How and why lightning occurs
Lightning in most cases forms in cumulonimbus clouds, and sometimes in large nimbostratus clouds. Thunderclouds stand out clearly from the rest due to their rich dark color.
The dark blue hue comes from the thickness of the cloud. Moreover, its lower edge is located at an altitude of about 1 km above the earth’s surface, and the upper edge reaches 6-7 km in height.
As you know, a cloud consists of water vapor. At altitude, the droplets freeze and turn into ice crystals. Due to uneven temperature distribution, heated air rises and carries with it small particles of ice. At the same time, larger frozen floes fall down - particles constantly collide.
Lightning formation
During a collision, the ice floes are electrified (the same phenomenon as during friction of different objects). Smaller particles receive a positive charge, and larger ones receive a negative charge. Different parts of the cloud are charged accordingly. At the top there is a thundercloud with a plus sign, and at the bottom with a minus sign.
The result is a potential difference. Moreover, it is formed both between different parts of the cloud, and between the cloud and the ground. This difference is measured in hundreds of thousands of volts.
Lightning does not appear instantly out of nothing, although it moves quite quickly. The formation of lightning can be divided into initial, middle and final stages.
initial stage
The discharge appears in a certain part of the cloud where a large number of ions are present. An ion is a particle with an electrical charge. It occurs when an atom or molecule gains or loses electrons.
The same thing happens with a thundercloud. Ions are formed due to molecules of water and gases, of which, in fact, the cloud consists. At this stage, the opinions of scientists differ, since it has not yet been possible to thoroughly study the nature of lightning.
Scheme of development of ground lightning
Some experts believe that a high concentration of ions is due to the acceleration of free electrons. They are always present in the air, albeit in a small volume. These electrons then collide with neutrally charged molecules, causing them to ionize.
According to another hypothesis, it's all about cosmic radiation. It also affects the Earth's atmosphere constantly. This is how air is ionized. Ionized gas is a good conductor of electricity, so current passes through it in the cloud.
Middle stage
Then a chain reaction starts. The current passing under high voltage heats the air in a certain area. More and more energetic particles are formed, which convert neighboring regions into ions. Therefore, lightning travels extremely quickly.
Stages of a downward lightning strike
Lightning has a dominant part - the most powerful channel, from which branches spread in different directions. This explains the tortuous shape of the discharges: with each new flash, the lightning seems to move in leaps and bounds further and further by about several tens of meters.
Interesting fact : sometimes the speed of the “main” lightning reaches 50,000 km per second.
At a certain moment, the most powerful discharge reaches the earth's surface or another part of the cloud. But this is not the end. As soon as an electrical discharge breaks through an ionized channel several centimeters thick, charged particles pass through it at high speed. In fact, this is lightning that we can observe.
Due to the high voltage, the temperature inside this channel is measured in thousands of degrees. That's why we see lightning as a very bright flash. Thunder is a consequence of a sharp change in temperature and pressure. During an electrical discharge, a huge amount of energy is released, despite the short duration of the phenomenon.
Final stage
The speed of charge movement along the channel decreases rapidly. However, the voltage and current still remain very high. It is at the final stage that lightning usually reaches the ground and various objects.
Final stage of lightning
If there are people nearby, lightning becomes very dangerous. The final stage takes not even a second, but tenths of it. But this is enough to cause damage, fires, etc. Lightning often strikes the same place several times if this path is the shortest and most “convenient” for the discharge.
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Physical nature of lightning
How is the origin of lightning explained? cloud-ground or cloud-cloud system 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. From the cloud to the ground, an ionized channel is laid, as it were. 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
Lightning is divided into many types. The main criterion is the nature of the discharge formation, because lightning can occur at different heights. They can also have different shapes, lengths and other parameters.
Types of lightning in the layers of the atmosphere
Linear (cloud-ground)
A common species that occurs due to different charges of the upper and lower parts of the cloud. Linear lightning appears and develops according to the principle described earlier - as a result of active ionization of air. From the main leading channel, flashes diverge stepwise in different directions, reaching the ground at the final stage.
Linear lightning
Earth-cloud
Objects located at high altitudes often attract lightning, accumulating electrostatic charge. Ground-to-cloud discharges occur as a result of the penetration of the atmospheric layer between the bottom of a thundercloud and the charged top.
Ground-to-cloud lightning
Cloud-cloud
Most lightning occurs among clouds. Flashes are formed as a result of different parts of clouds having different charges. Therefore, nearby clouds pierce each other with electrical discharges.
Cloud-to-cloud lightning
Interesting fact : in Venezuela there is a unique place where the Catatumbo River flows into Lake Maracaibo. There is a lot of lightning here all year round (usually at night), which flashes continuously for a long time. The frequency of discharges is 250 per square kilometer per year. The highest peak is May and October.
Horizontal
Similar to cloud-to-ground, but does not reach the earth's surface. The outbreaks spread in different directions. Such lightning is considered extremely powerful. For its formation, one thundercloud in a clear sky is enough.
Horizontal zipper
Tape
Lightning takes on an interesting form, in which several identical channels rush down parallel to each other at a short distance. The reason probably lies in the strong wind, which widens these channels.
