Winter is an incredibly picturesque season. It becomes especially beautiful in the cold season after fluffy snowflakes begin to fall from the sky, covering the ground and trees with a white blanket of snow.
When the first snow appears, people's spirits rise, because this phenomenon seems like a real miracle. When examining snowflakes, you will notice that they have a clear shape and many smooth edges, calibrated with amazing precision. Where do they come from? And why it's winter snow?
What is snow?
Snow is called shape atmospheric precipitation consisting of countless ice crystals. The reason for its appearance is the water cycle in nature. Under influence sun rays liquid in reservoirs and on the soil surface evaporates, then rises in the form of steam into the upper layers of the atmosphere and moves above the ground along with air masses.
When it enters an area with sub-zero temperatures, it freezes and turns into ice. It doesn't stop there, as certain atmospheric conditions are required for ice to turn into snowflakes. 
If these conditions are not met, then eventually the pieces of ice fall to the surface of the earth in the form of rain.
How is snow formed?
The transformation of ice into snow depends on air temperature and humidity. If the temperature above the soil surface is above zero, then when the ice floes fall to the ground they melt and turn into water. If it’s minus, then as they float in the air they collide with other pieces of ice and stick together.
At first, each piece of ice has an uneven shape, but over time, moisture condenses from it, which leads to crystallization and the appearance of smooth six-pointed shapes. Subsequently, new crystals stick to these hexagons, and the next ones stick to them, resulting in quite original compositions with bizarre patterns. At low humidity, all snowflakes can look the same; at high humidity, they have a variety of shapes.
Why does it snow in winter?
When ice floes are in the clouds, they are microscopic crystals with a diameter of no more than 0.1 mm, but when they stick together with other ice floes and when new crystals grow, they become larger and heavier. Air currents can no longer hold them above the surface, so upon reaching certain sizes under the weight of the actual weight, the snowflakes fall to the ground. 
This is how snowfalls occur in winter. It is generally accepted that snow falls, but in fact this process can only be called “falling” conditionally. As the weight increases, snowflakes move out of the clouds, after which they are picked up by lower air currents and moved into different directions– can be carried to the side, lifted up or lowered to the earth’s surface.
While traveling in air masses ah snowflakes are exposed to many “dangers”. If the weather is windy and humid outside, despite the frost, they partially melt and fall to the ground in the form of wet snow.
Sometimes the crystals do not reach the soil at all, but evaporate in the air. If during the soaring process they go through several stages of melting and freezing, then they fall not in flakes, but in small balls similar to cereal.
What types of snowfalls are there?
Winter snowfalls have many characteristics, varying depending on intensity, amount of water in the snowpack, or powderiness. Snowfalls are considered to be heavy when visibility on the roads is no more than 500 meters. These include blizzards or snow storms.
With moderate snowfall, distant objects are visible at a distance of up to 1 km, and with light snowfall - over 1 km. The intensity of snowfall is influenced by the location of clouds and air temperature. The colder the atmosphere and the higher the snow clouds are, the harder and denser the snow falls.
Why is snow white?
White color Snow is given by the air in it. When moisture condenses and the subsequent formation of crystals, light is reflected on the surfaces of the edges of snowflakes, and since it is white, it turns out white. However, this does not always happen. 
It has long been proven that when moving in air masses, various microorganisms and bacteria move along with moisture droplets. Due to their presence in water particles, snow is sometimes not pure white, but with a greenish or grayish tint.
Snow is a large number of tiny ice crystals. It is considered one of the main attributes of winter, falling at low temperatures and covering the ground with a fluffy white carpet.
It’s not for nothing that Russia is considered a country of snow and frost – snow cover lies on most of it. IN northern regions, such as Yakutia or Chukotka, snow can fall as early as the end of September and remain until June. In Moscow, snow cover begins in November, although the first snowflakes can be seen in mid-October, and it disappears only in March - April. In the south of Russia, the snow does not last long, 2 - 3 weeks, and the further south you go, the less snow there is.
But there are countries on our planet where there is no snow at all in winter. Even in winter, the temperature remains 20-25 0 C. But sometimes, in such countries there are icy precipitation, but this is not the norm and occurs extremely rarely.
So why does it snow in winter?
First, let's look at how snow crystals themselves form. The smallest drops of water, being in the clouds, are attracted and freeze - this is how snow is formed. At first, such ice crystals are very small - no more than 0.1 millimeters in diameter. But when snowflakes begin to fall down, moisture from the air is attracted to them, and as a result of condensation, the snowflakes grow, acquiring crystalline six-pointed shapes - this is how it snows in winter.
