A heap of thunderclaps and thunder. What is the difference between a thunderstorm and lightning: general and specific. Amazing fireball

Every second, approximately 700 lightning, and every year about 3000 people die due to 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 writers to learn more about the nature of lightning. How lightning appears, where lightning strikes, and why thunder thunders. 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.

Electric discharge is the process of current flow in a medium associated with a significant increase in its electrical conductivity relative to normal condition. Exist different types electrical discharges in gas: spark, arc, smoldering.

A spark discharge occurs at atmospheric pressure and is accompanied by a characteristic spark crack. A spark discharge is a set of filamentary spark channels that disappear and replace each other. Spark channels are also called streamers. The spark channels are filled with ionized gas, that is, plasma. Lightning is a giant spark, and thunder is a very loud crack. But it's not that simple.

Physical nature of lightning

How is the origin of lightning explained? System cloud-ground or cloud-cloud It is a kind of capacitor. The air plays the role of a dielectric between the clouds. The bottom of the cloud has a negative charge. When there is a sufficient potential difference between the cloud and the ground, conditions arise in which lightning occurs in nature.

Step leader

Before the main flash of lightning, a small spot can be observed moving from the cloud to the ground. This is the so-called stepped leader. Electrons, under the influence of a potential difference, begin to move towards the ground. As they move, they collide with air molecules, ionizing them. A kind of ionized channel is laid from the cloud to the ground. Due to the ionization of air by free electrons, the electrical conductivity in the leader’s trajectory zone 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.

Backfire

The moment the leader approaches the ground, the tension at his end increases. A response streamer (channel) is thrown out from the ground or from objects protruding above the surface (trees, roofs of buildings) towards the leader. This property of lightning is used to protect against it 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 seeks the shortest path between earth and sky. This is why it is dangerous to be on the plain or on the surface of the water during a thunderstorm.

When the leader reaches the ground, 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. The relevant question here is, where does the lightning come from? It is interesting that the leader spreads from the cloud to the ground, but the opposite 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 come from heaven to earth, but occurs between them.

Why does lightning thunder?

Thunder results from a shock wave generated by the rapid expansion of ionized channels. Why do we first see lightning and then hear thunder? It's all about the difference between 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 from you the lightning struck.

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Types of lightning and facts about lightning

Lightning between sky and earth is not the most common lightning. Most often, lightning occurs between clouds and does not pose a threat. In addition to ground-based and intra-cloud lightning, there are lightning that forms in upper layers atmosphere. What types of lightning are there in nature?

• Intracloud lightning;
• Ball lightning;
• "Elves";
• Jets;
• Sprites.

The last three types of lightning cannot be observed without special devices, since they are formed at an altitude of 40 kilometers and above.

Here are some facts about lightning:

• The length of the longest recorded lightning on Earth was 321 km. This lightning was spotted in Oklahoma 2007.
• The longest lightning lasted 7,74 seconds and was recorded in the Alps.
• Lightning is formed not only on Earth. We know for sure about lightning on Venus, Jupiter, Saturn And Uranus. Saturn's lightning is millions of times more powerful than Earth's.
• The current strength 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 in 6 once more temperature surface of the Sun.

Ball lightning

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

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

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

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

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

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

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

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

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

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

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

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

Rolling thunder

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, explosive vibrations of the air occur and thunder occurs. Thunder and lightning are closely interrelated with each other: the length of the discharge is often about eight kilometers, so the sound from different parts of it reaches the different time, forming thunderclaps.

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

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

Amazing fireball

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

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

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

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

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

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

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

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

Possible dangers

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

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

What to do in a thunderstorm

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

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

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

Lightning is a powerful electrical discharge. It occurs when clouds or ground are highly electrified. Therefore, lightning discharges can occur either inside a cloud, or between neighboring electrified clouds, or between an electrified cloud and the ground.

A lightning discharge is preceded by the occurrence of an electrical potential difference between neighboring clouds or between a cloud and the ground.

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

What causes clouds to electrify? After all, they do not rub against each other, as happens when an electrostatic charge forms on the hair and on the comb.

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

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

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

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

We ourselves can simulate lightning, even a miniature one. The experiment should be carried out in a dark room, otherwise nothing will be visible. We will need two oblong balloons. Let's inflate them and tie them. Then, making sure that they do not touch, we simultaneously rub them with a woolen cloth. The air filling them is electrified. If the balls are brought closer together, leaving a minimum gap between them, then sparks will begin to jump from one to another through a thin layer of air, creating light flashes. At the same time, we will hear a faint crackling sound - a miniature version of thunder during a thunderstorm.

