The processes themselves that occur during a thunderstorm have been studied quite well. Thunder is the sound of a powerful shock wave resulting from a giant electrical discharge.
How does lightning occur?
Friction between tiny pieces of ice and droplets of water vapor in the atmosphere creates static electricity. Air does not conduct current, that is, it is a dielectric. When an electric charge accumulates at a certain moment, the field strength exceeds a critical value, and molecular bonds are destroyed. In this case, air and water vapor lose their electrical insulating properties. This phenomenon is called dielectric breakdown. It can occur within a cloud, between two adjacent thunderclouds, or between a cloud and the ground.
As a result of the breakdown, a channel with high electrical conductivity is formed, filled with a giant spark discharge - this is lightning. This process releases a huge amount of energy. The flare length can reach 300 km or more. The air in the path of lightning very quickly heats up to 25,000 - 30,000°C. For comparison: the surface temperature of the Sun is 5726 °C.
Why does thunder occur?
Air heated by lightning expands. A powerful explosion occurs. It generates a shock wave, accompanied by a very loud sound, not a single sound, but with peals. This is thunder. The more kinks the lightning has, the more thunder it claps., because At every turn there is a new explosion. Plus the sound is reflected from neighboring clouds. Its maximum volume is 120 dB. Linear and pearly lightning cannot but be accompanied by a roar. It’s just that sometimes a thunderstorm is so far from the place from which the flash is visible that the sound does not have time to reach it.
Interesting fact: in ancient pagan religions there was always a thunder god. The roar during a thunderstorm was considered one of the manifestations of his anger. It is now obvious that this sound should be taken only as a warning of approaching danger. When it appears, you just need to estimate the distance to the thunderstorm and the degree of risk for people on the street.
How to determine the distance to lightning by the sound of thunder?
Some time always passes between lightning and thunder. This happens because the speed of light is a million times faster than the speed of sound. Therefore, at first a flash is visible and only after a few seconds a rumble is heard. If you measure this time, you can approximately calculate the distance to the thunderstorm.
Why does thunder roar and lightning flash?
Many people are afraid of thunderstorms. This is truly scary. Dark gloomy clouds cover the sun, thunder rumbles, lightning flashes, and then heavy rain begins. What's going on up there and where do the thunder and lightning come from?
I love the storm in early May,
When spring, the first thunder,
As if frolicking and playing,
Rumbling in the blue sky.
Young peals thunder,
The rain is splashing, the dust is flying,
Rain pearls hung,
And the sun gilds the threads.
A swift stream runs down the mountain,
The noise of birds in the forest is not silent,
And the din of the forest and the noise of the mountains -
Everything cheerfully echoes the thunder.
You will say: windy Hebe,
Feeding Zeus's eagle,
A thunderous goblet from the sky,
Laughing, she spilled it on the ground.
The poet was undoubtedly right at least in that thunder can be heard mainly only during a thunderstorm. Since time immemorial, people have perceived thunder and lightning as a manifestation of the wrath of the Gods, and, somewhere deep within us, this superstitious fear of this phenomenon still sits. How does science today explain why thunder thunders?
It turns out that the water vapor that forms the clouds accumulates electrical charges, which form a significant potential difference between the ground and the clouds.
The thunderclouds are huge. Usually their height is several kilometers. We can’t see it from the ground, but inside the thunderclouds everything is boiling and seething. Air flows in them quickly move from top to bottom and from bottom to top. At the very top of these clouds it is very cold, up to -40 degrees. Droplets of water, which actually make up thunderclouds, fall to the top and freeze. They produce pieces of ice that fly inside the clouds at great speed, collide, break apart and become charged with electricity. Smaller and lighter pieces of ice remain at the top. And the larger ones go down and melt, turning again into droplets of water. So it turns out that two electric charges are formed in a thundercloud - negative at the top and positive at the bottom.
The air between them plays a kind of dielectric role in a huge capacitor. When the electric charge becomes critical, lightning occurs, which discharges the cloud to the ground. And when a discharge occurs, lightning strikes the ground in a split second, heating the air along its path to a temperature of thousands of degrees Celsius. We hear air vibrations in places where lightning passes as thunder. And the booming sound is due to the fact that the speed of sound is low, and the length of lightning is sometimes several kilometers. Therefore, lightning will strike the ground a long time ago, and only after a few seconds we will begin to hear the long sound of thunder reaching us from various layers of air along the path of lightning.