Tape zipper
Beaded (dotted)
A rare type of lightning, the nature of which has been little studied. The discharge does not occur in a continuous line, but with frequent small intervals - dotted lines. It is possible that some areas of the lightning cool quickly, giving it this shape. The flash lasts a couple of seconds, and the lightning itself strikes in a wave and only in one trace.
Beaded lightning
Curtain
Occurs above the clouds, and not inside or below them, like previous types. How exactly it is formed is unknown. Externally, it is a wide luminous stripe consisting of a large number of discharges. At the same time, you can hear a low hum. The first time such lightning was captured was in 1994.
Curtain zipper
Sprite
If ordinary lightning occurs at an altitude of about 16 km, then sprites appear much higher - 50-130 km. They are electrical discharges of cold plasma shooting upward from the clouds.
Sprites
It’s difficult to see them, but sprites are formed in groups during every strong thunderstorm, a few seconds after powerful lightning. The average length of flashes is 60 km, diameter is up to 100 km, duration is up to 100 milliseconds.
Elf
Large-scale cone-shaped flares with weak red light (diameter approximately 400 km). Formed in the upper layers of thunderclouds. They reach a height of 100 km and last about 3 milliseconds.
Elf
Jet
Tubular-cone-shaped lightning with a blue glow. The height reaches the lower layers of the ionosphere (from 40 to 70 km). In terms of duration they are slightly ahead of the elves.
Jets
Volcanic
Occurs during a volcanic eruption. This is probably due to the fact that the ash and magma carry an electrical charge when ejected. In addition, these particles constantly collide, which causes discharges.
Volcanic lightning
Saint Elmo's Fire
In fact, this is not lightning, but discharges that occur at the pointed ends of towering objects. This includes the tops of rocks, trees, ship masts, towers, etc. They are formed due to high electric field strength. Most often this happens during a thunderstorm or snowstorm in winter.
Saint Elmo's Fire
Ball
Lightning in the form of a spherical plasma clot floating directly in the air. How and why such a discharge is formed has not yet been established by scientists. All we can say for certain is that such lightning behaves unpredictably. Many still doubt its existence.
Ball lightning, 19th century engraving
Electric potential: how lightning occurs and how dangerous it is
Thunderstorms occur on our planet more than 40 thousand times a day - about 100 lightning flashes every second. But this phenomenon has not yet been fully studied. “Theories and Practices” publishes an excerpt from the book “Through the Eyes of a Physicist” by Walter Lewin and Warren Goldstein. From the end of the rainbow to the border of time,” which the publishing house “MYTH” prepared for the Non/fiction exhibition. The authors explain what lightning is and whether a lightning rod, a car, or rubber-soled sneakers can save you from it.
“Through the eyes of a physicist.
From the end of the rainbow to the edge of time" Walter Levin, Warren Goldstein Of course, one of the most dangerous types of current is lightning, which is also one of the most remarkable electrical phenomena, powerful, not entirely predictable, not fully understood and mysterious - in general, a real cocktail. In the myths of various peoples - from the ancient Greeks to the Mayans - lightning bolts are described either as symbols of deities or as an instrument of their retribution. And this is not surprising. On average, there are about 16 million thunderstorms on Earth each year (more than 43 thousand daily and about 1800 hourly), which produce about 100 lightning flashes every second, or more than 8 million lightning strikes per day. This is on a planetary scale.
Lightning is a consequence of the charging of thunderclouds. Typically, the top of the cloud is positively charged and the bottom is negatively charged. Scientists have not yet fully figured out why this is so. Believe it or not, there are still many questions to be answered in atmospheric physics. For now, for the sake of simplicity of discussion, let's simplify the situation somewhat by imagining a cloud that is negatively charged on the side that is closer to the ground. Due to induction, the earth closest to the cloud becomes positively charged, and an electric field will arise between it and the cloud.
From a physical point of view, a lightning discharge is quite complex, but essentially a flash (electrical breakdown) occurs when the electrical potential between the cloud and the ground reaches tens of millions of volts. And although we often think of a lightning bolt as “shooting” from a cloud to the ground, in fact the movement occurs both from cloud to ground and from ground to cloud. The strength of the electric current during a lightning discharge of average intensity is about 50 thousand amperes (although it can reach several hundred thousand amperes), and the maximum power reaches about a trillion (1012) watts, but this lasts only a few tens of microseconds. However, the total energy released at the moment of a lightning strike rarely exceeds several hundred million joules, which is equivalent to the energy consumed in a month by a hundred-watt light bulb. So the idea of harvesting lightning energy is completely impractical and impractical.
Most of us know that we can determine how far away lightning strikes from us by the time that passes between the moments when we see the discharge and hear the thunder. The reason given for this also gives us some idea of the powerful forces involved in the process. And it, by the way, has nothing to do with the explanation I once heard from a student: that lightning creates a kind of low-pressure area where air rushes and collides with air coming from the other side, resulting in thunder. In fact, everything happens almost exactly the opposite. The discharge energy heats the air to approximately 20 thousand ° C, that is, to a temperature more than three times higher than the temperature of the surface of the Sun. This super-heated air then creates a powerful pressure wave that collides with the cold air around it, creating sound waves that travel through the air. Since sound waves in the air travel at about a mile every five seconds, by counting the seconds you can pretty easily figure out how far away from you lightning struck.
