How does lightning occur? Why lightning flashes and thunder rumbles.

Interesting Facts about lightning. The Aztecs believed that lightning, cutting through the air and going into the ground, accompanies souls of the dead V underworld. Below we present a number of scientifically proven facts about lightning.
There are about 1800 thunderstorms happening on Earth while you are reading these words.

Every year, the Earth is subject to 25,000,000 lightning strikes, which is more than 100 lightning strikes per second.

The average lightning lasts three quarters of a second, has a temperature of about 28 thousand degrees Celsius, which is 5 times hotter than the surface of the Sun, and is 8 kilometers or more long.

The energy of an average lightning bolt was enough to power a 100 W light bulb for 90 days.

"Lightning never strikes the same place twice", unfortunately, this is a myth. Lightning can strike the same place many times.

Sometimes, after being struck by lightning, trees may not be burned or injured. Electricity passes through the wet bark and goes into the ground.

Because of high temperature, lightning falling into the sand melt it into glass. If you walk through the sandy places after a thunderstorm, you can find pieces of glass.

If you are in wet clothes, then the lightning will do less harm.

Lightning also exists on other planets such as Venus, Saturn, Jupiter and Uranus.

Thunder after a lightning strike can be heard at a distance of 12 kilometers from the place of the strike.

At the same time, from 100 to 1000 fireballs can exist on Earth, but the chance that you will see it at least once in your life is 0.01% (So I was lucky, because once one of these flew into our apartment).

The chance of dying from a lightning strike is 1 in 2,000,000. You have the same chance of dying from falling out of bed.

When it hits a person, lightning leaves characteristic burns on him, which have the outlines of lightning. There are times when a lightning strike causes burns on the human body in the form of nearby objects - trees, buildings and other things. How lightning can project these things has not yet been figured out.

About 71% of people who were struck by lightning survived.

The state of Florida in the United States is known as the "Death State". This state has 2 times more lightning deaths than any other state on earth.

Every year, lightning strikes kill 200 people in the United States alone. By comparison, no more than 90 people a year die as a result of shark attacks worldwide.

The lightning is playing essential role in the formation of ozone. When electricity passes through the atmosphere and due to the highest temperatures, ozone is produced.

Lightning

We often think that electricity is something that is generated only in power plants, and certainly not in the fibrous masses of water clouds, which are so rarefied that you can easily stick your hand into them. However, there is electricity in the clouds, as there is even in the human body.

Nature of electricity

All bodies are made up of atoms, from clouds and trees to human body. Every atom has a nucleus containing positively charged protons and neutral neutrons. The exception is the simplest hydrogen atom, in the nucleus of which there is no neutron, but only one proton.

Negatively charged electrons revolve around the nucleus. Positive and negative charges attract each other, so the electrons revolve around the nucleus of an atom, like bees around a sweet pie. The attraction between protons and electrons is due to electromagnetic forces. Therefore, electricity is present everywhere we look. As we can see, it is also contained in atoms.

IN normal conditions The positive and negative charges of each atom balance each other, so bodies made up of atoms usually carry no net charge, either positive or negative. As a result, contact with other objects does not cause an electrical discharge. But sometimes balance electric charges in bodies can be broken. You may experience this yourself when you are at home on a cold winter day. The house is very dry and hot. You, shuffling your bare feet, walk around the palace. Unbeknownst to you, some of the electrons from your soles have passed to the atoms of the carpet.

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Why are lightning bolts different colors?

Now you are carrying an electrical charge, as the number of protons and electrons in your atoms is no longer balanced. Now try to take hold of the metal door handle. A spark will fly between you and her, and you will feel an electric shock. This is what happened - your body, which does not have enough electrons to achieve electrical equilibrium, seeks to restore balance due to the forces of electromagnetic attraction. And it is being restored. There is a flow of electrons between the hand and the doorknob towards the hand. If the room were dark, you would see sparks. Light is visible because the electrons emit light quanta when they jump. If the room is quiet, you will hear a slight crackle.

Electricity surrounds us everywhere and is contained in all bodies. Clouds in this sense are no exception. On the background blue sky they look very harmless. But just like you are in a room, they can carry an electrical charge. If so, beware! When the cloud restores electrical balance within itself, a whole firework bursts out.

How does lightning appear?

