Why does lightning flash and thunder roar? Why is there thunder? The formation of a thundercloud, the appearance of sound, explain why thunder rumbles and lightning flashes.
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 is accompanied by incredibly high temperatures, so the air around it also becomes 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.
Why does thunder not thunder at the same time as lightning?
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 is 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. The heated air is compressed, and its atmospheric pressure increases significantly and becomes from 10 to 100 times higher 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 is an electric 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 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 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 a rather dangerous natural phenomenon, and it is better to stay away from it. 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. Do not use the telephone, as lightning may strike external telephone lines. Do not turn on electrical equipment, computers, or 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.
A thunderstorm is an atmospheric phenomenon, although not as rare as, for example, the northern lights or the lights of St. Elmo, but no less bright and impressive with its indomitable strength and primordial power. It is not for nothing that all romantic poets and prose writers love to describe it in their works, and professional revolutionaries see in a thunderstorm a symbol of popular unrest and serious social upheaval. From a scientific point of view, a thunderstorm is torrential rain, accompanied by squalls of wind, lightning and thunder. But, if you probably already understand everything about the rain and wind, then it’s worth talking about the other components of the thunderstorm in a little more detail.
What is thunder and lightning
Lightning is the name given to powerful electrical discharges in the atmosphere, which can occur both between individual cumulus clouds and between rain clouds and the ground. Lightning is a kind of giant electric arc, the average length of which is 2.5 - 3 kilometers. The incredible power of lightning is evidenced by the fact that the current in the discharge reaches tens of thousands of amperes, and the voltage reaches several million volts. Considering that such fantastic power is released within a few milliseconds, a lightning discharge can well be called a kind of electrical explosion of incredible power. It is clear that such a detonation inevitably causes the appearance of a shock wave, which then degenerates into a sound wave and decays as it propagates in the air. Thus it becomes obvious what thunder is.
Thunder is a sound vibration that occurs in the atmosphere under the influence of a shock wave caused by a powerful electrical discharge. Considering that the air in the lightning channel instantly heats up to a temperature of about 20 thousand degrees, which exceeds the temperature of the surface of the Sun, such a discharge is inevitably accompanied by a deafening roar, like any other very powerful explosion. But lightning lasts less than a second, and we hear thunder in long peals. Why does this happen, why does thunder roar? Scientists who study atmospheric phenomena have an answer to this question.
Why do we hear thunder?
Thunderclaps arise in the atmosphere due to the fact that lightning, as we have already said, has a very long length and therefore the sound from its different parts does not reach our ear at the same time, although we see the light flash itself entirely at one moment. In addition, the occurrence of thunderclaps is facilitated by the reflection of sound waves from clouds and the surface of the earth, as well as their refraction and dispersion.
Thunder is the sound of lightning piercing the air. When the first lightning bolt hits the ground, it carries an electrical charge. A spark charge bursts out of the ground towards her. When they are connected, a current begins to rise to the cloud, gaining strength up to 20,000 amperes. And the temperature of the channel through which the current is directed can become higher than 250,000 C. From such a high temperature, air molecules fly apart, and the air itself expands at supersonic speed and forms shock waves. The deafening roar generated by such waves is called thunder ohm Due to the fact that the speed of light significantly exceeds the speed of sound, lightning is immediately visible, and thunder heard much later. Rumbles thunder but occur due to the fact that the sound comes from different parts of the lightning, which has a significant length. In addition, the discharge itself does not occur in an instant, but continues for a certain time. The resulting sound can echo off surrounding objects such as mountains, buildings and clouds. Therefore, people hear not one sound, but several echoes catching up with each other, thunder the bone of which can exceed 100 decibels. To approximately calculate at what distance lightning struck, you need to note the number of seconds that passed between the flash and the strike thunder A. And then divide the resulting number by three. By comparing such calculations, one can also conclude whether a thunderstorm is approaching or, conversely, moving away. Usually, thunder New rumbles can be heard at a distance of 15 to 20 kilometers from the lightning flash.
No matter how much science explains the essence of atmospheric electricity, people still flinch when lightning strikes and involuntarily shrink in anticipation of the clap of thunder. Obviously, in most people the memory of distant ancestors speaks, trying to find at least some kind of protection from heavenly fire.