The fact that lightning heats the air so much explains another phenomenon you may experience during a thunderstorm. Have you ever noticed how fresh, special the smell is in the air after a thunderstorm, as if the storm had cleansed it? Of course, in a big city it is difficult to feel this, because there the air is almost always saturated with exhaust gases from cars. But even if you are lucky enough to smell this wonderful aroma, you may well not know that it is the smell of ozone, an oxygen molecule made up of three oxygen atoms. As you know, normal oxygen molecules—without any odor—are made up of two oxygen atoms, and we write them as O2. But the tremendous heat from lightning breaks down these molecules—not all of them, but enough of them to have some effect. The resulting individual oxygen atoms are themselves unstable, so they attach to normal O2 molecules, creating the substance O3 - ozone.
However, it should be noted that ozone only smells pleasant in small quantities; in high concentrations its smell is not so attractive. It can be felt, for example, under high-voltage wires. If you hear a buzzing sound coming from the wires, it usually means there is sparking, called corona discharge, which creates ozone molecules. When there is no strong wind, you can usually smell a rather unpleasant odor.
“Lightning strikes airplanes on average more than once a year, but thanks to the skin effect, they survive these strikes safely.”
Now let’s return to the idea that a person can be saved from the consequences of a lightning strike by wearing rubber-soled sneakers. A 50,000 to 100,000 ampere lightning bolt, capable of heating the air to more than three times the surface temperature of the sun, will almost certainly burn you to ashes, cause you to convulse from a massive electric shock, or simply explode you, instantly turning all the water into your body into super-hot steam. Completely regardless of what you're wearing. This is exactly what happens to a tree that is struck by lightning - the sap in it explodes and tears off all the bark from it. One hundred million joules of energy - the equivalent of almost thirty kilograms of dynamite - is not a pound of raisins.
What about whether it's safe to be inside a car that protects you from lightning thanks to its rubber tires? A car can indeed protect you in this situation (no guarantees, however!), but for a completely different reason. The fact is that electric current flows through the surface layers of a conductor (this phenomenon is called the skin effect), and, sitting in a car, you find yourself inside a metal box, and metal, as we already know, is a good conductor. You can even touch the inside of the duct panel without causing any injury. However, I strongly urge you not to do this as it is extremely dangerous as most modern cars use fiberglass parts and this material does not have the skin effect. In other words, if lightning strikes your car, you - and your car - may experience some of the most unpleasant moments of your life. If you're interested, watch this short video of lightning striking a car. I think you will immediately understand that this is not something to joke about!
Fortunately for us, the situation with airplanes is completely different. Lightning strikes them on average more than once a year, but thanks to the same skin effect they survive these strikes safely. Watch the video.
© paulprescott72/iStock
There is another famous lightning experiment attributed to Benjamin Franklin, but I strongly advise you not to try it. We are talking about flying a kite during a thunderstorm with a metal key attached to it. Presumably Franklin intended to test the hypothesis that thunderclouds create electrical fire. He reasoned as follows: if lightning really is a source of electricity, then once the kite's string gets wet from the rain, it will become a good conductor (although the scientist did not use this word) of electricity and it will pass down to the key tied to its end. They also say that as soon as Franklin raised his hand to the key, a bright spark immediately appeared. So, just as in the case of Newton, who in the twilight of his life allegedly claimed that he was inspired to create the law of universal gravitation by an apple falling to the ground from a tree, there is no modern evidence that Franklin ever actually carried out this experiment. . There is only an account in a letter he sent to the Royal Scientific Society in England, and another written document compiled fifteen years later by Franklin's friend Joseph Priestley (by the way, the discoverer of oxygen).
“One hundred million joules of energy - the equivalent of almost thirty kilograms of dynamite - is not a pound of raisins.”
But whether Franklin carried out this experiment or not - which would have been fantastically dangerous and with a very high probability would have led to the death of the great inventor - he published an accurate description of the other experiment. In this case, the task was to lead the lightning into the ground, for which the scientist installed a long iron rod at the top of the tower. A few years later, the Frenchman Thomas-François Dalibard, who met Franklin and translated his ideas into French, carried out this experiment in a slightly different version and witnessed a truly incredible phenomenon. Dalibar installed an iron rod more than 10 meters long and, pointing it into the sky, saw sparks at its ungrounded base.
Subsequently, Professor Georg Wilhelm Richmann, an outstanding scientist born in Estonia and living in St. Petersburg, a member of the St. Petersburg Academy of Sciences, who had studied electrical phenomena for many years, apparently inspired by Dalibard's experiment, decided to try it too. As Michael Bryan tells in the interesting book Draw the Lightning Down: Benjamin Franklin and Electrical Technology in the Age of Enlightenment, Richman attached an iron rod to the roof of his house and connected it with a copper chain him with a device for measuring electricity in his laboratory located on the first floor.