Knowing the time that elapses between the flash of lightning and the clap of thunder, you can approximately determine the distance at which the thunderstorm is located. The speed of light is several orders of magnitude higher than the speed of sound; it can be neglected and only the speed of sound, which is 300-360 meters per second, taken into account. That is, if thunder was heard a second after a lightning strike, then the thunderstorm is about a kilometer away. Typically, thunder can be heard at a distance of up to 15-20 kilometers, so if an observer sees lightning but does not hear thunder, then the thunderstorm is more than 20 kilometers away.
It’s so simple, you ask, where is the mysticism? The thing is that scientists still cannot fully explain one important question: how electricity accumulates in clouds and a potential difference arises. There are suggestions that the ionization of the atmosphere for the passage of the discharge occurs under the influence of high-energy cosmic radiation.
We are amazed when lightning “rips” the sky. You can suffer from this formidable weapon of nature anywhere, even in a car or inside a building. Over 8,000,000 lightning strikes strike the surface of our planet every day. This is one of nature's most deadly weapons. The natural force contained in lightning can turn sand into a glassy mass and evaporate water from wood. You can devote your life to studying this phenomenon, or you can get real pleasure from contemplating lightning.
But you should still be afraid of lightning. Because it can kill or cause a fire. People have learned to protect their homes from lightning. To do this, they use metal poles that attract electricity and conduct it into the ground. But if a thunderstorm finds you in a forest or field, do not hide under tall trees. After all, they are the ones who attract lightning to themselves in the first place.
Without exaggeration, a thunderstorm can be called the most exciting natural phenomenon on earth. It is both beautiful when it pierces the sky with its rays and scary when the rolling of thunder is heard. Let's find out what happens in the sky during a thunderstorm.
Anyone who went to school probably remembers from physics lessons that clouds collect a charge of electricity. The formation of thunderclouds is facilitated by high temperatures (in tropical latitudes, for example).
The cloud gradually increases, rising into the higher layers of the atmosphere where the temperature is already negative, thus the formation of heavy ice crystals begins. The color of the cloud becomes dark, acquiring a “lead” tint.
When colliding with air particles, ice crystals and water droplets become electrified inside the cloud. As a result, drops of water and pieces of ice falling transfer a negative charge to the lower part of the cloud. At this time, there is an attraction between the upper part of the cloud, which is positively charged, and the lower part of the cloud, which is negatively charged.
A very large voltage of hundreds of millions of volts arises between the upper and lower parts of the cloud. A huge spark appears between the ground and a cloud several kilometers long - this is lightning.
The resulting flash heats the air, causing it to “explode” and this explosion is called thunder. It thunders with peals, echoing. This phenomenon can be explained by the fact that the speed of light is much higher than the speed of sound, which is why lightning is visible immediately, and we hear thunder a few seconds later.
Such complex atmospheric phenomena lead to the formation of lightning and thunderclouds.
In the old days, all people were afraid of thunderstorms. They believed that the gods were angry with them. But most of all people were afraid of thunder, not lightning. This fear was born out of ignorance; people did not understand what was thundering.
Let's figure it out why does thunder roar? It turns out that thunder comes from lightning. They cause all the rumble and crackling. But the thunder itself does no harm. You should be afraid of lightning, which caused thunder. Lightning is a huge electrical discharge. In a matter of seconds it flies several kilometers. Where it flies, the air instantly heats up and a powerful explosion occurs. We hear this terrifying sound, this is thunder. But you can't joke with lightning. Will hit lightning into a tree - it will smash into pieces, it will land in a barn and set it on fire, starting a fire. That's why people came up with a lightning rod. This is a metal pipe, one end of which rises above the buildings, and the other is buried in the ground. If it hits a lightning rod, it goes down it into the ground without causing harm to anyone. This is how people protect houses and other buildings from lightning, which can cause irreparable consequences.
If it thunders a few seconds after the lightning flashes, it means the storm front is very close, or maybe right above you, and if you do not hear thunder right away, then this means that the thunderstorm is not close to you.
Linear lightning is usually accompanied by a strong booming sound called thunder. Thunder occurs for the following reason. We have seen that the current in the lightning channel is generated within a very short period of time. At the same time, the air in the channel heats up very quickly and strongly, and when heated it expands. The expansion occurs so quickly that it resembles an explosion. This explosion produces a shock of air, which is accompanied by strong sounds. After a sudden cessation of current, the temperature in the lightning channel drops rapidly as heat escapes into the atmosphere. The channel cools quickly, and the air in it is therefore sharply compressed. This also causes the air to shake, which again produces sound. It is clear that repeated lightning strikes can cause prolonged rumble and noise. In turn, the sound is reflected from clouds, the ground, houses and other objects and, creating multiple echoes, lengthens the thunder. That's why thunderclaps occur.
