Heat transfer without a medium, such as through space, is called what?

Heat transfer without a medium, such as through space, is called what?

• A. Conduction
• B. Convection
• C. Evaporation
• D. Radiation

Answer: (D)

Heat transfer without a medium occurs via radiation, which is the emission and absorption of electromagnetic waves. This lets energy travel through empty space, like the Sun warming Earth through vacuum. Conduction needs direct contact between materials, and convection relies on moving fluids, so they don’t happen in space. Evaporation is a phase change, not a transport mode. Objects radiate energy based on their temperature (and how easily they emit), so hotter bodies send out more radiation. This is why radiation is the proper term for heat moving through space.

Heat transfer without a medium occurs via radiation, which is the emission and absorption of electromagnetic waves. This lets energy travel through empty space, like the Sun warming Earth through vacuum. Conduction needs direct contact between materials, and convection relies on moving fluids, so they don’t happen in space. Evaporation is a phase change, not a transport mode. Objects radiate energy based on their temperature (and how easily they emit), so hotter bodies send out more radiation. This is why radiation is the proper term for heat moving through space.