Why are there no identical snowflakes? Snow theory: no two snowflakes are alike Are there 2 snowflakes alike?

Nature in winter is beautiful: you just have to slow down for a minute, look at the snow-covered trees, fluffy snowdrifts and stretch out your palm - a few snowflakes will fall on it. There is nothing more beautiful and weightless than these miniature works of nature.

What a pity that their beautiful patterns can only be admired for a short time.

You may have heard the statement: no two snowflakes are alike. Let's look into this “winter issue”.

At first glance, the process of snowflake formation is very complex. The physical laws of interactions of elementary particles are involved here. In the atmosphere, at sub-zero temperatures, water molecules are attracted to dust molecules and solidify, forming six-pointed crystals. Between the individual rays of the crystal, due to the structure of the water molecule, angles of only 60 or 120 degrees are possible, and various shapes and patterns of snowflakes are formed thanks to new crystals joining the vertices of the hexagon.

Thus, we found out that:

• Snowflakes form inside an ice cloud from vapor, bypassing the liquid phase.
• The growth of snowflakes depends on external conditions: humidity and air temperature.
• The “embryos” of snowflakes have a hexagonal shape.
• The shape of a snowflake can change as it passes through the atmosphere.
• The falling speed of a snowflake is 15 m/minute.
• The ice that forms the snowflake is transparent.

Let's take a closer look at the last fact. Why, if a snowflake is transparent, then the snow is white? The laws of physics answer this question: light, reflected from the edges of snowflakes, creates the impression of a white mass, which we call snow.

So, the process of forming snowflakes has worried many minds.

The pioneers of the “snow” theory were farmer W.E. Bentley and Dr. N. Knight.

Over the course of his life, Bentley created a huge collection of photographs of snowflakes, which were of interest to both scientists and photographers. Dr. Knight was able to reproduce the process of snowflake formation in the laboratory.

Their knowledge and scientific work were systematized by a professor from the University of California, K. Libbrecht, who, in the process of studying this issue, put forward the statement: “If you see two identical snowflakes, they are still different!”

It was he who scientifically substantiated his statement, explaining that the molecules and atoms that form a crystal lattice can have a huge variety of ways of connecting.

Libbrecht stated that visually snowflakes may look the same, but when viewed under a microscope, the patterns will be completely different!

Now you know, if snow is falling outside the window, each of the snowflakes will be unique and inimitably beautiful in its own way!

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 layer of clouds, where water freezes more slowly, a crystal is created around a small speck of dust or soil particle. 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” - this is the poetic name its inhabitants came up with for Tibet.

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

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

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

Snowflakes appear white because of the air they contain: light of different frequencies is reflected on the edges between the crystals and scattered. The size of an ordinary snowflake is about 5 mm in diameter, and its mass is 0.004 g.

When scoring the film “Alexander Nevsky,” the creaking of snow was obtained by squeezing mixed sugar and salt.

It is believed that no two snowflakes are alike. This was first proven in 1885, when American farmer Wilson Bentley took the first successful photograph of a snowflake under a microscope. He devoted 46 years to this and took more than 5,000 photographs, on the basis of which the theory was confirmed.

Identical snowflakes are found 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 be found in nature.

Knight came to this conclusion after experimentally obtaining identical snowflakes in laboratory conditions. She proved her theory mathematically, through the theory of probability. She derived 100 distinctive features of snowflakes, from which one can judge that there are 10 to the 158th power of different variants of snowflakes. And although the resulting number is infinitely large, this does not exclude the possibility of coincidence of snowflakes, Knight says.

At the same time, according to Professor of Physics at the University of California Kenneth Libbrecht, externally identical snowflakes have differences in their 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 atomic structure.

How are snowflakes formed and why are their shapes different?

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

All snowflakes have six sides, because when water molecules freeze, they line up in a special order, resulting in a hexagonal geometric figure.

The growth of a snowflake is determined by the air temperature at which its formation occurred. The lower the temperature, the smaller the snowflake will be.

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

The pioneer of the study of the “snow theory” was the young farmer Wilson Alison Bentley, nicknamed “Snowflake”. Since 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 his mother gave him for his 15th birthday and tried to capture snowflakes. But it took almost five years to improve the technology - only on January 15, 1885, the first clear image was obtained.

Over the course of his life, Wilson photographed 5,000 different snowflakes. 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 complete snowflake on a black background.

Wilson's work has been highly praised by both scientists 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, never proving that no two snowflakes are alike.

The “snow theory” baton was picked up a hundred years later by National Center for Atmospheric Research researcher Nancy Knight. In a paper published in 1988, she proved the opposite statement - identical snowflakes can and should exist!

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

Further field observations and processing of experimental errors allowed Nancy Knight to claim that the occurrence of identical snowflakes is possible and is determined only by the theory of probability. Having compiled a comparative catalog of celestial crystals, Knight concluded that snowflakes have 100 signs of difference. Thus, the total number of appearance options is 100! those. almost 10 to the 158th power.

