Which form of heat transfer requires physical contact?

The correct choice is conduction, which is the form of heat transfer that requires direct physical contact between materials for the transfer to occur. When two objects are in contact and vary in temperature, heat transfers from the hotter object to the cooler one until thermal equilibrium is achieved. This process is exemplified by touching a hot stove or a metal spoon placed in a hot pot; the heat from the stove or the hot liquid transfers to the material of the spoon solely through direct contact.

In contrast, convection involves the movement of fluids (liquids and gases) and the transfer of heat through the bulk movement of the fluid itself, not through direct contact. This occurs, for example, when warm air rises and cooler air descends, creating a circulation pattern.

Radiation refers to the transfer of heat in the form of electromagnetic waves, such as the heat from the sun reaching the earth without the need for a medium or direct contact.

Evaporation is the process wherein liquid changes into vapor, resulting in cooling, again without the necessity of physical contact for heat transfer, as it occurs when the molecules at the liquid's surface gain enough energy to transition to the gaseous state.

Thus, conduction is distinct due to its requirement for physical contact between substance