As if on purpose—or perhaps it was a sign of fate—in August 1753, during a meeting of the Academy of Sciences, a severe thunderstorm broke out. Richman rushed home, taking with him the artist who was supposed to illustrate his new book. While Richman was observing the equipment, lightning struck, traveled down the rod and chain, jumped out half a meter from the scientist's head, shocked him and threw him across the room; the artist also received a strong electric shock and lost consciousness. On the Internet you can find several illustrations of this terrible scene, although it is not known for sure whether they were created by the artist who was directly involved in it.
Franklin invented a similar contraption, but his brainchild was grounded; today it is known as a lightning rod. The device is excellent at grounding lightning strikes, but not for the reason Franklin intended. He believed that a lightning rod would cause a continuous discharge between the charged cloud and the building, thereby keeping the potential difference low and therefore reducing the danger of a lightning strike. The scientist was so confident that he was right that he advised King George II to install lightning rods on the roof of the royal palace and in ammunition depots. Franklin's opponents argued that lightning rods would only attract lightning and that the effect of the discharge, by reducing the electrical potential difference between the building and the thunderclouds, would be very negligible. But the king, as the story goes, trusted Franklin and installed lightning rods.
Shortly thereafter, lightning struck directly one of the ammunition depots, but the damage was minimal. That is, the rod worked, but for completely different reasons. Franklin's critics were absolutely right: lightning rods do attract lightning, and the discharge of the rod is truly insignificant compared to the enormous charge of a thundercloud. But the lightning rod still has the desired effect - because when the rod is thick enough to handle 10-100 thousand amperes, the current will remain in the rod and the charge will go into the ground. It turns out that Franklin was not only a brilliant scientist - he was also very lucky!
Isn't it amazing that by understanding the quiet crackling noise we hear when we take off a polyester sweater in winter, we can also understand the essence of an eerie thunderstorm with lightning lighting up the night sky and understand the origin of one of the loudest and most terrifying sounds in nature?
In a sense, we are all modern versions of Benjamin Franklin, trying to figure out and comprehend in this formidable phenomenon what is still beyond our understanding. In the late 1980s, scientists first photographed different forms of lightning flashing high, high in the clouds. One variety is called red ghosts and consists of reddish-orange electrical discharges occurring 50–90 kilometers above the ground. And there are also blue jets - they are much larger, sometimes up to 70 kilometers long, and arise in the upper layers of the atmosphere. But we have only known about them for a little over twenty years, and we still know very little about the causes of this stunning natural phenomenon. Even though people have studied electricity in great detail, thunderstorms are still shrouded in mystery - and they happen on our planet about 45 thousand times a day.
Lightning color
Lightning can have different shades: bluish, white, yellow, orange, red. The color depends on the composition of the atmosphere. The lightning channel heats up 5 times hotter than the Sun. At this temperature, the air is characterized by blue and violet tones. Therefore, discharges visible nearby in a clear atmosphere acquire a bluish glow.
The bluish glow of lightning is the most common
At a greater distance, the flashes become white, and even further away they turn yellow. This happens because blue tones are scattered in the air. If there is a lot of dust in the atmosphere, the flashes turn orange.
Drops of water “color” the lightning in red shades. The most rare phenomenon is the creation of complex optical effects due to a high concentration of small ice particles in the air.
What is thunder
Thunder is the sound of lightning in the atmosphere. The origin of this phenomenon is associated with temperature changes in the air space. When discharged, the air mass becomes so hot that it explodes with a powerful sound. That's where thunder comes from.
How does thunder appear?
A few moments after the discharge, the pressure in the channel increases beyond the limit, the air mass heats up to several tens of degrees. A channel carrying an electric charge rushes to the ground. A spark comes towards you from the earth's surface. The charges connect and current rushes towards the cloud. When current flows, the temperature in the channel exceeds 250 thousand degrees. From such an incredible temperature, air molecules fly apart at tremendous speed, forming a supersonic wave. The result of the process is an explosion of air.
When thunder and lightning are nearby, you hear one peal. If a thunderstorm rages at a considerable distance, then several rumbles can be heard - this is an echo reflected from the unevenness of the earth's surface.
It is interesting to note why in winter there is no thunder and, in principle, there is no thunderstorm as such. To form electric charges, liquid in the atmosphere must be in three states: vapor, drops, and ice. The simultaneous presence of three states of aggregation is possible only in the warm period of the year. In winter, there is no liquid or vapor form of water in both the lower and upper atmospheric layers. Winter air is dry, precipitation is solid. There is nowhere for an electric discharge to come from, so thunder and lightning are impossible in winter. But autumn thunder, contrary to popular belief, does happen.
Speed and length of lightning
On average, lightning moves at a speed of about 56 thousand km/sec. In this case, a thunderstorm atmospheric phenomenon moves at a speed of 40 km/h. The average length of an electric discharge is 9.5 km.
Interesting: Why does thunder thunder?
Old photo of lightning in Boston
Interesting fact : the longest lightning strike in the world was recorded in the American state of Oklahoma - 321 km. And the longest discharge in time was observed in the Alps - for 7.74 seconds.
Ball lightning
Ball lightning is a separate type of 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.
