Which type of heat transfer does NOT require a medium to travel?

The correct answer is radiation, as it is the only mode of heat transfer that can occur without the need for a physical medium.

Radiation involves the transfer of energy in the form of electromagnetic waves, which can propagate through a vacuum. This is exemplified by the warmth felt from sunlight; even though space is a vacuum, the energy emitted by the sun reaches Earth through radiation.

In contrast, conduction and convection require a medium for thermal energy transfer. Conduction involves heat transfer through direct contact between materials; for example, when you place a metal spoon in a hot pot, heat moves through the spoon via conduction. Convection, on the other hand, involves the movement of fluids (liquids or gases) and relies on the physical properties of the medium to transfer heat, such as the rising of warm air and sinking of cooler air.

Induction is a process primarily associated with the use of electromagnetic fields to produce heat in conductive materials and also does not involve the transfer of heat through a medium in a traditional sense; however, it is a form of heating rather than a fundamental mode of heat transfer like the others.

Thus, radiation stands out as the only method that operates independently of a medium, enabling it to transfer energy through