Which heat transfer mode involves heat passing through a solid material?

• A. Heat passes through material.
• B. Heat transfer by movement of gas or liquid due to pressure difference.
• C. Heat transfer by electromagnetic waves.
• D. Heat stored as chemical energy.

Answer: (A)

Conduction is heat transfer through a solid by direct contact of its particles. When one part of a solid gets hotter, its particles have more energy and collide with neighboring particles, passing some of that energy along. This lets heat move from the hot region to the cooler region inside the solid without the material itself moving. The other modes involve different mechanisms: convection relies on the bulk movement of a fluid, radiation uses electromagnetic waves to carry energy, and storing heat as chemical energy isn’t a transfer mechanism at all.