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Why are snowflakes different for kids. Why are snowflakes so different in shape? Such are the interesting reasons for the emergence of a huge number of varieties of snowflakes.

Dear readers, hello! We have a new, well, very entertaining project. All of us have caught small white parachutes falling from the sky on mittens or in warm palms, and sometimes right in our mouths! But where do these patterned ice crystals come from, and do you know what snowflakes are?

Lesson plan:

How do snowflakes appear?

Snowflakes exist in nature thanks to water vapor. From the accumulation of water rain falls in the summer, but in winter the cold air freezes small droplets of water and as a result it snows.

How does this fragile miracle come about? The beginning of each patterned crystal is given by its middle - the core, which can be any speck of dust from the cloud. This speck of dust, as it moves through the clouds, is overgrown with transparent ice crystals, which give it a certain shape. Gradually, so many crystals are glued that the weight of the dust particle makes it fall to the ground.

If you carefully consider the patterns of snowflakes falling from the sky, you can easily notice that none of them is similar to the other.

Interesting Facts! An ordinary snowflake weighs about 1 milligram, rarely 2 or 3. But the most Bolshukhansky ones fell in 1944 in Moscow. You can't even call them snowflakes. The size of a palm, they looked more like ostrich feathers.

Why are snowflakes different?

The question of why ice crystals fall from the sky in different shapes has always been of interest to scientists. The first to think about their structure was the German astronomer Kepler. He wondered why pentagonal or heptagonal snowflakes did not fall from the sky.

The French mathematician Descartes first made a detailed description of what ice crystals might look like and divided them into groups. Rare forms are mentioned in his works.

When the microscope was invented, English physicist Hooke published graphic images of snowflakes, showing all the unique intricate patterns of the natural wonder.

Russian photographer Sigson even managed to take a photo of about two hundred different snowflakes. But the real snow pioneer of photography was the American Bentley, who took 5,000 pictures in his life, of which 2,500 were included in the book Snow Crystals.

Japanese physicist Nakaya learned how to grow snowflakes in the lab. He poetically called them letters from heaven.

As a result of the work of scientists from different countries, it became clear that

in nature there is no other form of snowflakes, except for hexagonal,
the species depends on the environment in which the ice crystal is born,
among the factors affecting the shape are air temperature and humidity,
the simplest patterns appear when the air is not very humid,
the higher the percentage of humidity and air temperature, the more complex and beautiful the snowflake turns out.
the angle between the beams can be either 60 or 120 degrees.

Interesting Facts! A snowflake falling on the water creates a high pitched sound. A person, of course, does not hear him, but, as scientists say, such noise is extremely unpleasant for fish.

Now you know where snowflakes come from and why they are different. All ice crystals were conventionally divided into seven simple groups and given their conventional names.

Plate

The simplest of all, thin and flat. She has many edges that divide the crystal into parts.

Column

These snowflakes, resembling a hollow hexagonal pencil, are the most common of all shapes. It can be blunt or pointed at the ends.

Column with a tip

This type is obtained if an ordinary column falls into certain conditions under which the crystal changes the direction of its growth and gradually turns into a plate at the ends. For example, this happens when moving to another temperature zone under the influence of wind.

Needle

This is a kind of columnar snowflake that has grown thin and long. It happens that they have a cavity inside, but sometimes they open at the ends in the form of branches.

Stars

This specimen has a beautiful branching silhouette that we love to admire. It has six absolutely symmetrical main rays and many different branches. They are about 5 mm in size and are usually flat.

Spatial dendrites

Amazing patterned crystals are voluminous due to the combination of various other types.

Wrong snowflakes

Yes, there is also such a group, which includes damaged representatives who, on the way to us, damaged their twigs or completely broke into pieces. Such crippled snowflakes are usually obtained in strong winds, there are many of them in wet snow.

Remember, we said that different forms are obtained under different conditions? So here it is

stars are usually obtained at temperatures down to -5 degrees,
but the needles - from -5 to -10,
for complex dendrites, the temperature should be at least -10 and not lower than -20 degrees,
but plates and columns of different sizes are formed even with air at -35.

Interesting Facts! It is estimated that half of the inhabitants of the Earth have never seen snowflakes. But they have a chance to come north or visit the world's only snowflake museum in Japan on the island of Hokkaido.

Here is an interesting project we have today. Look to us more often, there is still a lot of interesting things in the world to tell about!

By the way, we have already talked about many interesting things. For example, about why leaves turn yellow in autumn. we got acquainted with winter folk signs, and learned more about ball lightning.
Evgenia Klimkovich.

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 especially 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 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!” This is 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 the 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 atmospheric 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, their sharp corners are smoothed out. 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 world's population has 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.

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.

A snowflake begins its life in a cloud when an ice crystal forms around a small speck of dust. Ice crystals are shaped like a hexagon. It is because of this that most snowflakes are shaped like a six-pointed star.

How exactly a snowflake will grow at a given moment depends on the current conditions around the snowflake: humidity, temperature, pressure, shape of the snowflake. And even the smallest changes in these parameters can change the course of snowflake growth.

Conditions are constantly changing. And it turns out that the snowflake then grows in width, then its rays grow. In cold and dry weather, snowflakes generally grow in height, and not in width, and hexagonal columns are obtained, and not the spreading stars we are used to.

The direction of growth of snowflake changes is always due to the fact that ice crystals are hexagonal. Two crystals cannot be connected at an angle, they are always attached to each other by a face. Therefore, the rays always grow in six directions, and a "branch" can depart from the beam only at an angle of 60 or 120 degrees.

Since each snowflake lives its own life and the external conditions for all of them are at least minimal, but different, then all snowflakes are different. No snowflakes are exactly the same - each of them goes through different combinations of humidity, pressure and temperature.