Are there 2 identical snowflakes. Snow theory: there are no two identical snowflakes

Scientists identify two options for the formation of snow crystals. In the first case, water vapor carried by the wind to a very high altitude, where the temperature is about 40 ° C, can suddenly freeze, forming ice crystals. In the lower cloud layer, where water freezes more slowly, a crystal forms around a small speck of dust or soil particles. This crystal, of which there are from 2 to 200 in one snowflake, has the shape of a hexagon, so most snowflakes are a six-pointed star.

"Land of Snows" - such a poetic name was invented for Tibet by its inhabitants.

The shape of a snowflake depends on many factors: temperature around, humidity, pressure. Nevertheless, there are 7 main types of crystals: plates (if the temperature in the cloud is from -3 to 0 ° C), star crystals, columns (from -8 to -5 ° C), needles, spatial dendrites, columns with a tip, etc. irregular shapes. It is noteworthy that if the snowflake rotates when it falls, then its shape will be ideally symmetrical, but if it falls sideways or otherwise, then it will not.

Ice crystals are hexagonal: they cannot be connected by an angle - only by a face. Therefore, the rays from the snowflake always grow in six directions, and the branching from the ray can only depart at an angle of 60 or 120 °.

Since 2012, on the penultimate Sunday of January, the World Snow Day has been celebrated. This was initiated by the International Ski Federation.

Snowflakes appear white because of the air contained in them: light of different frequencies is reflected on the edges between the crystals and is scattered. The size of an ordinary snowflake is about 5 mm in diameter, and the mass is 0, 004 g.

When dubbing the film "Alexander Nevsky", the creak of snow was obtained by squeezing mixed sugar and salt.

It is believed that no two snowflakes are alike. This was first proved in 1885, when the American farmer Wilson Bentley took the first successful microscope picture of a snowflake. He devoted 46 years to this and took more than 5000 photographs, on the basis of which the theory was confirmed.

The statement, familiar to every schoolchild, that there are no two identical snowflakes, was repeatedly questioned. But the unique research of the California Institute of Technology was able to put the final point on this truly New Year's question.

Snow is formed when microscopic water droplets in clouds are attracted to dust particles and freeze.

Ice crystals appearing at the same time, not exceeding at first 0.1 mm in diameter, fall down and grow as a result of moisture condensation from the air on them. In this case, six-pointed crystalline forms are formed.

Due to the structure of water molecules, angles of only 60 ° and 120 ° are possible between the beams of the crystal. The main water crystal has the shape of a regular hexagon in the plane. On the tops of such a hexagon, then new crystals are deposited, on them new ones, and this is how various forms of snowflake stars are obtained.

University of California physics professor Kenneth Libbrecht has unveiled the results of many years of research by his research group. "If you see two identical snowflakes, they are still different!" - says the professor.

Libbrecht proved that in the composition of snow molecules for about every five hundred oxygen atoms with a mass of 16 g / mol, there is one atom with a mass of 18 g / mol.

The structure of the bonds of a molecule with such an atom is such that it assumes an infinite number of variants of compounds within the crystal lattice.

In other words - if two snowflakes really look the same, then their identity still needs to be checked at the microscopic level.

Studying the properties of snow (and, in particular, snowflakes) is not child's play. Knowledge about the nature of snow and snow clouds is very important when studying climate change.

The young farmer Wilson Alison Bentley, nicknamed "Snowflake", pioneered the study of the "theory of snow". From childhood, he was attracted by the unusual shape of crystals falling from the sky. In his hometown of Jericho, in the northern United States, snowfall was a regular occurrence, and young Wilson spent a lot of time outside studying snowflakes.

Whislon "Snowflakes" Bentley

Bentley adapted a camera to the microscope donated by his mother for the 15th birthday and tried to capture the snowflakes. But it took almost five years to improve the technology - only on January 15, 1885 the first clear picture was received.

Throughout his life, Wilson captured 5000 different snowflakes in photographs. He never ceased to admire the beauty of these miniature works of nature. To obtain his masterpieces, Bentley worked in sub-zero temperatures, placing each whole snowflake he found on a black background.

Wilson's work has been praised by both scholars and artists. He was often invited to speak at scientific conferences or exhibit photographs in art galleries. Unfortunately, Bentley died at the age of 65 from pneumonia, without proving that there are no identical snowflakes.

A hundred years later, Nancy Knight, a researcher at the National Center for Atmospheric Research, took up the baton of "snow theory". In a paper published in 1988, she proved the opposite - the same snowflakes can and should exist!

Dr. Knight tried to replicate the process of building snowflakes in a laboratory setting. To do this, she grew several water crystals, subjecting them to the same processes of hypothermia and supersaturation. As a result of the experiments, she managed to get snowflakes absolutely identical to each other.

