Question

which provides more cooling for a styrofoam cooler, one with 10 lb of ice at 0°c or one with 10 lb of water at 0°c?
multiple choice
the water provides more cooling since it is a better conductor.
the water provides more cooling because water can flow and ice cannot.
both provide the same cooling since they are the same temperature.
the ice provides more cooling because as ice undergoes the solid - to - liquid phase change it absorbs heat.

Explanation:

When ice at \(0^{\circ}C\) melts to water at \(0^{\circ}C\), it absorbs latent heat. This additional heat absorption (compared to just water at \(0^{\circ}C\) which doesn't undergo a phase change) means the ice - water system (with the phase change) can absorb more heat from the surroundings (the cooler's contents), providing more cooling. The conductivity (first option) and flowability (second option) are not the main factors here. Just having the same temperature (third option) ignores the latent heat aspect.

Answer:

The ice provides more cooling because as ice undergoes the solid - to - liquid phase change it absorbs heat.