Lightning discharges ( lightning) is the most common source of powerful electromagnetic fields natural origin. Lightning is a type of gas discharge with a very long spark length. The total length of the lightning channel reaches several kilometers, and a significant part of this channel is located inside a thundercloud. Lightning The cause of lightning is the formation of a large volumetric electric charge.

Ordinary source of lightning are thunderstorm cumulonimbus clouds that carry a cluster of positive and negative electric charges in the upper and lower parts of the cloud and forming electric fields of increasing intensity around this cloud. The formation of such space charges of different polarities in the cloud (cloud polarization) is associated with condensation due to the cooling of water vapor of rising warm air flows on positive and negative ions (condensation centers) and the separation of charged droplets of moisture in the cloud under the influence of intense ascending thermal air flows. Due to the fact that several charge clusters isolated from each other are formed in the cloud (mainly charges of negative polarity accumulate in the lower part of the cloud).

Lightning discharges by external signs can be divided into several types. Regular type - linear lightning, with varieties: ribbon, rocket, zigzag and branched. The rarest type of discharges is ball lightning. There are known discharges called “St. Elmo’s Fire” and “Glow of the Andes.” Lightning usually occurs multiple times, i.e. consists of several unit discharges developing along the same path, and each discharge, as well as the discharge received in laboratory conditions, begins with the leader and ends with the reverse (main) digit. The descent speed of the leader of the first single discharge is approximately 1500 km/s, the speed of the leaders of subsequent discharges reaches 2000 km/s, and the speed of the reverse discharge varies within 15000 -150000 km/s, i.e. from 0.05 to 0.5 speed Sveta. The leader channel, like the channel of any streamer, is filled with plasma and therefore has a certain conductivity.

The upper end of the leader channel is connected to one of the charged centers in the cloud, so part of the charges of this center flows into the leader channel. The charge distribution in the channel should be uneven, increasing towards its end. However, some indirect measurements suggest that absolute value charge on the leader head is small and, to a first approximation, the channel can be considered uniformly charged with a linear charge density S. The total charge in the leader channel in this case is equal to Q = S*l, where l is the length of the channel, and its value is usually about 10% of the value charge flowing into the ground during a single lightning strike. In 70-80% of all cases, this charge has a negative polarity. As the leader's channel advances under the influence of the electric field In the ground, a displacement of charges occurs, and charges that are opposite in sign to the charges of the leader (usually these are positive charges) tend to be located as close as possible to the head of the leader channel. In the case of homogeneous soil, these charges accumulate directly under the leader channel.

If the soil is heterogeneous and the main part of it has a large resistivity, charges are concentrated in areas with high conductivity (rivers, groundwater). In the presence of grounded elevated objects (lightning rods, chimneys, high buildings, trees wetted by rain) the charges are attracted to the top of the object, creating a significant field strength there. At the first stages of development of the leader channel, the electric field strength at its head is determined by the leader’s own charges and clusters of space charges located under the cloud. The leader's trajectory is not connected with earthly objects. As the leader descends, accumulations of charges on the ground and elevated objects begin to have an increasing influence. Starting from a certain height of the leader's head (orientation height), the field strength in one of the directions turns out to be the greatest, and the leader is oriented towards one of the ground objects. Naturally, in this case, elevated objects and areas of land with increased conductivity are predominantly affected (selective susceptibility). From very high objects, counter leaders develop towards the leader, the presence of which helps to orient the lightning towards a given object.

After the leader channel reaches the ground or the counter leader, a reverse discharge begins, during which the leader channel acquires a potential almost equal to the ground potential. At the head of the upwardly developing reverse discharge there is an area of ​​​​increased electric field strength, under the influence of which a restructuring of the channel occurs, accompanied by an increase in the plasma charge density from 10^13 - 10^14 to 10^16 - 10^19 1/m3, due to which the channel conductivity increases at least 100 times. During the development of a reverse discharge, a current iM = v passes through the impact site, where v is the speed of the reverse discharge. The process that occurs during the transition of the leader discharge to the reverse discharge is in many ways similar to the process of a vertical charged wire shorting to ground.

