Private Pilot Private Exam

Which processes add moisture to unsaturated air?

1. Condensation and precipitation

2. Evaporation and sublimation

3. Transpiration and absorption

4. Retroflection and evaporation

The correct answer is: Evaporation and sublimation

Evaporation and sublimation are processes that indeed add moisture to unsaturated air. When water evaporates, it changes from a liquid state to a gas (water vapor), increasing the amount of moisture in the air. Sublimation, on the other hand, is the process where ice or snow transitions directly into vapor without first becoming liquid, also contributing to the moisture content of the air. Both processes play a significant role in the natural water cycle, replenishing atmospheric moisture and influencing weather patterns. The other processes, while they may involve water, do not add moisture to unsaturated air in the same way. Condensation occurs when water vapor cools and changes back into liquid, thus not contributing to the moisture content of the unsaturated air but rather reducing it. Precipitation, such as rain or snow, also removes moisture from the atmosphere. Transpiration and absorption relate to how plants release and take up water, but they are not primary processes that add moisture directly to the surrounding air. Retroflection does not pertain to moisture processes in this context, making the selection of evaporation and sublimation the best choice for adding humidity to unsaturated air.