What are the three types of heat transfer in physical science?

The correct identification of the three types of heat transfer—convection, conduction, and radiation—is rooted in the fundamental principles of thermodynamics.

Convection involves the transfer of heat through fluids (liquids and gases) by the movement of the fluid itself. As a fluid is heated, it becomes less dense and rises, allowing cooler fluid to take its place, thereby creating a circulation pattern. This is commonly observed in boiling water or atmospheric weather patterns.

Conduction refers to the transfer of heat through direct contact between materials. It occurs at the molecular level, where faster-moving molecules collide with slower-moving ones, transferring energy. A classic example is a metal spoon becoming warm when placed in a hot pot of soup.

Radiation is the transfer of heat in the form of electromagnetic waves, primarily infrared radiation. Unlike convection and conduction, which require a medium to transfer heat, radiation can occur through a vacuum—such as the heat from the sun reaching the Earth.

These three mechanisms—convection, conduction, and radiation—are fundamental to understanding how heat energy moves in various environments and play a critical role in fire dynamics and investigation.