How frost patterns form on glass. Why are the patterns on the windows so beautiful in winter? trichyta star patterns

14.06.2020

Every winter, you can see magnificent patterns on the windows that the frost has painted. They are very diverse and intricate, mysterious and simply magnificent.

How are ice patterns formed on glass?

The air in the room is much warmer than outside, and the humidity is lower. But near glass, sometimes the temperature can be below the dew point, that is, the value when the steam begins to condense into dew. Small ice crystals form and ice drawings appear on the window.

Why are ice patterns always different?

Because the conditions inside the room and outside are changeable: temperature, humidity, pressure, wind speed. Even the thickness of the glass and its purity play a role.

First, frost patterns form on the surface of the glass, and when their thickness becomes so large that the removal of heat to the outside slows down, then ice patterns begin to grow in thickness.

"Plant" patterns appear at high humidity and a gradual decrease in temperature. First, the glass becomes wet, and then the moisture freezes, forming bizarre "thickets". The process starts at the bottom of the glass as more water collects there. Yes, and the picture there is larger, and towards the top it becomes smaller.

If the cooling process was fast, and the moisture did not have time to drain down the glass, then the “woody” pattern throughout the window will be the same size.

Window panes cannot be perfectly even and smooth; they almost always have minor defects and scratches. They also contribute to the formation of another frosty pattern. First, ice crystals appear along the scratch, forming a strip, and then curved stems begin to branch off from it.

Since the frosty patterns on the window appear under certain conditions, it means that if you change them, the glass will remain clean. Lower the air humidity or prevent the glass from cooling too much (make a good thermal insulation of the window) and Frost will not draw anything on your window.

On frosty days, stunning ice patterns appear on the windows in the form of unusual stars, bizarre curls, fabulous trees and flowers. In order for ice gardens to bloom on the windows, it is necessary that the air in the room is humid, and the temperature outside the window is below zero.

Why do frosty patterns appear on the window

Everyone remembers the parable that Grandfather Frost draws frosty patterns on the window. He imperceptibly sneaks up to the window at night and draws unique frosty pictures on it with a thin ice brush. In fact, everything is much more prosaic. If there is humid air in the room, and the temperature outside is from zero degrees Celsius and below, then excess moisture condenses on the cold surface of the glass. Here, the water vapor cools and passes from a vaporous state to a solid state, forming thin crystals.

How ice crystals are formed

Any perfect-looking glass has microscopic notches and scratches. The moisture that settles on the surface of the glass crystallizes first of all on these smallest defects, and only then new and new ones cling to the first crystals, forming patterns. Sometimes, for the appearance of ice patterns, there are enough dust particles with which the surface of the glass is dotted, or streaks that remain after washing the windows. And drafts and air currents contribute to the appearance of patterns. According to the method of formation, frost patterns are divided into two types: dendrites - branching patterns that resemble trees, and trichites, which are more like stars.

Tree patterns dendrites

Dendrites form at the bottom of the glass, where the water layer is thicker. Wide trunks of frosty patterns appear here, on which thinner branches gradually grow. The dendrites at the bottom of the glass are wide and thick, while those at the top are narrower and thinner. Such a frosty pattern resembles a thicket of an impenetrable fairy forest.

trichyta star patterns

If there are a lot of notches, dust particles and scratches on the glass, then trichites appear on it - frosty patterns that look like stars. First, the epicenter of the pattern freezes - a speck of dust or a notch, and then other crystals join it, like rays. As a result, frosty patterns become similar to a cluster of snowflakes or. When the temperature outside the window drops, trichites form dense ice fibers.

When the patterns on the windows don't appear

If the air humidity in the room is low and the window has good thermal insulation, then condensation does not form on the glass and frost patterns do not appear. That is why ice paintings, so familiar to residents of houses with old wooden windows, do not indulge residents of apartments with high-quality plastic windows with their appearance.

Chaotic lines, wide stripes and arcs, the smallest wood motifs… The main artist in winter is frost, which paints unique pictures on the windows. How does this happen?

