The heating of a spoon in a cup of soup is heat transfer by:

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

Answer: (A)

Heat transfer by conduction is at work when a spoon in hot soup gets warm. It happens through direct contact—energy moves from the hotter soup molecules to the cooler spoon surfaces they touch. In a metal spoon, free electrons also shuttle that energy quickly along the spoon, warming it throughout. Radiation would rely on energy traveling as infrared waves from the soup to the spoon, but the direct touch is the main path here. Evaporation involves liquid turning into vapor and isn’t how the spoon gains heat. Convection refers to heat moving with the fluid itself, which can heat the soup, but the spoon’s heating comes primarily from conduction at the contact surface.