The cloud is a mass of products of condensation of water vapor weighed in air. Drops of water and pieces of ice at the same time or separately can be a part of a cloud. Clouds are an important part of world water cycle.
Instruction
1. The water which is on the earth in reservoirs and the soil when heating by sunshine evaporates and passes into air. Thus, the big mass of the air saturated with water vapor rises up, at the same time the speed of rise is so high, and the volume of air is so big that it does not exchange heat with the environment, that is process can be considered adiabatic.
2. The rising air extends, and adiabatic expansion leads to its cooling. Thus, at a certain height air becomes so cold that condensation of water vapor can begin. Condensation can begin at a different temperature, everything depends on the number of the centers of condensation. Therefore clouds can appear also at low heights, and at big height.
3. While air rises above condensation border, the cloud continues to grow and stops the growth only when new damp air from below ceases to arrive. Two borders of a cloud - lower on which condensation, and the top, maximum height up to which damp air rose begins result.
4. So, rise in big mass of damp air is the cause of clouds. Rise can happen for several reasons: Because of convection which arises because the lower layers of air receive a large amount of heat from the warmed surface in hot days, warm air easier cold therefore it also rises up. As a result of collision of winds with natural heights, it pushes out the air which accumulated before the height upward. The majority of cumulonimbus clouds are formed thus. Air can rise in a point of impact of cold and hot fronts.
5. Depending on with what speed air rises, clouds of different types are formed. So, quickly rising air forms cumulus clouds, and layered clouds arise under the influence of very slow vertical streams.