At a high altitude above the ground at a temperature of 0 to 40 degrees, they quickly turn into ice crystals. Closer to the surface, the temperature gradually rises, slows down, new crystals are strung on its tops. The crystals will grow, they will stretch out the rays, or outgrowths of the rays, and turn into a snowflake. Each snowflake is born unlike the other, with its own special pattern.
How exactly the process takes place depends on humidity, temperature, pressure, and the initial shape of the snowflake. The slightest fluctuations in the parameters dramatically change the direction of snowflake growth. That's why there will be no identical snowflakes.
Why are snowflakes white? Light reflects off the boundary surfaces between the ice crystals and the air inside the snowflake and scatters.
A variety of patterns that we see on frosty evenings on window glass have the correct shape. Steam tends to create a continuous formation, to fill all the free space. This fact and the peculiarity of different surfaces affect the direction of crystal growth, so the "frosty" patterns do not retain the correct shape that a single snowflake has.
How do snowflakes appear?
Scientists dedicated to the study of snowflakes
The Frenchman Tissandier observed the process of snow formation from a balloon. He took to the sky in a heavy snowfall and noticed that meter by meter the snow flakes gradually decreased in size to individual snowflakes. At an altitude of 2000 meters, the air became completely transparent, only small crystals of snow were visible. The scientist, apparently, ended up in a snow laboratory.
The world's first crystallographic treatise
The form of snow crystals was discovered in 1611 by the German scientist, physicist, astronomer J. Kepler quite (for us) by accident.
By this time, the forty-year-old scientist had discovered the first two laws of planetary motion, published works on astronomy, and invented the telescope. Although he was a famous scientist, lived in poverty, and did not know how to feed his family. Thinking about how to make a light, weightless New Year's gift to one good person, he drew attention to the snowflakes falling on his coat. Entering the house, he took out a magnifying glass and began to examine the melting snow. Then he sat down at the table and expressed brilliant guesses about the geometric structure of crystals in nature. The book is written sincerely, playfully, in simple understandable language. Here he, reflecting on the shape of snowflakes, said that he did not understand why they have a hexagonal shape.
In America, naturalist photographer Bentley collected more than 5,000 photographs of snowflakes under a microscope for half a century. And imagine: among these photos there were no two identical! He was often approached by jewelers and artists, who used his work to create their own. In the pictures, the snowflakes really look like jewelry created by an unsurpassed master jeweler. That's what he called them: snow jewels. Subsequently, the American Weather Bureau from the collection released an atlas of snowflakes, which included half of the naturalist's photographs. He did not reveal the secret of obtaining high-quality images to anyone.
Taking a photo of a snowflake is not easy because it melts quickly and loses sharpness.
The Russians also discovered a method for photographing snow crystals, in which snowflakes were placed not on glass, but on the finest silk mesh. The photos were also of good quality, and the grid was then retouched. In 1933, Kasatkin, an observer at the polar station, took 300 photographs of various snowflakes. All snowflakes are mostly hexagonal, but there were special ones, those that resemble clocks (“crystal-clocks,” as Bentley called them).
The iodoform crystal is also hexagonal; Professor Leman obtained iodoform "snowflakes" in a laboratory way, noted their consistent formation and similarity to ordinary snowflakes.
snowflake formation
Hexagonal snowflake shape
Elementary - a tetrahedron that combines six water molecules. Each water molecule retains the ability to form hydrogen bonds. Therefore, tetrahedra can connect with each other, form new structures. In nature, there is a wide variety of them, but the basic structure is a hexagon, in which water molecules are combined into a ring. Thus, a snowflake is made up of prefabricated ice crystals. The hexagonal structure of ice determines the hexagonal shape of the snowflake.
Small crystals are connected to each other by edges, not corners; as a result, the rays will grow in six directions, and another ray will depart from the ray strictly at angles at 120 or 60 degrees. The conditions for the formation of a snowflake will be different each time. Therefore, it increases in width, then its rays will lengthen. On a dry frosty day, a snowflake of an unusual shape forms, it lengthens and turns into a hexagonal column.