Finally, we invite you to watch the video and remind you: if a coursework or test falls on your head like lightning on a sunny day, there is no need to despair. Student service specialists have been helping students since 2000. Seek qualified help at any time. We are ready to help you 24 hours a day, 7
Lightning frequency
Early studies showed that lightning strikes approximately 100 times per second across our planet. But satellites make it possible to observe the most remote or hard-to-reach places on Earth.
Lightning frequency (per square kilometer per year)
New data indicates 44 plus or minus 5 lightning strikes per second. This means that about 1.4 billion electrical discharges occur per year. Of these, approximately 25% strike the ground, and the remaining 75% erupt among the clouds.
Is it dangerous for lightning to hit a car, plane, or house?
Here, too, it is difficult to give a definite answer, but if everything is fine with the equipment, and there is a lightning rod on the building, then it is most likely safe. There are even statistics according to which lightning strikes airplanes on average every seven to ten thousand flight hours. This is quite common.
Lightning hitting the plane is not so colorful, but for obvious reasons there are no real photos.
In the case of cars, the hit is also safe. The fact is that the body is essentially a Faraday cage. The charge passes through it and does not harm the person inside. True, electrical equipment may be damaged. Everything is more secure on airplanes. The fuselage has additional protection elements that conduct current through it further into the ground. A lightning strike on an airplane is not even an emergency situation. The systems are simply checked and, if everything is normal, the plane continues to move.
This is what a Faraday cage looks like. The person is safe.
A Faraday cage is a device invented to shield equipment from external electromagnetic fields. Usually it is a cage made of conductive material. The cell can conduct current, negating the impact on the equipment inside.
A lightning rod in houses is an element placed above the roof, which is connected to the ground and reliably isolated from the structure of the house. Since lightning takes the shortest path to the ground, it hits this element and is safely discharged without causing harm to other objects. For example, the famous Empire State Building is struck by lightning about 25 times a year. The lightning rod decides.
This is what a lightning rod looks like on the roof of a house.
Usually there is no point in installing lightning rods on every house - one is enough for a relatively large area. Naturally, it must be on the highest building or a special tower.
How to determine the distance to lightning from thunder?
The distance to a thunderstorm can be determined approximately by thunder. To do this, it is recorded how many seconds pass between the sound of thunder and the flash of lightning. It is necessary to take into account the speed of sound - about 300 meters per second. So, 3 seconds is approximately 1 km before a thunderstorm.
Distance to lightning
Taking several measurements allows you to know whether a thunderstorm is approaching or moving away in relation to the observer. It is important to remember that lightning stretches for several kilometers. If lightning strikes are visible in the absence of thunder, it means that a thunderstorm is more than 20 km away.
Where does lightning come from before an earthquake?
There are lightnings that manifest themselves during earthquakes. Their nature is still unknown, but they also arise due to the accumulation of charge. Only in this case this occurs due to friction between the rock layers.
Initially, scientists did not take seriously the stories that earthquakes are accompanied by lightning, but the recent appearance of cameras has made them think about it. As a result, they began to experiment and came to the conclusion about the friction of rock layers.
Much better known are lightning during volcanic eruptions, which are also called “dirty lightning.” They also arise as a result of friction between particles flying out of the vent.
This is what lightning looks like inside a volcano.
The formation of lightning also accompanies other phenomena, for example, dust storms, tornadoes and some others, all leading to the same accumulation of charge.
Consequences of lightning
Lightning leaves behind a large number of different traces, depending on where the discharge strikes and its power. Consider the following manifestations of lightning:
- formation of fulgurites;
- hitting the ground;
- hitting trees, houses and other objects;
- hitting cars;
- hitting a person.
Fulgurite is a substance that is formed when an electrical discharge hits sand or any rock. Essentially, a certain amount of sand simply melts and hardens under short-term exposure to high temperature.
Fulgurite
Fulgurites are not easy to find. They are usually found on mountain tops or in areas where thunderstorms are common. Getting into sand deposits, lightning forms tubes of arbitrary shapes from it, hollow inside. In fact, they turn out to be glass.
There is always moisture and air between sand particles. A powerful blow quickly heats them to high temperatures and expands, as a result of which these tubes of various sizes and shapes appear. They are then instantly cooled.
Very rarely, lightning strikes strike the ground, since the shortest and most accessible path is preferable for them. But in the event of a hit, a depression remains on the surface, from which ornate lines, reminiscent of lightning in shape, go in different directions.
Lightning trace on the ground
Rising above other objects, trees most often attract lightning. In most cases, they burn out, and instantly. If ball lightning hits a tree, it sets it on fire from the inside. When lightning strikes a building, it often damages the roofing part and can also cause a fire.
Lightning struck a tree
If the discharge hits a closed vehicle, such as a car, it will quickly spread throughout the metal body and go into the earth's surface. It is believed that a car is a safe place in which you can wait out bad weather, since lightning does not get inside the cabin. However, the consequences of a direct hit are still serious.
Lightning struck a car
A person being struck by lightning is unpredictable. It is comparable to an electric shock, but the voltage is many times higher. Most often, lightning strikes the chest or head.