This is what happens: in a dark huge thundercloud, powerful air currents, which push together a variety of particles - grains of ocean salt, dust, and so on. In the same way that your soles are freed from electrons by rubbing against a carpet, and particles in a cloud are freed from electrons by collision, which jump to other particles. So there is a redistribution of charges. Some particles that have lost their electrons have positive charge, the others that have taken on the extra electrons now have a negative charge.

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Rain on other planets

For reasons that are not entirely clear, heavier particles are negatively charged, while lighter particles are positively charged. Thus, the heavier Bottom part clouds are negatively charged. The negatively charged lower part of the cloud repels electrons towards the ground, since like charges repel. Thus, a positively charged part is formed under the cloud earth's surface. Then, exactly according to the same principle, according to which a spark jumps between you and the doorknob, the same spark will jump between the cloud and the earth, only very large and powerful, this is lightning. Electrons fly in a giant zigzag towards the earth, finding their protons there. Instead of a barely audible crackle, there is a strong clap of thunder.

Lightning is a delightful and exciting natural phenomenon. At the same time, it is one of the most dangerous and unpredictable natural phenomena. But what do we really know about lightning? Scientists around the world are collecting lightning facts, try to reproduce them in their laboratories, measure their power and temperature, but still are not able to determine the nature of lightning and predict its behavior. But still, let's look at the interesting facts about lightning that are already known.

At this moment, about 1800 thunderstorms are raging in the world.

Every year, the Earth experiences an average of 25 million lightning strikes or over a hundred thousand thunderstorms. That's more than 100 lightning strikes per second.

An average lightning strike lasts a quarter of a second.

You can hear thunder 20 kilometers away from lightning.

The lightning discharge propagates at a speed of about 190,000 km/s.

The average length of a lightning discharge is 3-4 kilometers.

Some lightning travels in the air in a twisted path, which may not exceed the thickness of your finger in diameter, and the length of the lightning path will be 10-15 kilometers.

The temperature of a typical lightning can exceed 30,000 degrees Celsius - that's about 5 times the surface temperature of the sun.

"Lightning never strikes the same place twice." Unfortunately, this is a myth. Lightning often strikes the same place multiple times.

The ancient Greeks believed that when lightning strikes the sea, a new pearl appears.

Trees can sometimes take lightning strikes and still not catch fire. This is because the electricity passes through the wet surface straight into the ground.

When lightning strikes, the sand turns into glass. After a thunderstorm, you can find glass streaks in the sand.

If your clothes are wet, then the lightning will do you less harm.

During a 6-hour thunderstorm across the United States, 15,000 lightning bolts sparkled in the sky. There was a feeling that the lightning was constantly burning.

At the very high building in the world - CN tower, lightning strikes about 78 times a year.

Lightning flashes can also be seen on Venus, Jupiter, Saturn and Uranus.

In the Middle Ages, it was believed that thunder and lightning are the offspring of the devil, and church bells scare away evil spirits. Therefore, during a thunderstorm, the monks constantly tried to ring the bells, and, accordingly, most often became victims of lightning.

The irrational fear of lightning is called keraunophobia. Fear of thunder - brontophobia.

There are between 100 and 1000 instances of ball lightning on Earth at the same time, but the chance that you will see at least one of them is 0.01%.

On average, about 550 people die from lightning strikes in Russia.

Approximately a quarter of all people who have become victims of lightning die.

Men are killed by lightning about 6 times more often than women.

The telephone is one of the most common causes of a person being struck by lightning. Do not talk on the phone during a thunderstorm, even indoors. After a lightning strike, branched stripes remain on the human body - signs of lightning. Disappear when pressed with a finger.

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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. Considering 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, are electrified. Those who have 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 in more is spent on creating a light flash and 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 is that it a natural phenomenon capable of melting 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 species 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 species goes through several stages. Impact ionization begins at the first of them, which is created at the beginning free electrons, they are always present in the air. Under the influence electric field elementary particles acquire high speeds and head towards the ground, 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 everything vital important 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 it's made ball lightning and how unpredictable its trajectory is, if it nevertheless got 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.

Doctor biological sciences, Candidate of Physical and Mathematical Sciences K. BOGDANOV.