The shape of snow crystals depends on temperature: from -3 to 0 degrees (Celsius) - hexagonal flat shapes are formed, from -5 to -3 needle-shaped, from -8 to -5 - columns - prisms, from -12 to -8 - again flat. If the temperature drops, the snowflakes can take on many different shapes.
Each snowflake has its own life, since the formation of a snowflake each time occurs in new conditions. Each time, slightly, but, the parameters: humidity, temperature, pressure will change. When falling to the Earth, a snowflake changes shape: if it rotates like a top, it will be perfectly symmetrical, otherwise not. If the air temperature below the clouds rises to zero, it will be normal rain. It often happens that snowfall turns into rain.
Modern classification of snowflakes
In modern times, snowflake watching has grown into. The International Snow Commission has adopted a simple classification of solid precipitation as a basis. 7 types of crystals were recorded in the form of plates, star-shaped crystals, columns, needles, etc. The Russian scientist Zamorsky classified snowflakes into 9 classes and 48 types. So, the species list of snowflakes can be continued with hedgehogs, fluffs, cufflinks, prisms, stars, etc.
A scientist who synthesizes a twin snowflake
If you have ever noticed that they have different shapes. It is believed that there are about 350 million snowflakes in one cubic meter of snow! They are all hexagonal and have crystal-like structures, but each has its own unique shape. For years, scientists have tried to understand where this shape comes from, what affects such symmetry, and why it is different for everyone. Each received tiny piece of information reveals another amazing secret contained in a snowflake.
The variety and ideality of the hexagonal structure of snowflakes is a manifestation of the wisdom and creativity of God as the Creator. The formation of snowflakes is another manifestation of the infinite ingenuity of the Lord. These thin, small snowflakes are like stars or a needle head with many fragile tips. The shape of the snowflakes in the drawings is really amazing. For many years, such a structure has been the subject of people's interest. Since 1945, research has been conducted to determine the cause of the formation of geometric shapes from microscopic ice crystals. One snowflake is made up of over 200 ice crystals. Snowflakes are made up of water molecules that have taken on an intricate shape. Snow, nature's most architectural marvel, takes shape when water vapor freezes as it passes through a cloud. It happens in the following way.
When water molecules enter clouds, randomly scattered in water vapor, they begin to lose their chaotic motion due to an increase in temperature. After a while, the water molecules slow down, begin to gather into small groups and solidify. At the same time, they are ordered and have the form of hexagonal figures, which are often similar to each other. At first, each snowflake consists of one geometrically hexagonal water molecule. Then other similar molecules join it.
According to the researchers' theories, the main factor that determines the shape of a snowflake is that these hexagonal water molecules connect to each other like links in a chain. In addition, crystal particles, which should normally look the same, take on different shapes depending on temperature and humidity levels. (Roger Davey, David Stanley, "All about ice," New Scientist, September 6, 1993.)
And yet, why do all snowflakes have hexagonal symmetry and why are they all different from each other? Why are their contours angular and not even? Scientists are still trying to find answers to these questions. But one thing is clear: only God, the One Creator with great power, could provide a variety of thousands of billions of snowflakes.
The snowflake is one of the most beautiful creations of nature. We would have to work hard to create a shape comparable in beauty to the shape of a snowflake. When it snows, millions of snowflakes fall to the ground, and no two are alike.
Snow, as you already know, is just frozen water. Why then is snow white if it is frozen water? It must be colorless. Snow is white because the planes of the snowflake, which are ice crystals, reflect light, which is why snow appears white.
When water freezes, crystals form. This means that the molecules line up in a special order, forming a geometric shape, which we call a "crystal".