In scientific terms, frosting of the inner surface of the glass occurs. The fact is that the air temperature near the windows in the winter season is always lower than in the rest of the room. Cold air cannot contain as much moisture as warm air; it falls in the form of frost in winter or dew in summer. If the glass temperature is above zero, then the windows are covered with the smallest droplets of moisture - they fog up (those who wear glasses will understand what it is about). And if it is below zero, then water vapor does not settle in the form of water droplets, but immediately in the form of ice crystals (that is, water passes from a gaseous state immediately to a solid state - sublimation). Such ice crystals (hoarfrost) cover the glass with a thin layer.

And the pattern is associated with air movements in the room: people move, the hood works, windows open for ventilation, there are gaps in the frames, etc. An important role is played by the features of the glass surface (tiny scratches, dust or fingerprints, etc.). The combination of these factors forms a unique frosty pattern.

By the way, not only windows can become frosty, but also any objects cooled to a negative temperature that are brought into the building from the street. warm room. It’s just that frost doesn’t look so impressive on them, and these objects usually quickly heat up to room temperature. Another thing is windows, the low temperature of which is maintained by external cold.

And most importantly, the drawing on the windows also indicates that the room has poor thermal insulation. In modern double-glazed windows, where two or even three glasses are used, frosty patterns are no longer formed. In this case, there is a vacuum with zero moisture content between the glasses and there is simply nothing to settle on the cold glass (on the one adjacent to the street). Now the lot of frosty patterns is houses in villages, windows of some buses and trolleybuses. Progress leaves romance behind...

The symbol of winter in past centuries was not only severe frosts and snowdrifts, but also ice patterns on the windows, which, according to an old belief, are drawn by Santa Claus himself. Ice crystals form on the glass into unique pictures in which you can see the thicket, unusual animals, fabulous trees and flowers, the sea, stars. In order for ice gardens to bloom on the windows, it is necessary that the air in the room is humid, and the temperature outside the window is below zero.

Why do frosty patterns appear on the window

Everyone remembers the parable that Santa Claus draws frosty patterns on the window. He imperceptibly sneaks up to the window at night and draws unique frosty pictures on it with a thin ice brush. In fact, everything is much more prosaic. If there is humid air in the room, and the temperature outside is from zero degrees Celsius and below, then excess moisture condenses on the cold surface of the window glass. Here, the water vapor cools and passes from a vaporous state to a solid state, forming thin crystals.

Any perfect in appearance has microscopic notches and scratches. The moisture that settles on the surface of the glass crystallizes first of all on these smallest defects, and only then new and new ones cling to the first crystals, forming patterns. Sometimes, for the appearance of ice patterns, there are enough dust particles with which the surface of the glass is dotted, or streaks that remain after washing the windows. And drafts and air currents contribute to the appearance of patterns. According to the method of formation, frost patterns are divided into two types: dendrites - branching patterns that resemble trees, and trichites, which are more like stars.

Why are there no patterns on plastic windows?

Patterns on windows in a frosty winter appear when water vapor from the air condenses on the surface of cold glass and then crystallizes, forming ice. In other words, the glass and the layer of surrounding air must be sufficiently cold. At plastic windows thermal insulation properties are better than wooden windows, so the temperature of the glass on the inside is higher. Consequently, condensation with crystallization proceeds worse. Simply put, old wooden windows "breathe" and the cold enters the apartments, and patterns form from the temperature difference.

Old wooden windows are double-framed with single panes without insulating glass. The frames are not airtight, between them (and therefore between the glasses) there is ordinary room air, on the cold glass there are processes of moisture condensation and crystallization. And in PVC windows they use - two or three glasses, hermetically glued. Between the glass panes of a double-glazed window is not humid room air, but dry, cleaned of dust and moisture or an inert gas. So it turns out that there is nothing to condense on the coldest outer glass - there is no moisture in the double-glazed unit chamber, and patterns do not form on the inner glass, since it is too warm.

There is another reason: old wooden windows, as a rule, are “dirtier” than PVC windows, that is, there is more dust on the surface of such glasses, namely, water crystallizes on dust particles.

If ice patterns appear on PVC windows, this means that the windows are not installed quite correctly, they are not sufficiently sealed with a special rubber band, the double-glazed window is not tight ... Contact

It is always important for a person to know what the weather will be like, because it affects his activity and well-being. Observing nature in bad weather and on a sunny day, at dusk and at night, people noted the characteristic signs that precede certain changes in the weather. So there were numerous signs - evidence folk wisdom, many of which are based on a simple snow pattern.