If a charged wire is connected to ground through a resistance r, then the current at the grounding point is equal to: where z = characteristic impedance of the wire. Thus, even during a lightning discharge, the current at the strike site will be equal to v only if the grounding resistance is zero. When grounding resistances are different from zero, the current at the point of impact decreases. It is quite difficult to quantify this decrease, since the wave impedance of the lightning channel can only be roughly estimated. There is reason to believe that the characteristic impedance of the lightning channel decreases with increasing current, with the average value being approximately 200 - 300 Ohms. In this case, when the grounding resistance of an object changes from 0 to 30 Ohms, the current in the object changes by only 10%. In what follows, we will call such objects well grounded and assume that the full lightning current iM = v passes through them. Basic parameters of lightning and intensity of thunderstorm activity Lightning with high currents occurs extremely rarely. Thus, lightning with currents of 200 kA occurs in 0.7...1.0% of cases from total number observed discharges.

The number of cases of lightning strikes with a current value of 20 kA is about 50%. Therefore, it is customary to present the amplitude values ​​of lightning currents in the form of probability curves (distribution functions), for which the probability of the occurrence of lightning currents with the maximum value is plotted along the ordinate axis. Basic quantitative characteristics lightning is the current flowing through the affected object, which is characterized by the maximum value iM, the average steepness of the front and the pulse duration ti, which is equal to the time the current decreases to half the maximum value. Currently greatest number data is available on the maximum values ​​of lightning current, the measurement of which is carried out by the simplest measuring instruments- magnetic recorders, which are cylindrical rods made of steel filings or wires pressed into plastic. Magnetic recorders are strengthened near towering objects (lightning rods, transmission line supports) and are located along power lines magnetic field, which occurs when lightning current passes through an object. Since materials with high coercive force are used for the manufacture of recorders, they retain a large residual magnetization.

By measuring this magnetization, it is possible to determine the maximum value of the magnetizing current using calibration curves. Measurements with magnetic recorders do not provide great accuracy, but this disadvantage is partially compensated a huge amount measurements, which currently number in the tens of thousands. By placing a frame closed to an inductive coil near the affected object, you can measure the slope of the lightning current using a magnetic recorder placed inside the coil. Measurements have shown that lightning currents vary widely from several kiloamperes to hundreds of kiloamperes, therefore the measurement results are presented in the form of probability curves (distribution functions) of lightning currents, on which the probability of lightning currents with a maximum value exceeding the value indicated is plotted on the abscissa axis. ordinate.

In Ukraine, when calculating lightning protection, the curve is used. For mountainous areas, the ordinates of the curve are reduced by 2 times, since at short distances from the ground to the clouds, lightning occurs at a lower density of charges in clusters, i.e., the probability of large currents decreases. It is much more difficult to experimentally determine the steepness and duration of a lightning current pulse, so the amount of experimental data on these parameters is relatively small. The duration of the lightning current pulse is mainly determined by the time of propagation of the reverse discharge from the ground to the cloud and, therefore, varies within a relatively narrow range from 20 to 80-100 μs. The average duration of a lightning current pulse is close to 50 μs, which determined the choice of the standard pulse.

The most important from the point of view of assessing the lightning resistance of RES are: the amount of charge transferred by lightning, the current in the lightning channel, the number of repeated strikes along one channel and the intensity of lightning activity. All these parameters are not determined unambiguously and are probabilistic in nature. The charge transferred by lightning fluctuates during the discharge process in the range from fractions of a coulomb to several tens of coulombs. The average charge dropped into the ground by repeated lightning is 15 - 25 C. Considering that on average a lightning discharge contains three components, therefore, during one component, about 5 - 8 C are transferred to the ground. Of these, about 60% of the entire given accumulation of charges flows into the leader channel, which amounts to 3 - 5 C. A lightning strike to flat areas of the earth's surface carries a charge of 10 - 50 C (on average 25 C), with lightning strikes in the mountains - a charge of 30 - 100 C (on average 60 C), with discharges in TV towers the charge reaches 160 C.

