Everywhere turned white overnight
And there is a miracle in our apartment!
Outside the window the forest disappeared -
A magical forest has grown there! 
Frosty patterns on glass are a well-known and common phenomenon in winter; almost no one pays attention to them and even measures are taken to prevent them from appearing on windows. 
Why do frosty patterns appear?
"TO KNOW THE INVISIBLE, LOOK CAREFULLY AT THE VISIBLE"
If the glass has a negative temperature, and the inside of the room (or between the glasses) has a positive temperature, then instead of condensation (the process of water transitioning from a gaseous state to a liquid), a sublimation process will take place on the surface of the glass (the growth of crystals from the gas phase, bypassing the liquid state ). 
The process takes place in the form of an increase in stripes (lines) of crystalline water, which randomly intersect with each other, which creates a unique pattern on the glass. 
With high-quality glass sealing, patterns do not appear on the glass, because no temperature difference.
And by the way - as a result of the process of sublimation (I repeat - this is a transition from one state to another, bypassing the intermediate one) snowflakes and hail from thunderclouds are formed. 
Frosty patterns are simple in their chemical composition, but are very diverse. Tree-like formations and wavy structures are most common. They resemble grass, fern or palm leaves, spruce branches. 
The nature of the patterns is light, airy, joyful. The ice patterns are very beautiful and they say they serve as models for our northern lacemakers. These patterns are found in Vologda lace, in down scarves and headscarves. 
What kind of master is this?
Applied to glass
And leaves and grass
And thickets of roses... 
You can see in the frosty window
How a deer wanders through a magical land
Birds soar in the sparkling air
Fluffy snowflakes fly quietly 
On a window silver with frost,
The chrysanthemums bloomed overnight.
In the upper windows - the sky is light blue
And getting stuck in the snow dust
(Zastrakha - in peasant huts: the lower, hanging edge of the roof, as well as the beam supporting the lower edge of the roof. There is a swallow's nest under the zashrekha)
This work of nature does not last long - the sun begins to warm up and the frosty patterns become less clear, blur and flow in streams of water down the glass.
You can try to make the following patterns for yourself at home: First, prepare a colloidal solution: add 3-5 g of dry gelatin to a quarter glass of cold water and let it swell well. Heat the water to 50 degrees in a water bath and make sure that the gelatin is completely dissolved.
Ice patterns can be preserved on this jelly. Pour the still warm solution onto a piece of glass and immediately place it in the freezer. The water will crystallize, like on windows in winter. After three days, take it out and let the gelatin thaw. A clear pattern of ice crystals will remain on it.
But now I live in a house where there can be no frosty patterns - due to modern double-glazed windows. From the point of view of the architect and builder, frosty patterns, although beautiful, indicate a serious flaw in the house, leaky windows. I agree: double-glazed windows are of course a great convenience. But... How can it be: winter without frosty patterns! Of course, you can still find them here and there, for example, on buses or trolleybuses, but it’s not like at home, when you look at the street from comfort and warmth through this icy magic garden! I really wanted to arrange a winter fairy tale from my childhood for my daughter and I found it on the Internet a way to create artificial frost patterns, which is sometimes used to decorate store windows. A little experimentation - and we succeeded! Of course, these patterns are not so subtle and elegant, but they recreate the atmosphere wonderfully! And such patterns are not afraid of the sun. Now I feel like a sorceress.
Look what happened! And at the same time, I’ll tell you how to repeat our experience with my daughter.
How a natural frosty pattern appears on windows:
How to make an artificial frost pattern with your own hands:
Take 50 grams of magnesium sulfate (It is also magnesia or Epsom salts. This is a laxative that is sold in pharmacies.)
Dissolve magnesium sulfate in 100 ml. regular beer. (Stirring and waiting about 15 minutes)
After the foam has completely dissolved and settled, if there was any, take a sharp paint brush and apply the mixture to clean, grease-free glass - from the inside, from the side of the room. Since pattern crystals form only on a flat surface painted with a solution, it is worth paying attention Special attention the edges of the patterns - draw them subtly and naturalistically. When it dries, “frost patterns” appear - crystals. If you don’t like something, you can easily correct the pattern by washing it off with a window cleaner. Handmade patterns very easy to remove.
Be sure to make sure that children do not try the solution or touch the patterns with their hands! It's still a laxative. This method of drawing patterns is suitable for families where children are over 5 years old, or people without children. Or you need to make these patterns high up, where they are inaccessible to children.
In some sources I found that beer can be replaced with boiled water with the addition of a tablespoon of diluted gelatin. However, this method did not work for us - gelatin in any quantity coagulated in a magnesium solution and gave the desired effect - stabilization - in a very weak form. I also read about recipes for frosty patterns with sodium thiosulfate (also a medicine) or with photographic fixative. But we haven’t tried these methods yet, especially since they say the pattern comes out denser and whiter. We really liked our patterns this time. Combined with the frost outside the window, the upcoming Tatiana's Day and all the delights of winter, they create a great mood!
On frosty days, stunning ice patterns appear on the windows in the form of extraordinary stars, fancy curls, fabulous trees and flowers. In order for ice gardens to bloom on the windows, it is necessary that the air in the room be humid and the temperature outside the window be below zero.
Why do frosty patterns appear on the window?