There is, of course, nothing supernatural in atmospheric electricity, but this does not make lightning and the subsequent peals of thunder look any less impressive and menacing. So what exactly is lightning?
As you know from a school physics course, all objects have a very definite electric charge. The collision of charged particles with each other leads to the creation of large areas of positive and negative charges. When such areas are close enough to each other, a breakdown occurs and charged particles rush into the created channel. People perceive this breakdown as a lightning strike.
If it’s more or less clear with lightning, then why is it followed by a terrifying roar, reminiscent of artillery cannonade? After all, the same physics convinces people that electric current cannot be seen, heard or otherwise detected, with the exception of special devices.
As it turns out, the whole point is in the air, or rather, in its properties. The fact is that, being, in fact, an insulator, at the moment of breakdown it heats up to a temperature of about 30,000°C. Moreover, the rate of heating and, accordingly, expansion of the air environment expands explosively, which leads to the appearance of a shock wave, which the human ear perceives as roar or thunder.
Therefore, lightning and thunder are inseparable, since thunder is the result of lightning. The talk that there is supposedly lightning without thunder and vice versa is groundless.
On the other hand, there are quite a lot of inexplicable things associated with lightning and their manifestations. Such types of lightning as linear, cord, rope, tape are quite well known and relatively well studied. In turn, they are united and branched. The most mysterious and so far unexplored lightning is ball lightning. It is associated with the largest number of oddities and mysteries, both documented and unproven.
It has been repeatedly noted by many eyewitnesses that lightning flickers. The fact is that lightning consists of many successive discharges lasting only a few tens of millionths of a second. This creates the flickering effect.
Lightning discharges occur between individual thunderclouds, between a cloud and the ground, and sometimes, for unknown reasons, the discharge goes vertically into the sky.
As for lightning emanating from clouds to the ground, there are two known types: positive and negative. Moreover, according to scientists, it is positive discharges, as they are more powerful, that lead to fires.
Of course, everyone knows such an atmospheric phenomenon as a thunderstorm. Every day at least one and a half thousand thunderstorms occur on Earth. Most of them are observed over continents; there are much fewer of them over oceans. Maximum thunderstorm activity can be observed over the territory of Central Africa. Over the Arctic and Antarctic this phenomenon is practically absent.
Thunderstorm is one of the most dangerous natural phenomena. Few people know, but the number of deaths that occurred during thunderstorms can only be compared with floods. Electrical discharges - lightning - occur inside a thundercloud or between the earth's surface and cumulus clouds, which are accompanied by peals of thunder. Why does thunder boom during a thunderstorm? Many people are interested in this question, but before answering it, it is necessary to understand what thunder and lightning are. What is their nature, where do they arise from?
Storm
A thunderstorm is “launched” by the energy that occurs during air convection. Warmer air rises to the top; if the supply of moisture in the upper layers is sufficient, the preconditions for the formation of a thunderstorm arise. In the upper layers of the atmosphere, a difference in electrical charges arises between pieces of ice due to their rapid movement. High humidity, ice floes and warm air rising from the ground contribute to the formation of thunderclouds. Thunderstorms give rise to such a terrible phenomenon as tornadoes, which so often occur over the American continent. Tornadoes form under thunderclouds.
Lightning
Interesting fact: lightning doesn’t only happen on Earth. Astronomers have recorded lightning on Jupiter, Saturn, Venus and Uranus. The current strength in a lightning discharge ranges from 10 thousand to 100 thousand amperes, and the voltage can reach 50 million volts! Lightning reaches gigantic sizes - up to 20 kilometers. The temperature inside lightning can be five times higher than the temperature on the surface of the Sun.
The appearance of lightning in a thunderstorm is facilitated by the electrification of clouds. This happens because the thundercloud is very large. If the top of such a cloud is at an altitude of seven kilometers, then its lower edge can hang above the ground at an altitude of half a kilometer. At an altitude of 3-4 kilometers, the water freezes and turns into small pieces of ice, which are in constant motion from the rising warm currents of air rising from the ground.
Colliding with each other, the pieces of ice become electrified. Smaller ones are charged "positively", and larger ones - "negatively". Due to the difference in weight, small pieces of ice are at the top of a thundercloud, and large ones are at the bottom. It turns out that the top of the cloud is positively charged, and the bottom is negatively charged.