When lightning strikes into the ground, the overwhelming majority (85 - 90%) transfer a negative charge to the ground. The charge flowing into the ground during multiple lightning varies from fractions of a coulomb to 100 C or more. The average value of this charge is close to 20 C. The charge released into the ground during thunderstorms appears to play a significant role in maintaining the negative charge of the ground. The intensity of thunderstorm activity in different climatic regions varies greatly. As a rule, the number of thunderstorms throughout the year is minimal in the northern regions and gradually increases to the south, where increased air humidity and high temperatures contribute to the formation of thunderclouds. However, this trend is not always followed. There are centers of thunderstorm activity in mid-latitudes (for example, in the Kyiv region), where favorable conditions are created for the formation of local thunderstorms.

The intensity of thunderstorm activity is usually characterized by the number of thunderstorm days per year or the total annual duration of thunderstorms in hours. Last characteristic is more correct, since the number of lightning strikes into the ground does not depend on the number of thunderstorms, but on their total duration. The number of thunderstorm days or hours per year is determined on the basis of long-term observations of meteorological stations, the generalization of which makes it possible to draw maps of thunderstorm activity, on which lines of equal duration of thunderstorms are plotted - isokeranic lines. The average duration of thunderstorms per thunderstorm day for the territory of the European part of Russia and Ukraine is 1.5-2 hours.

Ancient people did not always consider thunderstorms and lightning, as well as the accompanying clap of thunder, to be a manifestation of the wrath of the gods. For example, for the Hellenes, thunder and lightning were symbols supreme power, while the Etruscans considered them signs: if a flash of lightning was seen from the eastern side, it meant that everything would be fine, and if it sparkled in the west or northwest, it meant the opposite.

The Etruscan idea was adopted by the Romans, who were convinced that a lightning strike from the right side was sufficient reason to postpone all plans for a day. The Japanese had an interesting interpretation of heavenly sparks. Two vajras (lightning bolts) were considered symbols of Aizen-meo, the god of compassion: one spark was on the deity’s head, the other he held in his hands, suppressing all the negative desires of humanity with it.

Lightning is a huge electrical discharge, which is always accompanied by a flash and thunderclaps (a shining discharge channel resembling a tree is clearly visible in the atmosphere). At the same time, there is almost never just one flash of lightning; it is usually followed by two or three, often reaching several dozen sparks.

These discharges almost always form in cumulonimbus clouds, sometimes in large-sized nimbostratus clouds: the upper boundary often reaches seven kilometers above the surface of the planet, while the lower part can almost touch the ground, staying no higher than five hundred meters. Lightning can form both in one cloud and between nearby electrified clouds, as well as between a cloud and the ground.

A thundercloud consists of large quantity steam condensed in the form of ice floes (at an altitude exceeding three kilometers these are almost always ice crystals, since temperatures here do not rise above zero). Before a cloud becomes a thunderstorm, ice crystals begin to actively move inside it, and they are helped to move by rising currents of warm air from the heated surface.

Air masses carry upward smaller pieces of ice, which during movement constantly collide with larger crystals. As a result, smaller crystals become positively charged, while larger ones become negatively charged.

After small ice crystals collect at the top and large ones at the bottom, top part The cloud turns out to be positively charged, the lower one – negatively. Thus, the electric field strength in the cloud reaches extremely high levels: a million volts per meter.

When these oppositely charged areas collide with each other, ions and electrons at the points of contact form a channel through which all charged elements rush down and an electrical discharge is formed - lightning. At this time, such powerful energy is released that its strength would be enough to power a 100 W light bulb for 90 days.

The channel heats up to almost 30 thousand degrees Celsius, which is five times higher than the temperature of the Sun, forming bright light(the flash usually lasts only three quarters of a second). After the channel is formed, the thundercloud begins to discharge: the first discharge is followed by two, three, four or more sparks.

