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Why does the thunder come from? What are thunder and lightning? About the origin of thunderclouds.

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Thunder and lightning

Thunder is a sound phenomenon in the atmosphere that accompanies a lightning strike. Thunder is air fluctuations under the influence of a very rapid increase in pressure along the path of lightning, due to heating up to about 30,000 ° C. Thunder rolls occur due to the fact that lightning has a significant length and sound from different parts of it and does not reach the observer's ear at the same time, in addition, the reflection of sound from clouds contributes to the occurrence of rolls, and also because, due to refraction, the sound wave propagates along different ways and comes with different delays, in addition, the discharge itself does not occur instantly, but continues for a finite time.

The volume of thunderclaps can be up to 120 decibels.

By measuring the time elapsed between a flash of lightning and a thunderclap, you can approximately determine the distance at which a thunderstorm is located. Since the speed of light is very high compared to the speed of sound, it can be neglected, considering only the speed of sound, which is approximately 350 meters per second. (But the speed of sound is very changeable, it depends on the air temperature, the lower it is, the lower the speed.) judge whether the thunderstorm is approaching the observer (the interval between lightning and thunder is reduced) or receding (the interval is increased). As a rule, thunder is 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 at a distance of at least 20 kilometers.

Spark discharge (electric spark)- non-stationary form of electric discharge occurring in gases. Such a discharge usually occurs at pressures of the order of atmospheric and is accompanied by a characteristic sound effect - the "crackle" of a spark. The temperature in the main channel of the spark discharge can reach 10,000 K. In nature, spark discharges often occur in the form of lightning. The distance "pierced" by a spark in air depends on the voltage and is considered equal to 10 kV per centimeter.

A spark discharge usually occurs when the power source is insufficient to sustain a steady state arc or glow discharge. In this case, simultaneously with a sharp increase in the discharge current, the voltage across the discharge gap for a very short time (from several microseconds to several hundred microseconds) falls below the extinction voltage of the spark discharge, which leads to the termination of the discharge. Then the potential difference between the electrodes increases again, reaches the ignition voltage and the process repeats. In other cases, when the power of the energy source is large enough, the entire set of phenomena characteristic of this discharge is also observed, but they are only a transient process leading to the establishment of a discharge of another type - most often an arc one. If the power source is not capable of supporting independent electrical discharge for a long time, a form of self-sustained discharge is observed, called a spark discharge.

A spark discharge is a bundle of bright, rapidly disappearing or replacing each other filamentary, often highly branched stripes - spark channels. These channels are filled with plasma, which, in a powerful spark discharge, includes not only the ions of the initial gas, but also the ions of the substance of the electrodes, which are intensively evaporated under the action of the discharge. The mechanism for the formation of spark channels (and, consequently, the occurrence of a spark discharge) is explained by the streamer theory of electrical breakdown of gases. According to this theory, streamers are formed from electron avalanches arising in the electric field of the discharge gap under certain conditions - dimly glowing thin branched channels that contain ionized gas atoms and free electrons split off from them. Among them are the so-called. the leader is a weakly luminous discharge, “paving the way” for the main discharge. Moving from one electrode to another, it closes the discharge gap and connects the electrodes with a continuous conducting channel. Then, in the opposite direction along the paved path, the main discharge passes, accompanied by a sharp increase in the current strength and the amount of energy released in them. Each channel rapidly expands, resulting in a shock wave at its boundaries. The aggregate of shock waves from the expanding spark channels generates a sound perceived as a “crackle” of a spark (in the case of lightning, thunder).

The spark ignition voltage is usually quite high. Tension electric field in a spark, it decreases from several tens of kilovolts per centimeter (kv / cm) at the moment of breakdown to ~ 100 volts per centimeter (v / cm) after a few microseconds. The maximum current in a powerful spark discharge can reach values of the order of several hundred thousand amperes.

A special type of spark discharge is a sliding spark discharge that occurs along the interface between a gas and a solid dielectric placed between the electrodes, provided that the field strength exceeds the breakdown strength of air. Areas of a sliding spark discharge, in which charges of any one sign prevail, induce charges of a different sign on the surface of the dielectric, as a result of which the spark channels spread over the surface of the dielectric, thus forming the so-called Lichtenberg figures. Processes similar to those occurring during a spark discharge are also characteristic of a brush discharge, which is a transitional stage between corona and spark.

