Each season is followed by the characteristic natural phenomena which will mark seasonal changes of the nature. So, one of signs of approach of winter traditionally call snow – one of a set of types of precipitation of the terrestrial atmosphere having the form of crystal water small pieces of ice.
Structure of snow
Snow is formed in the presence of two conditions: a large amount of moisture in air and temperatures are lower than 0 wasps. It is noticed that the most plentiful snowfalls occur at rather high temperatures (from - 9 wasps above). All because the air temperature is higher, the it is more in it than water vapor which, in fact, is construction substance for snow. Range of content of water in snow is rather high – from 0.1 to 4 cm in 10 cm of snow cover, depending on temperature, the speed of wind, crystal structure and so forth.
Despite the size (on average about 5 mm), the snowflake has ideal symmetry, but the special attention of researchers is drawn by the bizzare shapes and the most various patterns formed by an interlacing of its sides. In this sense each snowflake is unique. It is already known that all snowflakes have the accurate geometrical lines forming a hexagon. All because the water molecule also has the hexagonal form. Freezing and turning into the ice crystal, molecules which are in the close neighbourhood are taken on a chain by the same principle. Of course, the bizzare shape is influenced by both the level of humidity, and air temperature, but the fact that the snowflake is a set of links of a chain of the stood water molecules, does not raise today doubts any more.
Snow consists of small particles of ice, and therefore is substance loose and granulated. On the structure it is quite soft and pliable material if it is not condensed as a result of any external influence, for example a rain or strong wind. After several cycles of thawing and freezing, snow becomes heavy and turns into dense ice weight. Existence of snow cover lowers surrounding temperature. It occurs because white color of snow reflects sunlight, and that insignificant amount of heat which nevertheless is absorbed goes for snow thawing, but not for increase in its temperature. One more property of snow cover – absorption of a sound and decrease in impact of external noise on a landscape. It occurs because between snowflakes there are vials of air which weaken vibrations. Walks in frosty weather on snow cover are followed by a characteristic scratch. It is published by snow crystals which when squeezing rub the friend about the friend, are deformed and break. Snow has huge value in the course of natural activity. It is a peculiar natural insulator which keeps heat of the earth which is saved up in the summer, even in the most severe frosts. Thus, without allowing to die plants and small animals. Besides, he creates the necessary reserve of moisture necessary at spring awakening.