Types of lightning physics. What are the types of lightning? What to do when lightning approaches

"physical phenomenon"

A giant electrical spark discharge in the atmosphere, usually manifested by a bright flash of light and accompanying thunder. The electrical nature of lightning was revealed in the studies of the American physicist B. Franklin, on the basis of which an experiment was carried out to extract electricity from a thundercloud.

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

The process of ground lightning development 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 electrons, always present in a small amount in the air, which, under the action of an electric field, acquire significant speeds towards the ground and, colliding with air atoms, ionize them. That. electron avalanches appear, turning into filaments of electric discharges - streamers, which are well-conducting channels, which, merging, give rise to a bright thermally ionized channel with high conductivity - a step leader.

The movement of the leader to the earth's surface occurs in steps of several tens of meters at a speed of ~ 5 * 10,000,000 m/sec, after which its movement stops for several tens of microseconds, and the glow is greatly weakened; then, in the next stage, the leader again advances several tens of meters. A bright glow covers all the steps passed; then a stop and a weakening of the glow follow again. These processes are repeated when the leader moves to the earth's surface at an average speed of 2*100,000 m/s. As the leader moves towards the ground, the field strength at its end increases and under its action a response streamer is ejected from the objects protruding on the Earth's surface, connecting with the leader.

lightning shapes

Line lightning

A discharge of linear lightning occurs between clouds, inside a cloud, or between a cloud and the ground, and usually has a length of about 2-3 km, but there are lightnings up to 20-30 km long.

It looks like a broken line, often with numerous branches. Lightning color - white, yellow, blue or reddish

Most often, the diameter of the thread of such lightning reaches a couple of tens of centimeters. This type is the most common; we see it most often. Linear lightning appears when the electric field of the atmosphere is up to 50 kV / m, the potential difference in its path can reach hundreds of millions of volts. The lightning current of this kind is about 10 thousand amperes. A thundercloud that produces a linear lightning discharge every 20 seconds has an electrical energy of 20 million kW. The potential electrical energy stored in such a cloud is equal to the energy of a megaton bomb.

This is the most common form of lightning.

Flat zipper

Flat lightning looks like a scattered flash of light on the surface of clouds. Thunderstorms, accompanied only by flat lightning, are classified as weak, and they are usually observed only in early spring or late autumn.

Tape zipper

Ribbon lightning - several identical zigzag discharges from clouds to the ground, parallel shifted relative to each other with small or no gaps.

Bead lightning

A rare form of electrical discharge during a thunderstorm, in the form of a chain of luminous dots.The lifetime of bead lightning is 1–2 seconds. It is noteworthy that the trajectory of bead lightning often has a wave-like character. Unlike linear lightning, the trail of bead lightning does not branch - this is a distinctive feature of this species.

rocket lightning

Rocket lightning is a slowly developing discharge, lasting 1–1.5 seconds. Rocket lightning is very rare.

Fireball

Ball lightning is a bright luminous electric charge of various colors and sizes. Near the ground, it most often looks like a ball with a diameter of about 10 cm, less often it has the shape of an ellipsoid, a drop, a disk, a ring, and even a chain of connected balls. The duration of the existence of ball lightning is from several seconds to several minutes, the color of the glow is white, yellow, light blue, red or orange. Usually this type of lightning moves slowly, almost silently, accompanied by only a slight crackling, whistling, buzzing or hissing. Ball lightning can penetrate into enclosed spaces through cracks, pipes, windows.

A rare form of lightning, according to statistics, there are 2-3 ball lightning per thousand ordinary lightning.

The nature of ball lightning is not fully understood. There are many hypotheses about the origin of ball lightning, from scientific to fantastic.

curtain zipper

Curtain lightning looks like a wide vertical band of light, accompanied by a low low rumble.

Volumetric lightning

Bulk lightning is a white or reddish flash with low translucent clouds, with a strong crackling sound “from everywhere”. It is more often observed before the main phase of a thunderstorm.

strip zipper

Strip lightning - strongly resembles the aurora, "laid on its side" - horizontal stripes of light (3-4 stripes) are grouped on top of each other.

Elves, jets and sprites

Elves (English Elves; Emissions of Light and Very Low Frequency Perturbations from Electromagnetic Pulse Sources) are huge, but dimly luminous flash cones with a diameter of about 400 km, which appear directly from the top of a thundercloud.

The jets are blue tube-cones.

Sprites - a kind of lightning, beating up from the cloud. For the first time this phenomenon was recorded in 1989 by accident. Very little is known about the physical nature of sprites.

Jets and Elves form from the tops of the clouds to the lower edge of the ionosphere (90 kilometers above the Earth's surface). The duration of these aurora is a fraction of a second. To photograph such short-lived phenomena, high-speed imaging equipment is needed. Only in 1994, flying in an airplane over a big thunderstorm, did scientists manage to capture this amazing sight.

Other phenomena

flashes

Flashes are white or blue silent flashes of light observed at night in partly cloudy or clear weather. Flashes usually occur in the second half of summer.

Zarnitsa

Zarnitsy - reflections of distant high thunderstorms, visible at night at a distance of up to 150 - 200 km. The sound of thunder during lightning is not heard, the sky is cloudy.

Volcanic Lightning

There are two types of volcanic lightning. One arises at the crater of the volcano, and the other, as seen in this image of the Puyehue volcano in Chile, electrifies the smoke of the volcano. Water and frozen ash particles in the smoke rub against each other, and this causes static discharges and volcanic lightning.

Lightning Catatumbo

Catatumbo lightning is an amazing phenomenon that is observed in only one place on our planet - at the confluence of the Catatumbo River into Lake Maracaibo (South America). The most surprising thing about this type of lightning is that its discharges last about 10 hours and appear at night 140-160 times a year. Catatumbo lightning is clearly visible at a fairly long distance - 400 kilometers. Lightnings of this kind were often used as a compass, from which people even nicknamed the place of their observation - “Maracaibo Lighthouse”.

Most say that Catatumbo lightning is the largest single ozone generator on Earth, because. winds coming from the Andes cause thunderstorms. Methane, which is abundant in the atmosphere of these wetlands, rises to the clouds, fueling lightning discharges.

