The most interesting of them are presented in this article.

Linear lightning (cloud-ground)

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 earth-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 that lightning will strike it. So they say the truth - you should not hide from the rain under tall trees.

lightning cloud-cloud

Yes, individual clouds can “exchange” with 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 each other with electric charges.

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 plasma channels, 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, it exists, yes, 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.

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 beautiful, 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 the house

* 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 you can't, 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.

Municipal educational institution

Gymnasium "Laboratory Salakhov"

Creative work in physics

on the topic: Electrical phenomena in nature: lightning

Story

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. Franklin's experience in elucidating the electrical nature of lightning is widely known. In 1750 he published a work describing an experiment using a kite launched into a thunderstorm. Franklin's experience was described in the work of Joseph Priestley.

Physical properties of lightning

The average lightning length is 2.5 km, some discharges extend in the atmosphere for a distance of up to 20 km.

lightning formation

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

Linear lightnings are usually observed, which belong to the so-called electrodeless discharges, since they begin (and end) in clusters of charged particles. This determines some of their still unexplained properties that distinguish lightning from discharges between electrodes. So, lightning is 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 billions 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.

ground lightning

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, which are always present in a small amount in the air, which, under the action of an electric field, acquire significant velocities towards the ground and, colliding with the molecules that make up air, ionize them. According to more modern ideas, the discharge is initiated by high-energy cosmic rays, which trigger a process called runaway breakdown. Thus, electron avalanches arise, turning into filaments of electrical discharges - streamers, which are well-conducting channels, which, merging, give rise to a bright thermally ionized channel with high conductivity - a stepped lightning leader.

The movement of the leader to the earth's surface occurs in steps of several tens of meters at a speed of ~ 50,000 kilometers per second, after which its movement stops for several tens of microseconds, and the glow is greatly weakened; then, in the subsequent stage, the leader again advances several tens of meters. At the same time, 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 surface of the earth at an average speed of 200,000 meters per second.

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

In the final stage, the leader-ionized channel is followed by a reverse (from bottom to top), or main, lightning discharge, characterized by currents from tens to hundreds of thousands of amperes, a brightness significantly exceeding the brightness of the leader, and a high advance speed, initially reaching ~ 100,000 kilometers per second , and at the end decreasing to ~ 10,000 kilometers per second. The temperature of the channel during the main discharge can exceed 25,000 °C. The length of the lightning channel can be from 1 to 10 km, the diameter is several centimeters. After the passage of the current pulse, the ionization of the channel and its glow weaken. In the final stage, the lightning current can last hundredths and even tenths of a second, reaching hundreds and thousands of amperes. Such lightning is called protracted, they most often cause fires.

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

Intracloud lightning

Intracloud lightning usually includes only leader stages; their length varies from 1 to 150 km. The share of intracloud lightning increases with the shift to the equator, changing from 0.5 in temperate latitudes to 0.9 in the equatorial strip. The passage of lightning is accompanied by changes in electric and magnetic fields and radio emission, the so-called atmospherics. The probability of a ground object being struck by lightning increases as its height increases and with an increase in the electrical conductivity of the soil on the surface or at a certain depth (the action of a lightning rod is based on these factors). If there is an electric field in the cloud that is sufficient to maintain the discharge, but not enough to cause it to occur, a long metal cable or an airplane can play the role of the lightning initiator - especially if it is highly electrically charged. Thus, lightning is sometimes “provoked” in nimbostratus and powerful cumulus clouds.

"In every second, about 50 lightning strikes the earth's surface, and on average each square kilometer of it is struck by lightning six times a year."

The most powerful lightnings cause the birth of fulgurites.

people and lightning

Lightning is a serious threat to human life. The defeat of a person or animal by lightning often occurs in open spaces. electric current follows the shortest path "thundercloud-earth". Lightning often hits trees and transformer installations on the railway, causing them to ignite. It is impossible to be struck by ordinary linear lightning inside a building, but there is an opinion that the so-called ball lightning can penetrate through cracks and open windows. Ordinary lightning is dangerous for television and radio antennas located on the roofs of high-rise buildings, as well as for network equipment.