A lightning strike resembles an explosion and causes the formation of a shock wave, which is extremely dangerous for any living creature near the canal. A shock wave of a strong electrical discharge a few meters away is quite capable of breaking trees, injuring or concussing even without direct electric shock:

• At a distance of up to 0.5 m from the channel, lightning can destroy weak structures and injure a person;
• At a distance of up to 5 meters, buildings remain intact, but can break windows and stun a person;
• On long distances shock wave negative consequences does not carry and goes into sound wave, known as thunderclaps.

Rolling thunder

A few seconds after the lightning strike was recorded, due to a sharp increase in pressure along the channel, the atmosphere heats up to 30 thousand degrees Celsius. As a result, explosive vibrations of the air occur and thunder occurs. Thunder and lightning are closely interrelated with each other: the length of the discharge is often about eight kilometers, so the sound from different parts of it arrives at different times, forming thunderclaps.

Interestingly, by measuring the time that passes between thunder and lightning, you can find out how far the epicenter of the thunderstorm is from the observer.

To do this, you need to multiply the time between lightning and thunder by the speed of sound, which is from 300 to 360 m/s (for example, if the time interval is two seconds, the epicenter of the thunderstorm is a little more than 600 meters from the observer, and if three - at a distance kilometer). This will help determine whether a storm is moving away or approaching.

Amazing fireball

One of the least studied, and therefore most mysterious, natural phenomena is considered to be ball lightning - a glowing plasma ball moving through the air. It is mysterious because the principle of the formation of ball lightning is unknown to this day: despite the fact that it exists big number hypotheses explaining the reasons for the appearance of this amazing natural phenomenon, there were objections to each of them. Scientists have never been able to experimentally achieve the formation of ball lightning.

Ball lightning can exist for a long time and move along an unpredictable trajectory. For example, it is quite capable of hovering in the air for several seconds and then darting to the side.

Unlike a simple discharge, there is always only one plasma ball: until two or more fiery lightning bolts are detected simultaneously. The dimensions of ball lightning range from 10 to 20 cm. Ball lightning is characterized by white, orange or blue tones, although other colors, even black, are often found.

Scientists have not yet determined the temperature indicators of ball lightning: despite the fact that, according to their calculations, it should range from one hundred to a thousand degrees Celsius, people who were close to this phenomenon did not feel the heat emanating from the ball lightning.

The main difficulty in studying this phenomenon is that scientists are rarely able to record its occurrence, and eyewitness testimony often casts doubt on the fact that the phenomenon they observed was indeed ball lightning. First of all, testimonies differ regarding the conditions under which she appeared: she was mainly seen during a thunderstorm.

There are also indications that ball lightning can appear on a fine day: it can descend from the clouds, appear in the air, or appear from behind an object (a tree or a pole).

One more characteristic feature ball lightning is its penetration into closed rooms, it has even been noticed in pilot cockpits (the fireball can penetrate through windows, go down ventilation ducts and even fly out of sockets or a TV). Situations have also been repeatedly documented when a plasma ball was fixed in one place and constantly appeared there.

Often the appearance of ball lightning does not cause trouble (it moves calmly in air currents and after some time flies away or disappears). But sad consequences were also noticed when it exploded, instantly evaporating the liquid located nearby, melting glass and metal.

Possible dangers

Since the appearance of ball lightning is always unexpected, when you see this unique phenomenon near you, the main thing is not to panic, not to move abruptly and not to run anywhere: fire lightning is very susceptible to air vibrations. It is necessary to quietly leave the trajectory of the ball and try to stay as far away from it as possible. If a person is indoors, you need to slowly walk to the window opening and open the window: there are many stories when a dangerous ball left the apartment.

You cannot throw anything into a plasma ball: it is quite capable of exploding, and this is fraught not only with burns or loss of consciousness, but also with cardiac arrest. If it happens that the electric ball catches a person, you need to move him to a ventilated room, wrap him warmly, perform a heart massage, perform artificial respiration and immediately call a doctor.

What to do in a thunderstorm

When a thunderstorm begins and you see lightning approaching, you need to find shelter and hide from the weather: a lightning strike is often fatal, and if people survive, they often remain disabled.

If there are no buildings nearby, and a person is in the field at that time, he must take into account that it is better to hide from a thunderstorm in a cave. And here tall trees it is advisable to avoid: lightning usually hits the largest plant, and if the trees are the same height, it hits the one that conducts electricity better.