By approaching each other, differently charged areas create a plasma channel through which other charged particles rush. This is the lightning we see. Since all current flows along the path of least resistance, lightning appears zigzag.
Thunder
In ancient times, people were equally afraid of thunder and lightning. It is not for nothing that many peoples called the Supreme God the Thunderer. Any lightning strike is accompanied by thunder. In fact, thunder is vibrations in the air. Flying lightning creates strong pressure in front of it, this comes from strong heating. Then the air is compressed again. The sound wave is reflected repeatedly from the clouds, and at this moment thunderclaps occur.
By the way, by the time interval between a flash of lightning and thunder, you can determine the approximate distance to a thunderstorm. The speed of sound depends on the density of air; you can take its approximate value as 300 meters per second. Having done simple calculations, anyone will get the approximate distance to the raging elements. If the distance to the thunderstorm is very large (at least 20 kilometers), then the sounds of thunder will not reach a person’s ears.
During a thunderstorm, you should not hide under single trees. There is a very high probability that lightning will strike a tree. It is better to wait out the thunderstorm indoors with the windows closed. If this is not possible, then a thicket of forest is suitable for shelter.
A thunderstorm is a frightening phenomenon. No matter where we are. At home or on the street. It's still scary. The dazzling glare and the rolling roar are frightening. The sounds seem to be catching up with each other, now approaching, now moving away. In ancient times, people considered the heavenly roar to be the wrath of the gods. And lightning is a punishing sword. But we understand that there is a more earthly explanation for these phenomena. Why is there thunder? Why is he inseparable from lightning? Why does it rain during a thunderstorm?
How are thunderclouds formed?
There is water in the atmospheric air. In the form of steam. Under the influence of high air temperature, warm steam rises from the water surface of the earth. Warm air pushes it from below.
In the upper layers of the atmosphere the temperature is lower. The higher the water vapor rises, the colder it becomes around it. Accordingly, it cools down.
There are more than just gases and water in the atmosphere. There is also dust. Cooled steam condenses around its smallest particles. Small water droplets and pieces of ice turn into clouds. They are different. In the form of feathers or huge heaps, white stripes on the heavenly slope or torn rags.
Thunderclouds are formed due to the collision of air masses. Then many, many water crystals collect in the upper part. It turns out to be a kind of white dense veil. It illuminates the entire cloud with cold, which takes on a rich leaden shade. That’s why we call such clouds “lead,” “heavy.”
Spawn of Thunder and Lightning
Thunderclouds give birth to Bliskawitz. And lightning, in turn, is a heavenly roar. How does this happen? Why is there thunder?
1. Droplets and pieces of ice at the top of a thundercloud interact with air molecules and become charged with electricity. When they get heavy, they fall down. So the lower part of the cloud becomes negatively charged.
2. At the same time, a positive charge accumulates at the top of the cloud. And plus and minus attract.
3. Under the influence of the attraction of positive and negative, tension arises. Taking into account the size of the cloud (up to ten kilometers wide), this voltage reaches hundreds of millions of volts. This is how lightning is born.
4. A spark that appears from a cloud follows to the ground. Her temperature is enormous - more than twenty degrees. As a result of the rapid movement of the fiery arrow, great pressure is created in the atmosphere. And immediately behind it, the air sharply compresses, returning to its original state. The result is an explosive sound. This is how thunder is born.
FAQ:
Why do we first see lightning and then hear the sound of thunder?
Because the speed of light is hundreds of millions of times faster than the speed of sound.
Why do we hear thunder?
Because sound waves encounter various obstacles on their way (clouds, earth) and are reflected from them. This happens many times. Hence the rolling thunder sounds.
Sometimes we see bliskavitsa, but do not hear the thunder. Why?
The thunderstorm is too far from us, more than twenty kilometers.
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 is accompanied by incredibly high temperatures, so the air around it also becomes 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.
Why does thunder not thunder at the same time as lightning?
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 is 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. The heated air is compressed, and its atmospheric pressure increases significantly and becomes from 10 to 100 times higher 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 is an electric 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 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 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 a rather dangerous natural phenomenon, and it is better to stay away from it. 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. Do not use the telephone, as lightning may strike external telephone lines. Do not turn on electrical equipment, computers, or 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.