Federal Agency for Education

State educational institution of higher professional education

PETROZAVODSK STATE UNIVERSITY

Linear lightning.

Its birth and methods of use.

Petrozavodsk 2009

List of performers:

Egorova Elena,

1 course, group 21102

Lebedev Pavel,

1 course, group 21112

Shelegina Irina,

1 course, group 21102

Lightning. General information…………………………………….4

Story. Theories of origin……………………………5

Lightning formation……………………………………….6

Lightning. General information

Lightning is a spark discharge of static electricity accumulated in thunderclouds.

The length of linear lightning is several kilometers, but can reach 20 km or more.

The form of lightning is usually similar to the branched roots of a tree that has grown in the sky.

The main lightning channel has several branches 2-3 km long.

The diameter of the lightning channel is from 10 to 45 cm.

The duration of the existence of lightning is tenths of a second.

The average lightning speed is 150 km/s.

The current strength inside the lightning channel reaches 200,000 A.

The plasma temperature in lightning exceeds 10,000°C.

The electric field strength inside a thundercloud ranges from 100 to 300 volts/cm, but before a lightning discharge in separate small volumes it can reach up to 1600 volts/cm.

The average charge of a thundercloud is 30-50 coulombs. In each lightning discharge, 1 to 10 coulombs of electricity are transferred.

Along with the most common linear lightning, sometimes there are rocket, bead and ball lightning. Rocket lightning is very rare. It lasts 1-1.5 seconds and is a discharge slowly developing between the clouds. Beaded lightning should also be attributed to very rare types of lightning. It has a total duration of 0.5 seconds and appears to the eye against the background of clouds in the form of luminous beads with a diameter of about 7 cm. Ball lightning in most cases is a spherical formation with a diameter of 10-20 cm at the earth's surface, and up to 10 m at the height of the clouds.

On the Earth, about 100 linear lightning discharges are observed every second, the average power that is spent on the scale of the entire Earth for the formation of thunderstorms is 1018 erg / sec. That is, the energy released during precipitation from a thundercloud significantly exceeds its electrical energy.

2. The history of the study of the nature of lightning and the initial "theories" of the explanation of this natural phenomenon

Lightning and thunder were originally perceived by people as an expression of the will of the gods and,

in particular, as a manifestation of God's wrath. At the same time, an inquisitive human

the mind from ancient times tried to comprehend the nature of lightning and thunder, to understand them

natural causes. In ancient times, Aristotle thought about this. Above

Lucretius thought about the nature of lightning. Very naively

attempts to explain thunder as a consequence of the fact that "clouds collide there under

the onslaught of the winds."

For many centuries, including the Middle Ages, it was believed that lightning is a fiery

vapor trapped in clouds of water vapor. Expanding, it breaks through them in the most

weak point and quickly rushes down to the surface of the earth. In 1929, J. Simpson proposed a theory that explains electrification by the crushing of raindrops by air currents. As a result of crushing, falling larger drops are positively charged, while smaller ones remaining in the upper part of the cloud are negatively charged. In Ch.Wilson's theory of free ionization, it is assumed that electrization occurs as a result of the selective accumulation of ions by droplets of different sizes located in the atmosphere. It is possible that the electrification of thunderclouds is carried out by the joint action of all these mechanisms, and the main one is the fall of sufficiently large particles electrified by friction against atmospheric air.

In 1752, Benjamin Franklin experimentally proved that lightning is

strong electrical discharge. The scientist performed the famous experiment with air

a kite that was launched into the air at the approach of a thunderstorm.

Experience: A pointed wire was fixed on the crosspiece of the snake,

a key and a silk ribbon were tied to the end of the rope, which he held with his hand.

As soon as the thundercloud was above the kite, the sharpened wire became

extract an electric charge from it, and the kite, along with the towline, will become electrified.

After the rain wets the snake along with the string, making them thereby

free to conduct an electric charge, can be observed as an electric

the charge will "drain" as the finger approaches.

Simultaneously with Franklin, the study of the electrical nature of lightning

were engaged in M.V. Lomonosov and G.V. Richman. Thanks to their research in the middle of the 18th century, the electrical nature of lightning was proved. Since that time, it has become clear that lightning is a powerful electrical discharge that occurs when the clouds are sufficiently electrified.

3. Lightning shaping

Linear lightnings are usually observed, which belong to 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 not shorter than a few hundred meters; they arise in electric fields much weaker than the fields during interelectrode discharges; The collection of charges carried by lightning occurs in thousandths of a second from myriads of small, well-isolated particles located in a volume of several km3. The process of development of lightning in thunderclouds has been most studied, 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 some critical) volume of the cloud an electric field with a strength sufficient to start an electric discharge (~ 1 MV / m) is formed, and in a significant part of the cloud there is a field with an average strength sufficient to maintain the discharge that has begun (~ 0.1-0.2 MV / m). In lightning, the electrical energy of the cloud is converted into heat and light.

Lightning discharges can occur between neighboring electrified clouds or between an electrified cloud and the ground. The discharge is preceded by the occurrence of a significant difference in electrical potentials between neighboring clouds or between a cloud and the earth due to the separation and accumulation of atmospheric electricity as a result of such natural processes as rain, snowfall, etc. The resulting potential difference can reach a billion volts, and the subsequent discharge of the accumulated electrical energy through the atmosphere can create short-term currents from 3 to 200 kA.

4.Main phases of the first and subsequent

lightning components

The affinity of lightning with a spark discharge was proved by the works of Benjamin Franklin two and a half centuries ago. In saying such a phrase today, it is more correct to mention these two forms of electrical discharge in reverse order, since the most important structural elements of a spark were originally observed in lightning and only then were discovered in the laboratory. The reason for such a non-standard sequence of events is simple: the lightning discharge has a significantly longer length, its development takes longer, and therefore optical recording of lightning does not require equipment with a particularly high spatial and temporal resolution. The first and still impressive time sweeps of lightning discharges were performed using simple cameras with a mechanical mutual movement of the lens and film (Boyce cameras) back in the 30s. They made it possible to identify two main phases of the process: leader and home stages.