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

When struck by lightning, the first medical aid should be urgent. In severe cases (stopping breathing and palpitations), resuscitation is necessary, it should be provided, without waiting for medical workers, by any witness of the misfortune. Resuscitation is effective only in the first minutes after a lightning strike, started after 10 - 15 minutes, as a rule, it is no longer effective. Emergency hospitalization is necessary in all cases.

lightning victims

1. In mythology and literature:

1. Asclepius, Aesculapius - the son of Apollo - the god of doctors and medical art, not only healed, but also revived the dead. To restore the disturbed world order, Zeus struck him with his lightning.

2. Phaeton - the son of the sun god Helios - once undertook to drive the solar chariot of his father, but could not restrain the fire-breathing horses and almost destroyed the Earth in a terrible flame. Enraged Zeus pierced Phaethon with lightning.

2. Historical figures:

1. Russian academician G. V. Richman - in 1753 he died from a lightning strike.

2. On July 4, 2009, people's deputy of Ukraine, ex-governor of the Rivne region V. Chervoniy died from a lightning strike.

· Roy Sullivan survived after being struck by lightning seven times.

· American Major Summerford died after a long illness (the result of a third lightning strike). The fourth lightning completely destroyed his monument in the cemetery.

· Among the Andean Indians, a lightning strike is considered necessary to reach the highest levels of shamanic initiation.

Trees and lightning

The trunk of a lightning-struck poplar

Tall trees are a frequent target for lightning. Long-lived relict trees can easily be found with multiple lightning scars. It is believed that a tree standing alone is more likely to be struck by lightning, although in some forested areas, lightning scars can be seen on almost every tree. Dry trees catch fire when struck by lightning. Most often, lightning strikes are directed at oak, least often at beech, which, apparently, depends on the different amount of fatty oils in them, which present a great resistance to electricity.

Lightning travels in a tree trunk along the path of least electrical resistance, with the release of a large amount of heat, turning water into steam, which splits the trunk of a tree or more often tears off sections of bark from it, showing the path of lightning. In subsequent seasons, the trees usually regenerate damaged tissue and may close the entire wound, leaving only a vertical scar. If the damage is too severe, wind and pests will eventually kill the tree. Trees are natural lightning rods and are known to provide lightning protection for nearby buildings. Planted near the building, tall trees trap lightning, and the high biomass of the root system helps to ground the lightning strike.

From trees struck by lightning, musical instruments are made, attributing to them unique properties.

Lightning as a natural phenomenon

Lightning is a giant electric spark discharge between clouds or between clouds and the earth's surface, several kilometers long, tens of centimeters in diameter and tenths of a second long. Lightning is accompanied by thunder. In addition to linear lightning, ball lightning is occasionally observed.

The nature and causes of lightning

A thunderstorm is a complex atmospheric process, and its occurrence is due to the formation of cumulonimbus clouds. Strong cloudiness is a consequence of the significant instability of the atmosphere. Thunderstorms are characterized by strong winds, often heavy rain (snow), sometimes with hail. Before a thunderstorm (an hour or two before a thunderstorm), atmospheric pressure begins to drop rapidly until the wind suddenly picks up, and then begins to rise.

Thunderstorms can be divided into local, frontal, night, in the mountains. Most often, a person encounters local or thermal thunderstorms. These thunderstorms occur only in hot weather with high atmospheric humidity. As a rule, they occur in the summer at noon or afternoon (12-16 hours). The water vapor in the ascending stream of warm air condenses at a height, while a lot of heat is released and the ascending air streams are heated. The rising air is warmer than the surrounding air and expands until it becomes a thundercloud. Large storm clouds are constantly filled with ice crystals and water droplets. As a result of their crushing and friction between themselves and against the air, positive and negative charges are formed, under the influence of which a strong electrostatic field arises (the strength of the electrostatic field can reach 100,000 V / m). And the potential difference between the individual parts of the cloud, the clouds or the cloud and the earth reaches enormous values. When the critical tension of the electric air is reached, an avalanche-like air ionization occurs - a spark discharge of lightning.

A frontal thunderstorm occurs when masses of cold air enter an area dominated by warm weather. Cold air displaces warm air, while the latter rises to a height of 5-7 km. Warm layers of air invade vortices of various directions, a squall is formed, strong friction between the layers of air, which contributes to the accumulation of electric charges. The length of a frontal thunderstorm can reach 100 km. Unlike local thunderstorms, it usually gets colder after frontal thunderstorms. A night thunderstorm is associated with the cooling of the earth at night and the formation of eddy currents of the ascending air. The thunderstorm in the mountains is explained by the difference in solar radiation to which the southern and northern slopes of the mountains are exposed. Night and mountain thunderstorms are not strong and short.

