Question

Consider a shallow body of water. Is it possible for this water to freeze during a cold and dry night even when the ambient air and surrounding surface temperatures never drop to \(0^{\circ} \mathrm{C}\) ? Explain.

Short answer

Explain the factors that may affect the freezing process. Answer: Yes, it is possible for a shallow body of water to freeze during a cold and dry night, even if the ambient air and surrounding surface temperatures remain above 0°C. This is because of two main factors: heat transfer through conduction and convection, and evaporative cooling. Heat transfer between the water and the surrounding environment can result in the water losing enough heat to reach the freezing point. Evaporative cooling occurs when water molecules at the surface change from liquid to gas form, drawing energy from the remaining water molecules and cooling them down. The combination of these two factors can lower the water temperature to 0°C, causing the formation of ice.

Step-by-step solution

Consider heat transfer

To analyze the freezing process, we need to think about the heat transfer that occurs between the water, the surrounding air, and surfaces. Even if the air temperature is above 0°C, it can still transfer heat away from the water through conduction and convection. If the water loses enough heat in this process, its temperature can drop to the freezing point.

Consider evaporation

Another important factor to consider is evaporation, which can also cool the water. Water molecules at the surface can change from liquid to gas form (vapor), escaping into the surrounding air. This process requires energy, which is taken from the remaining water molecules, cooling them down. If the night is dry, the relative humidity is lower, and evaporation is more likely to occur, further cooling the water.

Analyze the combination of heat transfer and evaporation

The combination of heat transfer through conduction and convection and evaporative cooling can lead to the water temperature dropping to 0°C, even if the ambient air and surrounding surface temperatures are above 0°C. As heat is lost due to these processes, it is possible for the water temperature to reach the freezing point, causing the formation of ice.

Conclusion

In conclusion, it is possible for a shallow body of water to freeze during a cold and dry night, even when the ambient air and surrounding surface temperatures never drop to 0°C. This is because heat transfer through conduction and convection and evaporative cooling can work together to lower the water temperature to the point of freezing.