Lichtenberg figures
Special marks remain on the body, which resemble lightning in shape - they are called Lichtenberg figures. This mark remains as a result of damage to blood vessels. Being struck by lightning is extremely dangerous, so in the event of a thunderstorm you should take all necessary safety measures.
Why is a thunderstorm dangerous?
Since lightning is an electrical charge of enormous power, when it hits a building it can cause its destruction or fire. In addition, if such a discharge hits a person, it can cause severe injuries and even death. The brain is affected, the central nervous system is destroyed, and cardiac arrest may occur. And although, according to statistics, a direct hit by a lightning discharge on a person occurs in 1% of cases, this is extremely dangerous.
The shock wave of the released discharge is capable of breaking a tree, breaking windows, injuring, concussing, burning or stunning a person who happens to be nearby, therefore even lightning striking nearby is extremely dangerous.
Is it possible to use lightning energy?
There is a special term - lightning energy. This is the way in which lightning energy is “harvested” and directed into electrical networks. This energy belongs to the number of alternative renewable sources.
Electrical networks
The potential for using lightning energy is enormous. Its supply is endless - it will solve the problem of expensive electricity and reduce the damage that is currently being caused to the planet’s ecology. Currently, experimental installations for capturing lightning are being developed, and thunderstorm activity is being studied.
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But this method of energy consumption also has its disadvantages. It is difficult to predict where and when a thunderstorm will occur. In addition, the flash lasts a fraction of a second, so powerful, expensive equipment is required.
Lightning power in kilowatts - Construction Portal
Watt is a unit of measurement of active electrical power. In addition to active power, there is reactive power and apparent power. If we consider power from the point of view of physics, then this is a process in which energy is consumed in a certain unit of time. It turns out that one watt of electrical power is equal to the consumption of one joule (1 J) per second (1 s).
The name of the power unit comes from the name of the inventor of Scots-Irish origin named James Watt, who became famous for having created a steam engine in his time.
Before the modern unit of measurement of electrical power began to be used officially (since 1882), power was measured in horsepower. Now electrical power is indicated in watts (W). For more powerful consumers, electrical power is indicated in kilowatts (kW).
The content of the article:
Converting watts to kilowatts
In order to know how many watts are in one kilowatt, you need to understand that the prefix “kilo” denotes a multiple of one thousand. Those. 1 kilowatt = 1 * 1000 watts = 1000 watts. It follows from this that 2 kilowatts = 2 * 1000W = 2000 watts. If the power value is 0.5 kilowatts, then the power in watts will be 0.5 * 1000W = 500 watts.
If you need to calculate how many kilowatts are in one watt, then the calculation is done the other way around. It is necessary to divide the available power value in watts by a thousand. Those. 1 watt = 1/1000 watt = 0.001 kilowatt. It turns out that 1 watt is one thousandth of a kilowatt. Then 1000 watts = 1000/1000 watts = 1 kilowatt. If the power value is 500 watts, then the power in kilowatts will be 500/1000 watts = 0.5 kilowatts.
Where is the power indicated (W and kW)
For almost every consumer of electrical energy, its nominal power consumption is indicated. The power is indicated either in the consumer’s passport, or the value is printed on the device itself.
For example, on an incandescent lamp, the wattage is indicated on the glass part called the bulb. It can be 60 watts, 75 watts, 95 watts, 100 watts, 150 watts, 500 watts. It is worth noting that for ordinary incandescent lamps (and for other lamps), the power is also indicated on the cardboard packaging.
In addition to incandescent lamps, the rated power consumption is indicated on electric kettles, heaters, boilers, etc. The rated power of electric kettles is usually 1.5 kilowatts. The power of the heater can be 2 kilowatts, and the power of the boiler can even be 2.5 kilowatts.
Total power in watts (kilowatts)
Sometimes it is necessary to calculate the total power consumption of several appliances or devices. For example, this is necessary in order to select the correct cross-section of an electrical cable or wire. It is also advisable to know the total power when choosing switching or protective equipment.
To calculate the power of all electricity consumers, you need to know how many watts are in a kilowatt and vice versa, because on some consumers the power is indicated in watts, while on other consumers it is indicated in kilowatts for convenience. When calculating the total power, it is necessary to convert (convert) the power of individual consumers into watts or kilowatts.
Calculation of the total power of consumers
Let's say there are several consumers. These are a 75-watt incandescent lamp, a 100-watt incandescent lamp, a 2-kilowatt electric heater, a 2.5-kilowatt boiler and a 1,500-watt electric kettle.
As you can see, the power of incandescent lamps and a kettle is indicated in watts, and the power of an electric heater and boiler is indicated in kilowatts.
Therefore, to calculate the total power of all specified consumers, it is necessary to reduce all values to a single measurement value, i.e. to watts or kilowatts. Total power in watts
We determine the power in watts for those consumers whose power was initially indicated in kilowatts. This is an electric heater and boiler.
The heater has a power of 2 kilowatts, and since... There are 1000 watts in one kilowatt, then the heater power in watts will be 2 kilowatts * 1000 = 2000 watts. The value for the boiler is calculated similarly. Because its power in kilowatts is equal to 2.5 kilowatts, then the power in watts will be equal to 2.5 kilowatts * 1000 = 2500 watts.
