For the nature around us, water vapor is of great importance. It is present in the atmosphere, used in technology, serves as an integral part of the process of origin and development of life on Earth.
Physics textbooks say that water vapor is a gaseous state of water. Everyone can observe it, putting the kettle on fire. After a while, a stream of steam begins to burst from his nose. This phenomenon is due to the fact that water can be in different, as physicists determine, aggregate states - gaseous, solid, liquid. Such properties of water explain its comprehensive presence on Earth. On the surface - in a liquid and solid state, in the atmosphere - in a gaseous state.
Such a property of water and its gradual transition to different states create a water cycle in nature. The liquid evaporates from the surface, rises into the atmosphere, is transferred to another place in the form of water vapor, and there it drops out in the form of rain, providing new places with the necessary moisture.
In fact, a kind of steam engine works, the energy source for which is the Sun. In the considered processes, water vapor additionally heats the planet due to the reflection of the Earth’s thermal radiation back to the surface, causing the greenhouse effect. If there wasn’t such a peculiar “pillow”, then the temperature on the planet’s surface would be 20 ° C lower.
As confirmation of the foregoing, one can recall the sunny days in winter and summer. In the warm season, the humidity is high, and the atmosphere, like in a greenhouse, warms the Earth, in winter, in sunny weather, sometimes the most significant colds occur.
Like all gases, water vapor has certain properties. One of the parameters determining these will be the density of water vapor. By definition, this is the amount of water vapor contained in one cubic meter of air. In fact, this determines the absolute humidity of the latter.
The amount of water in the air is constantly changing. It depends on temperature, pressure, terrain. The moisture content in the atmosphere is an extremely important parameter for life, and it is constantly monitored, for which they use special devices - a hygrometer and a psychrometer.
The change in humidity is caused by the fact that the water content in the surrounding area changes due to the processes of evaporation and condensation. Condensation is the opposite of evaporation, in this case the vapor begins to turn into a liquid, and it falls to the surface.
In this case, depending on the ambient temperature, fog, dew, hoarfrost, ice can form.
When warm air saturated with water vapor comes into contact with cold earth, dew forms. In winter, at freezing temperatures, frost will form.
A slightly different effect occurs when the cold comes, or the air heated during the day begins to cool. In this case, fog forms.
If the temperature of the surface on which the vapor condenses is negative, then icing occurs.
Thus, numerous natural phenomena, such as fog, dew, hoarfrost, ice, owe their formation to water vapor contained in the atmosphere.
In this regard, it is worth mentioning the formation of clouds, which are also directly involved in the formation of weather. Water, evaporating from the surface and turning into water vapor, rises up. Upon reaching the height where condensation begins, it turns into a liquid, and clouds form. They can be of several types, but in the light of the issue under consideration, it is important that they participate in the creation of the greenhouse effect and the transfer of moisture to new places.
The stated material shows what constitutes water vapor, describes its effect on life processes occurring on Earth.