Every time with the arrival of winter and snowfall, we experience some kind of emotional outburst. The white veil that covered the city, dense forests and copses, endless fields and wide rivers, and wrapped trees in clothes bizarrely shimmering in the sun, will not leave indifferent either a child or an adult. As children, we could sit at the window for hours and watch how, slowly circling, snowflakes fly past and quietly fall to the ground … We often examined their structure, trying to find two identical ones, never ceasing to be surprised by the beauty and complexity of this magical splendor.
Snowy winter always fills a child's soul with a sense of joy and inexplicable delight. Over time, when the child grows up, this feeling dulls, but still, somewhere in the depths of the soul, everything freezes, and we enjoy the beauty sleeping under the white veil of nature. Babies often ask their parents:"And what is snow?" Adults usually answer in monosyllables, they say, this is frozen water. In our article, we will try to deal not only with the question of what snow is, but also consider its properties, both from the side of science and from the side of poetry.
What do encyclopedias say?
Dal's Dictionary answers the question of what snow is, as follows: it is frozen water vapor that falls in the form of flakes, shreds from clouds; loose ice that replaces rain in winter. As you can see, the explanation is rather stingy. The omniscient Wikipedia is also laconic, saying that snow is a form of precipitation that consists of small ice crystals. The Encyclopedic Dictionary reports the following: snow is solid atmospheric precipitation, which consists of ice crystals that differ in various shapes; snowflakes are most often in the form of hexagonal plates or stars; fall out when the air temperature drops below zero degrees Celsius. It turns out that all dictionaries and encyclopedias say the same thing, but they do not bring clarity to the question of what snow is. In this case, let's turn to the exact sciences.
Historical background
Where does snow come from? What does it consist of? What is its temperature? Scientists all over the world have been interested in these and many other issues related to this natural phenomenon for a very long time. So, back in 1611, the astrologer and astronomer Kepler published a scientific treatise called "On Hexagonal Snowflakes". The author has studied very pragmaticallysnow crystals throughout the severity of geometry. His work formed the basis of such a science as theoretical crystallography. Another famous figure of the seventeenth century, the French mathematician and philosopher René Descartes, also studied the shape of snowflakes. He wrote a sketch in 1635, which was subsequently included in the work "Experience on Meteors". In the future, the question of what snow is made of has been considered by scientists around the world countless times.
Do modern scientists study this phenomenon?
Today, even in kindergartens, kids are told that snowflakes are shaped like hexagons, that their pattern is unique, and that no two snowflakes are the same. It would seem that everything is already known: at what temperature snow melts, at what temperature it snows, and much more. Nevertheless, scientists have not lost interest in this miracle of nature and are still studying the processes of snowflake formation. It turns out that they form around the so-called crystallization nuclei, and, most interestingly, they can be the smallest particles of dust, soot, plant pollen and even spores.
The quality of snow sung by poets
Squeaking is an interesting effect. It can only be heard in exceptionally frosty weather. So, if there is a relatively warm day, then the snow cover will be silent. And it behaves quite differently during a real winter cold. People have long noticed: the lower the temperature of the snow and air, the higher the tone of the creak. Scientists were able to figure out that this effect occurs as a result of crushing microscopic ice crystals. When the temperature of the snow drops, these crystals become more brittle and hard, so they make a creaking sound, breaking under the wheels of cars and our feet. If we crush one such crystal, then we will not hear anything due to its small size. Such subtle sounds the human ear is not able to catch. But when united, the crystals are able to create an exceptional musical background. This very creak is sung by poets in their works.
Why is it snowing or raining?
Precipitation is associated with an imbalance (stability) of cloud masses, which consist of many elements of different structures and sizes. The more homogeneous this composition, the more stable the cloud, and, accordingly, the longer it will not give precipitation. In what form they fall to the ground depends on the temperature of the air mass in the subcloud layer, as well as the height and structure of the cloud itself (as a rule, it is mixed, that is, it consists of drops of chilled water and ice crystals). Let's see what follows from this. Falling out of the cloud, this mixture on the way to the surface of the planet passes through the subcloud masses. If the temperature is high enough, then the ice crystals melt and turn into ordinary rain with a positive droplet temperature. Sometimes, given the low height of the clouds, snowflakes may not have time to melt completely, in which case wet snow falls. This is why mixed rainfall can occur during the off-season. If the temperature of the subcloud mass is negative, then in this case it is simple snow.