Because Now the power in watts for all consumers is known, then the total power will be equal to the sum of the powers of all consumers. We add up the power of one and the second incandescent lamp, electric heater, boiler and electric kettle. We get a total power equal to 75 watts + 100 watts + 2000 watts + 2500 watts + 1500 watts = 6175 watts.
Total power in kilowatts
We determine the power in kilowatts for those consumers whose initially rated power is indicated in watts. These are incandescent lamps and an electric kettle. One lamp has a power of 75 watts, and since... one watt is a thousandth of a kilowatt, then the power of this lamp is 75 watts/1000 = 0.075 kilowatts. The power of the second lamp is 100 watts, which in kilowatts is 100 watts/1000 = 0.1 kilowatts. The power consumption of an electric kettle is 1500 watts, and in kilowatts it will be equal to 1500 watts/1000 = 1.5 kilowatts.
The power of each individual consumer is known, so the total power in kilowatts will be equal to the sum of all powers, i.e. 0.075 kilowatts + 0.1 kilowatts + 2 kilowatts + 2.5 kilowatts + 1.5 kilowatts = 6.175 kilowatts.
Value watt-hour or kilowatt-hour
In electricity, quantities commonly encountered are watt-hour and kilowatt-hour. Many people do not see any difference between the values of watt and watt-hour or kilowatt and kilowatt-hour, considering them to be the same value. However, in reality these are two different quantities, although their names are similar.
If watt and kilowatt are power, then watt-hour (Wh) or kilowatt-hour (kWh) is the amount of electricity consumed. In practice, it looks like this: a 100-watt incandescent lamp consumes 100 watt-hours of electricity in one hour. In two hours, such a lamp consumes 100 watts * 2 hours = 200 watt-hours. Well, in 10 hours, a 100-watt lamp consumes 100 watts * 10 hours = 1000 watt-hour electricity consumption, i.e. 1 kilowatt-hour.
Source: aquagroup.ru
What to do during a thunderstorm?
If you find a thunderstorm outside, you must follow these rules:
- You cannot hide under trees and other tall objects, or stand next to poles or road signs, which are most often struck by lightning. You should move away from them, since the tension diverges in different directions from the center of the impact.
- In an open area, you need to sit down and press your head to your knees, taking the lowest possible place.
- Move your umbrella and all metal and long objects away from you - they attract lightning.
- Turn off your phone and other devices.
- If possible, take shelter in the car.
- Do not approach the reservoir, especially do not swim.
What to do during a thunderstorm
While indoors, you should also turn off your telephone, electrical appliances, and gas supply. It is recommended to close all windows. There is a version that even the beam of a laser pointer aimed at the sky can attract a discharge.
Interesting fact : there is a concept of step voltage. It occurs between two points on the surface, and the greater the distance between these points, the higher the current strength. For example, cattle and horses are at greater risk because their front and rear legs are located far away.
we sing songs to the madness of the brave
Lightning energy is still only a theoretical direction. The essence of the technique is to capture lightning energy and redirect it to the power grid. This energy source is renewable and classified as alternative, i.e. environmentally friendly.
The process of lightning formation is very complex. Initially, from the electrified cloud, a leading discharge rushes to the ground, which was formed by electron avalanches that merged into discharges (streamers). This discharge leaves behind a hot ionized channel, along which the main lightning discharge, torn from the Earth by a powerful electric field, moves in the opposite direction. In a split second the process is repeated several times. The main problem is to catch the discharge and redirect it to the network.
Advantages
Benjamin Franklin also hunted for heavenly electricity. During a thunderstorm, he launched a kite into a cloud and realized that it was collecting an electrical charge.
Lightning energy is 5 billion joules of pure energy in one strike, which is comparable to 145 liters of gasoline. It is believed that 1 lightning bolt contains the amount of energy that the entire US population consumes within 20 minutes.
Every year, about 1.5 billion discharges are recorded worldwide, i.e. Lightning strikes the Earth's surface approximately 40-50 times per second.
Experiments
On November 11, 2006, Alternative Energy Holdings announced its success in creating a prototype design that could demonstrate "capturing" lightning and then converting it into "household" electricity. The company stated that the payback of the current industrial analogue will be 4-7 years at a retail price of $0.005 per 1 kWh. Unfortunately, after a series of practical experiments, the project management was forced to report failure. Then Martin A. Umani compared the energy of lightning with the energy of an atomic bomb.
In 2013, staff from the University of Southampton simulated an artificial charge in laboratory conditions, similar in all respects to natural lightning. Thanks to relatively simple equipment, scientists were able to “catch” it and fully charge the smartphone’s battery in just a few minutes.