Each snowflake is original and unique; no two snowflakes are alike. The largest collector of snowflakes is Kenneth Liebrecht. Studying the structure of snow, he says that even the simplest snowflakes may look the same, but they still have large differences at the molecular level.
We are used to seeing small floating snowflakes, but sometimes quite large flakes of snow fall to the ground. The largest snowflake was found in 1887, in the USA, in the state of Montana. Its diameter was equal 38 centimeters, and it weighed only a few grams.
Snowflakes are 90 percent air, therefore, having a low density, they fall to the ground very slowly - less than 1 kilometer per hour.
Sometimes, walking along a snowy street in winter, you can hear the crunch of snow. Moreover, the snow crunches only when the temperature is not higher than -5 0 C. Scientists identify two reasons:
1 - breaking crystals
2 - friction of crystals against each other under pressure.
The sound is also affected by the shape and size of snowflakes.
Every time winter comes and snow falls, we experience some kind of emotional outburst. The white blanket that covered the city and copses, endless fields and wide rivers and wrapped the trees in clothes that shimmered fancifully in the sun will not leave either a child or an adult indifferent. As a child, we could sit by the window for hours and watch how snowflakes, slowly circling, fly past and quietly fall to the ground... We often examined their structure, trying to find two identical ones, never ceasing to be amazed at the beauty and complexity of this magical splendor.
A snowy winter always fills a child's soul with a feeling of joy and inexplicable delight. Over time, when the child grows up, this feeling becomes dull, but still, somewhere in the depths of our souls, everything freezes, and we enjoy the beauty sleeping under the white blanket of nature. Kids often ask their parents: “What is snow?” Adults usually answer in monosyllables, saying it’s frozen water. In our article we will try to understand not only 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?
Dahl's dictionary answers the question of what snow is as follows: it is frozen water vapor that falls in the form of flakes and shreds from the clouds; loose ice that replaces rain in winter. As you can see, the explanation is rather sparse. The all-knowing Wikipedia is also terse; it says that snow is a form of precipitation that consists of small ice crystals. encyclopedic Dictionary reports the following: snow is a solid that consists of ice crystals that differ various shapes; snowflakes most often have the shape of hexagonal plates or stars; fall 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 reference
Where does snow come from? What does it consist of? What is its temperature? These and many other questions related to this natural phenomenon, scientists around the world have been interested in for a very long time. So, back in 1611, the astrologer and astronomer Kepler published a scientific treatise called “On Hexagonal Snowflakes.” The author very pragmatically studied snow crystals in all the rigor 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 later included in the work “An Experience on Meteors.” Subsequently, the question of what snow is made of has been considered countless times by scientists around the world.
Do modern scientists study this phenomenon?
Today, even in kindergartens, children are taught that snowflakes are shaped like hexagons, that their patterns are unique, and that no two snowflakes are alike. It would seem that everything is already known: at what temperature the snow melts, at what temperature it flows, and much more. And yet, 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 tiny particles dust, soot, pollen and even spores.
The quality of snow, sung by poets
The creaking is an interesting effect. It can only be heard exclusively frosty weather. So, if it is a relatively warm day, the snow cover will be silent. And he behaves completely differently during the real winter cold. People have long noticed: the lower the temperature of the snow and air, the higher the pitch of the squeak. Scientists were able to find out that this effect occurs as a result of crushing microscopic ice crystals. When the temperature of the snow drops, these crystals become more fragile and hard, so they make a creaking sound, breaking under the wheels of cars and our feet. If we crush one such crystal, we will not hear anything due to its small size. The human ear is unable to detect such subtle sounds. But when combined, crystals are capable of creating an exceptional musical background. It is this very creak that poets sing about 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 is, the more stable the cloud is, and, accordingly, the longer it will not produce precipitation. In what form they will 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 cooled water and ice crystals). Let's figure out what follows from this. Falling out of the cloud, this mixture passes through subcloud masses on its way to the surface of the planet. If the temperature is high enough, then the ice crystals melt and turn into ordinary rain with a positive drop temperature. Sometimes, if the cloud height is low, the snowflakes may not have time to melt completely, in which case wet snow falls. This is why mixed precipitation may occur during off-season periods. If the temperature of the subcloud mass is negative, then it is simply snowing.