Further field observations and processing of experimental errors allowed Nancy Knight to assert that the appearance of identical snowflakes is possible and is determined only by the theory of probability. After compiling a comparative catalog of celestial crystals, Knight concluded that there are 100 signs of difference in snowflakes. So, the total number of appearance options is 100! those. almost 10 to the 158th power.

The resulting number is twice as many as the number of atoms in the universe! But this does not mean that coincidences are completely impossible - Dr. Knight concludes in his work.

And now - new research on the "theory of snow". The other day, professor of physics at the University of California, Kenneth Libbrecht, announced the results of many years of research by his scientific group. "If you see two identical snowflakes, they are still different!" - says the professor.

Libbrecht proved that in the composition of snow molecules for about every five hundred oxygen atoms with a mass of 16 g / mol, there is one atom with a mass of 18 g / mol. The structure of the bonds of a molecule with such an atom is such that it assumes an infinite number of variants of compounds within the crystal lattice. In other words - if two snowflakes really look the same, then their identity still needs to be checked at the microscopic level.

Studying the properties of snow (and, in particular, snowflakes) is not child's play. Knowledge about the nature of snow and snow clouds is very important when studying climate change. And some of the unusual and unexplored properties of ice have practical applications.

The same snowflakes occur in nature. In exceptional cases. This was first recorded by specialists from the US National Center for Atmospheric Research in 1988.

Photo: pixabay.com

Researcher Nancy Knight in his work "No Two Alike?" proved that identical snowflakes can occur in nature.

Knight came to this conclusion after she experimentally obtained the same snowflakes in the laboratory. She proved her theory mathematically, through the theory of probability. She deduced 100 distinctive features of snowflakes, by which it can be judged that there are 10 to 158 degrees of different variants of snowflakes. And although the resulting number is infinitely large, this does not rule out the possibility of coincidence of snowflakes, says Knight.

At the same time, according to Professor of Physics at the University of California, Kenneth Libbrecht, outwardly identical snowflakes have differences in the internal structure, namely, in the crystal lattice. Therefore, it cannot be said that, in principle, it is possible to find completely identical snowflakes in shape and in atomic structure.

How are snowflakes formed and why are they different in shape?

The process of snowflake formation involves the sublimation of crystals from the gas phase, bypassing the liquid state. When a snowflake is formed, water molecules grow chaotically from the moment the initial crystal is formed. Thus, the snowflake grows in a disordered manner.

The growth of snowflakes depends on external conditions such as temperature and humidity. Depending on these and other conditions, new layers of molecules are superimposed on each other, each time forming a new shape of a snowflake.

All snowflakes have six faces, because when they freeze, the water molecules line up in a special order, as a result of which a hexagonal geometric figure is formed.

The growth of a snowflake is due to the air temperature at which it was formed. The lower the temperature, the smaller the size of the snowflake will be.

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

Table of contents.

Introduction.

Chapter 1.

1.1 Origin of snowflakes

1.2 Are snowflakes the same?

Chapter 2. My experiments.

Chapter 3 Interesting facts about snowflakes.

4. Conclusion.

5. Sources used.

PURPOSE OF THE STUDY:

explore snowflakes as an amazing natural phenomenon.

RESEARCH OBJECTIVES :

observing snowflakes in nature;

studying the formation of snowflakes;

identification of a variety of shapes of snowflakes;

experimentally observe the formation of snowflakes;

reveal students' knowledge of snowflakes.

HYPOTHESIS.

If water is formed when the snowflakes melt, then the snowflakes emerge from the water.

If there are so many snowflakes, then there must be a large number of identical snowflakes in nature.

SUBJECT OF STUDY.

snowflakes

snow

RELEVANCE OF THE TOPIC. Every little child is very curious and everyone is interested in what, where, how ...?

RESEARCH METHODS:

1. Study of literature about snowflakes.

2. Photographing snowflakes.

3. Conducting experiments.

4. Analysis of the work done.

Research time:January February2017 year.

Introduction.

I'll start with a touching, gentle and mesmerizing poem about a snowflake.

Snowflake.

Light fluffy, white snowflake,

How pure, how bold!

Dear stormy easily sweeps,

Not to the azure heights - asks to land.

Skillful glides in shining rays

Preserved white among the melting flakes.

But here the long road ends,

A crystal star touches the earth.

Lies a fluffy snowflake bold

How clean, how white!

(Constantin Balmont)

Chapter 1.

1.1 Origin of snowflakes

Snow lies. Snowflakes are flying. What is unusual here? It's just winter. And nevertheless, this is another miracle of nature, which this wonderful world gave us! Incredible beauty, isn't it? That's really really - amazing around us. So, when there is snow or snowflakes are flying, you and I observe not just the phenomenon of winter on earth, but a real miracle of nature worthy of study.