Like any sound, thunder travels through the air at a relatively low speed - approximately 330 meters per second. This speed is only one and a half times the speed of a modern aircraft. If an observer first sees lightning and only after some time hears thunder, then he can determine the distance that separates him from the lightning. Let, for example, 5 seconds pass between lightning and thunder. Since in every second sound travels 330 meters, in five seconds thunder has traveled a distance five times greater, namely 1650 meters. This means that lightning struck less than two kilometers from the observer.
In calm weather, thunder is heard after 70-90 seconds, covering 25-30 kilometers. Thunderstorms that pass from the observer at a distance of less than three kilometers are considered close, and thunderstorms that pass at a greater distance are considered distant.
In addition to linear, there are, although much less frequently, lightning of other types. Of these, we will consider one of the most interesting - ball lightning.
Sometimes lightning discharges are observed, which are fireballs. How ball lightning is formed has not yet been studied, but existing observations of this interesting type of lightning discharge allow us to draw some conclusions. Here we present one of the most interesting descriptions ball lightning.
Here is what the famous French scientist Flammarion reports: “On June 7, 1886, at half past eight in the evening, during a thunderstorm that broke out over the French city of Gray, the sky suddenly lit up with wide red lightning, and with a terrible crack, a fireball fell from the sky, apparently the diameter of , 30-40 centimeters. Scattering sparks, it hit the end of the roof ridge, knocked off a piece more than half a meter long from its main beam, split it into small pieces, filled the attic with debris and brought down the plaster from the ceiling of the upper floor. Then this ball jumped onto the roof of the entrance, punched a hole in it, fell onto the street and, having rolled along it for some distance, gradually disappeared. Fire ball
Didn’t produce or harm anyone, despite the fact that there were a lot of people on the street.”
In Fig. 13 shows ball lightning captured by a photographic camera, and Fig. 14 shows a picture of an artist who painted a ball of lightning that fell into the yard.
Most often, ball lightning has the shape of a watermelon or pear. It lasts for a relatively long time - from a small fraction of Fig. 13. Ball lightning. seconds to several minutes.
The most common duration of ball lightning is from 3 to 5 seconds. Ball lightning most often appears at the end of a thunderstorm in the form of red luminous balls with a diameter of 10 to 20 centimeters. In more rare cases, it also has larger times - 22
Measures. For example, a lightning bolt with a diameter of about 10 meters was photographed.
The ball can sometimes be dazzling white and have a very sharp outline. Typically, ball lightning makes a whistling, buzzing or hissing sound.
Ball lightning may disappear quietly, but may also produce a faint crackling sound or even a deafening sound.
Explosion. When it disappears, it often leaves a pungent-smelling haze. Near the ground or in enclosed spaces, ball lightning moves at the speed of a running person - approximately two meters per second. It can remain at rest for some time, and such a “settled” ball hisses and throws out sparks until it disappears. Sometimes it seems that ball lightning is driven by the wind, but usually its movement does not depend on the wind.
Ball lightning is attracted to enclosed spaces, into which they enter through open windows or doors, and sometimes even through small cracks. The pipes represent for them good way; Therefore, ball lightning often appears from ovens in kitchens. After circling around the room, ball lightning leaves the room, often leaving along the very path along which it entered.
Sometimes lightning rises and falls two or three times over distances ranging from several centimeters to several
Quite a few meters. Simultaneously with these ascents and descents, the fireball sometimes moves in a horizontal direction, and then it seems that the ball lightning is making leaps.
Often, ball lightning “settles” on conductors, preferring the highest points, or rolls along conductors, for example, along drainpipes. Moving over people's bodies, sometimes under clothes, ball lightning causes severe burns and even death. There are many descriptions of cases of fatal damage to people and animals by ball lightning. Ball lightning can cause very severe damage to buildings.
There is no complete scientific explanation for ball lightning yet. Scientists have persistently studied ball lightning, but so far all its various manifestations have not been explained. Much more remains to be done in this area. scientific work. Of course, there is nothing mysterious or “supernatural” about ball lightning. This is an electrical discharge, the origin of which is the same. like linear lightning. Undoubtedly, in the near future, scientists will be able to explain all the details of ball lightning as well as they were able to explain all the details of linear lightning,