During leader stage in the interval cloud-ground or between the clouds germinates a conducting plasma channel - the leader. It is born in the region of a strong electric field, which is certainly sufficient to ionize the air with an electron impact, but the leader has to pave the main part of the path where the strength of the external field (from the charge of thunderclouds) does not exceed several hundred volts per centimeter. Nevertheless, the length of the leader channel increases, which means that intense ionization occurs at its head, turning neutral air into a highly conductive plasma. This is possible because the leader himself carries his own strong field. It is created by a volume charge concentrated in the region of the channel head and moves along with it. The function of a conductor, galvanically connecting the head of the leader with the lightning start point, is performed by the plasma channel of the leader. The leader grows for quite a long time, up to 0.01 s - an eternity on the scale of the fleeting phenomena of a pulsed electric discharge. All this time, the plasma in the channel must maintain high conductivity. This is impossible without heating the gas to temperatures approaching the temperatures of an electric arc (over 5000-6000 K). The question of the balance of energy in the channel, which is required for

his warming up and to compensate for losses - one of the most important in the theory of the leader.

The leader is a necessary element of any lightning. In a multicomponent flare, not only the first, but also all subsequent components begin with the leader process. Depending on the polarity of the lightning, the direction of its development, and the number of the component (the first or any of the subsequent ones), the leader mechanism may change, but the essence of the phenomenon remains the same. It consists in the formation of a highly conductive plasma channel due to the local amplification of the electric field in the immediate vicinity of the leader head.

Main stage of lightning(return stroke) starts from the moment the leader contacts the ground or a grounded object. Most often, this is not direct contact. From the top of the object, its own leader channel, called the counter leader, can arise and move towards the lightning leader. Their meeting marks the beginning of the main stage. While moving in the cloud-to-ground gap, the head of the lightning leader carried a high potential, comparable to the potential of a thunderstorm.

clouds at the lightning start point (they differ in the voltage drop on the channel). After contact, the leader head takes on the ground potential, and its charge drains into the ground. Over time, the same thing happens to others.

sections of the channel with high potential. This "unloading" occurs through the propagation of the leader's charge neutralization wave through the channel from the ground to the cloud. Wave speed approaches the speed of light, up to 108 m/s. Between the wave front and the earth flows through the channel

a strong current that carries a charge to the ground from the “unloading” sections of the channel. The current amplitude depends on the initial potential distribution along the channel. On average, it is close to 30 kA, and for the most

powerful lightning reaches 200-250 kA. The transfer of such a strong current is accompanied by an intense release of energy. Due to this, the gas in the channel quickly heats up and expands; shock wave occurs. The roll of thunder is one of its manifestations. Energetically, the main stage is the most powerful. It is also characterized by the fastest change in current. The steepness of its rise can exceed 1011 A / s - hence the extremely powerful electromagnetic radiation that accompanies a lightning discharge. That is why a working radio or TV reacts intensely to a thunderstorm.

interference, and this occurs at distances of tens of kilometers.

Current pulses of the main stage accompany not only the first, but also all subsequent components of the downward lightning. This means that the leader of each next component charges the one moving towards the ground.

channel, and during the main stage part of this charge is neutralized and redistributed. Long peals of thunder are the result of the superposition of sound waves excited by current pulses of the entire population

subsequent components. For ascending lightning, the picture is somewhat different. First Component Leader

starts from a point with zero potential. As the channel grows, the head potential changes gradually until the leader process slows down somewhere in the depths of the thundercloud. This is not accompanied by any rapid charge changes, and therefore the first component of ascending lightning has the main

stage is missing. It is observed only in subsequent components that start already from the cloud and move towards the ground, no different from the subsequent components of descending lightning.

In scientific terms, the main stage of intercloud lightning is of great interest. The fact that it exists is indicated by peals of thunder, no less loud than during discharges into the ground. It is clear that the leader of intercloud lightning starts somewhere in the volume of one charged region of a thundercloud (a thunderstorm cell) and moves in the direction of another, opposite sign. The charged regions in the cloud cannot in any way be represented as some kind of conducting bodies, similar to the plates of a high-voltage capacitor, because the charges there are distributed over a volume with a radius of hundreds of meters and are located on small drops of water and ice crystals (hydrometeors) that do not contact each other. The appearance of the main stage in its physical essence necessarily implies the contact of the lightning leader with a highly conductive body of high electrical capacity, comparable or greater than the leader's capacity. It must be assumed that during an intercloud lightning discharge, the role of such a body is played by some other plasma channel that has simultaneously arisen and then contacts with the first one.

In measurements near the earth's surface, the current pulse of the main stage decreases by half of the amplitude value, on average, in about 10 -4 s. The spread of this parameter is very large - deviations from the average in each direction reach almost an order of magnitude. Positive lightning current pulses, as a rule, are longer than negative ones, and the pulses of the first components last longer than the subsequent ones.

After the main stage, a slightly varying current of the order of 100 A can flow through the lightning channel for hundredths, and sometimes even tenths of a second. In this final stage of continuous current, the lightning channel retains its conducting state, and its temperature is kept at the arc level. A continuous current stage may follow each lightning component, including the first upstream lightning component that does not have a main stage. Sometimes against the background of continuous current

bursts of current are observed with a duration of about 10 -3 s and an amplitude of up to 1 kA. They are accompanied by an increase in the brightness of the channel glow.

5. Linear zippers

The widespread linear lightning, which any person encounters many times, looks like a branching line. the magnitude of the current in the channel of linear lightning is on average 60 - 170 kA, lightning was registered with a current of 290 kA. an average lightning carries an energy of 250 kWh (900 MJ). energy is mainly realized in the form of light, heat and sound energies.

The discharge develops in a few thousandths of a second; at such high currents, the air in the zone of the lightning channel almost instantly heats up to a temperature of 30,000-33,000 ° C. As a result, the pressure rises sharply, the air expands - a shock wave occurs, accompanied by a sound impulse - thunder.