The resulting number is twice as large 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 “snow theory”. Recently, University of California physics professor 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 approximately 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 suggests an innumerable number of options for connections within the crystal lattice. In other words, if two snowflakes really look the same, then their identity still needs to be verified 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 can find practical application.

Table of contents.

Introduction.

Chapter 1.

1.1.Origin of snowflakes.

1.2.Are there any identical snowflakes?

Chapter 2. My experiments.

Chapter 3. Interesting facts about snowflakes.

4. Conclusion.

5. Sources used.

PURPOSE OF THE STUDY:

study snowflakes as an amazing natural phenomenon.

RESEARCH OBJECTIVES :

observing snowflakes in nature;

studying the formation of snowflakes;

identifying the diversity of snowflake shapes;

experimentally observe the formation of snowflakes;

identify students' knowledge about snowflakes.

HYPOTHESIS.

If water is formed when snowflakes melt, then snowflakes appear from 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 inquisitive and everyone wonders what, where, how...?

RESEARCH METHODS:

1. Studying literature about snowflakes.

2. Photographing snowflakes.

3. Conducting experiments.

4. Analysis of the work done.

Study time:January February2017.

Introduction.

I'll start with a touching, tender and bewitching poem about a snowflake.

Snowflake.

Light fluffy, white snowflake,

How pure, how brave!

The stormy road easily rushes by,

Not to the azure heights - it asks to land.

Skilfully glides in the shining rays

Among the melting flakes, it is still white.

But now the long road ends,

A crystal star touches the earth.

A brave fluffy snowflake lies

How pure, how white!

(Konstantin Balmont)

Chapter 1.

1.1.Origin of snowflakes.

There is snow. Snowflakes are flying. What's unusual here? Winter has just come. And yet, this is another miracle of nature that this wonderful world has given us! Incredible beauty, isn't it? It really is amazing all around us. So, when there is snow or snowflakes flying, you and I are observing 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 ice crystals that appear fall down and grow as a result of condensation of moisture from the air on them. This produces six-pointed crystalline forms. And the snowflake is sent to the ground as 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 again. Or these crystals melt and fall to the ground in the form of rain or cereals. And sometimes it happens that it’s snowing on the roof of a high-rise building, but it’s already raining outside.

The type of snowflakes depends on the water content in the cloud where it originated, air temperature, and altitude above sea level. Even if two identical snowflakes were “born”, they will have to travel to the ground at a speed of approximately 1 km. at one o'clock. They find themselves in different temperature conditions and reach the ground with completely different patterns, but always hexagonal in shape. Scientists have been able to identify several main forms of snowflakes. They were even given names:

star,

plate,

column,

needle,

fluff,

hedgehog,

stud.

The shape of 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 they are easy to see.

In mild frost, snowflakes look like snow balls - “snow pellets”. And when there is a strong wind, “snow dust” occurs, since the wind breaks off the rays and edges of the snowflakes.

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

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

But if a snowflake is a crystal, then why is it white, it should be transparent? This is thanks to the air (95%) contained in it! Light is reflected on the surfaces between the crystals and in the air and scattered. Thanks to the air, 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 any identical snowflakes?

Are there two identical snowflakes? No! Farmer Wilson Bentley proved this in his work in 1885; it was he who managed to take the first photograph of a snowflake under a microscope. And it took him 46 years to do this!
Since childhood, he studied the shape of crystals falling from the sky, for which he received the nickname “Snowflake”. Wilson devoted his entire life to the study of snowflakes, in total he took 5,000 photographs, and not one of them showed repeating 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 on Hexagonal Snowflakes, which can be called the first scientific work dedicated to snowflakes.

Chapter 2. Research.

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

Experiment 1.

I froze the water droplets, but the snowflakes didn’t turn out.And that means , snow does not appear from water droplets. Droplets of water can become hailstones, lumps of ice, but not snowflakes.

Experiment 2.

In the snow, I went outside and 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 even a small force, they break, which means snowflakes are very fragile.

I interviewed 40 elementary school students.

Based on the interview results

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

30 out of 40 guys claim that there are identical snowflakes;

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

For New Year I had a snowflake costume:

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

Chapter 3. Interesting things about snowflakes.

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

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

In the Far North, the snow can be so hard that when an ax hits it, it rings as if struck by iron.

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

Conclusion.

While working on the topic, I achieved my goal and learned a lot about snowflakes. In the process of study and research, I solved the problems I set. Unfortunately, my hypotheses were not confirmed. While working on the project, I learned that no two snowflakes are the same. I also learned that they appear from diamond dust, they always have a center, are symmetrical and hexagonal.

Used sources:

Are snowflakes the same, or what is hidden in 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