Why does thunder boom during a thunderstorm? Why does thunder occur?

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 of 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 a good path for them; 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 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. There is still a lot of scientific work to be done in this area. 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,

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 back 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 prolonged 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.

Everyone seems to know why thunder roars, but it’s somehow difficult to explain this fact. Of course, we are not ancient people and we no longer believe in the wrath of the gods, at least in this manifestation of it. Everything in nature, including thunder, has its own natural cause.

A little history

Of course, thunderclouds look impressive and even somewhat menacing. And when they are cut by the dazzling glare of lightning and a massive clap of thunder is heard, the full power of natural phenomena becomes visible. At such moments, a person feels especially acutely his insignificance. But this was mostly due to the fact that people did not know the reasons for what was happening. They came up with a deity who showed his anger to humanity in this way. No matter what civilization we are talking about the pantheon of gods, but everywhere there was a thunderer and he ruled over everyone, he was the strongest of the gods. Now in none of the world's religions is there any indication that this natural phenomenon has a supernatural basis. People have studied and explained everything that they have been afraid of for centuries.

Why does thunder occur in nature?

So, a bolt from the blue is nothing more than a metaphorical phrase. There really is no such thing, it’s nonsense. Therefore, it is inextricably linked with a thunderstorm and the corresponding cloud type. There are several different types of clouds: nacreous, cirrus, cirrocumulus and cumulus. They all differ from each other in appearance and structural features. It is a thundercloud that, as a rule, arises in the process of collision of various air masses. In this type of cloud, especially in its upper part, a large number of tiny ice crystals are formed. Thanks to this process, the entire upper part of the cloud begins to be covered with a specific white veil, and the cloud itself slowly, gradually acquires an increasingly darker, lead-like color.

Well, so to speak, the ground is already ready for lightning and the thunder that invariably accompanies it. Droplets of water point-to-point touch the needles of ice and air particles, as a result of all this they quickly become electrified. When the water, together with the ice floes, becomes heavy enough to overcome the resistance from the air, it begins to fall down, thereby transferring its negative charge from the upper to the lower part of the thundercloud. So it rains. There is a parallel accumulation of negative charges at the bottom and positive charges at the top of the thundercloud. If you remember a little about some school physics lessons, you can easily guess what happens next: the top and bottom of the cloud begin to attract each other with increasing force. This is how a voltage arises, sometimes of colossal power of tens or even hundreds of millions of volts, in fact, it generates a spark - what we call lightning. She immediately rushes to the ground. But at the same time, it greatly heats up the air around it, yet its temperature can reach 25,000 °C, and thereby creates pressure. As soon as it passes, the air compresses again. But this compression is accompanied by a sort of cracking sound. This is thunder. We hear it in waves, so to speak, peals, because from the physics course at school we remember that a sound wave is reflected more than once from the surface of both clouds and the ground. There is little time between light and sound. It's just the speed of sound.

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A thunderstorm is a frightening phenomenon. No matter where we are. At home or on the street. Still scary. The dazzling glare and the rolling roar are frightening. The sounds seem to be catching up with each other, now approaching, now moving away. In ancient times, people considered the heavenly roar to be the wrath of the gods. And lightning is a punishing sword. But we understand that there is a more earthly explanation for these phenomena. Why is there thunder? Why is he inseparable from lightning? Why does it rain during a thunderstorm?

How are thunderclouds formed?

There is water in the atmospheric air. In the form of steam. Under the influence of high air temperature, warm steam rises from the water surface of the earth. Warm air pushes it from below.

In the upper layers of the atmosphere the temperature is lower. The higher the water vapor rises, the colder the environment around it becomes. Accordingly, it cools down.

There are more than just gases and water in the atmosphere. There is also dust. Cooled steam condenses around its smallest particles. Small water droplets and pieces of ice turn into clouds. They are different. In the form of feathers or huge heaps, white stripes on the heavenly slope or torn rags.

Thunderclouds are formed due to the collision of air masses. Then many, many water crystals collect in the upper part. It turns out to be a kind of white dense veil. It illuminates the entire cloud with cold, which takes on a rich leaden hue. That’s why we call such clouds “lead,” “heavy.”

Spawn of Thunder and Lightning

Thunderclouds give birth to Bliskawitz. And lightning, in turn, is a heavenly roar. How does this happen? Why is there thunder?

1. Droplets and pieces of ice at the top of a thundercloud interact with air molecules and become charged with electricity. When they get heavy, they fall down. So the lower part of the cloud becomes negatively charged.

2. At the same time, a positive charge accumulates at the top of the cloud. And plus and minus attract.

3. Under the influence of the attraction of positive and negative, tension arises. Taking into account the size of the cloud (up to ten kilometers wide), this voltage reaches hundreds of millions of volts. This is how lightning is born.

4. A spark that appears from a cloud follows to the ground. Her temperature is enormous - more than twenty degrees. As a result of the rapid movement of the fiery arrow, great pressure is created in the atmosphere. And immediately behind it, the air sharply compresses, returning to its original state. The result is an explosive sound. This is how thunder is born.

FAQ:

Why do we first see lightning and then hear the sound of thunder?

Because the speed of light is hundreds of millions of times faster than the speed of sound.

Why do we hear thunder?

Because sound waves encounter various obstacles on their way (clouds, earth) and are reflected from them. This happens many times. Hence the rolling thunder sounds.

Sometimes we see bliskavitsa, but do not hear the thunder. Why?

The thunderstorm is too far from us, more than twenty kilometers.

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.