Snow, ice, drizzle, hail and rain are atmospheric precipitation. They are distinguished from frost and dew, which are nothing but condensed moisture, Settled on objects or plants. Such a phenomenon as fog also occurs from the temperature difference. For example, in the fall, water evaporates from more warm water bodies. Steam, hitting in the cold air, immediately condenses. But the water suspension because of its own gravity can not rise up and become a cloud, so it spreads near the ground, filling the lowlands and floodplains of rivers. However, here we are talking about precipitation. What hail differs from similar grains and icy rain? Learn from this article.
Transitional state?
Even a junior high school student will say what hail is: something between rain and snow. Droplets of water freeze and turn into ice cubes - small and large. Falling to the ground, they make a strong noise, as if nuts or pebbles are poured. Grads do not immediately melt. Sometimes you can see how they carpet the earth with a carpet that is several dozen centimeters high. But the icy rain, although it hurts the face, immediately turns into water. Sometimes you hear a crystal ringing of individual "drops" on the asphalt. But more often this type of precipitation is accompanied by the sounds of ordinary rain. A snow crock is strewed to the ground with a quiet rustle. These deposits also differ in appearance. The hailstones are large and translucent. The icy rain is like a splinter of glass. A groat can be likened to miniature snowballs.
How is snow formed?
To seriously understand the issue of what hail is, you just need to return to the basics of natural history and remember how clouds form that bring rain or snow. The moisture evaporates from the surface of the earth. But more often than not, clouds form above the oceans, where there is more water. Ascending air currents raise this steam up. At different altitudes, due to a drop in air temperature, moisture condenses. But it does not turn into droplets of water, but is transformed into ice crystals, bypassing the liquid state. If the cloud is small and light, it is driven by the wind in the drier areas, where it melts, and did not give the ground precipitation. A dense layer of the atmosphere can not hold heavy, low-flying clouds. Crystalline ice begins to drop. If the air temperature near the ground surface is plus, they melt, turning into droplets of rain. Well, if the window is below zero, the crystals merge together, forming snowflakes of a wide variety of shapes and sizes.
What is hail?
This is a completely different type of precipitation. And it appears in completely different clouds. Do you remember what clouds threaten us with rain? Dense, dark gray, sometimes even purple ... High, like a swirling tower, they fly swiftly, like a tornado. Unlike a shower, hailstorming is rarely accompanied by lightning and thunder. But there is always a gust of wind. Gradinka is born the same way as a snowflake - from an ice crystal. But it does not form in flat clouds, which carry snow. The hail itself generates a form of clouds. The high mass rises to a height of several kilometers. It is clear that there is a temperature difference between the lower and upper edges of such a cloud. The crystals that are closer to the earth melt, turning into drops of water (hail never falls in winter). But instead of spilling rain, the powerful ascending streams direct this moisture upwards, where it freezes, this time in the form of a small ice ball. If the movement of the wind inside the cloud is weak, a small hail falls out. But if the air flow is strong, then the melted ball was brought back up, where it accumulates another ice shell. Sometimes the hailstones collide and grow together. Then their form changes. This is not a ball, but a complex conical or pyramidal formation. The more a drop makes migrations, the larger the hail. The maximum size of ice pieces was 150 mm, and weight - more than a kilogram.
How to prevent hail
It is clear that falling to the ground at a speed of 150 kilometers per hour, serious injuries and damage can cause and not such huge copies. People have long thought how to prevent the death of crops and livestock from hail. In the Middle Ages, they found a regularity: if you make very loud and sharp sounds, then a shower will pour down from the cloud. Therefore, at the approach of danger, people beat a bell or fired a cannon. From the pulsation of air, the hailstones disintegrated, became smaller and melted, not reaching the ground. Now in a dangerous cloud shoot a special shell with a reagent of iodide silver or lead.
Now that we have learned what hail is, let's figure out what the snow is. These are small, 1-2 mm in diameter snowballs. Unlike hail, they are fragile, opaque, white in color. In fact, it's fused and compacted snowflakes.
For general development
In modern Russian, the word "grad" has another meaning. This is the name of the system of rocket fire, which replaced the obsolete "Katyusha". This deadly weapon was developed by AI Ganichev and the design bureau of the SNPP "Splav". The base complex is modified from year to year, generating "Grad-V", "P", "1A" and other installations.