Heat transfer is the process by which thermal energy moves from an area of higher temperature to an area of lower temperature. This fundamental physical phenomenon occurs through three primary mechanisms: conduction, convection, and radiation. Conduction involves the transfer of heat through direct contact between materials, relying on the vibration and collision of adjacent particles. Convection describes heat transfer through the movement of fluids, where heated, less dense fluid rises and cooler, denser fluid sinks, creating circulation patterns. Radiation is the transfer of heat energy via electromagnetic waves and does not require a physical medium to propagate, allowing heat to travel through a vacuum. The efficiency of heat transfer depends on the material properties, the difference in temperature, and the nature of the physical interaction.