The long-awaited retreat of the heat is accompanied by strong thunderstorms. St. Petersburg has experienced two severe thunderstorms over the past week. The sight was terrible. It seemed that the sky was cracking and tearing into pieces, flashes of lightning resembled explosions.
Why does such a thunderstorm arise, how does it originate in the atmosphere? Such questions come to mind precisely in this stormy time. Let's try to figure it out based on competent sources. How will you see that temperature plays a vital role here.
Where do thunderstorms most often occur?
Over continents in the tropics. There are an order of magnitude fewer thunderstorms over the ocean. One of the reasons for this asymmetry is intense convection in continental areas, where land is effectively heated by solar radiation. The rapid rise of heated air contributes to the formation of powerful convective vertical clouds, in the upper part of which the temperature is below - 40°C. As a result, particles of ice, snow pellets, and hail are formed, the interaction of which against the background of a rapid upward flow leads to the separation of charges.
Approximately 78% of all lightning is recorded between 30°S latitude. and 30°N. The maximum average density of the number of outbreaks per unit of Earth's surface is observed in Africa (Rwanda). The entire Congo River basin, with an area of about 3 million km2, regularly demonstrates the greatest lightning activity.
How is a thundercloud charged?
This is the most interesting question in “thunderstorm science”. The thunderclouds are huge. In order for an electric field comparable in magnitude to the breakdown field to arise on a scale of several kilometers (approximately 30 kV/cm for air under normal conditions), it is necessary that the random exchange of charges during collisions of cloud solid or liquid particles lead to a coordinated, collective effect of adding microcurrents into macroscopic current of very large magnitude (several amperes). As shown by measurements of the electric field on the surface of the earth, as well as inside the cloud environment (on cylinders, airplanes and rockets), in a typical thundercloud the “main” negative charge - on average several tens of coulombs - occupies the altitude range corresponding to temperatures from 10 to 25 ° C. The “main” positive charge is also several tens of coulombs, but is located above the main negative charge, so most of the cloud-to-ground lightning discharges give the ground a negative charge. However, a smaller (10 C) positive charge is also often found in the lower part of the cloud.
To explain the above-described (tripole) structure of the field and charge in a thundercloud, many charge separation mechanisms are considered. They depend, first of all, on factors such as temperature and phase composition of the medium. Despite the abundance of various microphysical mechanisms of electrification, many authors now consider the main non-inductive exchange of charges during collisions of small (with sizes from a few to tens of micrometers) ice crystals and snow grain particles. In laboratory experiments, it was established that there is a characteristic temperature value at which the sign of the charge changes, the so-called. reversal point, usually between 15 and 20°C. It is this feature that has made this mechanism so popular, since taking into account the typical temperature profile in the cloud, it explains the tripole structure of the charge density distribution.
Recent experiments have shown that many thunderclouds have even more complex space charge structures (up to six layers). Updrafts in such clouds may be weak, but the electric field has a stable multilayer structure. Near the zero isotherm (0 °C), fairly narrow (several hundred meters thick) and stable layers of space charge are formed here, which are largely responsible for high lightning activity. The question of the mechanism and patterns of formation of a layer of positive charge in the vicinity of the zero isotherm remains debatable. The model developed at IAP, based on the mechanism of charge separation during the melting of ice particles, confirms the formation of a layer of positive charge during the melting of ice particles near the zero isotherm at an altitude of about 4 km. Calculations showed that within 10 minutes a field structure with a maximum of about 50 kV/m is formed.
How does lightning strike?
There are several theories. Recently, a new lightning scenario related to the cloud reaching a regime of self-organized criticality was proposed and studied. In the model of electric cells (with a characteristic size of ~1-30 m) with a potential randomly growing in space and time, a separate small-scale breakdown between a pair of cells can cause an “epidemic” of intra-cloud micro-discharges - a stochastic process of fractal “metallization” of the intra-cloud environment is played out, i.e. rapid transition of the cloud environment into a state resembling a volumetric web of dynamic conducting threads, against the background of which a lightning channel visible to the eye is formed - a conducting plasma channel through which the main electrical charge is transferred
According to some ideas, the discharge is initiated by high-energy cosmic rays, which trigger a process called runaway electron breakdown. It is interesting that the presence of a cellular structure of the electric field in a thundercloud turns out to be essential for the process of accelerating electrons to relativistic energies. Randomly oriented electric cells, along with acceleration, sharply increase the lifetime of relativistic electrons in the cloud due to the diffusion nature of their trajectories. This makes it possible to explain the significant duration of bursts of X-ray and gamma radiation and the nature of their relationship with lightning flashes. The role of cosmic rays for atmospheric electricity should be clarified by experiments to study their correlation with thunderstorm phenomena. Such experiments are currently being conducted at the Tien Shan high-altitude scientific station of the Physical Institute of the Russian Academy of Sciences and at the Baksan Neutrino Observatory of the Institute for Nuclear Research of the Russian Academy of Sciences.
