Every time with the arrival of winter and snowfall we are experiencing some sort of emotional outburst.A white veil covered the city, dense forests and groves, endless fields and wide rivers, and wrap up the trees in the sun shimmering bizarre clothes, will impress any child or adult.As a child we could sit for hours at the window and watch as, slowly circling, fly past Snowflakes fall softly to the ground ... We have often considered the structure, trying to find two identical, still surprised by the beauty and complexity of this magical splendor.
Snowy winter always fills the child's soul a sense of joy and inexplicable delight.Eventually, when the child grows up, the feeling is dulled, but still somewhere in my heart all the stops, and we enjoy the beauty of sleeping under the white veil of nature.Toddlers often ask parents, "What is snow?"Adults usually respond in monosyllables, saying it is frozen water.In this article we try to understand not only the question of what is the snow, but also look at its properties, both on the part of science, and from the poetry.
What do the encyclopedia?
Dictionary Dahl answers the question of what is the snow, in the following way: it is frozen water vapor, which fall in the form of flakes, scraps from the clouds;loose ice, which replaces the rain in the winter.As you can see, the explanation is quite meager.Omniscient Wikipedia too laconic, she says that the snow - is a form of precipitation that consists of small ice crystals.Collegiate Dictionary says the following: the snow is a solid precipitation, which are composed of ice crystals that differ different forms;snowflakes often are in the form of hexagonal plates or stars;fall, when the temperature drops below zero degrees Celsius.It turns out that all the dictionaries and encyclopedias say the same thing, but clarity on what is snow, they do not contribute.In this case, it refers to the exact sciences.
Background
Where does the snow?What is it?What is the temperature?These and many other issues associated with this natural phenomenon, scientists around the world are interested in a long time.Thus, in 1611 the astrologer and astronomer Kepler published a scientific treatise, which has the name of "On the hexagonal flakes."The author is very pragmatically studied snow crystals with the utmost rigor of geometry.His work became the basis of a science as a theoretical crystallography.Another well-known figure of the seventeenth-century French mathematician and philosopher Rene Descartes, was also involved in the study form snowflakes.They were written in 1635 etude, which was subsequently included in the work "Experience of meteors."In the future, the question of what is in the snow, is considered by scientists around the world countless times.A
investigating whether this phenomenon modern scholars?
Today, even in kindergarten kids say that snowflakes are shaped like hexagons that their design is unique and that there are no identical snowflakes.It would seem that everything is already known: the temperature at which the snow melts, at what is, and much more.And yet scientists have not lost interest in this miracle of nature and are still studying the processes of formation of snowflakes.It turns out that they are built around the so-called nucleation, and, most interestingly, they may be tiny particles of dust, soot, pollen and even controversy.
Snow quality, praised by poets
Scrape - This is an interesting effect.It can be heard only in extremely cold weather.So, if you will stand a relatively warm day, the snow will be silent.And quite differently it behaves during this cold winter.People have long noticed: the lower the temperature of the snow and the air, the higher the pitch squeak.The scientists were able to ascertain that this effect is caused by crushing microscopic ice crystals.When the temperature of the snow falls, these crystals become more brittle and hard, so they emit a squeaking sound, breaking under the wheels of cars and our feet.If you crush one such crystal, then we will not hear anything because of its small size.Such subtle sounds the human ear is not able to grasp.But united, the crystals are able to create an exceptional background music.This very creaking and sung by poets in their works.
Why is snow or rain?
Precipitation due to the breach of equilibrium (stability) of cloud masses, which consist of a plurality of elements of different structures and sizes.The more homogeneous the composition, the more stable cloud, and therefore, the longer it will not give precipitation.In what form they reach the ground, depends on the temperature of the air mass in-cloud layer, and the height of the cloud and the structure (as a rule, it is mixed, i.e. comprises chilled water droplets and ice crystals).We will understand that this implies.Dropping out of the cloud, this mixture towards the surface of the planet passes through the-cloud mass.If the temperature in this case is quite high, the ice crystals melt and turn into the usual rain with positive temperature drops.Sometimes, it provided a low altitude clouds, snowflakes may not have time to melt completely, then wet snow falls.That is why in the off-season can fall mixed precipitation.If the temperature-cloud mass is negative, then the snow is easy.