Before and during a thunderstorm, occasionally in the dark, on the tops of tall pointed objects (tops of trees, masts, peaks of sharp rocks in the mountains, crosses of churches, lightning rods, sometimes in the mountains on people's heads, raised hands or animals) one can observe a glow that has received the name "St. Elmo's Fire". This name was given in ancient times by sailors who observed the glow on the tops of the masts of sailing ships. The glow arises due to the fact that on tall, pointed objects, the electric field strength created by the static electric charge of the cloud is especially high; as a result, air ionization begins, a glow discharge occurs and reddish glow tongues appear, sometimes shortening and again lengthening. no attempt should be made to extinguish these fires, as there is no combustion. at a high electric field strength, a beam of luminous filaments may appear - a corona discharge, which is accompanied by a hiss. linear lightning can also occasionally occur in the absence of thunderclouds. It is no coincidence that the saying arose - "thunder from a clear sky."

Line lightning

6.Physical processes during lightning discharge.

Lightning starts not only from a cloud to the ground, or from a grounded object to a cloud, but also from bodies isolated from the ground (aircraft, rockets, etc.). Attempts to elucidate the mechanisms of these processes are little helped by experimental data related to the lightning itself. There are almost no observations that would shed light on the physical essence of phenomena. Therefore, it is necessary to build speculative schemes, actively involving the results of the experiment and the theory of a long laboratory spark. Lightning is very interesting in its physical origin, but it is most important to consider in detail the main stage of lightning.

G the main stage, or the process of discharging the lightning channel, begins from the moment the gap between the cloud and the earth is closed by the descending leader. Having touched the ground or a grounded object, the leader channel (for definiteness, let it be a negative leader) should acquire their zero potential, since the capacitance of the ground is "infinite". Zero potential also acquires the channel of the ascending leader, which is a continuation of its "twin" of the descending one. The grounding of the leader channel, which carries a high potential, is accompanied by a strong change in the charge distributed along it. Before the beginning of the main stage, the charge τ 0 = C 0 was distributed along the channel. Here and in what follows, the “initial” potential for the main stage brought to the earth is denoted by Ui. As before, we consider it constant along the length of both leaders, ignoring the voltage drop along the channel, which is of little importance for our purposes. Let us assume that in the course of the main stage, as well as in the leader stage, the channel can be characterized by the capacitance Co, which does not change either along its length or in time. When the entire channel acquires zero potential (U = 0), the linear charge becomes equal to τ 1 = -CоUо(x). The part of the channel belonging to the negative descending leader not only loses its negative charge, but acquires a positive one (Uо 0). It not only discharges, but also recharges. The channel of the conjugated positive ascending leader high in the cloud becomes even more positively charged (see Fig.). Change in linear charge during the main stage ∆τ = τ-τ o = -С o U i . When U i (x) = const, the change in charge is the same along the entire length of the channel. It is as if a long conductor (long line), pre-charged to a voltage Ui, is completely discharged.

Measurements near the ground show that the downward leader channel is being discharged with a very strong current. In the case of negative lightning, the current pulse of the main stage with an amplitude IM ~ 10-100 kA lasts 50-100 µs at a level of 0.5. For about the same time, a short bright section, the head of the main channel, which is clearly visible on photographic scans, runs up the channel. His speed v r≈(1-0.5)s is only several times less than the speed of light. It is natural to interpret this as the propagation of a discharge wave along the channel, i.e. waves of decreasing potential and the appearance of a strong current. In the region of the wave front, where the potential drops sharply in magnitude from U i and a strong current is formed, due to the intense release energy, the former leader channel is heated to a high temperature (according to measurements, up to 30–35 kK). Because the front of the wave glows so brightly. Behind it, the channel, expanding, cools down and, losing energy to radiation, glows weaker. The main stage process has much in common with the discharge of an ordinary long line formed by a metal conductor.

The line discharge also has a wave character, and this process served as a prototype in the formation of ideas about the main stage of lightning. The lightning channel is discharged much faster than it was charging during its growth at the speed of the leaders v l 10 -3 -10 -2)v r. But changes in the potential and linear charge during charging and discharging are of the same order of magnitude: τ o =∆t. According to the speed, the channel is discharged v t /v l ~ 10 2 -10 3 times stronger current i M ~ ∆tv r than the leader i L ~ t 0 V L ~ 100 A. The linear resistance of the channel R 0 decreases approximately by the same amount at transition from the leader stage to the main stage. The reason for the decrease in resistance is the heating of the channel during the passage of a strong current, which increases the plasma conductivity. Therefore, the resistances of the channel and the streamer zone, through which the same current flows, are also comparable. This means that the same order of magnitude energy is dissipated per unit length of the leader channel and it is expressed in terms of the leader parameters

This gives It also turns out that the average electric field in the leader channel and behind the discharge wave in the already transformed channel is of the same order. This agrees with a similar conclusion that can be drawn by directly considering the steady states in the channels of the leader and main stages of lightning. The situation there is similar to that in a stationary arc. But in high-current arcs, the field in the channel is actually weakly dependent on the current. From what has been said, it follows that if in the leader and , then in the steady state behind the wave front of the main stage there should be , and the total ohmic resistance of the entire lightning channel several kilometers long turns out to be about 102 Ohm. This is comparable to the wave impedance Z of a perfectly conducting long line in air, while for a leader channel of the same length the impedance is two orders of magnitude greater than Z. If the channel resistance did not change, remaining at the level of the leader, the discharge wave of the lightning channel would damp and spread out without passing even a small fraction of the channel. The current through the channel's earth-to-earth point would also decay too quickly. Experience suggests the opposite: the visible luminous head has a sharp front, and a large current near the earth is recorded during the entire time of its rise. The transformation of the leader channel during the passage of the wave, which leads to a sharp decrease in its linear resistance, determines the entire course of the process of the main stage of lightning.

Dangerous factors of lightning exposure.

Due to the fact that lightning is characterized by high currents, voltages and discharge temperatures, the impact of lightning on a person, as a rule, ends in very serious consequences - usually death. about 3,000 people die every year from a lightning strike in the world, and cases of simultaneous defeat of several people are known.