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

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

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

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

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

• between a thundercloud and the ground,
• between two clouds
• inside the cloud,
• leaving the clouds for clear skies.

Most lightning and electrical discharges (about 80%) occur between thunderclouds and inside a thundercloud. But the power of electrical discharges between the earth and the clouds is incomparably greater, since the potential difference “between sky and earth” is much higher.

Lightning can have a branched pattern or be a single column ( linear zippers). They can be linear or branched. A rare and mysterious little-studied form of lightning is ball lightning.

Lightning in numbers

• The potential difference preceding lightning can reach a billion volts.
• Accumulated electric discharge current strength electrical energy through the atmosphere creates currents of up to 100,000 A.
• The air in the lightning channel heats up to 30 thousand degrees - this is five times more than the temperature of the surface of the Sun.
• Lightning propagation speed is 1,000,000 m/s. So lightning travels from the clouds to the Earth in 0.002 seconds.
• The lightning channel is very narrow. The visible channel has a diameter of about 1 meter, and the internal channel through which the current flows is 1 cm.
• A typical lightning flash lasts about 0.25 seconds and consists of 3-4 strikes.
• There are 1,800 thunderstorms in the world right now.
• The American Empire State Building is struck by lightning on average 23 times a year.
• Airplanes are struck by lightning on average once every 5-10 thousand flight hours.
• The chance of being killed by lightning is 1 in 2,000,000. Each of us has the same chances of dying from falling out of bed.
• Probability of seeing ball lightning at least once in a lifetime is 1 in 10,000.

Thunder- a sound in the atmosphere accompanied by a lightning discharge.

Lightning- This is a giant discharge in the atmosphere, usually appearing with a bright flash of light and accompanied by thunder.

Storm- This atmospheric phenomenon, in which strong electrical discharges occur between magnetic cumulonimbus clouds and the ground - lightning.

Droplets and ice crystals that move quickly up and down in cumulonimbus clouds accumulate positive and negative electrical charges. In the end, between differently charged sections of the cloud or between the cloud and the ground (water), a giant spark of lightning flashes, accompanied by thunder. The power of this “natural powerhouse” is colossal. The energy generated at these power plants around the world for several months is not enough for one single lightning strike.

Such discharges reach voltages of millions of volts, and the total power of the Earth’s “thunderstorm machine” is 2 million kilowatts (one thunderstorm consumes so much energy that it would be enough to supply the electricity needs of a small city for a year). The discharge speed reaches 100 thousand km/sec, and the current strength is 180 thousand amperes. The temperature in the lightning channel - due to the huge current flowing there - is 6 times higher than on the surface of the sun, so almost every object penetrated by lightning burns up. The width of the lightning discharge channel reaches 70 cm. Due to the rapid expansion of air overheating in the channel, thunderclaps are heard.

Thunderstorms

Lightning protection practice shows that lightning rods do not provide a 100% guarantee of safety. Out of 10 strikes, two or three overwhelm the lightning protection system.

Remember the tragedy on the football field in Pershetravinsk (Dnieper region) in 2002, there is a high-voltage line next to the stadium, which is protected from lightning discharges in accordance with all the rules and requirements of science. However, lightning struck and killed several thunderbolts right on the field.

According to statistics, 40 thousand thunderstorms occur annually in the world. 117 lightning flashes every second. Their duration is within an hour.

Thunderstorms often go against the wind. The distance to an approaching thunderstorm can be determined by counting the seconds separating the flash of lightning and the sound of the first clap of thunder. A second (1 second) pause means that a thunderstorm is at a distance of 300-400 m. A two-second (2 seconds) pause means 600-800 m. A three-second pause (3 seconds) means 1 km. Four-second (4 seconds) – 1.3 km, etc.

By taking readings several times over 50 minutes, you can calculate approximate speed the spread of a thunderstorm.

Lightning can - disrupt radio communications, disable navigation equipment, or even completely destroy an aircraft; cause fires; inflict defeat on people and animals. It is noteworthy that already in ancient times people tried to protect themselves from lightning. Ancient people surrounded the Temple of Jerusalem with high masts covered with copper (over its thousand-year history it was never damaged by lightning, although it was located in one of the most thunderstorm-prone areas on the planet). Thunderstorms lead to the most dangerous manifestation of the elements - fires.

