Snowflakes, unique and inimitable, have always interested scientists, and some of them have devoted their entire lives to the study of ice crystals.
One of the first scientists to think about the structure of snow was a German mathematician and astronomer. Johannes Kepler(1571-1630). In 1611, he published a short treatise, The New Year's Gift, or On Hexagonal Snowflakes, which can be called the first scientific work dedicated to snowflakes.
Since whenever it starts to snow, the first snowflakes are in the shape of a hexagonal star, there must be a reason for this. For if this is an accident, then why are there no pentagonal or heptagonal snowflakes, why do hexagonal ones always fall, unless they lose their shape from collisions, do not stick together in multitude, but fall rarely and separately?
- Johannes Kepler, New Year's gift, or On hexagonal snowflakes, 1611 (translated by Yu. A. Danilov)
Rene Descartes(1596-1650), French philosopher and mathematician, was the first to describe in detail the shape of snowflakes. Interestingly, even very rare forms of ice crystals are mentioned in Descartes' notes, for example, topped columns.
They were small plates of ice, flat, very smooth and transparent, about the thickness of a sheet of thick paper... perfectly folded into hexagons, the sides of which were so straight and the angles so equal... it is impossible for a person to create anything like that.
— René Descartes, 1635
The invention of the microscope allowed the English physicist Robert Hooke(1635-1703) to publish in 1665 a work called "Micrography", in which the scientist described everything that he could examine with the help of a new instrument. The publication includes many drawings of snowflakes, which for the first time showed the complexity and intricacy of snow crystals.
Drawing from "Micrography" by Robert Hooke
Quote
While examining snowflakes with a microscope, I found... the higher the magnification, the more asymmetrical they appear. But this asymmetry can be attributed to melting or damage during the fall, but not to a defect in Nature.
— Robert Hooke, Micrography, 1665
One of the first famous snowflake photographers was Andrei Andreevich Sigson(1840-1907), Russian photographer from Rybinsk. In total, he was able to take photographs of about 200 different forms of ice crystals. To do this, the photographer used a special technology: snowflakes were caught on a mesh of silk, then magnified by 15-24 times using a microscope. To prevent the fragile crystals from melting while photographing, Sigson cooled his hands and breathed through a special tube.
Snowflakes Sigson
The American pioneer of snowflake photography was Wilson Bentley(1865-1931). Throughout his life, he took about 5,000 pictures of snowflakes. 2500 of them were published in 1931 in the book Snow Crystals.
Snowflakes Bentley, 1902
Ukihiro Nakaya(1900-1962), Japanese physicist - the first scientist who systematized knowledge about ice crystals. Nakaya not only photographed snowflakes, but also learned how to grow them in the laboratory. The result of the scientist's research was the book "Snow Crystals: Natural and Artificial", released in 1954.
Snow crystals are letters sent to us from heaven.
— Ukihiro Nakaya, documentary"Snow Crystals", 1939
So how do snowflakes form?
Snowflakes originate in clouds, where ice crystals form on the smallest dust particles at a negative temperature. Then new ones grow on these crystals, and so on. The structure of the water molecule determines the hexagonal shape of the crystal; only 60° and 120° angles are possible between its rays.
Since at each moment in time the conditions in which a snowflake grows, at least minimally, are different, each crystal has a unique shape. Moreover, all the rays of one snowflake are very similar, since they crystallize simultaneously in very similar conditions.
How many types of snowflakes are there?
Despite the uniqueness of the crystals, they still lend themselves to classification. However, according to the American scientist Kenneth Libbrecht of the California Institute of Technology, this is not an easy task, since to some extent this is a matter of taste for each researcher. Libbrecht himself makes 35 types of snowflakes; Ukihiro Nakaya - 41 and the most complex classification proposed by meteorologists Magono and Lee in 1966 - 80 different types of snow crystals.
Classification Ukihiro Nakaya. U. Nakaya | Snow Crystals: Natural and Artificial (Harvard University Press, 1954)
However, there is a simpler classification developed in 1951 by the Snow and Ice Commission of the International Association for Scientific Hydrology - only 7 forms of snow crystals and 3 types of frozen precipitation.