Thunderstorm activity in different regions of our planet is different. World centers of thunderstorms: Java Island - 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.

By type of lightning are divided into linear, pearl and ball. Pearl and ball lightning is quite rare.

The lightning 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. Due to the fact that on high pointed objects the electric field strength created by the static electric charge of the cloud is especially high, a glow occurs; as a result, air ionization begins, a glow discharge occurs and reddish glow tongues appear, sometimes shortening and again lengthening. Do not attempt 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."

Lightning is one of those natural phenomena that have long inspired fear in the human race. The greatest minds, such as Aristotle or Lucretius, sought to understand its essence. They believed that it was a ball consisting of fire and sandwiched in the water vapor of the clouds, and, increasing in size, it breaks through them and falls to the ground with a swift spark.

The concept of lightning and its origin

Most often, lightning is formed in which are quite large. The upper part can be located at an altitude of 7 kilometers, and the lower one - only 500 meters above the ground. Taking into account the atmospheric air temperature, we can conclude that at a level of 3-4 km, the water freezes and turns into ice floes, which, colliding with each other, become electrified. Those that have the largest size receive a negative charge, and the smallest - a positive one. Based on their weight, they are evenly distributed in the cloud by layers. Approaching each other, they form a plasma channel, from which an electric spark, called lightning, is obtained. It got its broken shape due to the fact that on the way to the ground there are often various air particles that form barriers. And to get around them, you have to change the trajectory.

Physical description of lightning

A lightning discharge releases 109 to 1010 joules of energy. Such a colossal amount of electricity is mostly spent on creating a flash of light, which is otherwise called thunder. But even a small part of lightning is enough to do unthinkable things, for example, its discharge can kill a person or destroy a building. Another interesting fact suggests that this natural phenomenon is able to melt sand, forming hollow cylinders. This effect is achieved due to the high temperature inside the lightning, it can reach 2000 degrees. The time of impact with the ground is also different, it cannot be more than a second. As for power, the pulse amplitude can reach hundreds of kilowatts. Combining all these factors, the most powerful natural discharge of current is obtained, which brings death to everything that it touches. All existing types of lightning are very dangerous, and meeting with them is extremely undesirable for a person.

Thunder formation

All types of lightning cannot be imagined without thunder, which does not carry the same danger, but in some cases can lead to network failure and other technical problems. It occurs due to the fact that a warm wave of air, heated by lightning to a temperature hotter than the sun, collides with a cold one. The sound resulting from this is nothing but a wave caused by air vibrations. In most cases, the volume increases towards the end of the roll. This is due to the reflection of sound from the clouds.

What are lightning

It turns out they are all different.

1. Line lightning - the most common variety. An electric peal looks like an overgrown tree turned upside down. Several thinner and shorter "processes" depart from the main canal. The length of such a discharge can reach 20 kilometers, and the current strength is 20,000 amperes. The speed of movement is 150 kilometers per second. The temperature of the plasma filling the lightning channel reaches 10,000 degrees.

2. Intracloud lightning - the origin of this type is accompanied by a change in electric and magnetic fields, radio waves are also emitted. Such a roll is most likely to be found closer to the equator. In temperate latitudes, it appears extremely rarely. If there is lightning in the cloud, then a foreign object that violates the integrity of the shell, such as an electrified aircraft or a metal cable, can also induce it to get out. The length can vary from 1 to 150 kilometers.

3. Ground lightning - this type goes through several stages. On the first of them, impact ionization begins, which is created at the beginning by free electrons, they are always present in the air. Under the action of an electric field, elementary particles acquire high speeds and head towards the earth, colliding with the molecules that make up the air. Thus, there are electron avalanches, otherwise called streamers. They are channels that, merging with each other, cause a bright, thermally insulated lightning. It reaches the ground in the form of a small ladder, because there are obstacles in its path, and in order to get around them, it changes direction. The speed of movement is approximately 50,000 kilometers per second.

