What process involves heat transfer without physical contact?

Radiation is the correct answer because it refers to the transfer of heat through electromagnetic waves, which can occur without the need for any physical medium, such as air or water. Unlike conduction, which requires direct contact between materials for heat transfer, and convection, which needs a fluid medium to circulate heat, radiation can transfer energy through empty space. A common example of radiation is the warmth felt from the sun, where heat energy travels through the vacuum of space and heats objects upon contact. This principle plays a crucial role in understanding various applications in exercise science and physiology, particularly in how the body dissipates heat during physical activity and how environmental factors can affect performance.