Why does it sometimes snow in summer and rain in winter?
We figured out at what temperature it snows and at what temperature it rains. However, sometimes incredible phenomena happen, for example, snow can fall in summer, and rain can fall in winter. What explains such cataclysms? Let's try to understand why this happens. Scientists explain this phenomenon as a deviation from the normal course of development of processes in the atmosphere. So, in winter, masses of warm air rich in moisture, moving from the basins of the warm southern seas, can enter the middle latitudes. As a result, thaws begin, which are manifested in the melting of fallen snow, as well as precipitation in the form of rain. In the summer, we can observe the opposite situation, that is, cold air masses from the Arctic can break through to the south. When the warm front retreats, very powerful clouds form, and precipitation is very plentiful on the dividing line of two air masses with different temperatures. First in the form of rain, and then, with subsequent cooling and under low cloud cover, in the form of simple or wet snow. In the southern regions, this rarely happens, while the temperature on the surface of the earth remains positive.
Snow rolls - what is this anomaly?
When you first see this miracle of nature, you will decide that this is a creation of human hands. In fact, such paths or rolls are twisted by nature itself. This is a rather rare meteorological phenomenon. Snow rolls are created by the wind rolling the snow until it gains weight and size. I usually have such figurescylinder shape, but there are exceptions. This phenomenon can only be observed in regions with strong gusty winds, light wet snow and only in open areas. Snow rolls roll across the steppe like empty barrels. Their size can reach 30 cm in diameter and 30 cm in width. In fact, hundreds of individual rolls can appear simultaneously on a snowy field. Each of them leaves a trace - a kind of path that indicates the trajectory of the path traveled. Snow rolls often form during the passage of winter storms when the wind is strong and the snow is fresh. The air temperature should be close to zero.
Snow roll forming process
This happens as follows: the surface of the earth must be covered with a ground ice crust, or old packed snow, in which case the falling snowflakes with the underlying layer have little adhesion. In this case, the lower layer should have a negative temperature, and the upper one - positive (slightly above zero degrees). Then fresh snow will have a high "stickiness". The optimum temperature is considered to be minus two degrees for the lower layer and plus two for the upper one. Gusty wind must have a speed of more than 12 m/s. The formation of the roll will begin when the wind "digs out" a piece of snow. Further, small lumps are formed, rolling across the field under the influence of the wind, overgrown with each meter with an increasing layer of wet snow. When the roll becomes too heavy, it stops. So its size directly depends on the airflow speed.
Interesting facts about snow
1. A snowflake is 95% air. Due to this, she falls very slowly, at a speed of 0.9 km/h.
2. The white color of snow is due to the presence of air in its structure. In this case, the rays of light are reflected from the border of the ice crystal with air and scattered.
3. History has recorded cases of colored snow falling. So, in 1969 black snow fell in Switzerland, and green snow in California in 1955.
4. In the high mountains and Antarctica, you can find a snow cover of pink, red, purple, yellowish-brown colors. This is facilitated by a creature - snow chlamydomonas, which lives in the snow.
5. When a snowflake falls into water, it emits a strong high-frequency sound. The human ear can't pick it up, but fish can, and according to scientists, they really don't like it.
6. Under normal conditions, snow melts at zero degrees Celsius. However, when exposed to sunlight, it can evaporate even at sub-zero temperatures, while bypassing the liquid form.
7. In winter, snow reflects up to 90% of the sun's rays from the earth's surface, thereby preventing it from warming up.
8. In 1987, the largest snowflake in the world was recorded in Fort Coy (USA). Its diameter was 38 cm.
In closing
So we analyzed this weather phenomenon, which is so sparingly described by encyclopedias and dictionaries. Now we know at what temperature snow melts, at what temperature it melts, how, when and why snow rolls appear and much more.another, connected with this most beautiful herald and companion of winter.