At every moment in different points The earth sparkles with lightning more than 2000 thunderstorms. In every second, about 50 lightning strikes the earth's surface, and on average each of its square kilometer lightning strikes six times a year. B. Franklin also showed that lightning strikes the earth from thunderclouds - these are electrical discharges that transfer a negative charge of several tens of pendants to it, and the amplitude of the current during a lightning strike is from 20 to 100 kA. High-speed photography showed that the lightning discharge lasts a few tenths of a second and consists of several even shorter discharges. Lightning has long been of interest to scientists, but in our time we know only a little more about their nature than 250 years ago, although we were able to detect them even on other planets.

Science and life // Illustrations

The ability to electrify by friction of various materials. The material from the rubbing pair, which is higher in the table, is positively charged, and below it is negatively charged.

The negatively charged bottom of the cloud polarizes the surface of the Earth below it so that it is positively charged, and when conditions for electrical breakdown, a lightning strike occurs.

Distribution of the frequency of thunderstorms over the surface of land and oceans. The darkest places on the map correspond to frequencies of no more than 0.1 thunderstorms per year per square kilometer, and the brightest - more than 50.

Umbrella with lightning rod. The model was sold in the 19th century and was in demand.

Shooting a liquid or laser at a thundercloud hanging over the stadium diverts the lightning bolt to the side.

Several lightning strikes caused by the launch of a rocket into a thundercloud. The left vertical line is the trace of the rocket.

A large "branchy" fulgurite weighing 7.3 kg, found by the author on the outskirts of Moscow.

Hollow cylindrical fragments of fulgurite formed from melted sand.

White fulgurite from Texas.

Lightning is an eternal source of recharging the Earth's electric field. At the beginning of the 20th century, atmospheric probes were used to measure the electric field of the Earth. Its strength at the surface turned out to be about 100 V/m, which corresponds to the total charge of the planet about 400,000 C. Ions serve as charge carriers in the Earth's atmosphere, the concentration of which increases with height and reaches a maximum at an altitude of 50 km, where an electrically conductive layer, the ionosphere, was formed under the action of cosmic radiation. Therefore, the electric field of the Earth is the field of a spherical capacitor with an applied voltage of about 400 kV. Under the action of this voltage, a current of 2-4 kA flows from the upper layers to the lower ones, the density of which is 1-2. 10 -12 A/m 2 , and energy up to 1.5 GW is released. And this electric field would disappear if there were no lightning! Therefore, in good weather, the electric capacitor - Earth - is discharged, and during a thunderstorm it is charged.

A person does not feel the electric field of the Earth, since his body is a good conductor. Therefore, the charge of the Earth is also on the surface of the human body, locally distorting the electric field. Under a thundercloud, the density of positive charges induced on the ground can increase significantly, and the electric field strength can exceed 100 kV / m, 1000 times its value in good weather. As a result, the positive charge of each hair on the head of a person standing under a thundercloud increases by the same amount, and they, repelling from each other, stand on end.

Electrification - removal of "charged" dust. To understand how a cloud separates electrical charges, let's remember what electrization is. The easiest way to charge a body is by rubbing it against something else. Electrification by friction is the oldest method of obtaining electric charges. The very word "electron" in translation from Greek into Russian means amber, since amber has always been negatively charged when rubbed against wool or silk. The magnitude of the charge and its sign depend on the materials of the rubbing bodies.

It is believed that the body, before it was rubbed against another, is electrically neutral. Indeed, if a charged body is left in the air, then oppositely charged dust particles and ions will begin to stick to it. Thus, on the surface of any body there is a layer of "charged" dust, which neutralizes the charge of the body. Therefore, electrification by friction is the process of partial removal of "charged" dust from both bodies. In this case, the result will depend on how much better or worse the "charged" dust is removed from the rubbing bodies.

The cloud is a factory for the production of electric charges. It is hard to imagine that there are a couple of materials listed in the table in the cloud. However, different "charged" dust can appear on the bodies, even if they are made of the same material - it is enough that the surface microstructure differs. For example, when a smooth body rubs against a rough one, both will be electrified.