To protect a free-standing building or structure from lightning, a high mast is usually installed near it, at the top of which there is a pointed metal rod securely connected to a thick wire; at the other end there is a metal object buried deep in the ground. The operation scheme is simple: the rod from a thundercloud is always charged with a charge opposite to the cloud, which, flowing down the wire underground, neutralizes the charge of the cloud. This device is called a lightning rod and is installed on all buildings in cities and other human settlements.

Just recently the clear, clear sky was covered with clouds. The first drops of rain fell. And soon the elements demonstrated their power to the earth. Thunder and lightning pierced the stormy sky. Where do such phenomena come from? For many centuries, humanity has seen in them a manifestation of divine power. Today we know about the occurrence of such phenomena.

Origin of thunderclouds

Clouds appear in the sky from condensation rising high above the ground and float in the sky. The clouds are heavier and larger. They bring with them all the “special effects” that come with bad weather.

Thunderclouds differ from ordinary clouds in that they are charged with electricity. Moreover, there are clouds with a positive charge, and there are clouds with a negative one.

To understand where thunder and lightning come from, you need to rise higher above the ground. In the sky, where there are no obstacles to free flight, the winds blow stronger than on the ground. They are the ones who provoke the charge in the clouds.

The origin of thunder and lightning can be explained by just one drop of water. It has a positive charge of electricity in the center and a negative charge on the outside. The wind breaks it into pieces. One of them remains with a negative charge and has less weight. Heavier positively charged drops form the same clouds.

Rain and electricity

Before thunder and lightning appear in a stormy sky, the wind separates the clouds into positively and negatively charged ones. Rain falling on the ground takes some of this electricity with it. An attraction forms between the cloud and the surface of the earth.

The negative charge of the cloud will attract the positive one on the ground. This attraction will be located evenly on all surfaces that are elevated and conduct current.

And now the rain creates all the conditions for the appearance of thunder and lightning. The higher the object is to the cloud, the easier it is for lightning to break through to it.

Origin of lightning

The weather has prepared all the conditions that will help all its effects appear. She created the clouds from which thunder and lightning come.

A roof charged with negative electricity attracts the positive charge of the most exalted object. Its negative electricity will go into the ground.

Both of these opposites tend to attract each other. The more electricity there is in a cloud, the more it is in the most elevated object.

Accumulating in a cloud, electricity can break through the layer of air located between it and the object, and sparkling lightning will appear and thunder will thunder.

How lightning develops

When a thunderstorm rages, lightning and thunder accompany it incessantly. Most often, the spark comes from a negatively charged cloud. It develops gradually.

First, a small stream of electrons flows from the cloud through a channel directed toward the ground. In this place of the cloud, electrons moving at high speed accumulate. Due to this, electrons collide with air atoms and break them up. Individual nuclei are obtained, as well as electrons. The latter also rush to the ground. While they move along the channel, all primary and secondary electrons again split the air atoms standing in their way into nuclei and electrons.

The whole process is like an avalanche. It is moving upward. The air heats up and its conductivity increases.

More and more electricity from the cloud flows to the ground at a speed of 100 km/s. At this moment, lightning makes its way to the ground. Along this road laid by the leader, electricity begins to flow even faster. A discharge of enormous force occurs. Reaching its peak, the discharge decreases. The channel, heated by such a powerful current, glows. And lightning becomes visible in the sky. Such a discharge does not last long.

After the first discharge, a second one often follows along a laid channel.

How does thunder appear?

Thunder, lightning, and rain are inseparable during a thunderstorm.

Thunder occurs for the following reason. The current in the lightning channel is generated very quickly. The air becomes very hot. This makes it expand.

It happens so quickly that it resembles an explosion. Such a shock shakes the air violently. These fluctuations lead to the appearance loud sound. This is where lightning and thunder come from.

As soon as the electricity from the cloud reaches the ground and disappears from the channel, it cools very quickly. Compressing air also causes thunder to sound.