The lightning discharge follows the path of least electrical resistance. since the distance between a tall object and a thundercloud, and hence the electrical resistance, is smaller, lightning usually strikes tall objects, but not necessarily. for example, if you place two masts side by side - a metal one and a higher wooden one, then lightning is likely to strike a metal mast, although it is lower, because the electrical conductivity of the metal is higher. lightning also strikes clay and wet areas much more often than dry and sandy ones, because The former are more electrically conductive.

For example, in the forest, lightning also acts selectively. A tree splits when struck by lightning. the mechanism of this is as follows: tree sap and moisture in the discharge area instantly evaporate and expand, creating huge pressures,

which break the wood. A similar effect, accompanied by scattering of chips, can occur when lightning strikes the wall of a wooden structure. therefore, being under a tall tree during a thunderstorm is dangerous.

It is dangerous to be on or near water during a thunderstorm. water and land near water have a high electrical conductivity. at the same time, being inside reinforced concrete buildings, metal structures (for example, metal garages) during a thunderstorm is safe for humans.

In addition to damaging people and animals, linear lightning often causes forest fires, as well as residential and industrial buildings, especially in rural areas.

During a thunderstorm, being in a city is less dangerous than in open areas, since steel structures and tall buildings work well as lightning rods.

A fully or partially closed electrically conductive surface forms the so-called "Faraday chamber" inside which no significant and dangerous potential for humans can form. therefore, passengers inside a car with an all-metal body, a tram, a trolleybus, a train car are safe during a thunderstorm until they go outside or start opening windows.

Lightning can strike an aircraft, but since modern aircraft are all-metal, passengers are fairly well protected from being struck by a discharge.

statistics show that for 5000-10000 flight hours there is one lightning strike on an aircraft, fortunately, almost all damaged aircraft continue to fly. among the various causes of air crashes, such as glaciation, heavy rain, fog, snow, storm, tornado, lightning takes the last place, but still, aircraft flights during a thunderstorm are prohibited.

Lightning almost always strikes the world-famous Eiffel Tower in Paris during a thunderstorm, but this does not pose a danger to people on the observation deck, because. the openwork metal lattice of the tower forms a faraday chamber, which is an excellent protection against electric lightning.

A sign that you are in an electric field can be hair standing on end, which will begin to make a slight crackle. But that's just dry hair.

If you are struck by lightning, but you are still able to think, you should see a doctor as soon as possible. Doctors believe that a person who survived after a lightning strike, even without severe burns to the head and body, can subsequently receive complications in the form of deviations in cardiovascular and neuralgic activity from the norm.

Lightning strikes the Eiffel Tower, 1902 photograph

8. How often does lightning strike?

Lightning strikes on ground structures. From everyday experience it is known that lightning most often strikes high structures, especially those that dominate the surrounding area. On the plain, most blows are to free-standing masts, towers, chimneys, etc. In mountainous areas, low buildings often suffer if they stand on separate high hills or on top of a mountain. On a worldly level, the explanation for this is simple: it is easier for an electrical discharge, which is lightning, to block a shorter distance to a towering object. For example, a mast 30 meters high on average in Europe has 0.1 lightning strikes per year (one strike in 10 years), while for a solitary 100-meter object there are almost 10 times more. With a more careful attitude, such a sharp dependence of the number of impacts on height no longer seems trivial. The average height of the starting point of a downward lightning is about 3 km, and even a 100-meter height is only 3% of the distance between the cloud and the earth. Random curvatures change the total length of the trajectory ten times more strongly. We have to admit that the final surface stage of lightning development is distinguished by some special processes that quite rigidly predetermine the last section of the path. These processes lead to the orientation of the descending leader, his attraction to high objects.

From the experience of scientific observations of lightning, one can speak of an approximately quadratic dependence of the number of strokes N M from height h concentrated objects (they have h much larger than all other sizes); for extended ones, lengths I such as overhead power line, N M ~ h i . This suggests the existence of some equivalent lightning contraction radius R uh~h. All lightnings displaced from the object horizontally by a distance r R uh fall into it, the rest pass by. Such a primitive orientation scheme as a whole leads to the correct result. For ratings, you can use R uh~ 3h; Based on them, special maps of the intensity of thunderstorm activity are built. In the European tundra n m R uh= 0.3 km and for her

impact per year, if we focus on the average figure n m = 3.5 km -2 year -1 The estimate makes sense for flat terrain and only for not too high objects h

Human Defeat

The radius of lightning constriction into a person is only 5-6 m, the area of constriction is no more than 10 -4 km 2 . In fact, lightning has many more victims and a direct strike has nothing to do with it. Human experience does not recommend being in a forest during a thunderstorm, especially in open areas, near tall trees. And it is right. A tree is about 10 times taller than a person and lightning strikes it 100 times more often. Being under a tree crown, a person has a noticeable chance of being in the zone of lightning current spreading, which is not safe. After a lightning strike at the top of a tree, its current I M spreads along a well-conducting trunk, and then spreads through the roots into the ground. The root system of the tree becomes, as it were, a natural grounding conductor. Due to the current, an electric field appears in the earth, where p is the resistivity of the soil, j is the current density. Let the current flow in the soil strictly symmetrically. Then the equipotentials are hemispheres with a diametral plane on the earth's surface. The current density at a distance r from the tree trunk j(r) =,

the potential difference between close points is equal to ∆ U=. If, for example, a person stands at a distance r ≈ 1 m from the center of a tree trunk sideways to a tree, and the distance between his feet is ∆r ≈ 0.3 m, then for an average lightning current Im\u003d 30 kA, the voltage drop on the soil surface with p \u003d is . This voltage is applied to the soles of the shoes, and after their inevitable very rapid breakdown - to the human body. The fact that a person will suffer, and most likely be killed, is beyond doubt - the stress acting on him is too great. Note that it is proportional to ∆r. This means that standing with your legs wide apart is much more dangerous than standing at attention with tightly compressed feet, and lying along the radius from a tree is even more dangerous, because in this case the distance between the extreme points in contact with the ground becomes equal to the height

person. It is best, like a stork, to freeze on one leg, but such advice is easier to give than to carry out. By the way, lightning strikes large animals more often than humans, also because they have more distance between their legs.

