The sun warms the ground. A hot oven warms a cold kitchen. A campfire warms a person's hands. Hot soup warms a metal spoon handle.
I gave my students this multiple choice question: Heat transfer is part of everyday life. Which of these examples involving heat transfer occurs mainly by conduction?

Only one answer is correct among these 4 choices:
- The sun warms the ground.
- A hot oven warms a cold kitchen.
- A campfire warms a person's hands.
- Hot soup warms a metal spoon handle.

Could you tell me which one is correct?

Hot soup warms a metal spoon handle.