After the lightning has passed its way, it ends its movement for several tens of microseconds, while the light weakens. After that, the next stage begins: the repetition of the path traveled. The most recent discharge surpasses all the previous ones in brightness, the current strength in it can reach hundreds of thousands of amperes. The temperature inside the channel fluctuates around 25,000 degrees. This type of lightning is the longest, so the consequences can be devastating.

Pearl Lightning

When answering the question of what kind of lightning are, one cannot lose sight of such a rare natural phenomenon. Most often, the discharge passes after the linear one and completely repeats its trajectory. Only now it looks like balls that are at a distance from each other and resemble beads made of precious material. Such lightning is accompanied by the loudest and rolling sounds.

Ball lightning

A natural phenomenon when lightning takes the form of a ball. In this case, the trajectory of its flight becomes unpredictable, which makes it even more dangerous for humans. In most cases, such an electric lump occurs together with other species, but the fact of its appearance even in sunny weather has been recorded.

How it is formed It is this question that is most often asked by people who have encountered this phenomenon. As everyone knows, some things are excellent conductors of electricity, and so it is in them, accumulating their charge, that the ball begins to emerge. It can also appear from the main lightning. Eyewitnesses say that it just appears out of nowhere.

Lightning diameter ranges from a few centimeters to a meter. As for the color, there are several options: from white and yellow to bright green, it is extremely rare to find a black electric ball. After a rapid descent, it moves horizontally, about a meter from the surface of the earth. Such lightning can suddenly change its trajectory and just as suddenly disappear, releasing huge energy, due to which melting or even destruction of various objects occurs. She lives from ten seconds to several hours.

lightning sprite

More recently, in 1989, scientists discovered another type of lightning, which was called sprite. The discovery happened quite by accident, because the phenomenon is extremely rare and lasts only tenths of a second. They are distinguished from others by the height at which they appear - approximately 50-130 kilometers, while other subspecies do not overcome the 15-kilometer line. Also, the lightning sprite has a huge diameter, which reaches 100 km. They appear vertical and flash in clusters. Their color varies depending on the composition of the air: closer to the ground, where there is more oxygen, they are green, yellow or white, but under the influence of nitrogen, at an altitude of more than 70 km, they acquire a bright red hue.

Behavior during a thunderstorm

All types of lightning carry an extraordinary danger to health and even human life. To avoid electric shock, the following rules should be followed in open areas:

1. In this situation, the highest objects fall into the risk group, so open areas should be avoided. To become lower, it is best to sit down and put your head and chest on your knees, in case of defeat, this posture will protect all vital organs. In no case should you lie flat, so as not to increase the area of ​​\u200b\u200ba possible hit.
2. Also, do not hide under tall trees and unprotected structures or metal objects (for example, a picnic shed) will be undesirable shelter.
3. During a thunderstorm, you should immediately get out of the water, because it is a good conductor. Getting into it, a lightning discharge can easily spread to a person.
4. Under no circumstances should you use your mobile phone.
5. To provide first aid to the victim, it is best to perform cardiopulmonary resuscitation and immediately call the rescue service.

Rules of conduct in the house

Indoors, too, there is a danger of injury.

1. If a thunderstorm starts outside, the first thing to do is close all windows and doors.
2. All electrical appliances must be turned off.
3. Stay away from wired telephones and other cables, they are excellent conductors of electricity. Metal pipes have the same effect, so you should not be near plumbing.
4. Knowing how ball lightning is formed and how unpredictable its trajectory is, if it does get into the room, you must immediately leave it and close all windows and doors. If these actions are not possible, it is better to stand still.

Nature is still beyond the control of man and carries many dangers. All types of lightning are, in essence, the most powerful electrical discharges, which are several times more powerful than all artificially created current sources by man.

Every second, approximately 700 lightning, and every year about 3000 people are killed by lightning strikes. The physical nature of lightning has not been fully explained, and most people have only a rough idea of ​​what it is. Some discharges collide in the clouds, or something like that. Today we turned to our physics authors to learn more about the nature of lightning. How lightning appears, where lightning strikes, and why thunder rumbles. After reading the article, you will know the answer to these and many other questions.

What is lightning

Lightning- spark electric discharge in the atmosphere.

electrical discharge- this is the process of current flow in the medium, associated with a significant increase in its electrical conductivity relative to the normal state. There are different types of electrical discharges in gas: spark, arc, smoldering.