Lightning- a giant electrical spark discharge in the atmosphere, usually occurs during a thunderstorm, manifested by a bright flash of light and an accompanying thunder. Lightning has also been recorded on Venus, Jupiter, Saturn and Uranus. The current in a lightning discharge reaches 10-20 thousand amperes, so few people manage to survive after being struck by lightning.

The electrical nature of lightning was revealed in the studies of the American physicist B. Franklin, on whose idea an experiment was carried out to extract electricity from a thundercloud. Franklin's experience in elucidating the electrical nature of lightning is widely known. In 1750 he published a work describing an experiment using a kite launched in a thunderstorm. Franklin's experience was described in the work of Joseph Priestley.

The average length of lightning is 2.5 km; some discharges extend in the atmosphere for a distance of up to 20 km. The current in a lightning discharge reaches 10-20 thousand amperes.

Lightning formation

Most often, lightning occurs in cumulonimbus clouds, then they are called thunderstorms; sometimes lightning is formed in stratus clouds, as well as when volcanic eruptions, tornado and dust storms.

Usually observed linear lightning, which belong to the so-called electrodeless discharges, since they begin (and end) in clusters of charged particles. This determines some of their still unexplained properties that distinguish lightning from discharges between electrodes. So, lightning is never shorter than a few hundred meters; they arise in electric fields that are much weaker than fields during interelectrode discharges; the collection of charges carried by lightning occurs in thousandths of a second from billions of small, well-isolated particles located in a volume of several km³. The most studied process of lightning development in thunderclouds, while lightning can pass in the clouds themselves - intracloud lightning, and can strike the ground - ground lightning. For lightning to occur, it is necessary that in a relatively small (but not less than a certain critical) volume of the cloud an electric field (see atmospheric electricity) with an intensity sufficient for the onset of an electric discharge (~ 1 MV / m) to exist, and in a significant part of the cloud there would be a field with an average intensity sufficient to maintain the incipient discharge (~ 0.1-0.2 MV / m). In the lightning Electric Energy clouds turn into heat and light.

Ground lightning

The development process of ground lightning consists of several stages. At the first stage, in the zone where the electric field reaches a critical value, impact ionization begins, initially created by free charges, which are always present in small quantities in the air, which, under the action of an electric field, acquire significant velocities towards the ground and, colliding with the molecules that make up air, ionize them. For more modern ideas, the discharge is initiated by high-energy cosmic rays, which trigger a process called runaway breakdown. Thus, electronic avalanches appear, transforming into filaments of electrical discharges - streamers, which are well-conducting channels, which, merging, give rise to a bright thermo-ionized channel with high conductivity - a stepped lightning leader.

Leader's movement towards the earth's surface occurs in steps of several tens of meters at a speed of ~ 50,000 kilometers per second, after which its movement is suspended for several tens of microseconds, and the glow weakens greatly; then, in the next stage, the leader again moves several tens of meters. At the same time, a bright glow covers all the steps passed; then stop and weakening of the glow follow again. These processes are repeated when the leader moves to the surface of the earth with average speed 200,000 meters per second.

As the leader moves to the ground, the field strength at its end increases and under its action, a response streamer is thrown out of objects protruding on the Earth's surface, connecting with the leader. This feature of the lightning is used to create a lightning rod.

At the final stage, a reverse (bottom-up) or main lightning discharge follows along the channel ionized by the leader, characterized by currents from tens to hundreds of thousands of amperes, a brightness significantly exceeding the leader's brightness, and a high speed of advancement, initially reaching ~ 100,000 kilometers per second , and at the end it decreases to ~ 10,000 kilometers per second. The channel temperature during the main discharge can exceed 25,000 ° C. The length of the lightning channel can be from 1 to 10 km, the diameter is several centimeters. After the passage of the current pulse, the ionization of the channel and its luminescence become weaker. In the final stage, the lightning current can last for hundredths and even tenths of a second, reaching hundreds and thousands of amperes. Such lightning strikes are called lingering, they most often cause fires.

Even 250 years ago, the famous American scientist and public figure Benjamin Franklin established that lightning is an electrical discharge. But until now, it has not been possible to fully reveal all the secrets that lightning keeps: to study it a natural phenomenon difficult and dangerous.

(20 photos of lightning + video Lightning in slow motion)

Inside the clouds

A thundercloud cannot be confused with an ordinary cloud. Its gloomy, lead color is explained by its great thickness: the lower edge of such a cloud hangs at a distance of no more than a kilometer above the ground, while the upper one can reach a height of 6-7 kilometers.