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, it may snow in the summer and rain in the 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 time masses very rich in moisture can enter the middle latitudes warm air moving from warm pools south seas. As a result, thaws begin, which manifest themselves in the melting of fallen snow, as well as precipitation in the form of rain. IN summer time we can observe the opposite situation, that is, cold weather from the Arctic may break through to the south. When retreating warm front very thick clouds are forming, at the dividing line of two air masses with different temperatures precipitation is very heavy. First in the form of rain, and then, with subsequent cooling and under conditions of low cloudiness, 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?
The first time you see this miracle of nature, you will decide that it is the work of man. In fact, nature itself turns such paths or rolls. This rather rare Snow Roll is created by wind that rolls the snow until it gains weight and size. Usually such figures have the shape of cylinders, but there are exceptions. This phenomenon can only be observed in regions with strong gusty winds, light wet snow and only open area. Rolls of snow 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. Behind each of them there is a trace - a kind of path that indicates the trajectory of the path traveled. Snow rolls often form during winter storms when the wind is strong and the snow is fresh. The air temperature should be close to zero.
The process of forming snow rolls
This happens as follows: the surface of the earth should be covered with a ground-in ice crust, or with old compacted snow, in which case falling snowflakes with the underlying layer have weak adhesion. Wherein bottom layer must have negative temperature, and the top one is positive (slightly above zero degrees). Then fresh snow will have high “stickiness”. Optimal temperature It is considered minus two degrees for the bottom layer and plus two for the top. Gusty winds must have a speed of more than 12 m/s. The formation of a roll will begin when the wind “dug out” a piece of snow. Then small lumps form, rolling across the field under the influence of the wind, becoming overgrown with every meter with an increasing layer of wet snow. When the roll becomes too heavy, it stops. So its size directly depends on the air flow speed.
1. A snowflake is 95% air. Thanks to this, it 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 light rays are reflected from the boundary of the ice crystal with air and scattered.
3. Cases of colored snow falling have been recorded in history. So, in 1969, black snow fell in Switzerland, and in 1955, green snow fell in California.
4. B high mountains And in Antarctica you can find snow cover of pink, red, purple, yellowish-brown colors. This is facilitated by a creature - chlamydomonas snow, which lives in the snow.
5. When a snowflake falls into water, it makes a strong high-frequency sound. The human ear can't detect it, but fish can, and according to scientists, they don't like it very much.
6. Under normal conditions, the temperature is 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 off earth's surface up to 90% of the sun's rays, 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.
Finally
So we analyzed this, which is so sparingly described in encyclopedias and dictionaries. Now we know at what temperature snow melts, at what temperature it falls, how, when and why snow rolls appear, and much more related to this most beautiful messenger and companion of winter.
Why in the summer it's raining, and in winter there is snow?
Snow is the same as rain, and how exactly precipitation falls depends on the time of year, and, more precisely, on the air temperature. That is, snowflakes are the same as raindrops, but due to the low air temperature, raindrops turn into snowflakes and fall to the surface of the earth in this form. Therefore, in warm weather, precipitation falls in the form of rain, and in cold weather, in the form of snow.
In summer the temperature is above zero, so precipitation falls in the form of moisture and condensation. In winter low temperature turns water droplets into ice crystals or snowflakes, that is, cooled droplets of water fall onto the ground, taking on bizarre shapes.
This is all due to air temperature; snow forms in winter, because... microscopic drops of water are attracted to dust particles and freeze when cold temperature and form ice crystals, which increase during the fall. Therefore, when warm temperature air, raindrops fall on the surface.
Anyone who took geography lessons knows about the concept of the water cycle in nature.
Water evaporates from the surface of the earth and rises into the sky in the form of clouds. There, the precipitation turns into an aggregate state (if it is winter and cold) or it remains in a liquid state (if it is summer and hot), then precipitation occurs back to the ground. After, the operation is repeated again and again.
Everything is simple: the type of precipitation depends on temperature.
Rain and snow are the same thing - it's water.
In winter, the temperature is low, so the water turns into a crystallized form - snowflakes fall out.
In summer it is warm and water falls from the clouds in its usual liquid form - it rains.
In fact, the question is quite simple and many schoolchildren know the answer. Rain is droplets of moisture formed in the atmosphere and, according to the laws of physics, falling to the surface. Snow is the same droplets of moisture formed at lower temperatures and, as a result, having a slightly different state of aggregation.
It's all a matter of air temperature; by the way, it happens that it's summer snow, and all because the air temperature outside drops significantly, hence precipitation that could have been rain becomes snow or hail, this is quite normal.
In summer, the air temperature is higher, which is why raindrops fall. Therefore, in winter low temperature air and drops, in the process of falling, turn into snow. It turns out that in the summer falling droplets simply cannot freeze.