Thundercloud is great amount steam, part of which condenses into tiny droplets or ice floes. Top thunder cloud can be located at a height of 6-7 km, and the bottom hangs over the ground at a height of 0.5-1 km. Above 3-4 km, the clouds consist of ice floes of different sizes, since the temperature there is always below zero. These ice cubes are in constant motion caused by updrafts warm air from the heated surface of the earth. Small pieces of ice are easier than large ones to be carried away by ascending air currents. Therefore, "nimble" small pieces of ice, moving in upper part clouds, all the time collide with large ones. With each such collision, electrification occurs, in which large pieces of ice are charged negatively, and small ones are positively charged. Over time, positively charged small pieces of ice are at the top of the cloud, and negatively charged large ones at the bottom. In other words, the top of a thunderstorm is positively charged, while the bottom is negatively charged. Everything is ready for a lightning discharge, in which a breakdown of air occurs and a negative charge from the bottom of the thundercloud flows to the Earth.

Lightning - hello from space and source x-ray radiation. However, the cloud itself is not able to electrify itself so as to cause a discharge between its bottom and earth. The electric field strength in a thundercloud never exceeds 400 kV/m, and electrical breakdown in air occurs at a strength greater than 2500 kV/m. Therefore, for lightning to occur, something else is needed besides an electric field. In 1992, the Russian scientist A. Gurevich from Institute of Physics them. P. N. Lebedev of the Russian Academy of Sciences (FIAN) suggested that a kind of ignition for lightning can be cosmic rays- high-energy particles that fall on the Earth from space at near-light speeds. Thousands of such particles every second bombard each square meter earth's atmosphere.

According to Gurevich's theory, a particle of cosmic radiation, colliding with an air molecule, ionizes it, resulting in the formation of a huge number of high-energy electrons. Once in the electric field between the cloud and the earth, the electrons are accelerated to near-light speeds, ionizing the path of their movement and, thus, causing an avalanche of electrons moving with them to the earth. The ionized channel created by this avalanche of electrons is used by lightning to discharge (see "Science and Life" No. 7, 1993).

Everyone who has seen lightning has noticed that this is not a brightly luminous straight line connecting the cloud and the earth, but broken line. Therefore, the process of formation of a conductive channel for a lightning discharge is called its "step leader". Each of these "steps" is the place where the electrons accelerated to near-light speeds stopped due to collisions with air molecules and changed the direction of movement. Evidence for such an interpretation of the stepped character of lightning is the X-ray flashes coinciding with the moments when the lightning, as if stumbling, changes its trajectory. Recent studies have shown that lightning is a fairly powerful source of X-ray radiation, the intensity of which can be up to 250,000 electron volts, which is about twice that used in chest x-rays.

How to trigger a lightning bolt? It is very difficult to study what will happen in an incomprehensible place and when. Namely, this is how scientists studying the nature of lightning have worked for many years. It is believed that the storm in the sky is led by Elijah the prophet and we are not given to know his plans. However, scientists have been trying to replace Elijah the prophet for a very long time, creating a conductive channel between a thundercloud and the earth. B. Franklin for this during a thunderstorm launched kite, ending with a wire and a bunch of metal keys. By doing this, he caused weak discharges flowing down the wire, and was the first to prove that lightning is a negative electrical discharge flowing from clouds to the ground. Franklin's experiments were extremely dangerous, and one of those who tried to repeat them, the Russian academician G. V. Richman, died in 1753 from a lightning strike.

In the 1990s, researchers learned how to summon lightning without endangering their lives. One way to call lightning is to launch from the ground small rocket right into the storm. Along the entire trajectory, the rocket ionizes the air and thus creates a conductive channel between the cloud and the ground. And if the negative charge of the bottom of the cloud is large enough, then a lightning discharge occurs along the created channel, all parameters of which are recorded by devices located near the rocket launch pad. To create more Better conditions for a lightning discharge, a metal wire is attached to the rocket, connecting it to the ground.

Lightning: the giver of life and the engine of evolution. In 1953, biochemists S. Miller (Stanley Miller) and G. Urey (Harold Urey) showed that one of the "building blocks" of life - amino acids can be obtained by passing an electric discharge through water, in which the gases of the "primitive" atmosphere of the Earth are dissolved ( methane, ammonia and hydrogen). Fifty years later, other researchers repeated these experiments and got the same results. Thus, scientific theory the origin of life on Earth assigns a fundamental role to the lightning strike.

When short current pulses are passed through bacteria, pores appear in their shell (membrane), through which DNA fragments of other bacteria can pass inside, triggering one of the mechanisms of evolution.

