Why does the snow squeak underfoot? What is snow and why is it white? Why does snow squeak underfoot in cold weather?

Snow is a sign real winter. It is formed when small raindrops freeze. Fluffy White snow- a real miracle. Children make snowmen out of it, play snowballs with them, and the northern peoples build their homes out of snow. A thick layer of snow warms the ground. It does not allow frosty air to approach it, and maintains a positive temperature deep in the soil.

What is snow and how is it formed?

Scientifically speaking, snow is a type atmospheric precipitation. This means that snow falls from the sky as frozen rain. The snow is cold, white and fluffy. It consists of individual snowflakes that look like six-pointed stars. I wonder how snow is formed?

The first condition for snow to appear is cold. The temperature at which water turns into ice is 0ºC. When it gets cold outside, the water in puddles and lakes becomes covered with ice (freezes). At this time, rain clouds freeze in the sky. Raindrops turn into snow in them.

The second method of snow formation is scientifically called evaporation. Listen to how it happens. If you wash your clothes and hang them outside in winter, the wet sheet will first freeze and become hard. After a few days, the sheet will turn into a soft, dry cloth. What happened? First, the water in the sheet turned into ice. It happened pretty quickly. Then the ice began to evaporate: small microscopic pieces of ice came off the sheet and rose into the sky. These pieces of ice were so small that, looking at the drying sheet, we did not notice their flight.

Why is it snowing?

Many small pieces of ice are found in the heights of the sky. There they gather into a snow cloud. There are so many snowflakes in the cloud that they join together several at a time. Several small ice stars make a large snowflake, which becomes too heavy and falls down. This is how the snow begins.

It doesn't take one wet sheet to form a big snow cloud. Many tiny pieces of ice rise into the sky from a frozen lake, puddle or river. There they gather into large snow clouds.

The wind can carry such a cloud far. For example, where there is no frost. Thanks to the wind, snow can fall even in places where lakes and rivers have not yet frozen.

How are snowflakes formed?

Have you ever seen a snowflake under a microscope? It looks like a six-pointed star. Each end of the star consists of a white branch on which small white twigs grow.

These branches are scientifically called crystals. They intersect in the middle of the snow star. Each snowflake begins to grow from the center - from the place where the snow branches intersect. The growth of a snowflake is similar to the growth of a tree: six trunks grow from the center, on each of which branches begin to grow. Stars can have different branches (long or short, thick or thin), but only 6 large branches always grow in a snow star.

When water freezes in a river or puddle, it turns into ice. The stars in the ice are located close to each other. When fog or cloud freezes, the stars are located at some distance from each other. If there are too many stars, they connect several at a time and fall down. This is how snow pours out of a cloud and covers roads, houses and fields. Adults call the fall of snowflakes snowfall.

Why does the snow squeak underfoot?

If it is slightly frosty outside (-2 or -3 ºС), then there is a lot of water in the fallen snow. They say about this kind of snow that it is “wet”. It’s easy to make snowballs and a snow woman from wet snow, and build “fortresses.”

When the frost gets stronger (the air temperature drops to -5 or -10 ºC), the snow freezes harder and becomes dry. It’s impossible to make a snowman out of dry snow, but it creaks loudly underfoot. Why does dry snow squeak?

Each snowflake looks like a small star. If we step on the snow, the branches in the icy snowflakes break. So, when breaking many snowflakes, a crunch and creaking is formed.

Snow creaks with any pressure:

• if it was stepped on;
• went skiing;
• went sledding.

The snow stops creaking only when it becomes almost warm (the air temperature approaches 0ºC). Or when it was rolled heavily (this happens on slides, where the snow rolls away and turns into ice).

When does the snow squeak very loudly?

Snow can creak louder or quieter. When does the creaking of snow become very loud?

This happens when severe frost. For example, in the far north, at -50ºC, the crunch of snow becomes so loud that it can be heard on the next street.

With warming, when the air temperature approaches 0ºC, the crunching disappears completely. The snowflakes become soft, drops of water appear on their icy branches, which prevents the icy stars from creaking.

Scientists are conducting interesting experiments with frozen water. It turns out that water hears us and reacts differently to kind and rude words. This is what the next video is about.

Children love to ask different questions, which can be difficult to answer. We have already found out why the snow fell white. At first glance, the answer to this question is very simple. But actually it is not. This time we will talk about snow again, we will figure out why it makes a characteristic sound, crunching or squeaking at sub-zero temperatures.

To answer this question, why the snow crunches under your feet, you first need to understand what it is – snow. High above the ground, among the clouds, water freezes and turns into small crystals. These crystals are called snowflakes. They always take the shape of a hexagon.

After freezing, they begin their journey to the ground, and in the process, more and more crystals freeze to each of the six corners. This happens randomly for some time, so the probability of finding two identical snowflakes is extremely low. Each snowflake has its own unique size and shape.