A snowflake is a complex symmetrical structure consisting of ice crystals. Snow forms when microscopic water droplets in clouds are attracted to dust particles and freeze. The resulting ice crystals fall down and grow as a result of moisture condensation from the air on them. In this case, six-pointed crystalline forms are formed. And the snowflake is sent to the ground with a six-pointed star. But they reach the ground in the form of snow only if the temperature is below zero. If the temperature is higher, the snowflakes evaporate and turn into water vapor, which rises up again. Or, these crystals melt and fall to the ground in the form of rain or grains. And sometimes it happens that it is snowing on the roof of a high-rise building, but on the street it is already raining.

The type of snowflakes depends on the water content in the cloud where it originated, the air temperature, and the height above sea level. Even if two identical snowflakes were "born", they have to travel to the ground at a speed of about 1 km. in hour. They fall into different temperature conditions and reach the ground with a completely different pattern, but always of a hexagonal shape. Scientists have been able to identify several basic forms of snowflakes. They were even given names:

star,

plate,

column,

needle,

fluff,

hedgehog,

stud.

The shape of the snowflakes depends on the weather.

On a windless frosty day, snowflakes fall slowly. They are large, shiny, like stars. Snowflakes fall one at a time, so it's easy to see them.

In mild frost, snowflakes look like snow balls - "snow pellets". And when the wind is strong, there is "snow dust", as the wind breaks off the rays and edges of the snowflakes.

When there is no frost, falling to the ground, snowflakes stick to each other and form "snow flakes". They are large and resemble pieces of cotton wool. "

Each snowflake is as unique as a fingerprint or human DNA. There are no identical snowflakes, just as there are no identical leaves on trees, identical raindrops, identical people.

But if a snowflake is a crystal, then why is it white, should it be transparent? This is thanks to the air (95%) contained in it! Light is reflected on surfaces between crystals and in the air and scattered. Thanks to the air, the snowflakes are very light. Even during very heavy snow drifts, people or animals can breathe under the snow for a long time.

1.2. Are there the same snowflakes?

Are there two identical snowflakes? No! Farmer Wilson Bentley proved this in his works in 1885, and he managed to take the first photograph of a snowflake under a microscope. And it took him 46 years for this!
Since childhood, he studied the shape of crystals falling from the sky, for which he received the nickname "Snowflake". Wilson devoted his whole life to the study of snowflakes, in total he took 5,000 pictures, and none of them showed repetitive snowflakes.

One of the first scientists to think about the structure of snow was the German mathematician and astronomer Johannes Kepler (1571-1630). In 1611, he published a short treatise "A New Year's Gift, or About Hexagonal Snowflakes", which can be called the first scientific work devoted to snowflakes.

Chapter 2. Research.

I always thought that if water forms after the snow melts, then after freezing the water droplets will turn into snowflakes.

Experiment 1.

I froze the water droplets, but the snowflakes did not work.Which means , snow does not appear from water droplets. Water droplets can become hailstones, lumps of ice, but not snowflakes..

Experiment 2.

In the snow, I went outside, put my mitten under the snow. Several snowflakes fell on her. I began to examine them through a magnifying glass.

WITH nezhinki can be clearly seen only when they fall on the palm. Under the influence of some even small force, they break, which means that the snowflakes are very fragile.

I interviewed 40 primary school students.

Based on interview results

35 out of 40 children say that a snowflake is made of water;

30 out of 40 children say that there are identical snowflakes;

Since I really like snowflakes, I learned how to cut them out of paper, decorate and draw.

For New Years I had a snowflake costume:

And also, my parents and I recalled how I built a house from the details of the designer. I took small parts, but the building turned out to be large. Nature also knows how to build. But she does not build houses, but snowflakes from an unusual ice constructor - from tiny pieces of ice!

Chapter 3. Interesting about snowflakes.

During a snowfall in 1987 in Fort Coe (Montana, USA), a world record-breaking snowflake with a diameter of 38 cm was found.

More than half of the world's population has never seen snow, except in photographs.

In the Far North, the snow is so hard that the ax, when it hits it, rings like a blow to iron.

In Japan, scientists call snowflakes letters from heaven, which are written in secret hieroglyphs.

Conclusion.

Working on the theme, I achieved my goal and learned a lot about snowflakes. In the process of studying and researching, I solved the tasks set by me. Unfortunately, my hypotheses were not confirmed. While working on the project, I learned that snowflakes are never alike. I also learned that they appear from diamond dust, they always have a center, symmetrical and hexagonal.

Used sources:

Are the snowflakes the same, or What is hidden in the frozen water? - Access mode:http://shkolazhizni.ru/archive/0/n-33171/

Poems about snow and snowflakes. - Access mode:http://www.razumniki.ru/stihi_ro_sneg_i_sneginki.html