Snowflake classes according to the International Snow Classification. A. K. Dyunin, In the kingdom of snow, Publishing house "Science", Novosibirsk, 1983
1. Records
The simplest of snowflakes are flat hexagonal prisms.
High-high in the sky, where the air temperature is -30 and less, water vapor clouds form snowflakes. They don't appear on their own. Like pearls, they need a core, a starting point from which the rays of a snow star will grow. It can be anything - a frozen droplet, a particle of smoke, dust. First, a hexagonal shell is formed around the nucleus, from the corners of which rays can then grow.
The shape of a snowflake depends on temperature, humidity, wind, and whether the snowflake fell flat or edge-on.
There are a lot of types of snowflakes, but there are several main types:
Prisms- hexagonal plates or thin columns.
Sometimes a cavity can form inside the column, then it is called hollow column.
Needles- long, thin crystals.
Dendrites- snowflakes, as they are most often drawn and cut out of paper.
The name of these snowflakes means "tree-like". Their rays actually resemble tree branches. Separately allocate fern dendrites- they resemble flat fern bushes.
Poles with tips- a hexagonal column, at the ends of which symmetrical plates have grown.
If the column is short, and the plates are of different sizes, then such a snowflake is called double plate.
Twelve ray snowflakes- sometimes plates of columns with tips are formed with a rotation relative to each other and the rays that have grown from them create a twelve-ray star.
Dimensional Crystals are obtained when not one, but several snowflakes grow from the nucleus. Over time, they can split into individual stars.
crystals irregular shape appear when many small snowflakes have grown together with each other.
Actually hexagonal, just three of the six arms are shorter than the others.
are among the most common. Their rays do not branch, growing in breadth.
If the edges appear on the rays, then the snowflake is called plate with sectors.
Snowflakes are transparent. But when they stick together in flakes, the light gets tangled in their edges and therefore the snow looks white.
Very high, in the sky, where the temperature is -30, there is an accumulation of water droplets - clouds. In the warm season, drops of water fall in the form of rain, and when winter comes, the cold freezes microscopic drops of water and turns them into ice crystals - snowflakes. There are so many snowflakes and they are all different - no one is the same.
The largest snowflake ever recorded was 12 cm in diameter. Typically, snowflakes are about 5 mm in diameter with a mass of 0.004 g.
There is even a classification of snowflakes according to a similar type:
Prisms- there are both 6-coal plates and thin columns with a 6-coal section. Prisms are tiny and almost invisible to the naked eye. The edges of the prism are very often decorated with various complex patterns.
Needles- thin and long snow crystals, they form at a temperature of about -5 degrees.
When viewed, they look like small light hairs.
Dendrites- or tree-like, have pronounced branching thin rays. More often these are large crystals, they can be seen with the naked eye. The maximum size of a dendrite can reach 30 cm in diameter.
12-ray snowflakes- sometimes columns with tips are formed with the rotation of the plates relative to each other by 30 degrees. When rays grow from each plate, a crystal with 12 rays is obtained.
double records- in this type, the posts with tips have a short vertical part. The plates grow very quickly, from water vapor one of the bottom obscures the second and as a result grows larger in size.
hollow posts- inside columns with a hexagonal section, cavities sometimes form. Interestingly, the shape of the cavities is symmetrical with respect to the center of the crystal. High magnification is needed to see half of the small snowflakes.
fern-like dendrites- this type is one of the largest. The branches of stellate dendrites grow thin and very frequent, as a result, the snowflake begins to look like a fern.
Dimensional Crystals- it happens that from a microscopic drop several snow crystals begin to grow in different directions. And then they can take on a complex shape. Such intergrown crystals can disintegrate into several simple snowflakes.
artificial snow- with the help of special snow guns, small drops of water are sprayed into the air, which freeze in flight. As a result, such artificial snowflakes look like frozen drops of water.
