Why do patterns form on windows in winter? Winter patterns on glass, painted with frost What are the names of the patterns on the windows in winter.

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 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. Plastic windows have better thermal insulation properties 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

Remember how in childhood we clung to the windows on which the frost painted intricate patterns? How interesting it was to look at them and find the outlines of fantastic colors in each, invent fairy tales or just run your finger along the arcs, lines and bends. Where did these frosty patterns come from?

Moving away from the language of romance to the language of science, frosty patterns are nothing more than frosting on the inner surface of the glass. In the cold season, the air temperature near the windows is always lower than in the room. Cold air cannot hold as much moisture as warm air. Therefore, its excess falls out as frost. If the glass temperature is below zero, water settles on it in the form of ice crystals from the gaseous state, bypassing the liquid phase. These crystals (hoarfrost) cover the glass in a thin layer.

But where does the drawing itself come from? It is formed due to two factors. The first is the movement of air inside the room. The second is the features of the glass surface. Any scratch, dust, fingerprint allow you to create your own unique pattern on frosty glass. The most common frost pattern structures are dendrites and trichites. Dendrites - tree-like structures - are formed if glass cooling began at a positive temperature and continued at a negative one. In this case, a thin water film is formed on the glass, which freezes in the form of dendrites during crystallization.

Trichites are fibrous structures that form at the sharp edges of scratches found on glass. At the same time, narrow parallel strips are first formed, and as a result of further cooling, peculiar “fibers” depart from them. In modern double-glazed windows, thermal insulation does not allow frost to draw patterns on the glass. It is with great pleasure that we cling to the windows on which we see winter paintings, recalling the happy moments of our childhood. Do you also like to look at winter art on glass?

Frost patterns on windowpanes are essentially the same as the frost that forms on the ground and on tree branches. The mechanism of frost formation and these patterns is the same.

As the air cools, its moisture content decreases. Frosty patterns on glass and frost needles are formed if moist air is cooled to the freezing point of water, that is, to 0 ° C. At this temperature, excess moisture contained in humid air condenses on cold surfaces. In this case, the water crystallizes, that is, it turns into the smallest ice crystals. Thus, the water contained in humid air at 0°C passes from the gaseous state to the solid (crystalline), bypassing the liquid phase.

Why do ice crystals form such bizarre shapes? This is due to bumps and scratches on the glass surface. On them, ice crystals are formed in the first place. Crystals are deposited one after another, on top of each other - and amazing unique patterns are obtained. In addition to glass irregularities, dust particles on the glass surface and air currents are involved in the "drawing" of patterns.

Among the variety of frosty patterns, the most common are tree-like structures - they are called dendrites and fibrous forms - trichites.

Dendrites are formed if the air humidity is increased, and the cooling of the glass began even at a positive temperature and continued with a further decrease in temperature. In this case, a water film first forms on the glass, which, when frozen, crystallizes in the form of dendrites. Most often, this process begins at the bottom of the glass, because there, under the influence of gravity, more water accumulates. That is why the dendrites in the lower part of the window panes are usually larger, and the higher, the thinner and smaller the ice "branches". If the glass is evenly moistened during cooling, that is, it is covered with a more or less even film of water, then the "branches" of dendrites are approximately the same in size over the entire surface of the glass.

If there are scratches on the glass, then a second type of pattern is formed on their sharp edges - trichitis. First, narrow parallel crystalline stripes form. With further cooling, the fibers extending from the main "stem" appear. Most often, both the "stem" and the "fibers" extending from it are not straight, but slightly curved.

Is it possible to prevent frosty patterns from appearing on window panes in winter? Can!

We have already said that an indispensable condition for the formation of frost patterns is an increased moisture content in the air and cold glass. If you exclude any of these factors, Santa Claus will not be able to decorate window panes with his paintings.

So, for example, you can reduce the humidity of the air near the glass surface, then water condensation on it will not occur. To do this, you can put a glass of concentrated sulfuric acid between the window panes - it is known that it absorbs moisture from the air well.

The second way is to prevent the glass from getting too cold. This is done by carefully insulating the outer window glass at the points of contact with the frame.