A beautiful snow pattern on the windows in the brilliance of the morning sun and in the thick blue of winter twilight, when you get out of bed early in the morning, stretch, go to the window ... And, oh, MIRACLE!!! There's magic on the window again. Yes Yes. Do not wonder. The most real magic: fabulous trees, enchanting forest, unusual flowers. It is so attractively beautiful, unusual and mysterious that I am always interested to know: why does frost draw snow patterns on the windows? Can patterns predict the weather? What magical transformations are formed on glass and do they depend on air temperature?

Turns out it's water! Transparent water vapor, which is always in the air. He is also in the room. And between the double window frames - everywhere! Warm water vapor settles on the cold glass windows and turns into ice crystals, just like snowflakes in the sky. There are many such crystals, they are connected to each other. In order for crystallization to begin, the first ice crystals need to settle on something. On a window that is not yet frozen, the first crystals appear, first of all, in those places where there are scratches and dirt on the glass. Sometimes, on completely unfrozen glass, frost will string a garland of snowflakes along a barely noticeable scratch. Sometimes the glass seems cleanly worn, and the frost will draw patterns on it, showing traces of a napkin that was used to wipe the window.

The first ice crystals on glass are always six-rayed stars or six-sided stems. But, increasing, expanding, they meet each other, put pressure on each other, bend, bend. And patterns appear.

The stronger the frost on the street, the more ice crystals are formed and

clings to scratches and dust particles on the glass.

During the growth of crystals, especially if the growth is very fast, so-called skeletal forms and branched crystals, or dendrites, are often formed. Examples of dendritic crystals are ice patterns on glass and snowflakes.

Among the snowflakes there are "plates", "pyramids", "columns", "needles", "arrows", simple or complex "stars" with highly branched rays.

Each of them is one of a kind. But at the same time, they all have six faces and one axis of symmetry.

Spatial lattice of ice crystals.

The balls represent oxygen atoms; positions of hydrogen atoms

not shown. The first to note this feature of snowflakes was the German astronomer Johannes Kepler.

Scientists have found that the shape of a snow crystal repeats the molecular structure of ice - its crystal lattice just consists of hexagons.

It turns out that the internal structure of a snow crystal determines its appearance.

The first systematic studies of snow crystals were undertaken in the 1930s by the Japanese Ukihiro Nakaya. He singled out 41 types of snowflakes, made the first classification and found out that the size and shape of the resulting ice crystals depend on temperature and humidity.

On the glass of a frozen window, it is easy to see how ice crystals arise, grow and gradually change their shape. First, frosty drawings begin to appear at the bottom of the window. It usually accumulates here a large number of water, and then frosty crystals gradually rise up.

It is possible to clear a round “peephole” in the opaque layer of ice that has covered the window by breathing on the frozen glass or by placing a finger on it. If you stop warming the peephole, it will again be covered with a layer of ice, just as an ice-hole on a river freezes from the cold breath of frost.

If you look more closely at how the peephole closes, you can see: first, thin needles stretch from its edges to the middle - a delicate, barely visible pattern. From these needles, new needles, feathers, stars branch off to the sides. For now, the entire eye is covered with them, like the thinnest lace, and a new layer of needles and stars grows from the edges of the eye, closing the first weave - individual branches are connected, merging into a continuous layer. This is how ice crystals grow.

New crystals always begin to grow from the edges of the eye, from layers of ice that have not melted. There is a simple and understandable explanation for this: it is easier for water particles to attach themselves to an already prepared crystal lattice than to start building a new lattice.

A snow crystal often grows like a fractal, forming a complex irregular structure, the parts of which are similar to the whole.

In nature, fractals can be seen everywhere - in the outlines of mountains, rivers, seashores, trees, the vascular system ... And in frosty patterns on the windows!

Fractals are sets with an extremely irregular branched and jagged structure. The term was introduced by B. Mandelbort in 1975, although such objects have been studied in mathematics since the end of the 19th century. The main characteristic of a fractal is its fractional dimension.

When the air cools, its moisture content decreases, excess water condenses on window glass. When the air temperature drops below 0ºС, water crystallizes.

Why do drawings appear on the window glass in the cold? On the one hand, the crystals themselves have their own structure, which determines the pattern. In addition, scratches on the glass surface, dust particles, air currents help Santa Claus create beautiful patterns on the windows.