible for the flow of air during convection.