Irregular crystals- snow crystals are often small, asymmetrical and fused with each other. To get beautiful symmetrical crystals, you need to have a good combination of many weather conditions.
triangular crystals- such snowflakes are formed at a temperature of about -2 degrees. In fact, these are hexagonal prisms, some of the sides of which are much shorter than others. But on the faces of such rays can grow.
Poles with tips- such snowflakes are rarely seen. Crystals begin to grow in the form of columns, but after the wind carries them to a zone with other weather conditions, and then plates begin to grow at their ends.
star-shaped snowflakes- such snowflakes are widespread. These are thin lamellar crystals, in the form of stars with six rays. More often they are decorated with symmetrical various patterns. Such snowflakes appear at -2 °C or at -15 °C.
Plate with sectors is a star-shaped lamellar snowflake, but with particularly prominent edges that indicate the angles between adjacent prism faces.
Snowflakes, unique and inimitable, have always interested scientists, and some of them have devoted their entire lives to the study of ice crystals.
One of the first scientists to think about the structure of snow was a German mathematician and astronomer. Johannes Kepler(1571-1630). In 1611, he published a short treatise, The New Year's Gift, or On the Hexagonal Snowflakes, which can be called the first scientific work on snowflakes.
Since whenever it starts to snow, the first snowflakes are in the shape of a hexagonal star, there must be a reason for this. For if this is an accident, then why are there no pentagonal or heptagonal snowflakes, why do hexagonal ones always fall, unless they lose their shape from collisions, do not stick together in multitude, but fall rarely and separately?
- Johannes Kepler, New Year's gift, or On hexagonal snowflakes, 1611 (translated by Yu. A. Danilov)
Rene Descartes(1596-1650), French philosopher and mathematician, was the first to describe in detail the shape of snowflakes. Interestingly, even very rare forms of ice crystals are mentioned in Descartes' notes, for example, topped columns.
They were small plates of ice, flat, very smooth and transparent, about the thickness of a sheet of thick paper... perfectly folded into hexagons, the sides of which were so straight and the angles so equal... it is impossible for a person to create anything like that.
— René Descartes, 1635
The invention of the microscope allowed the English physicist Robert Hooke(1635-1703) to publish in 1665 a work called "Micrography", in which the scientist described everything that he could examine with the help of a new instrument. The publication includes many drawings of snowflakes, which for the first time showed the complexity and intricacy of snow crystals.
Drawing from "Micrography" by Robert Hooke
Quote
While examining snowflakes with a microscope, I found... the higher the magnification, the more asymmetrical they appear. But this asymmetry can be attributed to melting or damage during the fall, but not to a defect in Nature.
— Robert Hooke, Micrography, 1665
One of the first famous snowflake photographers was Andrei Andreevich Sigson(1840-1907), Russian photographer from Rybinsk. In total, he was able to take photographs of about 200 different forms of ice crystals. To do this, the photographer used a special technology: snowflakes were caught on a mesh of silk, then magnified by 15-24 times using a microscope. To prevent the fragile crystals from melting while photographing, Sigson cooled his hands and breathed through a special tube.
Snowflakes Sigson
The American pioneer of snowflake photography was Wilson Bentley(1865-1931). Throughout his life, he took about 5,000 pictures of snowflakes. 2500 of them were published in 1931 in the book Snow Crystals.
Snowflakes Bentley, 1902
Ukihiro Nakaya(1900-1962), Japanese physicist - the first scientist who systematized knowledge about ice crystals. Nakaya not only photographed snowflakes, but also learned how to grow them in the laboratory. The result of the scientist's research was the book "Snow Crystals: Natural and Artificial", released in 1954.
Snow crystals are letters sent to us from heaven.
— Ukihiro Nakaya, documentary Snow Crystals, 1939
So how do snowflakes form?
Snowflakes originate in clouds, where ice crystals form on the smallest dust particles at a negative temperature. Then new ones grow on these crystals, and so on. The structure of the water molecule determines the hexagonal shape of the crystal; only 60° and 120° angles are possible between its rays.