Why do snowflakes crunch when you step on them?

It’s very simple - when you press on the snow, many crystals break against each other. It is especially interesting that the loudness of the crunch depends on the air temperature - the colder it is, the louder the snowflakes break.

This happens because as the temperature drops, the crystals become harder and harder, and they also break more easily. There is another hypothesis - the crunching occurs because snowflakes rub against each other.

But if we pick up and break one snowflake, we will not hear any sound. He is very quiet, and no one in the world can distinguish him. The crunching effect occurs only when a huge number of ice crystals break at once. It is because so many snowflakes break at the same time that we hear this sound.

If the temperature rises, the crystals begin to turn into water, it becomes more difficult to break them, and the sound disappears.

Children are able to greatly puzzle parents and other adults with questions: “Why is the sky above us blue?”, “Why is the sun shining?”, “Why is the river flowing?”... In winter, their favorite children's question: “Why is the snow white, crunches and creaks underfoot?” And it’s worth dealing with this interest right away, since this winter is not the last, and if you hush up the issue now, it will arise before parents in just a year.

Snow color

We’ll figure out why the snow crunches underfoot a little later; let’s first decide on the first part of the question. Children who are ripe for it already know that snow is frozen water, that is, ice. Ice is transparent and therefore colorless, so why is snow white?

If you catch a snowflake and look closely at it, it is not difficult to see that it is also mostly transparent. It acquires color only when its edges reflect light - no matter whether it is sunny or artificial. And if the snowflakes were neatly stacked, they would seem transparent, except that the edges would be painted - the color of the sky or the nearest advertising billboard. However, the snow falls randomly, the edges are exposed to the sun at different angles, reflect and refract it, again chaotically. As a result, the eyes perceive a freshly falling snowdrift as perfectly white (of course, if there are no clouds in the sky).

When the snow crunches

Now it remains to find out why the snow creaks underfoot. Keeping in mind that snowflakes are pieces of ice, the answer to this question is not too difficult. The ice crystals that they are are quite fragile, although they are hard. When pressure is applied to them (for example, under the weight of a person walking in the snow), the snowflakes collapse, producing a barely audible crunch. It is accompanied by the same almost (but only almost!) silent creaking from the friction of tiny pieces of ice one against the other. If only one snowflake broke, the human ear would not be able to hear such a small sound. However, there are tens of thousands, or even millions, of them - and the creaking crunch becomes audible. In addition, very thin connections-bridges appear between individual snowflakes in a snowdrift due to frost, invisible to the eye, but adding their own note to the noise.

When the snow doesn't creak

The offspring are not always satisfied with the answer: either they consider it abstruse, or it does not coincide with their vision of the world. However, much more often the following questions arise, logically following from your explanations: “Then why does the snow crunch under your feet in cold weather, but when it’s not very cold, it doesn’t?” First of all, because snowflakes with slight cold become more flexible, elastic and do not break immediately - many manage to melt under pressure. There is also no friction between individual crystals - it is “lubricated” by water, which does not have time to freeze. And bridge-layers don’t form either, so there’s nothing to burst. Accordingly, the question: “Why does the snow crunch underfoot” will not arise for a child walking next to you. True, only until the next cold snap!

However, parents who have explained why the snow crunches under their feet and have wiped the sweat from their foreheads with relief should not relax. Very soon their child will make them happy next question- and who knows how successfully it will be answered.

Snow is a type of precipitation characteristic of a certain season of the year. It forms high in the clouds. Tiny particles of water collect around microscopic dust particles and then freeze. The resulting micro-ice flakes initially do not exceed 0.1 mm in diameter. As they fall down, they grow, expanding their body due to the condensation of air and moisture on their parts. The size and lace of falling snowflakes depends on the height and temperature of the cloud from which they formed. But why in cold weather does the snow creak under your feet?

To understand why snow creaks underfoot, you first need to understand the structure of a snowflake.

Snowflake structure

The molecular structure of water is designed in such a way that in the formation of a snowflake the angles can only be 120 and 60 degrees. New crystalline growths form on the edges and tops of the snowflake, and the next layers freeze on top of them. As a result of these processes, various amazing forms are born, but almost all resemble the shape of a star.

Related materials:

Why does snow melt faster in the city than outside the city?

Basic shapes of snowflakes

Scientists have identified several basic forms of snowflakes:

1. The needle is a crystal that resembles a long knitting needle made of ice, sometimes it is hollow, and the ends branch into several growths;
2. Star - the formation resembles a weaving structure of ice fibers. The fibers are usually arranged in random branching;
3. Dendrites - are formed when snowflake crystals grow together, forming symmetrical branched growths;
4. Fluffy - snowflakes that have lost some parts along the way or broken completely. This happens for several reasons, one of them is strong wind;
5. Column - large flat snowflakes, are the most common, resembling the shape of a column or pencil, usually hexagonal, pointed at the end;
6. Plate – come in the form of a petal, which is divided into sectors by ice ribs.

