Which description matches conduction?

• A. The transfer of heat energy by direct contact
• B. The movement of heat energy through the motion of matter such as steam or hot air
• C. The transfer of energy with the help of electromagnetic waves
• D. The conversion of thermal energy into mechanical work

Answer: (A)

Conduction is heat transfer through direct contact, where energy moves from one object to another or within a material as particles collide and pass kinetic energy along. It happens most readily in solids, like a metal spoon warming when it sits in a hot pot, but it also occurs in liquids and gases. In contrast, convection involves heat transfer carried by the bulk motion of a fluid (like warm air rising or steam circulating), radiation is heat transfer by electromagnetic waves (no direct contact needed), and converting thermal energy into mechanical work is about energy conversion, not the transfer of heat.