Of course, it depends on the temperature outside. In winter the temperature is usually below zero (snow), and in summer it is above zero (rain). If it’s +4 degrees outside, it’ll be raining and it’s raining, which means it’s January on the calendar (we had a kind of anomaly in 2016).
Why does it rain in summer and snow in summer, because the air temperature is warmer than zero degrees, so in summer precipitation falls in the form of rain, and in winter the air temperature is below zero, and precipitation freezes and falls in the form of snow.
Snow is a sign real winter. It is formed when small raindrops freeze. Fluffy White snow- a real miracle. Children make snowmen out of it, play snowballs with them, and northern peoples build their homes from snow. A thick layer of snow warms the ground. It does not allow frosty air to approach it, and maintains a positive temperature deep in the soil.
What is snow and how is it formed?
If we talk scientific language, then snow is a type of precipitation. This means that snow falls from the sky as frozen rain. The snow is cold, white and fluffy. It consists of individual snowflakes that look like six-pointed stars. I wonder how snow is formed?
The first condition for snow to appear is cold. The temperature at which water turns into ice is 0ºC. When it gets cold outside, the water in puddles and lakes becomes covered with ice (freezes). The sky is freezing at this time rain clouds. Raindrops turn into snow in them.
The second method of snow formation is scientifically called evaporation. Listen to how it happens. If you wash your clothes and hang them outside in winter, the wet sheet will first freeze and become hard. After a few days, the sheet will turn into a soft, dry cloth. What happened? First, the water in the sheet turned into ice. It happened pretty quickly. Then the ice began to evaporate: small microscopic pieces of ice came off the sheet and rose into the sky. These pieces of ice were so small that, looking at the drying sheet, we did not notice their flight.
Why is it snowing?
Many small pieces of ice are found in the heights of the sky. There they gather into a snow cloud. There are so many snowflakes in the cloud that they join together several at a time. Several small ice stars make a large snowflake, which becomes too heavy and falls down. This is how the snow begins.
It doesn't take one wet sheet to form a big snow cloud. Many tiny pieces of ice rise into the sky from a frozen lake, puddle or river. There they gather into large snow clouds.
The wind can carry such a cloud far. For example, where there is no frost. Thanks to the wind, snow can fall even in places where lakes and rivers have not yet frozen.
How are snowflakes formed?
Have you ever seen a snowflake under a microscope? It looks like a six-pointed star. Each end of the star consists of a white branch on which small white twigs grow.
These branches are scientifically called crystals. They intersect in the middle of the snow star. Each snowflake begins to grow from the center - from the place where the snow branches intersect. The growth of a snowflake is similar to the growth of a tree: six trunks grow from the center, on each of which branches begin to grow. Stars can have different branches (long or short, thick or thin), but only 6 large branches always grow in a snow star.
When water freezes in a river or puddle, it turns into ice. The stars in the ice are located close to each other. When fog or cloud freezes, the stars are located at some distance from each other. If there are too many stars, they connect several at a time and fall down. This is how snow pours out of a cloud and covers roads, houses and fields. Adults call the fall of snowflakes snowfall.
Why does the snow squeak underfoot?
If it is slightly frosty outside (-2 or -3 ºС), then there is a lot of water in the fallen snow. They say about this kind of snow that it is “wet”. It’s easy to make snowballs and a snow woman from wet snow, and build “fortresses.”
When the frost gets stronger (the air temperature drops to -5 or -10 ºC), the snow freezes harder and becomes dry. It’s impossible to make a snowman out of dry snow, but it creaks loudly underfoot. Why does dry snow squeak?
Each snowflake looks like a small star. If we step on the snow, the branches in the icy snowflakes break. So, when breaking many snowflakes, a crunch and creaking is formed.
Snow creaks with any pressure:
- if it was stepped on;
- went skiing;
- went sledding.
The snow stops creaking only when it becomes almost warm (the air temperature approaches 0ºC). Or when it was rolled heavily (this happens on slides, where the snow rolls away and turns into ice).
When does the snow squeak very loudly?
Snow can creak louder or quieter. When does the creaking of snow become very loud?
This happens when severe frost. For example, in the far north, at -50ºC, the crunch of snow becomes so loud that it can be heard on the next street.
With warming, when the air temperature approaches 0ºC, the crunching disappears completely. The snowflakes become soft, drops of water appear on their icy branches, which prevents the icy stars from creaking.
Scientists are conducting interesting experiments with frozen water. It turns out that water hears us and reacts differently to kind and rude words. This is what the next video is about.
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