The more lightning that passes through the channel (there can be up to 50 of them), the longer the air tremors. This sound is reflected from objects and clouds, and an echo occurs.

Why is there an interval between lightning and thunder?

In a thunderstorm, lightning is followed by thunder. Its delay from lightning occurs due to the different speeds of their movement. Sound moves at a relatively low speed (330 m/s). This is only 1.5 times faster than the movement of a modern Boeing. The speed of light is much greater than the speed of sound.

Thanks to this interval, it is possible to determine how far flashing lightning and thunder are from the observer.

For example, if 5 s passed between lightning and thunder, this means that the sound traveled 330 m 5 times. By multiplying, it is easy to calculate that the lightning from the observer was at a distance of 1650 m. If a thunderstorm passes closer than 3 km from a person, it is considered close. If the distance, in accordance with the appearance of lightning and thunder, is further, then the thunderstorm is distant.

Lightning in numbers

Thunder and lightning have been modified by scientists, and the results of their research are presented to the public.

It has been found that the potential difference preceding lightning reaches billions of volts. The current strength at the moment of discharge reaches 100 thousand A.

The temperature in the channel heats up to 30 thousand degrees and exceeds the temperature on the surface of the Sun. From the clouds to the ground, lightning travels at a speed of 1000 km/s (in 0.002 s).

The internal channel through which the current flows does not exceed 1 cm, although the visible one reaches 1 m.

There are about 1,800 thunderstorms occurring continuously around the world. The chance of being killed by lightning is 1:2000000 (the same as dying from falling out of bed). The chance of seeing ball lightning is 1 in 10,000.

Ball lightning

On the way to studying where thunder and lightning come from in nature, the most mysterious phenomenon ball lightning appears. These round fiery discharges have not yet been fully studied.

Most often, the shape of such lightning resembles a pear or watermelon. It lasts up to several minutes. Appears at the end of a thunderstorm in the form of red clumps from 10 to 20 cm in diameter. The largest ball lightning ever photographed was about 10 m in diameter. It makes a buzzing, hissing sound.

It may disappear quietly or with a slight crash, leaving a burning smell and smoke.

The movement of lightning does not depend on the wind. They are drawn into closed spaces through windows, doors and even cracks. If they come into contact with a person, they leave severe burns and can be fatal.

Until now, the reasons for the appearance of ball lightning were unknown. However, this is not evidence of its mystical origin. Research is being conducted in this area that can explain the essence of this phenomenon.

By becoming familiar with phenomena such as thunder and lightning, you can understand the mechanism of their occurrence. This is a consistent and rather complex physical and chemical process. It is one of the most interesting natural phenomena that occurs everywhere and therefore affects almost every person on the planet. Scientists have solved the mysteries of almost all types of lightning and even measured them. Ball lightning today is the only unsolved mystery of nature in the field of formation of such natural phenomena.

Have you ever wondered why birds sit on high-voltage wires, and a person dies when he touches the wires? Everything is very simple - they sit on a wire, but no current flows through the bird, but if the bird flaps its wing, simultaneously touching two phases, it will die. Usually large birds such as storks, eagles, and falcons die this way.

Likewise, a person can touch a phase and nothing will happen to him if no current flows through him; for this you need to wear rubberized boots and God forbid you touch a wall or metal.

Electric current can kill a person in a split second; it strikes without warning. Lightning strikes the earth one hundred times per second and over eight million times per day. This force of nature is five times hotter than the surface of the sun. The electrical discharge strikes with a force of 300,000 amperes and a million volts in a split second. IN Everyday life we think we can control the electricity that powers our homes, our outdoor lights, and now our cars. But electricity in its original form cannot be controlled. And lightning is electricity on a huge scale. And yet lightning remains a big mystery. It can strike unexpectedly and its path can be unpredictable.

Lightning in the sky does no harm, but one in ten lightning strikes the surface of the earth. Lightning is divided into many branches, each of which is capable of striking a person located at the epicenter. When a person is struck by lightning, the current can pass from one person to another if they come into contact.

