What mechanism involves the transfer of heat between objects without touching?

The correct mechanism that involves the transfer of heat between objects without any physical contact is radiation. This process occurs when heat energy is emitted in the form of electromagnetic waves, such as infrared radiation, and travels through a medium or even through a vacuum. A classic example of radiation is the warmth one feels from the sun, despite the fact that the sun and a person are not in direct contact.

This is distinct from the other mechanisms listed: conduction, which requires direct contact between materials to transfer heat, involves heat moving through substances like metals; convection, which is the transfer of heat through a fluid (liquid or gas) caused by the movement of the fluid itself, involves warm fluids rising and cool fluids sinking; and evaporation, which is the process of a liquid turning into vapor and does not primarily concern heat transfer but rather a change in state of matter. Hence, radiation is the exclusive method that allows heat transfer without the need for direct contact.