Pails of hot and cold water are set out in freezing weather. Explain how (a) if the pails have lids, the cold water will freeze first, but (b) if the pails do not have lids, it is possible of the hot water to freeze first.

Heat energy will transfer by using three modes; conduction, convection, and radiation. Evaporation is the phase transition from liquid to gas. If more molecules leave the water than return to it, then water gradually evaporates into steam. Colder water freezes slower than hot water. The process of evaporation will be slower case of cold water in the pails that have lids. Due to evaporation, the mass loss in cooling will be very less. That is why the cold water freezes first in the pails which have lids. In the second case the evaporation will be faster case of hot water in the pails without having lids, thus mass loss in cooling will be significant. Therefore hot water freezes first in the pails which have no lids.