Why are thunderstorms so rare in winter? F. I. Tyutchev, having written “I love a thunderstorm in early May, when the first thunder in spring ...”, knew that there are almost no thunderstorms in winter. To form a thundercloud, ascending currents of moist air are needed. Concentration saturated vapors increases with temperature and reaches its maximum in summer. The temperature difference on which ascending air currents depend is the greater, the higher its temperature near the earth's surface, since at an altitude of several kilometers its temperature does not depend on the season. This means that the intensity of the ascending currents is also maximum in summer. Therefore, we have thunderstorms most often in summer, and in the north, where it is cold in summer, thunderstorms are quite rare.

Why are thunderstorms more common over land than over sea? In order for the cloud to discharge, there must be a sufficient number of ions in the air below it. Air, consisting only of nitrogen and oxygen molecules, does not contain ions, and it is very difficult to ionize it even in an electric field. But if there are a lot of foreign particles in the air, such as dust, then there are also a lot of ions. Ions are formed by the movement of particles in the air in the same way as they are electrified by rubbing against each other. various materials. Obviously, there is much more dust in the air over land than over oceans. That is why thunderstorms rumble over land more often. It has also been noted that, first of all, lightning strikes those places where the concentration of aerosols in the air is especially high - smoke and emissions from the oil refining industry.

How Franklin deflected lightning. Fortunately, most lightning strikes occur between clouds and therefore do not pose a threat. However, lightning is believed to kill more than a thousand people worldwide every year. At least in the United States, where such statistics are kept, about 1000 people are affected by lightning each year and more than a hundred of them die. Scientists have long tried to protect people from this "punishment of God." For example, the inventor of the first electrical capacitor(of a Leyden jar) Pieter van Muschenbroek (1692-1761) in an article on electricity written for the famous French Encyclopedia, defended traditional ways lightning prevention - bell ringing and cannon fire, which, he believed, were quite effective.

Benjamin Franklin, trying to protect the Capitol of the capital of Maryland, in 1775 attached a thick iron rod to the building, which towered several meters above the dome and was connected to the ground. The scientist refused to patent his invention, wishing that it would serve people as soon as possible.

The news of Franklin's lightning rod quickly spread throughout Europe, and he was elected to all academies, including the Russian one. However, in some countries, the devout population met this invention with indignation. The very idea that a person could so easily and simply tame the main weapon of "God's wrath" seemed blasphemous. Therefore, in different places, people broke lightning rods for pious reasons. A curious incident occurred in 1780 in the small town of Saint-Omer in northern France, where the townspeople demanded the removal of an iron lightning rod mast, and the case went to trial. The young lawyer who defended the lightning rod from the attacks of obscurantists built his defense on the fact that both the human mind and its ability to conquer the forces of nature have divine origin. Everything that helps to save a life is for the good - the young lawyer argued. He won the process and gained great fame. The lawyer's name was Maximilian Robespierre. Well, now the portrait of the inventor of the lightning rod is the most coveted reproduction in the world, because it adorns the well-known hundred-dollar bill.

How you can protect yourself from lightning with a water jet and a laser. Recently it has been proposed new way fight against lightning. A lightning rod will be created from ... a jet of liquid, which will be shot from the ground directly into thunderclouds. The lightning liquid is a saline solution to which liquid polymers are added: the salt is intended to increase the electrical conductivity, and the polymer prevents the jet from "breaking up" into separate droplets. The jet diameter will be about a centimeter, and maximum height- 300 meters. When the liquid lightning rod is finalized, it will be equipped with sports and playgrounds, where the fountain will turn on automatically when the electric field strength becomes high enough and the probability of a lightning strike is maximum. A charge will flow down a stream of liquid from a thundercloud, making lightning safe for others. A similar protection against a lightning discharge can be done with the help of a laser, the beam of which, by ionizing the air, will create a channel for an electric discharge away from crowds of people.

Can lightning lead us astray? Yes, if you use a compass. IN famous novel G. Melvila "Moby Dick" described just such a case when a lightning discharge, which created a strong magnetic field, remagnetized the compass needle. However, the ship's captain took a sewing needle, struck it to magnetize it, and replaced it with a broken compass needle.

