We pack two identical coolers for a picnic, placing 24 12-ounce soft drinks and five pounds of ice in each. However, the drinks that we put into cooler A were refrigerated for several hours before they were packed in the cooler, while the drinks that we put into cooler B were at room temperature. When we open the two coolers three hours later, most of the ice in cooler A is still present, while nearly all of the ice in cooler B has melted. Explain this difference.

Key Concepts

Heat Transfer

Heat transfer is the process by which thermal energy moves from one object to another due to a temperature difference. In this scenario, the warmer drinks in cooler B transfer heat to the ice, causing it to melt more quickly. In contrast, the colder drinks in cooler A have less thermal energy to transfer, allowing the ice to remain solid for a longer period.

Specific Heat Capacity

Specific heat capacity is the amount of heat required to raise the temperature of a unit mass of a substance by one degree Celsius. The drinks in cooler A, being pre-cooled, have a lower initial temperature, which means they require less heat to reach equilibrium with the surrounding environment. This property helps maintain the ice's solid state longer in cooler A compared to the warmer drinks in cooler B.

Phase Change and Latent Heat

Phase change refers to the transition of a substance from one state of matter to another, such as from solid to liquid. Latent heat is the energy absorbed or released during this process without a change in temperature. In cooler B, the ice absorbs a significant amount of heat from the warmer drinks to melt, while in cooler A, the ice absorbs less heat due to the lower temperature of the drinks, resulting in less melting.