What's going on inside this cloud? The water vapor that makes up the clouds freezes and exists in the form of ice crystals. Upward currents of air coming from the heated ground carry small pieces of ice upward, forcing them to collide with large pieces of ice that settle down all the time.

By the way, in winter the earth heats up less, and at this time of the year, practically no powerful ascending currents are formed. Therefore, winter thunderstorms are extremely rare.

In the process of collisions, the ice floes are electrified, just as it happens with friction. various subjects one on the other - for example, combs on hair. Moreover, small pieces of ice acquire a positive charge, and large ones - negative. For this reason, the upper part of the lightning cloud acquires a positive charge, and the lower one - a negative one. There is a potential difference of hundreds of thousands of volts at every meter of distance - both between the cloud and the ground, and between parts of the cloud.

Lightning development

The development of lightning begins with the fact that in a certain place of the cloud a hearth appears with increased concentration ions - water molecules and, constituting air, gases, from which electrons were taken away or to which were added.

According to some hypotheses, such an ionization center is obtained due to the acceleration in an electric field of free electrons, which are always present in the air in not large quantities, and colliding them with neutral molecules, which are immediately ionized.

According to another hypothesis, the initial shock is caused by cosmic rays, which constantly penetrate our atmosphere, ionizing air molecules.

Ionized gas serves as a good conductor of electricity, so a current begins to flow through the ionized areas. Further - more: the passing current heats up the ionization region, causing more and more high-energy particles that ionize the nearby regions - the lightning channel spreads very quickly.

Following the leader

In practice, the development of lightning occurs in several stages. First, the leading edge of the conductive channel, called the "leader", moves in leaps of several tens of meters, each time slightly changing direction (this makes the lightning winding). Moreover, the speed of advancement of the "leader" can, at some moments, reach 50 thousand kilometers in one single second.

Eventually, the "leader" reaches the ground or another part of the cloud, but this is not yet the main stage in the further development of lightning. After the ionized channel, the thickness of which can reach several centimeters, is "pierced", charged particles rush along it at a tremendous speed - up to 100 thousand kilometers in just one second, this is the lightning itself.

The current in the channel is hundreds and thousands of amperes, and the temperature inside the channel, at the same time, reaches 25 thousand degrees - that's why the lightning gives such a bright flash visible from tens of kilometers away. And instantaneous temperature drops, in thousands of degrees, create the strongest air pressure drops, spreading in the form of a sound wave - thunder. This stage does not last long - thousandths of a second, but the energy that is released is enormous.

Final stage

At the final stage, the speed and intensity of the movement of charges in the channel decreases, but, all the same, they remain rather large. It is this moment that is most dangerous: final stage can last only tenths (or even less) of a second. Such long-term exposure to objects on the ground (for example, dry trees) often leads to fires and destruction.

Moreover, as a rule, the matter is not limited to one discharge - new "leaders" can move along the beaten path, causing repeated discharges in the same place, the number reaching several dozen.

Despite the fact that lightning has been known to mankind since the appearance of man himself on Earth, until now it has not yet been fully studied.

Many people are afraid terrible phenomenon nature - thunderstorms. This usually happens when the sun is covered with dark clouds, there is a terrible thunder and it is raining heavily.

Of course, you should be afraid of lightning, because it can even kill or become.This has been known for a long time, which is why they came up with various means for protection against lightning and thunder (for example, metal poles).

What is happening up there and where does the thunder come from? And how does lightning arise?

Thunderclouds

Usually huge. They reach several kilometers in height. Visually, you cannot see how everything boils and boils inside these explosive clouds. This air, including water droplets, moves at high speed from bottom to top and vice versa.

The uppermost part of these clouds in terms of temperature reaches -40 degrees, and water droplets falling into this part of the cloud freeze.

About the origin of thunderclouds

Before we know where thunder and lightning come from, how it arises, let's briefly describe how thunderclouds are formed.

Most of these phenomena occur not over the water surface of the planet, but over the continents. In addition, thunderstorm clouds form intensively over the continents of tropical latitudes, where the air near the earth's surface (in contrast to the air above the water surface) warms up strongly and rises rapidly upward.

Usually, on the slopes of different heights, a similar heated air is formed, which draws in wet air from vast areas of the earth's surface and raises it up.

Thus, the so-called cumulus clouds are formed, turning into thunderclouds, described just above.

Now let's clarify what lightning is, where does it come from?