What determines the shape of snowflakes?

Among these groups there are 48 various types formation of snowflakes. The shape of snowflakes directly depends on the environmental conditions in which they are formed. First of all, the silhouette of a snowflake is affected by temperature; the cloud is colder the higher it is. If the temperature of the cloud is relatively high - 30 to 0, then the formation of a snowflake will resemble a hexagon with flat body. At temperatures from – 5 to – 3 degrees, snowflakes resemble needle-shaped crystals. From – 8 to – 12, the shape again resembles a flat hexagon, and at temperatures from – 13 to – 16, snowflakes are formed in the form of crystalline stars.

Related materials:

Why is snow white?

Why does the snow squeak?

As described above, snow is a formation of various small crystals. In the body of a snowflake, among the crystals, there is also air. When a certain amount of snow is compressed, it becomes denser, the entire composition of the air is displaced, and the crystals of the snowflakes break against each other. P When friction and fracture occurs, the crystal produces a sound, which is perceived by the human ear as a crunch or creaking. This noise is not always heard.

The snow creaks. In very frosty weather, its creak can be heard several tens of meters away. What causes this phenomenon? Why do sounds either get stronger or weaker when the temperature changes?


It turns out that the creaking is a consequence special structure snow, and with an increase/decrease in temperature this structure changes and different sounds are formed.

Snowflakes: formation and structure

Snow is “composed” of individual snowflakes - crystalline formations consisting of frozen water (about 5%) and air (about 95%). The composition determines their fragility, lightness and extremely low strength, and the predominant proportion of air is.

Scientists have studied in detail the process of snowflake formation. Water evaporating from the Earth's surface in the form of steam rises into the atmosphere, where it cools and concentrates into droplets, forming rain clouds.

With significant cooling, microscopic drops, in contact with dust particles, freeze, forming six-pointed crystals.

Dust, as well as smoke particles, even insects become the core of crystallization. Snow researcher A.D. Zamorsky talks about a snowflake, in the core of which there was small midge- a crystal grew around the frozen insect.

The six-pointed nature of the main snowflake crystal is due to the peculiarity of the water molecule, due to which the angle between the rays can only be 120° or 60°. But each of us, looking at a snowflake, saw how much more complex and beautiful its design was than an ordinary hexagon. The patterning is caused by the growth of other crystals on the main rays, with their own angles.


There are also snowflakes irregular shape. It was formed due to the constant movement of snow in air layers, where it either thaws or crystallizes again, growing new rays onto the deformed parts.

In the mid-twentieth century, the Snow and Ice Commission, which is a department International Association scientific hydrology, adopted as the fundamental International Classification of Snow. Scientists have divided all snowflakes into ten large groups. Each could now be defined into one of the classes:

— stars, or dendrites;

— spatial (complex) dendrites;

- irregular crystals;

— plates;

- columns;

- columns topped;

- hailstones;

- grains;

— freezing rain.

Each class has subspecies, for example - broken crystals, complex particles from many crystals, particles in frost and many others.


The disadvantage of the classification is that it does not take into account the shape and structure of snow grains in the snow cover, which is even more complex and diverse.

What determines the shape of a snow crystal?

Professor-researcher U. Nakaya, an employee of Hokkaido University, has been studying this issue all his life. At the beginning of the twentieth century, in 1936, in his tiny laboratory, he was the first on earth to obtain an artificial snowflake in terms of appearance.

In memory of the “master of snow,” the Japanese created a park on the territory of the former laboratory in which a monument was erected.

The professor found out that the shape of a snow crystal depends on the moisture content in the air and its temperature. Thus, the most beautiful snowflakes - stars - are formed in a narrow range from -14°C to -17°C.

All data were obtained and repeatedly confirmed by U. Nakaya experimentally. The process has never received a theoretical justification or interpretation and is awaiting its discovery.

Causes of snow squeaking (crunching)

It is easy to guess from the previous explanations that the creaking of snow is crystals breaking when pressed. When we step on snowflakes, their extremely fragile rays break.

Additional creaking and crunching is created by the friction of the crystals against each other. Snow creaks especially loudly in cold weather - 1000–1600 Hz, when the crystals acquire increased (for them) hardness and fragility and lose the water lubricant permanently present on their surface - evaporation.

As the temperature rises, the snow melts, evaporation increases, water softens the friction of the crystals, and the snowflakes themselves become less fragile - “soft.” When pressed, they break and crumple. The sound from the destruction of “soft” crystals is in the range of 250-400 Hz. When the temperature rises to −6 °C and above, the crunching and creaking noticeably weaken until they disappear completely.


If the snow has compacted or the snowflakes have melted into crust, the bonds between them become much stronger, and they are able to crunch even at 0°C. True, it doesn’t sound much like a squeak, more like a rustling or specific noise.