Note also that discharge phenomena in the middle atmosphere, correlating with thunderstorm activity, received different names depending on the height above the Earth. These are sprites (the glow area extends from altitudes of 50-55 km to 85-90 km above the ground, and the duration of the flash ranges from units to tens of milliseconds), elves (altitudes - 70-90 km, duration less than 100 μs) and jets (discharges starting at the top of the cloud and sometimes spreading to mesospheric heights at a speed of about 100 km/s).
Lightning Temperature
In the literature you can find data that the temperature of the lightning channel during the main discharge can exceed 25,000 °C. Clear evidence that the temperature of lightning can reach 1700 ° C is found on rocky mountain peaks and in areas with strong thunderstorm activity: fulgurites (from the Latin fulgur - lightning strike) - quartz tubes sintered from a lightning strike, which can be of various bizarre shapes.
The photo shows a fulgurite found in 2006 in Arizona, USA (details on the website www.notjustrocks.com). The appearance of a glass tube is due to the fact that there is always air and moisture between the grains of sand. The electric current of lightning heats air and water vapor to enormous temperatures in a fraction of a second, causing an explosive increase in air pressure between grains of sand and its expansion. The expanding air forms a cylindrical cavity inside the molten sand. Subsequent rapid cooling fixes the fulgurite, a glass tube in the sand. Fulgurites, consisting of melted silica, usually appear as cone-shaped tubes as thick as a pencil or a finger. Their inner surface is smooth and melted, and the outer surface is formed by grains of sand and foreign inclusions adhering to the melted mass. The color of fulgurites depends on the mineral impurities in the sandy soil. Fulgurite is very fragile, and attempts to remove adhered sand often lead to its destruction. This especially applies to branched fulgurites formed in wet sand. The diameter of the tubular fulgurite is no more than a few centimeters, the length can reach several meters; fulgurite 5-6 meters long has been found.
The study of lightning and atmospheric electricity in general is a very interesting and important scientific area. Many scientific papers and popular articles have been published on this topic. A link to one of the most comprehensive review papers is provided at the end of our note.
In conclusion, I would like to note that lightning is a serious threat to human life. The defeat of a person or animal by lightning often occurs in open spaces since the electric current follows the shortest path “thundercloud-ground”. Often lightning strikes trees and transformer installations on the railway, causing them to catch fire. It is impossible to be struck by ordinary linear lightning inside a building, but there is an opinion that so-called ball lightning can penetrate through cracks and open windows. Normal lightning is dangerous for television and radio antennas located on the roofs of high-rise buildings, as well as for network equipment.
Thunderclouds are a huge mass of many drops of water. Air currents cause the clouds to move, and during this movement they become electrically charged. When this charge becomes too large, a discharge occurs. Lightning, which we see jumping between the sky and the earth, discharges the clouds, but at the same time the air heats up, resulting in an “explosion”. This explosion is accompanied by a loud sound, which is called thunder. However, Why does thunder not just sound like a single clap?, and long-term peals?
There is a simple explanation for this. Lightning can be several kilometers long, and we see it immediately and completely. Since the speed of light is much greater than the speed of sound, we hear thunder after a certain period of time and not immediately, but in waves, that is, peals.
Now it becomes clear why does thunder roar rumbles and thanks to this feature you can calculate how many kilometers away a thunderstorm is from you. To do this, you need to count the time between the lightning and the first clap of thunder. Every three seconds is equal to one kilometer, so you need to divide the calculated time by three, and the result will be exactly the distance at which lightning struck from you.
During a thunderstorm, it is best to stay at home, however, if it catches you on the street, then under no circumstances should you hide from it under a tree. As studies have shown, lightning strikes a tall, pointed object, which is why lightning rods are made long and sharp.