It is called the dew point at which the water vapor becomes saturated in a given amount of air.
We know that by lowering the temperature, the maximum voltage of the saturating vapors is also low; This explains the formation of fog and clouds. When the temperature of the cloud is below 0 ° C, we have a passage from the liquid state to the solid, in the form of tiny ice crystals, which may fall, no longer in the form of rain, but in the form of snow.
Clouds can be located from ground level to the base of the stratosphere (10 km). When the soil temperature falls below 0 ° C, the water vapor is deposited under a solid state, constituting no more dew, but frost. The phenomenon is usually followed by the solidification of the sap in the vegetables, causing them to perish.
Knowledge of the hygrometric state of the air is an element of great importance in general.
Various experiments have led to the conclusion that the human body depends on relative humidity of the air as much as temperature.
The ideal conditions for existence is:
Temperature: 22 ° C to 26 ° C
Relative humidity: 45% to 50%
When the relative humidity is much lower than these values described above, perspiration becomes fast as the sweat evaporates in less time, giving an unpleasant sensation of cold to the skin. When, on the contrary, the relative humidity is high, the evaporation of the sweat is delayed; The skin becomes wet and hot.
Currently, air conditioning systems multiply and consist of and artificially adjust the temperature and humidity of the air inside the buildings by means of special equipment. Thus, cinemas, theaters, hospitals, shops and various environments. These environments are mostly equipped with air conditioning, which cool the air in the summer, warm in the winter and adjust the relative humidity of the air.