Since at each moment in time the conditions in which a snowflake grows, at least minimally, are different, each crystal has a unique shape. Moreover, all the rays of one snowflake are very similar, since they crystallize simultaneously in very similar conditions.
How many types of snowflakes are there?
Despite the uniqueness of the crystals, they still lend themselves to classification. However, according to the American scientist Kenneth Libbrecht of the California Institute of Technology, this is not an easy task, since to some extent this is a matter of taste for each researcher. Libbrecht himself makes 35 types of snowflakes; Ukihiro Nakaya - 41 and the most complex classification proposed by meteorologists Magono and Lee in 1966 - 80 different types of snow crystals.
Classification Ukihiro Nakaya. U. Nakaya | Snow Crystals: Natural and Artificial (Harvard University Press, 1954)
However, there is a simpler classification developed in 1951 by the Snow and Ice Commission of the International Association for Scientific Hydrology - only 7 forms of snow crystals and 3 types of frozen precipitation.
Snowflake classes according to the International Snow Classification. A. K. Dyunin, In the kingdom of snow, Publishing house "Science", Novosibirsk, 1983
1. Records
The simplest of snowflakes are flat hexagonal prisms.
It seems that there is nothing more weightless than tiny snowflakes: if it falls on your hand, you won't feel it. A thin “net” seems to be hanging in the air, and they all fall, fall - hundreds, millions, billions ... In a few hours, vast spaces are covered with a fluffy “blanket”. When it snows, you rarely think about the nature of snow, even less often - snowflakes. (Hurry up to go home - in warmth!) But it turns out - this is a complex structure of ice crystals linked to each other. There are many options for “assembling” snowflakes - so far it has not been possible to find two identical ...
A crystal snowflake floated in the sky.
Friends are flying nearby - it's not scary in the clouds.
One she is a snowflake, and millions are snow,
And from a height of heaven - a swift run.
The flight is pleasant in the sky, but soon on the ground
They will turn into snowdrifts to the joy of the children! ..
Crystal snowflake - when she is alone!
Oleg ESIN
Mystery of birth
How does ordinary water, freezing, form such a multitude of symmetrical lacy shapes? To understand why snowflakes look so beautiful, let's get acquainted with the life story of one snow crystal.
Clouds always contain ice or foreign dust particles. They serve as the basis for the tiny core of the snowflake. Molecules of water vapor, moving chaotically, cool down and, losing speed, “are eager to land”. And then there's the dust! Thanks to the crystals, it acquires patterns and turns from an “ugly duckling into a beautiful swan” - a crystal snowflake.
Law breakers
Each snowflake is unique. Back in the 17th century, the philosopher and mathematician R. Descartes wrote that these creatures look like roses, lilies, wheels with six teeth. He was particularly struck by the “tiny white dot” located in the center of the snowflake, as if it were the footprint of a compass, which was used to outline its circumference. The great astronomer I. Kepler explained the shape of snowflakes by the will of God... Be that as it may, isn't it a miracle?! Real magic!
Magic is magic, but how does such a variety of snowflakes turn out? It turns out that under some conditions, the “ice” grows intensively along the axis, forming elongated columns and needles, in others they prefer to grow perpendicular to the axis, eventually showing plates or stars. Everything seems to be simple and clear.
And yet there is one mystery - the secret of the structure of snowflakes. According to physical laws, where strict order reigns, there is no place for chaos. And vice versa. And only at the birth of these creatures order and chaos somehow coexist together.
It is known that a solid body must be either in the form of a crystal (the atoms are ordered) or in an amorphous state (they form a random grid). Snowflakes, on the other hand, break all laws: they have a lattice, where oxygen atoms (and later water molecules) are lined up strictly in places, like soldiers in the ranks, and hydrogen atoms are random. But, joining the oxygen atoms, the hydrogen "tramps" form smooth faces, and... regular hexagonal prisms are born.
Young snowflakes are never pentagonal or heptagonal. Every time I never cease to admire the amazing mathematical precision with which nature creates its masterpieces. Amazing! Jewelers are just relaxing...
