Heaps of thunderstorms rumbles and thunder. What is the difference between a thunderstorm and lightning: general and particular. Amazing fireball

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 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.

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

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

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

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

A thundercloud consists of a large amount of steam condensed in the form of ice (at a height exceeding three kilometers it is almost always ice crystals, since the temperature here does not rise above zero). Before the cloud becomes a thunderstorm, ice crystals begin to actively move inside it, while the currents of warm air rising from the heated surface help them to move.

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

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

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

The channel heats up to nearly 30,000 degrees Celsius, five times the temperature of the Sun, producing a bright light (the flash typically lasts only three-quarters of a second). After the formation of the channel, the thundercloud begins to discharge: the first discharge is followed by two, three, four or more sparks.

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

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

Thunder rolls

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

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

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

Amazing fireball

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

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

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

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

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

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

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

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

Possible dangers

Since the appearance of ball lightning is always unexpected, when you see this unique phenomenon near you, the main thing is not to panic, not to move sharply 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.

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

What to do in a thunderstorm

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

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

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

Lightning is a powerful electrical discharge. It occurs when there is a strong electrification of the clouds or the earth. Therefore, lightning discharges can occur either within a cloud, or between neighboring electrified clouds, or between an electrified cloud and the ground.

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

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

What causes clouds to become electrified? 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 ice floes. The top of a thundercloud can be at a height of 6-7 km, and the bottom hangs above 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 floes are in constant motion, caused by ascending currents of 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 ice floes, moving to the upper part of the cloud, all the time collide with large ones. Each such collision leads to electrification. In this case, large pieces of ice are charged negatively, and small pieces 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 thundercloud is positively charged, while the bottom is negatively charged.

The electric field of the 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 the rest of the charged particles rush after them. This is how lightning occurs.

During this discharge, huge 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 the external manifestations of these atmospheric phenomena in the form of lightning.

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

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

Thus, lightning is a breakdown of a capacitor, in which the dielectric is air, and the plates are clouds and earth. The capacitance of such a capacitor is small - about 0.15 microfarads, but the energy reserve is huge, 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 according to the shape and direction of the discharge. Discharges can occur:

• between the storm cloud and the earth,
• between two clouds
• inside the cloud
• move out of the clouds into the clear sky.

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

Zippers 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.
• The current strength of the electrical discharge of the accumulated electrical energy through the atmosphere creates currents up to 100,000 A.
• The air in the lightning channel heats up to 30,000 degrees - five times more than the surface temperature of the Sun.
• Lightning propagation speed - 1,000,000 m/s. Thus, 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 inner one, through which the current flows, is 1 cm.
• A typical lightning lasts about 0.25 seconds and consists of 3-4 strikes.
• 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 chance of seeing ball lightning at least once in a lifetime is 1 in 10,000.

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

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

Thunderstorm- this is an atmospheric phenomenon in which strong electrical discharges occur between magnetic cumulonimbus clouds and the earth - lightning.

Drops and ice crystals that move rapidly up and down in cumulonimbus clouds build up positive and negative electrical charges. In the end, between the differently charged sections of the cloud or between the cloud and the earth (water), a giant spark of lightning jumps, accompanied by thunder. The power of this "natural power plant" is colossal. The energy generated at these power plants of the world for several months is not enough for one single lightning.

Such discharges reach a voltage of millions of volts, and the total power of the Earth's "lightning machine" is 2 million kilowatts (with one thunderstorm, so much energy is consumed that it would be enough to meet the needs of a small city for electricity during the year). The discharge speed reaches 100 thousand km / s, 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 pierced by lightning burns. The width of the discharge channel of lightning reaches 70 cm. Due to the rapid expansion of the air overheating in the channel, thunder is heard.

Thunderstorms

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

Remember the tragedy on the football field in Pershetravinsk (Dnipro region) in 2002, a high-voltage line passes near the stadium, which is protected from lightning discharges in accordance with all the rules and requirements of science. However, lightning struck several to death and thundered right onto the field.

According to statistics, 40 thousand thunderstorms occur annually in the world. There are 117 lightning bolts 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 between the flash of lightning and the sound of the first roll 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 is 600-800 m. A three-second (3 seconds) pause is 1 km. Four-second (4 seconds) - 1.3 km, etc.

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

Lightning can - disrupt radio communications, disable navigation equipment, or even completely destroy an aircraft; cause fires; inflict damage 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 studded with copper (for a thousand-year history, it has never been damaged by lightning, although it was located in one of the most thunderous areas on the planet). Thunderstorms lead to the most dangerous manifestation of the elements - fires.

What is thunder? Thunder is the sound that accompanies lightning during a thunderstorm. Sounds simple enough, but why does lightning sound that way? All sound is made up of vibrations that create sound waves in the air. Lightning is a huge discharge of electricity that shoots through the air, causing vibrations. Many have wondered more than once about where lightning and thunder come from and why thunder precedes lightning. There are quite understandable reasons for this phenomenon.

How does thunder rumble?

Electricity passes through the air and sets the air particles into a state of vibration. Lightning is accompanied by an incredibly high temperature, so the air around it is also very hot. Hot air expands, increasing the strength and number of vibrations. What is thunder? These are the sound vibrations that occur during lightning discharges.

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 the place where the storm is raging. However, from a mathematical point of view, this assumption has no scientific justification, since the speed of sound is approximately 330 meters per second.

Thus, it takes 3 seconds for the thunder to travel one kilometer. 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 is lightning

The heat from lightning electricity raises the temperature of the surrounding air to 27,000°C. Since lightning moves at an incredible speed, the heated air simply does not have time to expand. The heated air is compressed, its atmospheric pressure at the same time increases many times and becomes from 10 to 100 times higher than normal. Compressed air rushes outward from the lightning channel, forming a shock wave of compressed particles in every direction. Like an explosion, rapidly propagating waves of compressed air create a loud, booming burst of noise.

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

What causes lightning?

Lightning is an electrical current. 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 an electrical charge. After a while, the whole cloud is filled with electric charges. Positive charges, protons, form at the top of the cloud, and negative charges, electrons, form at the bottom of the cloud. And as you know, opposites attract. The main electric charge is concentrated around everything that sticks out above the surface. It can 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 that lightning makes, 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 is heated 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.

Such an amazing and at the same time frightening spectacle of thunder and lightning is a combination of dynamic vibrations of air molecules and their disruption by electrical forces. This magnificent show once again reminds everyone of the powerful force of nature. If the roar of thunder was heard, lightning will soon flash, it is better not to be on the street at this time.

Thunder: fun facts

• You can judge how close lightning is by counting the seconds between the flash and the thunder. For every second, there are about 300 meters.
• It is common to see lightning and hear thunder during a big thunderstorm, but thunder during snowfall is a rarity.
• 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.

Watch out, lightning!

Lightning is a rather dangerous natural phenomenon, and it is better to stay away from it. If you are indoors during a thunderstorm, you should avoid water. It is an excellent conductor of electricity, so you should not shower, wash your hands, wash dishes or do laundry. Do not use the telephone, as lightning can strike outside telephone lines. Do not turn on electrical equipment, computers and home appliances during a storm. Knowing what thunder and lightning are, it is important to behave correctly if suddenly a thunderstorm caught you by surprise. Stay away from windows and doors. If someone is struck by lightning, you need to call for help and call an ambulance.