What is thunder? Thunder is the sound that accompanies a lightning strike during a thunderstorm. Sounds simple enough, but why does lightning sound the way it does? Any sound consists of vibrations that create sound waves in the air. Lightning is a huge bolt of electricity that shoots through the air, causing vibrations. Many people have repeatedly wondered where lightning and thunder come from and why thunder precedes lightning. There are quite understandable reasons for this phenomenon.

How does thunder thunder?

Electricity passes through the air and causes air particles to vibrate. Lightning accompanied incredibly high temperature, so the air around it also gets very hot. Hot air expands, increasing the strength and number of vibrations. What is thunder? These are the sound vibrations that occur during lightning strikes.

We see lightning before we hear thunder because light travels faster than sound. There is an old myth that by counting the seconds between a flash of lightning and thunder, you can find out the distance to where the storm is raging. However, from a mathematical point of view, this assumption has no scientific basis, since the speed of sound is approximately 330 meters per second.

Thus, for thunder to travel one kilometer, it will take 3 seconds. Therefore, it would be more correct to count the number of seconds between the flash of lightning and the sound of thunder, and then divide this number by five, this will be the distance to the thunderstorm.

This mysterious phenomenon- lightning

The heat from lightning's electricity raises the temperature of the surrounding air to 27,000°C. Since lightning moves at incredible speeds, the heated air simply does not have time to expand. Heated air is compressed, it Atmosphere pressure at the same time it increases several times and becomes from 10 to 100 times more than normal. Compressed air rushes out from the lightning channel, forming a shock wave of compressed particles in each direction. Like an explosion, fast-moving waves of compressed air create a loud, booming burst of noise.

Based on the fact that electricity follows the shortest path, the predominant number of lightning strikes are close to vertical. However, lightning can also branch, as a result of which the sound color of the thunder roar also changes. Shock waves from different lightning forks bounce off each other, and low-hanging clouds and nearby hills help create the continuous rumble of thunder. Why is there thunder? Thunder is caused by the rapid expansion of air surrounding the lightning path.

What causes lightning?

Lightning represents electricity. Inside a thundercloud high in the sky, numerous small pieces of ice (frozen raindrops) collide with each other as they move through the air. All these collisions create electric charge. After some time, the whole cloud is filled with electrical charges. Positive charges, protons, form at the top of the cloud, and negative charges, electrons, form at the bottom of the cloud. And as we know, opposites attract. The main electrical charge is concentrated around everything that protrudes above the surface. These could be mountains, people or lonely trees. The charge goes up from these points and eventually combines with the charge going down from the clouds.

What causes thunder?

What is thunder? This is the sound caused by lightning, which is essentially a stream of electrons flowing between or within a cloud, or between a cloud and the ground. The air around these streams heats up to such an extent that it becomes three times hotter than the surface of the Sun. Simply put, lightning is a bright flash of electricity.

This stunning and at the same time terrifying spectacle of thunder and lightning is a combination of dynamic vibrations of air molecules and their disruption through electrical forces. This magnificent show once again reminds everyone of the powerful force of nature. If you heard the roar of thunder, lightning will soon flash; it is better not to be outside at this time.

Thunder: Fun Facts

• You can judge how close the lightning is by counting the seconds between the flash and the clap of thunder. For every second there are about 300 meters.
• During a large thunderstorm, seeing lightning and hearing thunder is a common occurrence; thunder during snowfall is very rare.
• Lightning is not always accompanied by thunder. In April 1885, five lightning bolts struck the Washington Monument during a thunderstorm, but no one heard the thunder.

Be careful, lightning!

Lightning is quite dangerous a natural phenomenon, and it’s better to stay away from her. When indoors during a thunderstorm, you should avoid water. It is an excellent conductor of electricity, so do not shower, wash your hands, wash dishes or do laundry. You should not use your phone, as lightning may strike external telephone lines. Do not turn on electrical equipment, computers and household appliances during a storm. Knowing what thunder and lightning are, it is important to behave correctly if suddenly a thunderstorm takes you by surprise. You should stay away from windows and doors. If someone is struck by lightning, they need to call for help and an ambulance.