If you have a dacha with a lightning rod and a special grounding conductor has been built for it, make sure that during a thunderstorm there are no people near the grounding conductor and the grounding descent to it. The situation here is similar to that just considered.

7. Rules of conduct during a thunderstorm.

We see a flash of lightning almost instantly, because. light travels at a speed of 300,000 km/s. the speed of sound propagation in air is approximately 344 m/s, i.e. Sound travels 1 kilometer in about 3 seconds. thus, dividing the time in seconds between the flash of lightning and the first clap of thunder that followed it, we determine the distance in kilometers to the location of the thunderstorm.

If these time intervals decrease, then a thunderstorm is approaching, and it is necessary to take measures to protect against lightning strikes. Lightning is dangerous when a flash of thunder immediately follows, i.e. a thundercloud is above you and the danger of being struck by lightning is most likely. Your actions before and during a thunderstorm should be as follows:

do not leave the house, close windows, doors and chimneys, take care that there is no draft that could attract ball lightning.

during a thunderstorm, do not heat the stove, because. the smoke coming out of the chimney has a high electrical conductivity, and the probability of a lightning strike into a chimney rising above the roof increases;

disconnect radios and TVs from the network, do not use electrical appliances and telephones (especially important for rural areas);

during the walk, hide in the nearest building. Thunderstorms are especially dangerous in the field. When looking for shelter, give preference to a large metal structure or a structure with a metal frame, a residential building or other building protected by a lightning rod; if it is not possible to hide in a building, do not hide in small sheds, under lonely trees;

not to be on hills and open unprotected places, near metal or mesh fences, large metal objects, wet walls, lightning rod grounding;

in the absence of shelter, lie down on the ground, while preference should be given to dry sandy soil, remote from the reservoir;

if a thunderstorm caught you in the forest, you need to take cover in a stunted area. You can not hide under tall trees, especially pines, oaks, poplars. It is better to be at a distance of 30 m from a single tall tree. pay attention to whether there are any nearby trees that were previously struck by a thunderstorm, split. it is better to stay away from this place in this case. the abundance of trees struck by lightning indicates that the soil in this area has a high electrical conductivity, and a lightning strike in this area is very likely;

during a thunderstorm you can not be on the water and near the water - swim, fish. it is necessary to move away from the coast;

in the mountains, move away from mountain ridges, sharp towering cliffs and peaks. when approaching a thunderstorm in the mountains, you need to go down as low as possible. metal objects - climbing hooks, ice axes, pots, collect in a backpack and lower on a rope 20-30 m down the slope;

during a thunderstorm, do not play sports outdoors, do not run, because. it is believed that sweat and rapid movement "attracts" lightning;

if you are caught in a thunderstorm on a bicycle or motorcycle, stop moving and wait out the thunderstorm at a distance of about 30 m from them;

8. Lightning energy technology.

Chinese scientists have developed a technology for using lightning energy for scientific and industrial purposes,

"The new development makes it possible to capture lightning in the air and redirect it to collectors on the ground for research and use," said Tse Xiushu of the Institute of Atmospheric Physics.

To capture lightning, rockets equipped with special lightning rods will be used, which will be launched into the center of a thundercloud. The YL-1 missile is due to take off a few minutes before the lightning strike.

"Checks have shown that the accuracy of the launches is 70%," the developers of the device said.

The energy of lightning, as well as the electromagnetic radiation it produces, will be used to genetically modify agricultural crops and produce semiconductors.

In addition, the new technology will significantly reduce the economic damage from thunderstorms, since the discharges will go to safe places. According to statistics, about a thousand people die every year from lightning strikes in China. Economic damage from thunderstorms in China reaches 143 million dollars a year.

Researchers are also trying to find a way to use lightning in energy. According to scientists, one lightning strike produces billions of kilowatts of electricity. Around the world, 100 lightning strikes occur every second - this is a huge source of electricity.

Bibliography:

Stekolnikov I.K., Physics of lightning and lightning protection, M. - L., 1943;

Imyanitov I. M., Chubarina E. V., Shvarts Ya. M., Electricity of clouds, L., 1971;

Renema.py, Lightning.URL: http:// www. renema. en/ info/ lightning_ nature. shtml

History of lightning. URL: http://en.wikipedia.org/wiki/Lightning

Imyanitov I.M., Chubarina E.V., Shvarts Ya.M. Cloud electricity. L., 1971

Science and Technology: Physics. URL: http://www.krugosvet.ru/enc/nauka_i_tehnika/fizika/MOLNIYA.html

Autonomous luminous formations in the open air. URL: http://elibrary.ru/item.asp?id=9199806

Bazelyan E.M., Raiser Yu.P. Physics of lightning and lightning protection. Moscow: Fizmatlit, 2001.

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

The idea of the Etruscans 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 head of the deity, he held the other in his hands, suppressing all the negative desires of mankind with it.

Lightning is a huge electrical discharge, which is always accompanied by a flash and thunderous peals (a shining discharge channel resembling a tree is clearly visible in the atmosphere). At the same time, a flash of lightning is almost never one, it is usually followed by two, three, and often reaches several tens of sparks.

These discharges are almost always formed in cumulonimbus clouds, sometimes in large stratus clouds: the upper limit 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 a large amount of steam condensed in the form of ice floes (at a height exceeding three kilometers it is almost always ice crystals, since the temperature here does not rise above zero). Before the cloud becomes a thunderstorm, ice crystals begin to actively move inside it, while the currents of warm air rising from the heated surface help them to move.

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

After small ice crystals gather at the top and large ones at the bottom, the top of the cloud is positively charged, the bottom is negatively charged. Thus, the electric field strength in the cloud reaches extremely high levels: a million volts per meter.

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

The channel heats up to nearly 30,000 degrees Celsius, five times the temperature of the Sun, producing a bright light (the flash typically lasts only three-quarters of a second). After the formation of the channel, 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 that finds itself near the channel. The shock wave of the strongest electric discharge a few meters away from itself is quite capable of breaking trees, injuring or concussing even without a direct electric shock:

At a distance of up to 0.5 m to the channel, lightning can destroy weak structures and injure a person;
At a distance of up to 5 meters, the buildings remain intact, but can knock out windows and stun a person;
At long distances, the shock wave does not carry negative consequences and turns into a sound wave, known as thunder peals.