Lightning and thunder

From those very frozen droplets, pieces of ice are formed, which also move in the clouds at a tremendous speed, colliding, collapsing and being charged with electricity. Those pieces of ice that are lighter and smaller remain at the top, and those that are larger melt, going down, again turning into water droplets.

Thus, two electric charges arise in a thundercloud. Negative at the top, positive at the bottom. When different charges meet, a powerful one arises and lightning occurs. Where it comes from, it became clear. What happens next? A flash of lightning instantly heats up and expands the air around it. The latter heats up so much that an explosion effect occurs. This is the thunder that frightens all life on earth.

It turns out that all these are manifestations. Then the next question arises as to where the latter comes from, and in such large quantities. And where does it go?

Ionosphere

What is lightning, where does it come from, they figured out. Now a little about the processes that conserve the Earth's charge.

Scientists have found that the Earth's charge is generally small and is only 500,000 coulombs (like 2 car batteries). Then where does the negative charge that is carried by lightning closer to the Earth's surface disappear?

Usually, in clear weather, the Earth is slowly discharged (a weak current constantly passes between the ionosphere and the Earth's surface through the entire atmosphere). Although air is considered an insulator, it contains a small fraction of ions, which allows current to exist in the volume of the entire atmosphere. Due to this, albeit slowly, but a negative charge is transferred from the earth's surface to the height. Therefore, the volume of the total charge of the Earth always remains unchanged.

Today, the most common opinion is that ball lightning is special kind charge in the form of a ball, and the existing one is quite long time and moving along an unpredictable trajectory.

Today there is no unified theory of the occurrence of this phenomenon. There are many hypotheses, but so far none have received recognition among scientists.

Usually, as eyewitnesses testify, it occurs in a thunderstorm or in a storm. But there are also cases of its occurrence in sunny weather. More often it is generated by ordinary lightning, sometimes it appears and descends from the clouds, and less often it appears unexpectedly in the air or even can come out of some object (pillar, tree).

Some interesting facts

Where do thunderstorms and lightning come from, we found out. Now a little about the curious facts regarding the above-described natural phenomena.

1. Every year the Earth experiences approximately 25 million lightning flashes.

2. The lightning has medium length approximately 2.5 km. There are also discharges extending 20 km in the atmosphere.

3. There is a belief that lightning cannot strike twice in one place. In reality, this is not the case. Analysis results (by geographic map) of places of lightning strikes over the previous several years show that lightning can strike the same place several times.

So we found out what lightning is, where it comes from.

Thunderstorms are formed as a result of the most complex atmospheric phenomena planetary scale.

About 50 lightning flashes occur on planet Earth every second.

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Thunder and lightning

The volume of thunderclaps can be up to 120 decibels.

A spark discharge usually occurs when the power source is insufficient to sustain a steady state arc or glow discharge. In this case, simultaneously with a sharp increase in the discharge current, the voltage across the discharge gap for a very short time (from several microseconds to several hundred microseconds) falls below the extinction voltage of the spark discharge, which leads to the termination of the discharge. Then the potential difference between the electrodes increases again, reaches the ignition voltage and the process repeats. In other cases, when the power of the energy source is large enough, the entire set of phenomena characteristic of this discharge is also observed, but they are only a transient process leading to the establishment of a discharge of another type - most often an arc one. If the current source is not able to sustain a self-sustained electrical discharge for a long time, then a form of self-discharge is observed, called a spark discharge.

The spark ignition voltage is usually quite high. The electric field strength in the spark decreases from several tens of kilovolts per centimeter (kv / cm) at the moment of breakdown to ~ 100 volts per centimeter (v / cm) after a few microseconds. The maximum current in a powerful spark discharge can reach values of the order of several hundred thousand amperes.

The average length of lightning is 2.5 km; some discharges extend in the atmosphere for a distance of up to 20 km. The current in a lightning discharge reaches 10-20 thousand amperes.

Lightning formation

Most often, lightning occurs in cumulonimbus clouds, then they are called thunderstorms; sometimes lightning is formed in stratus clouds, as well as during volcanic eruptions, tornadoes and dust storms.