It so happened that the water molecule consists of three particles - two hydrogen atoms and one oxygen atom. Therefore, during crystallization, it can form a three- or hexagonal figure. Water turning into snow is a form of water vapor in the atmosphere. When freezing, water crystals are so small that they are not visible. When snow forms, these crystals are moved up and down by air currents in the atmosphere.
During such movements, they are grouped around the smallest particles of dust or water droplets. Such a group of crystals becomes more and more, several hundred such crystals can gather around one such nucleus.
This group becomes large, heavy and falls to the ground. We call it "snowflake". Some snowflakes reach three centimeters in diameter. The size of snowflakes depends on temperature. The lower the temperature, the smaller the snowflakes.
Why are snowflakes this shape? Everything is simple! Here:
H2O molecule- this is a tetrahedron, in the center of which there is oxygen, and on two vertices - hydrogen protons, which are involved in the formation of a bond with oxygen. Two free vertices are occupied by a pair of oxygen electrons that do not participate in the formation of intramolecular bonds. At the nodes of the crystal lattice, the oxygen atoms are ordered and form regular hexagons, while the hydrogen atoms occupy arbitrary positions along the bonds.
Since, due to the anisotropy of the crystal, freezing occurs unevenly, all snowflakes look different. But since an ice crystal has three axes of the second order, a snowflake can only be hexagonal.
If you don't understand anything from this explanation, don't worry. We didn’t understand him either, we just quoted the textbook. To understand why a snowflake has this shape, let's go back to the water molecule. It is a triangle: 
Ice crystals, on the other hand, have the shape of a hexagon, which consists of the aforementioned triangles: 
This very first crystal is the future snowflake. His/her further growth will occur due to the addition of new water vapor molecules to the crystal. 
Although the order of attachment of new molecules is chaotic, they eventually line up in hexagons, the same as our first crystal. 
Further, branches will begin to grow at the snowflake. How exactly they will look depends on temperature, humidity, pressure and a bunch of other factors. The crystals always join each other at a face and never at an angle, so the snowflake ray will always be hexagonal. 
Branches may extend from the beam, but they will always grow at an angle of 60° or 120°. 
It was the perfect snowflake. In reality, a huge cluster of "branches" that grow in a chaotic manner makes each snowflake unique. So snowflakes might look like this: 
Or like this: 
Or like this: 
And even so (when two snowflakes "link" together, a 12-ray snowflake is obtained): 
Rumor has it that there are triangular snowflakes:
In fact, these are the same hexagonal snowflakes, in which some of the sides are shorter than others.
Dependence of the shape of snowflakes on external conditions
There is a simplified statistics of the dependence of the shape of snowflakes on temperature. It is based on long-term observations of scientists:
0..-3°С: flat hexagons
-4..5°С: needle crystals
-6..-8°С: prism columns
-9..-12°С: flat hexagons again
-13..-16°С: snowflake stars
>16°C: snowflakes of any shape, including very complex ones
And yet it is impossible to predict the shape of snowflakes more accurately - too many factors influence this. Modeling the process of creating snowflakes is not possible, as each individual case would have to be modeled. It is believed that each new snowflake is not like the one already created.
Snow flakes and colored snow
Snowflakes can also interlock with each other (as in the picture above), forming complex polygonal snow flakes. Sometimes these flakes are of record size - in Serbia, snow somehow fell with a flake diameter of up to 30 cm! It was in the winter of 1971. But most often their size does not exceed 1-2 cm.
There is also colored snow - small particles of dust fall into the clouds, coloring the snowflakes yellow, reddish or brown. It happens in areas located near deserts, where sandstorms rage. By the way, snow sometimes falls in the deserts themselves, delighting local residents with the variety and beauty of snowflakes.
Once upon a time there were snowflakes, and since they did not find a better occupation for themselves, they flew down to the ground. Many ended up in the field and stayed there, many fell on the roofs and stayed there, and one snowflake hit the open window, but the story is silent about its fate, probably, it stayed there.
Robert Walser. Tanner family
The air in which they arise is filled with creative genius. I don't think I'd be more excited
even if real stars fell on my coat.