Everyone remembers the parable that Santa Claus draws frosty patterns on the window. He quietly creeps up to the window at night and paints unique frosty pictures on it with a thin icy brush. In fact, everything is much more prosaic. If the air in the room is humid, and the temperature outside is zero degrees Celsius or lower, then excess moisture condenses on the cold surface of the glass. Here the water vapor cools and changes from a vapor to a solid state, forming thin crystals.How ice crystals form
Any glass that looks perfect has microscopic nicks and scratches. The moisture that settles on the surface of the glass crystallizes first of all on these tiny defects, and only then more and more cling to the first crystals, forming patterns. Sometimes, for the appearance of icy patterns, all it takes is dust particles that litter the surface of the glass, or stains that remain after washing the windows. Drafts and air currents also contribute to the appearance of patterns. According to the method of formation, frost patterns are divided into two types: dendrites - branchy patterns that resemble trees, and trichites, which are more like stars.Tree-like dendrites
Dendrites form at the bottom of the glass, where the water layer is thicker. Here wide trunks of frosty patterns appear, on which thinner branches gradually grow. The dendrites in the lower part of the glass are wide and thick, and in the upper part they are narrower and thinner. This frosty pattern resembles the thicket of an impenetrable fairytale forest.Trichite star patterns
If there are a lot of nicks, dust particles and scratches on the glass, then trichites appear on it - frosty patterns that look like stars. First, the epicenter of the pattern - a speck of dust or a jagged - freezes, and then other crystals join it, like rays. As a result, frosty patterns look like a cluster of snowflakes or. When the temperature outside the window drops, trichites form dense ice fibers.When patterns don't appear on windows
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 frosty patterns do not appear. That is why ice paintings, so familiar to residents of houses with old wooden windows, do not spoil residents of apartments with high-quality plastic windows.Frosty patterns on window glass are essentially the same thing as frost that forms on the ground and on tree branches. The mechanism for the formation of frost and these patterns is the same.
If the air cools, its moisture content decreases. Frosty patterns on glass and needles of frost are formed when 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, turns into tiny ice crystals. Thus, water contained in humid air at 0°C passes from a gaseous state to a solid (crystalline) state, bypassing the liquid phase.
Why do ice crystals form such bizarre shapes? This is due to unevenness and scratches on the surface of the glass. Ice crystals form on them first. The crystals are deposited one after another, on top of each other - and amazing, unique patterns are obtained. In addition to glass unevenness, dust particles on the glass surface and air currents also participate 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 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 more water accumulates there under the influence of gravity. That is why in the lower part of window glass the dendrites are usually larger, and the higher they are, the thinner and smaller the ice “branches” are. If the glass is moistened evenly during cooling, that is, covered with a more or less even film of water, then the “branches” of dendrites are approximately equal 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 - trichites. First, narrow parallel crystalline stripes are formed. With further cooling, fibers appear, extending from the main “stem”. 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 glass in winter? Can!
We have already said that an indispensable condition for the formation of frosty patterns is an increased moisture content in the air and cold glass. If any of these factors are excluded, Santa Claus will not be able to decorate window glass with his paintings.
For example, you can reduce the air humidity near the surface of the glass, then water condensation will not occur on it. To do this, you can place 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 external window glass at the points of contact with the frame.
The ice patterns on the windows are a sight of rare beauty.
On cold, frosty days, if you have to travel by bus or trolleybus, take your time to thaw and wipe the frozen glass.
There is no less interesting on the glass than behind it. All these beautiful patterns, similar to painted Christmas trees, seem to be similar to each other, but when you look, you won’t see the same ones. Each pattern is special. Either large straight branches, then rounded ones, then small needles ran into different sides. Every glass has a new pattern.The most curious thing is that frost draws these patterns with our help. The warm, moist air exhaled by people comes into contact with very cold glass, freezes and turns into ice crystals. They form complex drawing.
This is easy to check. If you thaw frozen glass with your palm and then breathe on it, you can see how the needles of ice crystals grow. And they always run apart at the same angle! When ice needles meet each other, they grow together, forming a pattern consisting of many crystals. 
In cold rooms, frosty patterns will also form on the glass of shop windows. But there, ice crystals settle from the air without the help of people. The air always contains water vapor - a colorless and invisible gas. Frost's only concern is to draw with it.
If you are observant, you will notice that the frosty patterns are colored: sometimes blue - in cloudy weather, sometimes yellow - in the sun, sometimes pink and purple - at sunset. Just have time, sketch!
A long time ago, people used frosty patterns to determine the weather:
if the branches of the patterns were directed downward, the weather will be snowy and cloudy;
if up – clear and sunny.
Also according to folk signs, straight patterns foreshadow even greater cold, oblique ones - thaws, and more intricate patterns - snowfall.
It's hard to believe that all this was painted without the help of human hands. It is impossible to take your eyes off these intricate works of art by an unsurpassed master. The further you look at the drawings, the more surprised you are at the skill of the unknown artist, whose name is Moroz. These amazing paintings can be looked at and looked at, and each time you see something new. Here is a magic tree, there is a peacock’s tail, a long branch of a palm tree, a fluffy spruce. A wonderful flower has blossomed. And on the other window there are fabulous animals.
It is especially beautiful when a ray of sunlight falls on the window, then the whole picture sparkles. Watching snow patterns, I noticed that they are colored: sometimes blue in cloudy weather, sometimes yellow in the sun, sometimes pink and purple at sunset. In the evening, when it becomes completely dark outside the window and the glass looks black, frosty patterns sparkle like stars.
Patterns do not appear on the window if the window is open. In this case, the air temperature in the room near the glass decreases, becoming the same as the temperature of the glass itself. With high-quality sealing of glass, patterns on the glass also do not appear, because... no temperature difference.
Everyone knows that patterns on glass are short-lived - the sun begins to warm up and the frosty patterns become less clear, blur and flow in streams of water down the glass. They disappear forever.
