The formation of ice on the surface of the water, whether it is a river, a lake, or a glass left in the cold is an amazing phenomenon. It is associated with the physical properties of liquid substances.
В тепле молекулы воды образуют собой цепочки, long and stretched. It is because of this that water is an amorphous substance. The transition to such an aggregate state as ice is possible only when the thermometer's column drops to zero marks. In this case, the water molecules are lined up in special lattices. In fact, it looks like the formation of ice. The second name is ice. This living nature is so arranged that the freezing of water bodies in it is usually stretched for a long period. This phenomenon has a connection with weather conditions. For the formation of the primordial enough that a couple of nights stood a good frost with relative winds. However, sharp warming, wet snow with rain, wind and damp fog can cause the water to return to its liquid state. Then the period of freeze-up will be delayed for an unknown time.
All summer and warm autumn water reservoirs accumulateheat, so the beginning of the first frosts the water is warmer than the surrounding air. No wonder, because the density of water is much greater! The contact of warm water and cooled air leads to a reaction called heat exchange.
When the water on the surface will have a temperature+4 degrees Celsius, the surface layer of water will begin to mix, with deeper. The liquid that was on the surface becomes dense, and the warm water from below displaces it because of its lower density. Thus, the whole water column cools down evenly.
Ledostav is a phenomenon in which the temperaturewater becomes zero degrees, and ice appears on the pond. In real life, the temperature minimum can differ by several degrees. This is due to the presence of various impurities in the water, as well as the type of reservoir, its depth, current, bottom relief.
Ledostav - this is an extremely dangerous period for exiton the ice of the river. On a constant current, ice forms later, than on unproductive reservoirs. But the increase in ice here occurs much faster due to the fact that the water is colder.
The main danger of pervolodya on the rivers is the changewater level. Groundwater freezes and stops feeding the water artery, because of this the water level sharply becomes lower, and the formed first ice starts to break. The ice floes are knocked down by a current into one place, where they then freeze safely, forming ice hummocks.
It is believed that the ice thickness of 5 cm is capable ofsustain the weight of one person. However, lovers of winter fishing is not recommended to open the season, until the thickness of the ice reaches at least 10 cm - it is believed that at this thickness ended the ice sheet. It is not necessary to check every day. Do not constantly go to the river. It is enough to make simple calculations and approximately to orient with the date of the exit to the ice. It is believed that with the existing ice of 10 cm and air temperature minus 5 degrees, the thickness of the cover over the day will add 4 cm, at a temperature of -10 - 6 cm. Almost twice the thickness of the ice, if the day keeps the temperature at -20 degrees.
