Question

if a very hot rock is placed directly on top of a block of ice, what is the best explanation for what will happen?
the rock will get hotter from contact with the ice.
energy will be transferred from the hot rock to the ice through particle collisions.
the ice will melt without touching the rock.
no energy will be transferred unless the rock is also a liquid.

Explanation:

Heat transfer occurs through particle collisions. When a hot rock is in contact with ice, energy (heat) is transferred from the hot rock to the ice via particle - to - particle collisions. This energy transfer causes the ice to melt. The first option is incorrect as heat transfer is from the rock to the ice (so the rock should get cooler, not hotter). The third option is wrong because ice melts when it gains energy (from the rock), and it does not melt without touching the rock (no heat source in that case). The fourth option is incorrect because a rock is a solid (not a liquid in this context), and energy transfer (heat transfer) occurs between the solid rock and solid ice (as long as there is a temperature difference).

Answer:

Energy will be transferred from the hot rock to the ice through particle collisions.