Thunder rolls

A few seconds after a 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 of this, explosive vibrations of the air arise and thunder occurs. Thunder and lightning are closely interconnected with each other: the length of the discharge is often about eight kilometers, so the sound from different parts of it reaches at different times, forming thunder peals.

Interestingly, by measuring the time that has passed 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 kilometers). This will help determine if the storm is moving away or approaching.

Amazing fireball

One of the least studied, and therefore the most mysterious phenomena of nature, is ball lightning - a luminous plasma ball moving through the air. It is mysterious because the principle of the formation of ball lightning is still unknown: despite the fact that there are a large number of hypotheses explaining the reasons for the appearance of this amazing natural phenomenon, there were objections to each of them. Scientists have not been able to experimentally achieve the formation of ball lightning.

Spherical lightning is able to exist for a long time and move along an unpredictable trajectory. For example, it is quite capable of hanging in the air for several seconds, and then rushing to the side.

Unlike a simple discharge, there is always one plasma ball: until two or more fire lightnings were simultaneously recorded. The size of ball lightning varies from 10 to 20 cm. Ball lightning is characterized by white, orange or blue tones, although other colors are often found, up to black.

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

The main difficulty in studying this phenomenon is that scientists rarely manage to fix its appearance, and the testimony of eyewitnesses often casts doubt on the fact that the phenomenon they observed was really ball lightning. First of all, testimony differs as to the conditions in which it appeared: basically it was seen during a thunderstorm.

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

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

Often, the appearance of ball lightning does not cause trouble (it moves quietly in air currents and flies away or disappears after a while). But, the sad consequences were also noticed when it exploded, instantly evaporating the nearby liquid, 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, do not move sharply and do not 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.

Nothing can be thrown into a plasma ball: it is quite capable of exploding, and this is fraught not only with burns or loss of consciousness, but with cardiac arrest. If it happened that the electric ball caught a person, you need to transfer him to a ventilated room, wrap him up warmer, do a heart massage, artificial respiration and immediately call a doctor.

What to do in a thunderstorm

When a thunderstorm starts 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. But it is advisable to avoid tall trees: lightning usually aims at the largest plant, and if the trees are of the same height, it falls into something that conducts electricity better.

To protect a detached building or structure from lightning, they usually install a high mast near them, on top of which a pointed metal rod is fixed, 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: a 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 of cities and other human settlements.

Scientists know that linear lightning - the kind you often see during thunderstorms - is a spark discharge of huge electric charges that accumulate under special conditions in the lower atmosphere. The shape of lightning usually resembles the roots of a giant tree that has suddenly grown in the sky. The length of linear lightning is usually several kilometers, but can reach 20 km or more. The main "spark" of lightning has several branches 2-3 km long. The diameter of the lightning channel is from 10 to 45 cm, and it "lives" only tenths of a second. Its average speed is about 150 km/s.

Most often, lightning occurs in powerful cumulonimbus clouds - they are also called thunderstorms. Less commonly, lightning occurs in nimbostratus clouds, as well as during volcanic eruptions, tornadoes, and dust storms.

Lightning discharges can occur between neighboring electrified clouds, between a charged cloud and the ground, or between different parts of the same cloud. In order for a discharge to occur, a very significant difference in electrical potential must occur. This can happen during rain, snowfall, hail and other complex natural processes. The potential difference can be tens of millions of volts, and the current inside the lightning channel reaches 20,000 amperes.

Scientists still have not come to a consensus on how and why such huge charges arise in thunderclouds. There are several theories on this subject, and each of them describes at least one of the reasons for this phenomenon. So, in 1929, a theory appeared that explains the electrification in a thundercloud by the fact that raindrops are crushed by air currents. Larger drops are positively charged and fall down, while smaller ones remaining in the upper part of the cloud acquire a negative charge. Another theory - it is called induction - suggests that the electric charges in the cloud are separated by the electric field of the Earth, which itself is negatively charged. There is another theory - its authors believe that electrification occurs as a result of the fact that drops of different sizes in the atmosphere absorb gas ions with different charges.

About 100 linear lightning discharges occur on Earth every second, and during the year it strikes every square kilometer of its surface six times. Sometimes lightning can behave in a completely inexplicable way.

There are cases when lightning:

She burned linen on a man, leaving his outer clothing intact;

She snatched metal objects from the hands of a person and did not harm him;

Melted together all the coins in the wallet without damaging the paper money;

She completely destroyed the medallion on the chain worn around the neck, leaving on the skin of a person the imprint of the chain and the medallion, which did not come off for several years;

Three times she hit a man without harming him, and when he died after a long illness, for the fourth time she landed on a monument on his grave.

Even stranger stories are told about people struck by lightning, but not all of them have confirmation. The only thing that the statistics show is that lightning strikes men six times more often than women.

Even though the force of the discharge is incredibly high, most people who get struck by lightning do not die. This happens because the main lightning current seems to “flow” over the surface of the human body. Most often, the case is limited to severe burns and lesions of the cardiovascular and nervous systems, and the victim of this natural phenomenon needs urgent medical attention.

The most frequent "target" of lightning are tall trees, primarily oaks and beeches. Interestingly, among violin and guitar makers, the wood of trees struck by lightning is considered endowed with unique acoustic properties.

Most likely, many readers of the site " Earth Science News» know that there are several types of lightning, but even the most educated people are sometimes unaware of how many types of lightning actually exist. It turns out that there are more than ten types of them, and reviews of the most interesting lightning are given in this article. Naturally, there are not only bare facts here, but also real photographs of real lightning. To be honest, the authors are surprised by the professionalism of photographers who are able to capture these atmospheric phenomena so clearly.

So, the types of lightning will be considered in order, from the most common linear lightning to the rarest sprite lightning. Each type of lightning is given one or more photos that help to understand what such lightning really is.

