The article tells about why icicles appear, how to make them yourself and what is their danger in a big city.
Cold
There are many climatic zones on our planet. There are both hot regions and those where summer never happens, and human life is almost impossible. In some places it rains almost always, and in others they are very rare, and it is difficult for their residents to imagine frequent thunderstorms and even more so water in its non-liquid state - snow and hail.
But all the cold regions and places where in winter the temperature drops below zero, another common phenomenon is common to us. These are icicles. So why do icicles appear? First you need to understand what cold and ice are.
Definition
According to generally accepted terminology, cooling is a phenomenon that occurs as a result of lowering the temperature or removing heat from the object in one way or another. For most living forms, low temperatures are fatal, as are high temperatures. And by the way, absolute cold is designated as -273.15 degrees Celsius. Under such conditions, not only water freezes, but also metals become fragile, like glass, and the movement of elementary particles in matter practically stops.
Ice
When the temperature drops below zero degrees Celsius, the water turns into ice. This is a solid state of a substance, which usually has a liquid form. But if there is no rain in the winter, and all the liquid freezes, then why do icicles appear on the eaves of houses? The thing is that in winter periods the temperature can vary over quite wide ranges, and precipitation will begin to melt, and then again the onset of frost will stop it. That is why water, which was snow, begins to drain from the roofs of houses, and as the temperature drops, it gradually freezes, which is why drops, slipping along the icicles, do not reach the ground in full, leaving some of the liquid in the form of ice.
But sometimes in winter there is no positive temperature at all, and ice can still be observed. Why do icicles appear in this case?
Warmly
In this case, the heating of the houses comes into effect. According to statistics, in the winter, most houses lose up to 30% of their heat precisely through the roof, and the snow, though slowly but still melts. This is especially true in private homes.
Danger
These ice formations pose a rather great danger. Especially in cities where there are many high-rise buildings. And all because getting to their eaves is very problematic, and icicles sometimes grow to enormous sizes. As a result, if they fall, they can kill a random passerby. And, frankly, getting even a small piece of ice on the head that fell from the 15th floor is a pleasure so-so.
Therefore, every winter utilities spend a lot of effort to bring down icicles.
How to make an icicle?
There are several ways. The first, the most "natural." On a frosty day you need to stock up with patience and a bottle of water. Then find on the street an object from which the liquid would merge slowly and evenly, and ideally - drop by drop. This process is not quick, but with the advent of the first ice, things will go more fun.
The second way you can do it at any time of the year. You just need to prepare the appropriate form, fill with water and place in the refrigerator freezer. But here the main thing to remember - when freezing, the liquid expands greatly and can destroy the mold material, so glass is not suitable for it.
Well, the third is to get a block of dry ice and cut a narrow long cone in the form of an icicle from it. True, this will not be an icicle in the usual sense, since dry ice consists of frozen carbon dioxide, which does not melt, but evaporates. You can also get cold skin “burns” from it.
Now we know how icicles appear, and we also learned how to make them.