Perspective
Lightning farms are still a dream. They would become inexhaustible environmentally friendly sources of very cheap energy. The development of this area of energy is hampered by a number of fundamental problems:
- It is impossible to predict the time and place of a thunderstorm. This means that even where the maximum for lightning strikes is set, quite a lot of “traps” need to be installed;
- Lightning is a short-term burst of energy, lasting a fraction of a second, and must be mastered very quickly. To solve this problem, we need very powerful capacitors that do not yet exist, and their price is likely to be very high. You can also use a variety of oscillatory systems with circuits of the 2nd and 3rd kind, which make it possible to match the load with the internal resistance of the generator;
- The power of the discharges also varies greatly. Most lightning is 5-20 kA, but there are flashes with a current intensity of 200 kA, and each of them must be brought to the standard of 220 V and 50-60 Hz alternating current;
- lightning can be negative, formed from energy accumulated in the lower part of the cloud, and positive, accumulated in its upper part. This factor also needs to be taken into account when equipping a lightning farm. Moreover, in order to capture a positive charge, energy will be required, as proven by the example of Chizhevsky’s chandelier;
- the density of charged ions in 1 cubic meter of atmosphere is low, air resistance is high. Accordingly, only an ionized electrode, raised as much as possible above the surface of the earth, can “catch” lightning, but it can only capture energy in the form of microcurrents. If you raise the electrode too close to electrified clouds, this can provoke lightning, i.e. a short-term but powerful surge in voltage will result, which will lead to breakdown of the lightning farm equipment.
Despite the obvious difficulties, the idea of creating lightning farms is alive: humanity really wants to tame nature and gain access to huge renewable energy reserves.
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How are planes protected from lightning?
The entire aircraft body is protected by a special shell, which contains a metal shielding mesh inside. Thus, when struck by lightning, the shell conducts current, but prevents the electrical discharge from penetrating into the aircraft. People and equipment inside remain safe.
Arresters on the wing of an airplane
Also, all technical equipment of the aircraft is equipped with additional protection against electrical discharges. A lightning strike occurs on the nose of the aircraft, the discharge moves towards the wings and tail. Passengers and crew may hear a loud sound during an impact, but this does not always happen.
Interesting fact : before the aircraft is put into operation, it undergoes a thorough check. One of its stages is the simulation of a lightning strike.
What is lightning
Lightning is a sparking electrical discharge in the atmosphere.
An electric discharge is the process of current flow in a 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, glow.
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.
How do you protect equipment from lightning?
You need to understand that there is no protection against direct lightning strikes on equipment. We are talking about lightning protection - this is special equipment that allows you to protect equipment from damage caused by thunderstorms. Lightning rods are also installed and equipment is protected from overvoltage.
Lightning protection
The main purpose of lightning protection is to protect equipment from static electricity. It has a certain protection indicator, designated as ESD Protection. This indicator is measured in kilovolts and is indicated as a numerical value.
Lightning protection standard is 15-20 kV. It is a diode bridge. When a voltage difference of 6 V or more is detected in the wires, a protective diode is triggered, which grounds the wires.
Interesting Facts
There are many interesting and shocking facts related to this natural phenomenon:
- only a quarter of the discharges reach the earth's surface;
- the chance of death from being struck by lightning is only 1 in 2 million, the same is the risk of dying from falling out of bed;
- the longest discharge was recorded in 2007 and its length was 321 km;
- the longest lightning flash lasted 7.74 seconds;
- Lightning causes about 10 thousand forest fires annually;
- on average, around the world, about 3 thousand people die from lightning strikes;
- the most common reason for a person to be struck by lightning is the fact of talking on a mobile phone during a thunderstorm;
- 70% of people struck by lightning survive. It is known that the American Roy Sullivan was hit by lightning seven times and after that he remained alive;
- The lifespan of ball lightning is 10 seconds, and the probability of seeing it at least once in your life is comparable to 1:10000;
- A similar phenomenon is observed not only in the earth’s atmosphere. Thunderstorms and flares also occur on Jupiter, Saturn, Uranus and Venus.
Understanding how lightning is formed in thunderclouds and what it is will help you treat this phenomenon without neglect. If you behave incorrectly during a thunderstorm, lightning poses a direct danger to human health and life. Therefore, it is important not to forget to turn off your mobile phone in time and try to find suitable shelter during the storm.
History of the study
People have been able to observe lightning since ancient times, but for a long time there was no explanation for this phenomenon. Initially, it was believed that flashes in the sky were the result of the activities of the gods. Even ancient Greek philosophers noticed that lightning strikes tall objects.
Mariners made a significant contribution to the study of lightning. On the open sea, electrical discharges turned out to be even more powerful. The connection between lightning and electricity was put forward in the 17th and 18th centuries, during the development of physics.
Lightning in the sea
Benjamin Franklin described this hypothesis in most detail in his studies. In 1750, he presented a scientific work in which the now famous experiment to determine the electrical nature of lightning was described.
The essence of the experiment was to fly a kite during a thunderstorm. At the same time, a copper rod was attached to the kite, and a metal key was attached to the cable. The purpose of the experiment is to prove the electrical nature of lightning.
The Benjamin Franklin Experience, illustration
To confirm the hypothesis, lightning must strike the kite, travel along the cable and leave a mark on the key. Franklin carried out the experiment in June, taking care of the lightning rod. It is worth saying that it was successful and confirmed all the physicist’s guesses.
In the 20th century, scientists discovered unusual types of lightning (sprites, jets, elves) that occur in the upper atmosphere. Currently, lightning research is carried out using satellites.