Henry David Thoreau
Snowflake- the beautiful and graceful form of frozen water - has always been extremely popular with people. As is known, snowflake is a snow or ice crystal, usually in the form of hexagonal plates and six-pointed stars.
During very severe frosts (at temperatures below -30 ° C), ice crystals fall out in the form of " diamond dust”- in this case, a layer of very fluffy snow is formed on the surface of the earth, consisting of thin ice needles.
Usually, during their movement inside the ice cloud, ice crystals grow due to the direct transition of water vapor into the solid phase. How exactly this growth occurs depends on external conditions, in particular on temperature and humidity. Scientists have identified the nature of the dependence in general terms, but have not yet been able to explain it.
Under certain conditions, ice hexagons grow intensively along their axis, and then elongated snowflakes form - snowflakes-columns, snowflakes-needles. Under other conditions, hexagons grow mainly in directions perpendicular to their axis, and then snowflakes form in the form hexagonal plates or hexagonal stars. A drop of water can freeze to a falling snowflake - as a result, irregular shaped snowflakes.
At different times, they were interested in snowflakes Rene Descartes- French naturalist; Baron Nikolai Vasilyevich Kaulbars- General and military writer, member of the Imperial Russian Geographical Society, who discovered snowflakes of an unusual shape; American Wilson Alvin Bentley- one of the first snowflake photographers; Japanese nuclear physicist Ukihiro Nakaya published a book in 1954 Snow Crystals: Natural and Artificial”, where he examined in detail the nature of snowflakes; Kenneth Libbrecht- American physics professor who published the book " Snowflakes. The mystery of the beauty of winter nature».
He was the first to study snowflakes Johannes Kepler(1571-1630) - famous German astronomer and mathematician.
Also in 1611 In the year he published a treatise "", in which he analyzed the geometric aspects of their structure. This well-known scientific and artistic work in an accessible form reveals the nature of small crumbs. Despite the fact that the author does not give a definitive answer to the question posed, this work had a significant impact on the development of science and is considered the starting point in the development of crystallography.
The high scientific achievements of Kepler's treatise were once appreciated by V. I. Vernadsky in his work Fundamentals of Crystallography. Vernadsky noted:
"The significance of the work lies in the fact that he proved for the first time that crystals obey the laws of geometry."
« New Year's gift, or about hexagonal snowflakes"- an elegant miniature-joke. Your labor Johannes Kepler dedicated to a friend Johann Matthias Wacker von Wackenfels, adviser to Emperor Rudolph II, who Kepler as a New Year's gift, I thought of giving "Nothing". So, in search of a New Year's gift, I. Kepler reflects:
“I'm crossing a bridge tormented by shame - I left you without a New Year's gift! And then I get a good opportunity! Water vapor, condensed from the cold into snow, falls like snowflakes on my clothes, all as one, hexagonal, with fluffy rays. I swear by Hercules, here is a thing that is smaller than any drop, has a shape, can serve as a long-awaited New Year's gift to a lover of Nothing, and is worthy of a mathematician who possesses Nothing and receives Nothing, because it falls from the sky and conceals in itself the likeness of a hexagonal star!
Johannes Kepler knowingly compares "Nothing" and a snowflake. After all, in Latin Nix means "snow" in German Nihil- "nothing". The scientist wonders why the snowflakes, before falling into large flakes, fall in hexagons and fluffy, like feathers with six rays.
And why, whenever it starts to snow, the first snowflakes have the shape of a hexagonal star. Therefore, there must be a specific reason for this. Turning to geometry, the scientist noticed that the honeycombs are also built in a hexagonal order:
“any cell in the honeycomb is surrounded by six other cells, each of which has one common wall with it. The base of each cell has three planes, which, connecting with its sides, form six polyhedral angles. The trihedral bottom of the cell has a shape that geometers call a rhombus. But why do bees build hexagonal combs and not another? But because the regular hexagon covers the largest area without gaps. Bees intuitively tend to build as large a comb as possible in order to store more honey.