However, sooner or later, snowflakes begin to gain weight: new water molecules are attracted to each face and tubercle - irregularities appear. When traveling in the clouds, snowflakes grow rapidly: one thick beam appears from the edge, branches from the tubercles. If all six faces are in the same conditions, “twin” rays are formed.
Air waltz
When the snowflakes grow up and they, the numerous “children of the clouds”, become crowded in their father’s house, they, with “bold curiosity”, decide to try their luck - to go on an air journey to the earth, which can only conditionally be called a fall. K. Balmont colorfully described the flight of a snowflake: “Under the blowing wind it trembles, rises, on it, cherishing, it sways lightly.”
Air currents pick up light “fluffs”, carry them to the side, lift them up, circle in a whirlwind of dance - “snowflakes, like laughter, dance on the fly ...” And they are “light, winged, like night butterflies”, know yourself having fun and sing a song by A. Tvardovsky on the fly:
We are white snowflakes
We fly, we fly, we fly.
Paths and paths
We'll screw everything up.
Let's circle over the garden
On a cold winter day
And quietly sit next to each other
With people like us.
Dancing over the fields
We lead our round dance.
Where, we don't know
The wind will carry us.
And at first glance it may seem that “... They don't care about anything! - In light dresses with lace, with a bare shoulder ... ”But this is not entirely true!
Losing shape
Snowflakes fluttering in the air are in danger. Once in the warmer "edges", they can melt, turning into raindrops or grits. In addition, their enemy is evaporation, especially in the wind and at low humidity. The smaller the snowflake, the faster it melts: sharp tips are smoothed out, lacy bulges disappear. And the longer it falls, the more it rounds.
When there is no wind, snowflakes cling to each other into huge flakes - swirling “saucers”. And it happens that during severe frosts (below -30 ° C), ice crystals “freeze”, a strong wind mercilessly breaks their fragile rays, or they break and crumble, colliding with each other, and fall to the ground in the form of “diamond dust” - very fluffy snow made of thin ice needles.
Only a small part of the “princesses of the air ball” reaches the earth without incident - safe and sound. However, their girlfriends, who have changed beyond recognition, are also snowflakes, although they are asymmetrical. And the opinion that they must necessarily be hexagonal stars is erroneous. Those who have just been born - yes, but those “wise with experience”, who have known heat, wind and water, lose their former beauty. Their forms are no longer so elegant and regular, but still very diverse.
whole science
It is difficult to classify a phenomenon that has no repetition in nature. All snowflakes are different, and separating them is largely a matter of personal preference. For a long time, scientists could not photograph a snowflake under a microscope.
For the first time this was done in 1885 by the American W. Bentley, nicknamed “Snowflake”. For 46 years, he has created a collection of over 5,000 unique photographs, proving that no pair of snowflakes are exactly alike. Their study turned into a science, and in 1951 the International Commission on Snow and Ice adopted a classification of ice crystals, including seven main types of snowflakes and three types of icy precipitation (fine snow grains, ice grains and hail).
However, it's time for the snowflakes to introduce themselves - so many times we have mentioned their magic and uniqueness.
Let's get acquainted!
I am a snowflake fluff, a beautiful and amazing creation of nature. Not without reason remarkable verses are devoted to me. Listen to how K. Balmont wrote about me: “Light-fluffy, white snowflake, how pure, how bold!” It's about me! But I'm not alone. We are very, very many.
The most beautiful are thin (only 0.1 mm thick) star-shaped crystals, or dendrites (I also belong to this group). Our tree-like, openwork, branching body (diameter 5 mm or more) consists of six symmetrical main branches and many branches - as you like.
Our closest relatives are the disc sisters. They are flat and thin, like us. However, they are inferior to us in beauty: a lot of ice ribs divide the blades of their body into sectors - also nothing, but there is no such grace as ours!
And let there be few of us, but my sisters and I are masterpieces. It is we - lamellar snowflakes - that attract the eye more than other types of snowflakes. And the most numerous of our relatives are columns, or columns. This is a form of crystals in the form of hexagons and pencils, with caps, pointed at the ends...