So let's start with cloud-to-ground linear lightning

How to get such lightning? Yes, it's very simple - all that is required is a couple of hundred cubic kilometers of air, a height sufficient for the formation of lightning and a powerful heat engine - well, for example, the Earth. Ready? Now take the air and sequentially begin to heat it. When it starts to rise, with each meter of rise, the heated air cools, gradually becoming colder and colder. Water condenses into ever larger droplets, forming thunderclouds. Remember those dark clouds above the horizon, at the sight of which the birds fall silent and the trees stop rustling? So, these are the thunderclouds that give rise to lightning and thunder.

Scientists believe that lightning is formed as a result of the distribution of electrons in the cloud, usually positively charged from the top of the cloud, and negatively from. The result is a very powerful capacitor that can be discharged from time to time as a result of the abrupt transformation of ordinary air into plasma (this is due to the increasingly strong ionization of atmospheric layers close to thunderclouds). Plasma forms peculiar channels, which, when connected to the ground, serve as an excellent conductor for electricity. Clouds are constantly discharged through these channels, and we see the external manifestations of these atmospheric phenomena in the form of lightning.

By the way, the air temperature in the place where the charge (lightning) passes reaches 30 thousand degrees, and the speed of lightning propagation is 200 thousand kilometers per hour. In general, a few lightning bolts were enough to power a small town for several months.

lightning ground- cloud

And there are such lightning. They are formed as a result of the accumulating electrostatic charge on top of the tallest object on earth, which makes it very "attractive" for lightning. Such lightning is formed as a result of "breaking through" the air gap between the top of a charged object and the bottom of a thundercloud.

The higher the object, the more likely it is to be struck by lightning. So they say the truth - you should not hide from the rain under tall trees.

lightning cloud-cloud

Yes, individual clouds can also “exchange” lightning, striking each other with electric charges. It's simple - since the upper part of the cloud is positively charged, and the lower part is negatively charged, nearby thunderclouds can shoot electric charges at each other.

It is quite common for lightning to break through one cloud, and much rarer for lightning to travel from one cloud to another.

Horizontal zipper

This lightning does not hit the ground, it spreads horizontally across the sky. Sometimes such lightning can spread across a clear sky, coming from a single thundercloud. Such lightning is very powerful and very dangerous.

Tape zipper

This lightning looks like several lightning bolts running parallel to each other. There is no mystery in their formation - if a strong wind blows, it can expand the channels from the plasma, which we wrote about above, and as a result, such a differentiated lightning is formed.

Beaded (dotted zipper)

This is a very, very rare lightning, yes, it exists, but how it is formed is still anyone's guess. Scientists suggest that dotted lightning is formed as a result of the rapid cooling of some sections of the lightning track, which turns ordinary lightning into dotted lightning. As you can see, this explanation clearly needs to be improved and supplemented.

sprite lightning

So far, we have only talked about what happens below the clouds, or at their level. But it turns out that some types of lightning are higher than clouds. They have been known since the advent of jet aircraft, but these lightning bolts were photographed and filmed only in 1994. Most of all, they look like jellyfish, right? The height of the formation of such lightning is about 100 kilometers. So far, it is not very clear what they are.

Here are photos and even videos of unique sprite lightning. Very beautiful, isn't it?

Ball lightning

Some people claim that ball lightning does not exist. Others post videos of fireballs on YouTube and prove it's all real. In general, scientists are not yet firmly convinced of the existence of ball lightning, and the most famous proof of their reality is a photo taken by a Japanese student.

Saint Elmo's fires

This, in principle, is not lightning, but simply the phenomenon of a glow discharge at the end of various sharp objects. The fires of St. Elmo were known in antiquity, now they are described in detail and captured on film.

Volcanic lightning

These are very beautiful lightning bolts that appear during a volcanic eruption. It is likely that the charged gas-dust dome, penetrating several layers of the atmosphere at once, causes disturbances, since it itself carries a rather significant charge. It all looks very nice, but creepy. Scientists do not yet know exactly why such lightning is formed, and there are several theories at once, one of which is outlined above.

Here are some interesting facts about lightning that are not often published:

* Typical lightning lasts about a quarter of a second and consists of 3-4 discharges.

* An average thunderstorm travels at a speed of 40 km per hour.

* There are 1,800 thunderstorms in the world right now.

* The US Empire State Building is struck by lightning an average of 23 times a year.

* Lightning strikes aircraft on average once every 5-10 thousand flight hours.

* The probability of being killed by lightning is 1 in 2,000,000. Each of us has the same chance of dying from falling out of bed.

* The probability of seeing ball lightning at least once in a lifetime is 1 in 10,000.

* People who were struck by lightning were considered marked by God. And if they died, they supposedly went straight to heaven. In ancient times, victims of lightning were buried at the place of death.

What should you do when lightning approaches?

In home

* Close all windows and doors.
* Unplug all electrical appliances. Do not touch them, including phones, during thunderstorms.
* Keep away from bathtubs, faucets and sinks as metal pipes can conduct electricity.
* If ball lightning has flown into the room, try to get out quickly and close the door on the other side. If not, at least freeze in place.

On the street

* Try to go into the house or car. Do not touch metal parts in the car. The car should not be parked under a tree: suddenly lightning will strike it and the tree will fall right on you.
* If there is no shelter, go out into the open and, bending over, snuggle up to the ground. But you can't just lie down!
* In the forest, it is better to hide under low bushes. NEVER stand under a free-standing tree.
* Avoid towers, fences, tall trees, telephone and electrical wires, bus stops.
* Stay away from bicycles, barbecues, other metal objects.
* Keep away from the lake, river or other bodies of water.
* Remove all metal from yourself.
* Do not stand in the crowd.
* If you are in an open area and you suddenly feel your hair stand on end or hear a strange noise coming from objects (that means lightning is about to strike!), bend forward with your hands on your knees (but not on the ground). The legs should be together, the heels pressed against each other (if the legs do not touch, the discharge will pass through the body).
* If a thunderstorm caught you in a boat and you no longer have time to swim to the shore, bend down to the bottom of the boat, join your legs and cover your head and ears.