Observing that water vapor thickens under the influence of cold, the scientist asks the question: can cold be considered the reason why snow has a hexagonal shape? And why do frosty patterns form on the windows in winter? The answer is:
“The winter chill seeps in through cracks in the windows. Near these narrow cracks there is a confrontation with heat. Heat moves up and cold goes down. Indeed, in heat, the substance expands, and in the cold it becomes denser and heavier, and from this the heat is pushed upwards. Therefore, when the vapor accumulated inside rushes out, the cold accumulated outside rushes inward, which makes the edges of an open window or crack especially cold. Reaching them, the steam will constantly freeze, and the movements of steam and air in one direction or the other create those stripes and sharp rays. Steam settles on them.
However, the reason for the hexagonal shape of snowflakes is still not clear. Finally Kepler I noticed that snowflakes do not immediately fall flat when they fall. For a few moments, individual parts of them stood upright and only some time later fell to the ground. Why?
“Hexagonal stars arise when three lowered diameters fall, connected at one point so that their ends are evenly distributed around the circumference, and fall to the ground with only three lowered rays, while the other three rays, which serve as continuations of the first, remain raised until , until the rays on which the asterisk rests unbend and the other rays sticking up descend on the same plane in the intervals between the first three rays.
If you ask a mathematician in which figure the three diameters intersect at one point orthogonally, or in the form of a double cross, then the mathematician will answer: in an octahedron, the opposite vertices of which are connected. But the octahedron has exactly six vertices. How does it happen that falling snow, before becoming flat, with its three diameters at right angles to each other, forms the skeleton of an octahedron?
So, the cubic arrangement in space of the drops that make up the snow is due to the internal heat of the vapor. It fixes imaginary vapor drops along three diameters, placing them in an octahedral order so that the substance, condensing, accumulates along the indicated diameters. It should also be added that all the fluffs from the center are directed outward, like needles on a spruce branch. This indicates that the formative force is concentrated in the center and acts from there equally in all directions.
Kepler suggested that three chosen diameters arise for the same reason that there are three chosen directions in the bodies of living beings: top, bottom, front and back, as well as right and left sides.
The emergence of six chosen directions in the bodies of animals suggests that the bodies of animals are not only created according to the archetype of geometric figures, namely the cube, but also because of the need to achieve a certain goal. A person can also be likened to a cube assembled from various elements.
So, having studied everything that was possible, the scientist came to the following conclusion: "The hexagonal shape of the snow is due to constant numerical ratios."
What is the purpose of snow formation? I. Kepler answers:
“The formative principle not only seeks to achieve the goal, but also contributes to decoration, not only gives rise to natural bodies, but is also not alien to fleeting amusements, as evidenced by numerous examples of fossils. And if nature is amused, not devoid of a sense of humor, then life without philosophy is dead!
Weightless snowflakes are the fabulous beauty of the miraculous nature! Currently, beautiful photographs of snowflakes taken with a macro lens were created by a Canadian photographer Don Komarechka (Don Komarechka).
Understanding the process of shaping allowed scientists to create snowflakes themselves, obtaining information about the physics of crystal growth and models of their formation. The study of snowflakes can also help in the study of climate change and the properties of water in general.
Miniature I. Kepler " About hexagonal snowflakes”is not only a rarity of science, a document of theoretical crystallography and the pride of its history. According to the historian of crystallography I. I. Shafranovsky:
"This is the abundance of the deepest ideas, the breadth of approach in considering the causes of the formation of snowflakes, wonderful geometric generalizations, the boldness and wit of the hypotheses expressed."
And although the work was written more than four centuries ago, but even today the reader is fascinated by how accurate scientific information Johannes Kepler managed to teach in a playful form of a New Year's story.
Happy reading!
Reznik Marina Vasilievna,
librarian of the city lending department