It happens that the columns, flying in a whirlwind of dance into a zone with a different temperature, change their “orientation” - they turn into plates. And they are already called columns (or columns) with tips.
Among columnar crystals, individual “accelerate” specimens grow long and thin. They are called needles. Sometimes cavities remain inside them, and the ends split into branches.
Some of our “flat and columnar” relatives decide to live in “families” - three-dimensional structures. By the way, very interesting complex creations are obtained - spatial dendrites: crystals, growing together, retain their individuality - each branch is located in its own plane.
A lot of troubles fall to the share of “snowflakes-ballerinas”: in heat or in a strong wind they lose branches, break. Usually there are a lot of such “cripples” in wet snow. These are irregularly shaped crystals.
colorful snow
The fact that snow is not pure white, but slightly blue, has long been known. Make a hole in it about a meter. The light in the thickness of the snow near the edge of the hole will appear yellowish, deeper - yellowish-green, bluish-greenish, and finally bright blue. The reflection of the sky has nothing to do with it. And in cloudy weather, and when using a cardboard tube - nothing will change. Why does blueness occur?
The ice of snowflakes is transparent, and sunlight, reflected and scattered on their many faces, loses red and yellow rays, retaining only bluish-green, blue or bright blue - depending on the thickness of the crystal. But when there are a lot of snowflakes, the impression of a white mass is created.
In different areas - "their" snow, a special shape and color. In the arctic regions, you can see pink or red snow - this color it acquires due to algae living between the crystals. There are cases when blue, green, gray and even black snow fell (apparently due to soot and industrial air pollution).
He's getting old just like us.
But let's get back to fresh loose snow in the form of stars, needles, columns ... Myriads of snowflakes are not like grains of sand: like living beings, being together, they immediately begin to actively interact: they evaporate, sharp corners. Excess steam goes into a solid (or liquid) state. Ice builds up in the center of the snowflakes. Small crystals disappear, large ones become larger, losing their uniqueness. Ice bridges appear. There is less and less air in the snow “house”, the snow is compacted, hardens, turning into compacted, then compacted and, finally, into firn - dense coarse-grained snow from compressed ice grains.
These processes are observed in any “long-playing” snow cover. They are accelerated by thaws, they are affected by winds. And if the snowflakes fell in the form of grains, forming already dense snow, then its “aging” accelerates ...
“Snow is swirling, snow is falling - snow! Snow! Snow!..” Fresh snow on a frosty day is always accompanied by a cheerful crunch underfoot. And it is nothing but the sound of breaking crystals. We cannot perceive the sound of one broken snowflake, but a myriad of crushed crystals create a very distinct creak.
Try to catch this fragile celestial beauty on a mitten and examine it properly. You will see for yourself that this is magic, a real miracle! And marvel at its magnificence!
Figures and facts:
- More than half of the population the globe never seen real snow.
- In 1 m3 of snow there are 350 million snowflakes, and throughout the Earth - 10 to the 24th degree. The weight of a snowflake is only about 1 mg, rarely - 2-3 mg. However, when combined, billions of almost weightless snowflakes can even affect the speed of the Earth's rotation. By the way, by the end of winter, the mass of snow cover on the planet reaches 13,500 billion tons.
- German meteorologists managed to calculate that several septillions (a number with 24 zeros) of snowflakes fall on Germany every year, among which there are not even two identical ones.
- The diameter of most snowflakes is about 5 mm. Although there are exceptions. On April 30, 1944, amazing snow fell in Moscow - palm-sized snowflakes resembling ostrich feathers. The officially registered “record holder” had a circumference of 12 cm.
- It turns out that white color gives the snow ... air (95 percent). Loose and fluffy snow is saturated with air bubbles, from the walls of which light is reflected. The presence of air also determines the very low density of snowflakes and snow and the slow speed of their fall (0.9 km/h).
- The Japanese scientist N. Ukichiro called snow "a letter from heaven, written in secret hieroglyphs." He was the first to create a classification of snowflakes. The only snowflake museum in the world on the island of Hokkaido is named after him.