Spark discharge occurs at atmospheric pressure and is accompanied by a characteristic spark crack. A spark discharge is a collection of disappearing and replacing each other filamentous spark channels. Spark channels are also called streamers. The spark channels are filled with ionized gas, i.e. plasma. Lightning is a giant spark, and thunder is a very loud crack. But not everything is so simple.

The physical nature of lightning

How is the origin of lightning explained? System cloud-earth or cloud-cloud is a kind of capacitor. Air plays the role of a dielectric between clouds. The lower part of the cloud has a negative charge. With a sufficient potential difference between the cloud and the ground, conditions arise in which lightning occurs in nature.

Stepped leader

Before the main lightning flash, you can observe a small spot moving from the cloud to the ground. This is the so-called step leader. Electrons under the action of a potential difference begin to move towards the ground. As they move, they collide with air molecules, ionizing them. An ionized channel is being laid from the cloud to the ground. Due to the ionization of air by free electrons, the electrical conductivity in the zone of the leader trajectory increases significantly. The leader, as it were, paves the way for the main discharge, moving from one electrode (cloud) to another (ground). Ionization occurs unevenly, so the leader can branch out.

Backfire

The moment the leader approaches the ground, the tension at his end rises. From the ground or from objects protruding above the surface (trees, roofs of buildings), a response streamer (channel) is thrown towards the leader. This property of lightning is used to protect against them by installing a lightning rod. Why does lightning strike a person or a tree? In fact, she doesn't care where to hit. After all, lightning is looking for the shortest path between earth and sky. That is why during a thunderstorm it is dangerous to be on the plain or on the surface of the water.

When the leader reaches the ground, a current begins to flow through the laid channel. It is at this moment that the main lightning flash is observed, accompanied by a sharp increase in current strength and energy release. Here is the question, where does lightning come from? It is interesting that the leader spreads from the cloud to the ground, but the reverse bright flash, which we are used to seeing, spreads from the ground to the cloud. It is more correct to say that lightning does not go from heaven to earth, but occurs between them.

Why does lightning strike?

Thunder is the result of a shock wave generated by the rapid expansion of ionized channels. Why do we see lightning first and then hear thunder? It's all about the difference in the speeds of sound (340.29 m/s) and light (299,792,458 m/s). By counting the seconds between thunder and lightning and multiplying them by the speed of sound, you can find out at what distance the lightning struck from you.

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Types of lightning and facts about lightning

Lightning between heaven and earth is not the most common lightning. Most often, lightning occurs between clouds and does not pose a threat. In addition to terrestrial and intracloud lightning, there are lightnings that form in the upper atmosphere. What are the types of lightning in nature?

• Intra-cloud lightning;
• Ball lightning;
• "Elves";
• Jets;
• Sprites.

The last three types of lightning cannot be observed without special instruments, as they form at an altitude of 40 kilometers and above.

Here are the facts about lightning:

• The length of the longest recorded lightning on Earth was 321 km. This lightning was seen in Oklahoma, 2007.
• The longest lightning lasted 7,74 seconds and was recorded in the Alps.
• Lightning is formed not only on Earth. Know exactly about lightning on Venus, Jupiter, Saturn and Uranus. Saturn's lightning is millions of times more powerful than Earth's.
• The current in lightning can reach hundreds of thousands of amperes, and the voltage can reach billions of volts.
• The temperature of the lightning channel can reach 30000 degrees Celsius is 6 times the surface temperature of the sun.

Ball lightning

Ball lightning is a separate type of lightning, the nature of which remains a mystery. Such lightning is a luminous object moving in the air in the form of a ball. According to the limited evidence, ball lightning can move along an unpredictable trajectory, split into smaller lightning bolts, explode, or simply disappear unexpectedly. There are many hypotheses about the origin of ball lightning, but none can be recognized as reliable. The fact is that no one knows how ball lightning appears. Some hypotheses reduce the observation of this phenomenon to hallucinations. Ball lightning has never been observed in the laboratory. All that scientists can be content with is eyewitness accounts.

Finally, we invite you to watch the video and remind you: if the course paper or control fell on your head like lightning on a sunny day, do not despair. Student Services Specialists have been helping students since 2000. Seek qualified help at any time. 24 hours a day, 7 days a week we are ready to help you.