Why is it sometimes snows in summer, and rain in the winter?
We dismantled, at what temperature it is snowing, but at what - rain.However, sometimes there are extraordinary events, such as summer snow can fall, and winter - to rain.What explains such cataclysms?Let's try to understand why this happens.Scientists explain this phenomenon is the deviation from the normal course of development processes in the atmosphere.So, in the winter in the middle latitudes can get very rich moisture mass of warm air moving from pools of warm southern seas.As a result of the thaw begins, which appear in the melting of snow and precipitation in the form of rain.In the summer, we can observe the reverse situation, that is to the south may break cold air masses from the Arctic.During the retreat of the warm front is formed by a very powerful Rain, on the line between two air masses of different temperatures are very heavy rainfall.First, in the form of rain, and then, at the subsequent cold weather and low clouds in the form of a simple or sleet.In southern regions this rarely happens, and the temperature at the surface is positive.
Snow rolls - what is this anomaly?
first time seeing this wonder of nature, you decide that this is the handiwork of man.In fact, such a track twists or rolls by nature.It is a rare meteorological phenomenon.Snow rolls creates the wind, ride the snow as long as he does not pick up in weight and size.Typically, these figures have the form of cylinders, but there are exceptions.This phenomenon can be observed only in regions with strong gusty winds, light snow and wet only in open areas.Snow rolls roll over the steppe as empty barrels.Their size can reach 30 cm in diameter and 30 cm in width.In fact, on a snow-covered field can occur at the same time hundreds of individual rolls.Each of them left a trace - a kind of track that indicates the path distance traveled.Snow rolls are often formed during the passage of winter storms, when the wind is strong and fresh snow.The air temperature must be close to zero.
The formation of snow rolls
This occurs as follows: the ground surface must be covered with a ground-ice crust or old packed snow, then falling snowflakes to the underlying layer have a weak grip.The lower layer should have a negative temperature and the upper - positive (slightly above zero degrees).Then fresh snow will have a high "tack".The optimum temperature is considered to be minus two degrees for the lower layer, plus the two - to the top.Gusty wind speed must be more than 12 m / s.Forming roll will start when the wind "dig" a piece of snow.Then small lumps are formed, rolling across the field by the wind, gathering every meter of growing a layer of wet snow.When the roll is too heavy, it stops.So that its size depends on the speed of the air flow.
Interesting facts about snow
1. Snowflake 95% air.Due to this it falls very slowly, with a speed of 0.9 km / h.
2. The white color of the snow due to the presence of air in its structure.At the same time the light rays are reflected from the boundaries of ice crystals with air and scattered.
3. In the history of recorded cases of loss of color of snow.So, in 1969 in Switzerland, black snow fell, and 1955 in California - Green.
4. In the high mountains and the Antarctic you can find snow pink, red, purple, yellowish-brown color.This contributes to the creature - chlamydomonas snowy, who lives in the snow.
5. When snowflakes fall into the water, it makes a lot of high-frequency sound.The human ear is not able to catch it, but the fish can, and according to scientists, it is not like them much.
6. Under normal conditions, the snow melts at a temperature of zero degrees Celsius.However, when struck by sunlight, and it can evaporate at temperatures below zero, thus bypassing the liquid form.
7. In winter, the snow reflects the earth's surface up to 90% of the sun's rays, thus preventing it to warm up.
8. In 1987, at Fort Something (USA) recorded the biggest flake in the world.Its diameter is 38 cm.
In conclusion
So we sorted out this weather phenomenon, which is so sparingly describe encyclopedias and dictionaries.Now we know the temperature at which the snow melts, at what is, how, when and why there are rolls of snow and more connected with this beautiful messenger and companion of winter.
