Question 1 Report
Four solid rods, each a different metal, project from the side of a tank of boiling water. A small ball is stuck near the free tip of every rod with candle wax. As energy travels along the rods the wax softens and the balls drop off. Which ball is the last to fall off?
The correct answer is the ball on the steel rod. Steel is the poorest conductor of the four metals, so energy travels along it most slowly and its wax takes longest to soften, making its ball the last to drop. Copper is the best conductor and its ball falls first, with brass and iron falling before steel.
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