Linear lightnings are usually observed, which are referred to as electrodeless discharges, since they begin (and end) in clusters of charged particles. This determines some of their still unexplained properties that distinguish lightning from discharges between electrodes. So, lightning is never shorter than a few hundred meters; they arise in electric fields that are much weaker than fields during interelectrode discharges; the collection of charges carried by lightning occurs in thousandths of a second from billions of small, well-isolated particles located in a volume of several km³. The most studied process of lightning development in thunderclouds, while lightning can pass in the clouds themselves - intracloud lightning, and can strike the ground - ground lightning. For lightning to occur, it is necessary that in a relatively small (but not less than a certain critical) volume of the cloud an electric field (see atmospheric electricity) with an intensity sufficient for the onset of an electric discharge (~ 1 MV / m) to exist, and in a significant part of the cloud there would be a field with an average intensity sufficient to maintain the incipient discharge (~ 0.1-0.2 MV / m). In lightning, the electrical energy of the cloud is converted into heat and light.

Ground lightning

The development process of ground lightning consists of several stages. At the first stage, in the zone where the electric field reaches a critical value, impact ionization begins, initially created by free charges, which are always present in small quantities in the air, which, under the action of an electric field, acquire significant velocities towards the ground and, colliding with the molecules that make up air, ionize them. According to more modern concepts, the discharge is initiated by high-energy cosmic rays, which trigger a process called runaway breakdown. Thus, electronic avalanches appear, transforming into filaments of electrical discharges - streamers, which are well-conducting channels, which, merging, give rise to a bright thermo-ionized channel with high conductivity - a stepped lightning leader.

The leader moves to the earth's surface in steps of several tens of meters at a speed of ~ 50,000 kilometers per second, after which its movement stops for several tens of microseconds, and the glow weakens greatly; then, in the next stage, the leader again moves several tens of meters. At the same time, a bright glow covers all the steps passed; then stop and weakening of the glow follow again. These processes are repeated when the leader moves to the surface of the earth at an average speed of 200,000 meters per second.

The main discharge often discharges only part of the cloud. Charges located on high altitudes, can give rise to a new (arrow-shaped) leader moving continuously at a speed of thousands of kilometers per second. The brightness of its luminescence is close to the brightness of the stepped leader. When the arrow-shaped leader reaches the surface of the earth, a second follows main blow similar to the first. Typically, lightning includes several repeated discharges, but their number can go up to several dozen. The duration of multiple lightning can exceed 1 sec. The displacement of the channel of multiple lightning by the wind creates the so-called ribbon lightning - a luminous strip.

Intra-cloud lightning

Intracloud lightning usually includes only leader stages; their length ranges from 1 to 150 km. The share of intracloud lightning increases as it moves to the equator, varying from 0.5 V temperate latitudes up to 0.9 in the equatorial band. The passage of lightning is accompanied by changes in electric and magnetic fields and radio emission, the so-called atmospherics.

The likelihood of a lightning strike on a ground object increases with an increase in its height and with an increase in the electrical conductivity of the soil on the surface or at a certain depth (the action of a lightning rod is based on these factors). If there is an electric field in the cloud that is sufficient to sustain the discharge, but not sufficient for its occurrence, a long metal cable or plane can play the role of a lightning initiator - especially if it is highly electrically charged. Thus, sometimes lightning is "provoked" in nimbostratus and powerful cumulus clouds.

Lightning in upper atmosphere

In 1989, a special kind of lightning was discovered - elves, lightning in the upper atmosphere. In 1995, another type of lightning was discovered in the upper atmosphere - jets.

Elves (English Elves; Emissions of Light and Very Low Frequency Perturbations from Electromagnetic PulseSources) are huge, but weakly luminous flares-cones with a diameter of about 400 km, which appear directly from the top of a thundercloud. The height of the elves can reach 100 km, the duration of the flashes - up to 5 ms (on average 3 ms).

Jets are cone tubes of blue color... The height of the jets can reach 40-70 km (the lower boundary of the ionosphere), the jets live relatively longer than the elves.

Interaction of lightning with the surface of the earth and objects located on it

"Every second, about 50 lightning strikes the surface of the earth, and on average, every square kilometer of lightning strikes six times a year."

The most powerful lightning bolts cause the birth of Fulgurites.

People and lightning

Lightning is a serious threat to human life. The defeat of a person or an animal by lightning often occurs in open spaces, since the electric current flows along the shortest path "thunderstorm cloud to earth". Often lightning strikes trees and transformer installations on railroad causing them to ignite. It is impossible to be struck by an ordinary linear lightning inside a building, however, there is an opinion that the so-called ball lightning can penetrate through cracks and open windows... Normal lightning strikes are hazardous to rooftop television and radio antennas and network equipment.