There is a rule of thirty and thirty: if you see lightning and hear thunder less than thirty seconds later, you must seek shelter, and then you must wait thirty minutes from the last clap of thunder before going outside. But lightning does not always obey a strict order.

There is such an atmospheric phenomenon as thunder among clear skies. Often lightning, leaving a cloud, travels up to sixteen kilometers before striking the ground. In other words, lightning can appear out of nowhere. Lightning needs wind and water. When strong winds lift moist air, the conditions are created for destructive thunderstorms to occur.

It is impossible to decompose into components something that fits into a millionth of a second. One false belief is that we see lightning as it travels to the ground, but what we actually see is the lightning's return path into the sky. Lightning is not a unidirectional strike to the ground, but is actually a ring, a path in two directions. The flash of lightning that we see is the so-called return stroke, the final phase of the cycle. And when the return stroke of lightning heats up the air, its calling card appears - thunder. The return path of lightning is the part of lightning that we see as a flash and hear as thunder. A reverse current of thousands of amperes and millions of volts rushes from the ground to the cloud.

Lightning regularly electrocutes people indoors. It can enter a structure in different ways, through drainpipes and water pipes. Lightning can penetrate electrical wiring, the current strength of which in an ordinary house does not reach two hundred amperes and overloads the electrical wiring in jumps from twenty thousand to two hundred thousand amperes. Perhaps the most dangerous path in your home leads directly to your hand through the phone. Nearly two-thirds of indoor electric shocks occur when people pick up a landline telephone during a lightning strike. Cordless phones are safer during thunderstorms, but lightning can electrocute someone standing near the phone's base. Even a lightning rod cannot protect you from all lightning, since it is not capable of catching lightning in the sky.

About the nature of lightning

There are several different theories explaining the origin of lightning.

Typically, the bottom of the cloud carries a negative charge and the top carries a positive charge, making the cloud-ground system like a giant capacitor.

When the difference electrical potentials becomes large enough, a discharge known as lightning occurs between the ground and the cloud, or between two parts of the cloud.

Is it dangerous to be in a car during lightning?

In one of these experiments, a meter-long artificial lethal lightning was aimed at the steel roof of a car in which a person was sitting. Lightning passed through the casing without harming a person. How did this happen? Since charges on a charged object repel each other, they tend to move as far apart as possible.

In the case of a hollow mechanical ball pi cylinder, the charges are distributed over the outer surface of the object. Similarly, if lightning strikes the metal roof of a car, then the repelling electrons will spread extremely quickly over the surface of the car and go through its body into the ground. Therefore, lightning along the surface of a metal car goes into the ground and does not get inside the car. For the same reason, a metal cage is perfect protection against lightning. As a result of artificial lightning striking a car with a voltage of 3 million volts, the potential of the car and the body of the person in it increases to almost 200 thousand volts. The person does not experience the slightest sign of impact electric current, since there is no potential difference between any points of his body.

This means that staying in a well-grounded building with a metal frame, of which there are many in modern cities, almost completely protects against lightning.

How can we explain that birds sit on the wires completely calmly and with impunity?

The body of a sitting bird is like a branch of a chain (parallel connection). The resistance of this branch with the bird is much greater than the resistance of the wire between the bird's legs. Therefore, the current strength in the bird’s body is negligible. If a bird, sitting on a wire, touched the pole with its wing or tail, or otherwise connected with the ground, it would be instantly killed by the current that would rush through it into the ground.

Interesting facts about lightning

The average length of lightning is 2.5 km. Some discharges extend up to 20 km in the atmosphere.

Lightning is beneficial: they manage to snatch millions of tons of nitrogen from the air, bind it and send it into the ground, fertilizing the soil.

Saturn's lightning is a million times stronger than Earth's.

A lightning discharge usually consists of three or more repeated discharges - pulses following the same path. The intervals between successive pulses are very short, from 1/100 to 1/10 s (this is what causes lightning to flicker).

About 700 lightning flashes on Earth every second. World centers of thunderstorms: the island of Java - 220, equatorial Africa - 150, southern Mexico - 142, Panama - 132, central Brazil - 106 thunderstorm days a year. Russia: Murmansk - 5, Arkhangelsk - 10, St. Petersburg - 15, Moscow - 20 thunderstorm days a year.

