Final answer:
Convection is the process described in the student's question, where heated air is replaced by cooler air, causing a transfer of thermal energy and influencing the temperature of the surroundings.
Step-by-step explanation:
The motion that results from the continual replacement of the heated air in the vicinity of a medium by the cooler air nearby is called convection. Convection is heat transfer by the macroscopic movement of mass, and it can occur in both gases and liquids.
It is driven by the tendency of hotter (less dense) material to rise and colder (denser) material to sink under the influence of gravity. This process can be further enhanced by external means, such as using a fan, which increases the flow of air and thus the rate of heat transfer. In essence, convection involves the transfer of thermal energy from one place to another, facilitating the warming or cooling of a space, as exemplified by its application in forced-air furnaces and weather systems.