In the body of the victims, the same pathological changes are noted as in the case of electric shock. The victim loses consciousness, falls, may experience convulsions, and often stops breathing and heartbeat. On the body, you can usually find "current marks", places of entry and exit of electricity. In the event of a fatal outcome, the cause of the termination of basic vital functions is a sudden cessation of breathing and heartbeat, from the direct action of lightning on the respiratory and vasomotor centers of the medulla oblongata. The so-called lightning marks often remain on the skin, tree-like light pink or red stripes that disappear when pressed with fingers (persist for 1 - 2 days after death). They are the result of expansion of capillaries in the zone of contact of lightning with the body.

When struck by lightning, the first health care must be urgent. In severe cases (cessation of breathing and heartbeat), resuscitation is necessary, it should be provided without waiting medical professionals, any witness to misfortune. Resuscitation is effective only in the first minutes after being struck by lightning, started after 10 - 15 minutes, as a rule, it is no longer effective. Emergency hospitalization is required in all cases.

Lightning is a powerful electrical discharge. It occurs when clouds or earth are strongly electrified. Therefore, lightning strikes can occur either inside a cloud, or between adjacent electrified clouds, or between an electrified cloud and the ground. A lightning strike is preceded by an electrical potential difference between adjacent clouds or between a cloud and the ground.

Electrification, that is, the formation of the forces of attraction of an electrical nature, is well known to everyone from everyday experience.

If you brush clean, dry hair with a plastic comb, it will attract or even sparkle. After that, the comb can attract other small objects, for example, small pieces of paper. This phenomenon is called friction electrification.

What causes clouds to electrify? After all, they do not rub against each other, as is the case with the formation of an electrostatic charge on the hair and on the comb.

A thundercloud is a huge amount of steam, part of which is condensed in the form of tiny droplets or pieces of ice. The top of a thundercloud can be at an altitude of 6-7 km, and the bottom may hang above the ground at an altitude of 0.5-1 km. Above 3-4 km, the clouds consist of pieces of ice of different sizes, since the temperature there is always below zero. These pieces of ice are in constant motion caused by updrafts. warm air from the heated surface of the earth. Small pieces of ice are easier than large ones to be carried away by ascending air currents. Therefore, "nimble" small pieces of ice, moving in upper part clouds collide with large ones all the time. Each such collision results in electrification. In this case, large ice floes are charged negatively, and small ones - positively. Over time, positively charged small pieces of ice appear in the upper part of the cloud, and negatively charged large ones - at the bottom. In other words, the top of the thundercloud is positively charged and the bottom negative.

The electric field of the cloud has a tremendous intensity - about a million V / m. When large oppositely charged regions come close enough to each other, some electrons and ions, running between them, create a luminous plasma channel through which the rest of the charged particles rush behind them. This is how a lightning discharge occurs.

During this discharge, huge energy is released - up to a billion J. The temperature of the channel reaches 10,000 K, which gives rise to the bright light that we observe during a lightning discharge. Clouds are constantly discharging through these channels, and we see external manifestations of these atmospheric phenomena in the form of lightning.

The incandescent medium explosively expands and causes a shock wave perceived as thunder.

We ourselves can simulate lightning, albeit a miniature one. The experiment should be carried out in a dark room, otherwise nothing will be seen. We need two oblong air balloon... We inflate them and tie them up. Then, making sure that they do not touch, rub them with a woolen cloth at the same time. The air filling them is electrified. If the balls are brought together, leaving a minimum gap between them, then sparks will begin to skip from one to the other through a thin layer of air, creating light flashes. At the same time, we will hear a faint crackle - a miniature copy of thunder in a thunderstorm.

Everyone who saw the lightning noticed that it was not a brightly glowing straight line, but a broken line. Therefore, the process of forming a conductive channel for a lightning discharge is called a "step leader". Each of these "steps" is a place where electrons accelerated to near-light speeds stopped due to collisions with air molecules and changed the direction of movement.

Thus, lightning is a breakdown of a capacitor, in which the dielectric is air, and the plates are clouds and the earth. The capacity of such a capacitor is small - about 0.15 μF, but the energy reserve is huge, since the voltage reaches a billion volts.

One lightning usually consists of several discharges, each of which lasts only a few tens of a millionth of a second.

Lightning most often occurs in cumulonimbus clouds. Lightning also occurs in volcanic eruptions, tornadoes, and dust storms.

There are several types of lightning in shape and direction of discharge. Discharges can occur: