When does the most evaporation take place: on a hot, windy day or on a hot, still day and why?
1 Answer
Hot windy day
Explanation:
Evaporation is the movement of water from the liquid phase to the gaseous phase below the boiling point. The average kinetic energy of the water molecules is below the level needed to escape the attraction to the other water molecules. There are a number of molecules that have greater than the average kinetic energy, these molecules can escape the attraction of the other water molecules and become a gas.
On a still day the molecules with a higher than average kinetic energy that become a gas will collide with one another. Some of the molecules that had become a gas will lose kinetic energy and become a liquid again falling back down into the liquid water below.
On a windy day the molecules with a higher than average kinetic energy will be carried away from the liquid water. There will be fewer gaseous water molecules in air above the water to collide with each other. This means that more molecules will be able to evaporate and fewer will return to the liquid state.
On a still day evaporation will occur at the same rate as a windy day but the reverse reaction of molecules returning to the liquid state will be much higher on a still day than on a windy day. The result is that the amount of evaporation will be greater on a windy day.
