Which type of heat transfer involves the movement of air or liquid?

Convection is the type of heat transfer that involves the movement of air or liquid. This process occurs when a fluid, which can be either a gas or a liquid, is heated and becomes less dense, causing it to rise. As it rises, cooler, denser fluid moves in to take its place, creating a cycle. This process is commonly observed in everyday situations, such as when heating water in a pot or feeling warm air from a heater circulate in a room.

In the context of firefighting, understanding convection is crucial, as it can contribute to the spread of fire and smoke. Hot gases generated during a fire rise and can transport heat to other areas, potentially igniting materials that are not in direct contact with the flames. By recognizing the principles of convection, firefighters can better strategize their approach to controlling and extinguishing fires.