Can you be struck by lightning inside a house or plane? Unfortunately yes! Lightning current can enter a house through a telephone wire from a nearby pole. Therefore, during a thunderstorm, try not to use a regular phone. It is believed that talking on a radiotelephone or on a mobile phone is safer. Do not touch pipes during thunderstorms central heating and plumbing that connects the house to the ground. For the same reasons, experts advise turning off all electrical appliances, including computers and televisions, during a thunderstorm.

As for airplanes, generally speaking, they try to fly over areas with thunderstorm activity. And yet, on average, one of the planes is struck by lightning once a year. Its current cannot hit passengers, it flows along the outer surface of the aircraft, but it can disable radio communications, navigation equipment and electronics.

Fulgurite is petrified lightning. During a lightning discharge, 10 9 -10 10 joules of energy are released. Most of it is spent on creating shock wave(thunder), air heating, light flash and others electromagnetic waves, and only a small part stands out at the point where the lightning enters the ground. However, even this "small" part is quite enough to cause a fire, kill a person and destroy a building. Lightning can heat up the channel through which it travels up to 30,000 ° C, five times the temperature on the surface of the Sun. The temperature inside the lightning is much higher than the melting temperature of sand (1600-2000°C), but whether the sand melts or not also depends on the duration of the lightning, which can range from tens of microseconds to tenths of a second. The amplitude of the lightning current pulse is usually equal to several tens of kiloamperes, but sometimes it can exceed 100 kA. The most powerful lightning and cause the birth of fulgurites - hollow cylinders of melted sand.

The word "fulgurite" comes from the Latin fulgur, which means lightning. The longest of the excavated fulgurites went underground to a depth of more than five meters. Fulgurites are also called reflow solid rocks, formed by a lightning strike; they are sometimes in large numbers found on rocky mountaintops. Fulgurites, composed of remelted silica, are usually cone-shaped tubes as thick as a pencil or a finger. Their inner surface smooth and melted, and the outer one is formed by grains of sand adhering to the melted mass. The color of fulgurites depends on the mineral impurities in the sandy soil. Most of them are reddish brown, gray or black, but greenish, white or even translucent fulgurites are also found.

Apparently, the first description of fulgurites and their association with lightning strikes was made in 1706 by Pastor D. Hermann. Subsequently, many found fulgurites near people struck by lightning. Charles Darwin during world travel on the ship "Beagle", found on the sandy shore near Maldonado (Uruguay) several glass tubes that go vertically down more than a meter into the sand. He described their size and connected their formation with lightning discharges. Renowned American physicist Robert Wood got an "autograph" of the lightning bolt that nearly killed him:

“A strong thunderstorm passed, and the sky above us had already cleared up. I went through the field that separates our house from the house of my sister-in-law. I walked about ten yards along the path, when suddenly my daughter Margaret called me. I stopped for about ten seconds and barely moved farther on, when suddenly a bright blue line cut through the sky, with the roar of a twelve-inch gun, striking the path twenty paces in front of me and raising a huge column of steam. I went on to see what trace the lightning had left. burnt clover five inches in diameter, with a hole in the middle half an inch.... I went back to the laboratory, melted eight pounds of tin and poured into the hole... as it should be, in the handle and gradually converging towards the end. It was a little longer than three feet "(quoted by W. Seabrook. Robert Wood. - M .: Nauka, 1985, p. 285).

The appearance of a glass tube in the sand during a lightning discharge is due to the fact that there is always air and moisture between the grains of sand. Electricity lightning in a split second heats up air and water vapor to enormous temperatures, causing an explosive increase in air pressure between grains of sand and its expansion, which Wood heard and saw, miraculously not becoming a victim of lightning. The expanding air forms a cylindrical cavity inside the molten sand. Subsequent rapid cooling fixes fulgurite - a glass tube in the sand.

Often carefully excavated from the sand, fulgurite is shaped like a tree root or a branch with numerous branches. Such branched fulgurites are formed when a lightning discharge hits wet sand, which, as you know, has a higher electrical conductivity than dry sand. In these cases, the lightning current, entering the soil, immediately begins to spread to the sides, forming a structure similar to the root of a tree and the resulting fulgurite only repeats this shape.Fulgurite is very fragile, and attempts to remove adhering sand often lead to its destruction.This is especially true for branched fulgurites formed in wet sand.