The air in the zone of the lightning channel almost instantly heats up to a temperature of 30,000-33,000 ° C. On average, about 3,000 people die from lightning strikes in the world every year

Statistics show that every 5,000-10,000 flight hours there is one lightning strike on an aircraft; fortunately, almost all damaged aircraft continue to fly.

Despite the crushing power of lightning, protecting yourself from it is quite simple. During a thunderstorm, you should immediately leave open areas, under no circumstances should you hide under isolated trees, or be near high masts and power lines. You should not hold steel objects in your hands. Also, during thunderstorms, you cannot use radio communications or mobile phones. Televisions, radios and electrical appliances must be turned off indoors.

Lightning rods protect buildings from lightning damage for two reasons: they allow the charge induced on the building to flow into the air, and when lightning strikes the building, they take it into the ground.

If you find yourself in a thunderstorm, you should avoid taking shelter near single trees, hedges, elevated places and being in open spaces.

Lightning is a powerful discharge of electrical energy. The nature of its occurrence lies in the strong electrification of clouds or earth's surface. For this reason, discharges occur in the clouds themselves, or between two adjacent ones, or between a cloud and the ground. Most people are afraid of thunderstorms. The phenomenon is truly scary. Gloomy-looking clouds cover the sun, thunder rumbles, lightning flashes, and heavy rain falls. But where does lightning come from, how to explain to a child what is happening above?

Where does thunder and lightning come from - explanation for children

Thunder rumbles and lightning appears. The process of lightning occurrence is divided into the first strike and all subsequent ones. The reason is that the primary shock creates a path for electrical discharge. A negative discharge accumulates at the bottom of the cloud.

And the earth's surface has a positive charge. For this reason, electrons located in the cloud are attracted to the ground and rush down. As soon as the first electrons reach the surface of the earth, a channel free for the passage of electrical discharges is created, through which the remaining electrons rush down. Electrons near the ground are the first to leave the channel. Others are rushing to take their place. A condition is created in which all the negative energy discharge comes out of the cloud, creating a powerful flow of electricity directed into the ground. It is at such a moment that a flash of lightning is possible, accompanied by a clap of thunder.

Where does ball lightning come from?

Is lightning called ball lightning? Such lightning is considered special kind, represents floating through the air glowing ball. Its size is from ten to twenty centimeters, the color is blue, orange or white. The temperature of such a ball is so high that if it unexpectedly ruptures, the liquid surrounding it evaporates, and metal or glass objects melt.

Such a ball can exist for a long time. When moving, it can unexpectedly change its direction, hover in the air for several seconds, or sharply deviate to one side.

Ball lightning most often forms during a thunderstorm, but there are times when it is seen in sunny weather. Its appearance occurs in one copy, unexpectedly. The ball is capable of descending from the clouds, appearing in the air from behind a pillar or tree quite unexpectedly. She is able to enter a confined space through an outlet or TV.

Where do thunder and lightning come from?

The elements need certain circumstances to manifest their power. Electrified clouds create lightning. But in order to break through the atmospheric layer, not every cloud contains sufficient power for this. A cloud whose height reaches several thousand meters will be considered a thunderstorm. The bottom of the cloud is located near the earth's surface, the temperature regime there is higher than in the upper part of the cloud, where water droplets can freeze.

Air masses are in constant motion. Warm air goes up and goes down. When particles move, they become electrified. IN various parts clouds accumulate unequal potential. When a critical value is reached, a flash occurs, accompanied by peals of thunder.

Dangerous lightning

Usually the first blow is followed by a second. This is due to the fact that electrons in the first flash ionize the air, creating the possibility of a second passage of electrons. Therefore, subsequent outbreaks occur almost without pause, striking in the same place. Lightning emerging from a cloud can cause significant harm to its electrical discharge for a person. Even if her blow is nearby, the consequences will negatively affect your health.

During a thunderstorm, you need to be on land, as close to the surface of the earth as possible. It is advisable not to use mobile devices.