Erroneously, many people tend to believe that lightning and lightning are the same thing, but for science, these are very different things. However, both are natural phenomena that have fascinated mankind almost always.
Differences between lightning and lightning
To begin, we must differentiate lightning from lightning. The lightning is briefly summarized as a electrostatic discharge in the atmosphere and occurs between two clouds or between a cloud and the surface. The lightning occurs when the difference in electrical potential between two points exceeds a limit of approximately 30.000 volts. That is when the dielectric breakdown of the air occurs, turning it into an electrical conductor and producing an electric shock in the form of lightning.
On the other hand, lightning is the glow resulting from this great discharge, which releases so much energy and so suddenly, that it forces a light manifestation. How exactly lightning is produced is a process that science does not quite understand at all and of which there are several explanations (not to mention the usual controversies).
How is lightning produced?
The explanations referred to do not refer to positive rays, since these are a more rare variety of the phenomenon, which occurs in the positively charged regions of the cloud. Now let's see the Electrostatic Induction Theory, the most accepted and recurring when explaining this phenomenon of nature.
This indicates that electrical charges are mobilized by processes that are still unknown. The separation of charges would require strong updrafts that would bring small drops of water up, cooling to temperatures between -10 and -20 degrees Celsius. These tiny drops collide with ice crystals to form a mixture of water and ice. The collisions also cause a slight positive charge to be transferred to the ice crystals and a slight negative charge to the mixture of ice and water.
So the updrafts bring the lighter ice crystals upward, causing the cloud to increase its positive charge. Gravity causes the mixture of ice and negatively charged water to fall in the middle and bottom of the cloud, creating a negative charge. The separation of charges and accumulation continue until the electric potential is sufficient to initiate an electric shock, which occurs when the distribution of positive and negative charges forms a sufficiently strong electric field.
This is the most accepted and verified theory, the absence of a complete explanation for the polarization mechanism being its main problem. An alternative explanation to the induction hypothesis is that water and ice drops naturally polarize as they fall through the Earth's electric field.
Lightning is one of the most powerful and devastating forces in the world, but in 80% of the cases that one impacts on a human being, it comes alive. Using satellite images, it has been estimated that every second some 44 rays worldwide.
How does lightning occur?
The prelude to a lightning bolt is the separation of electric charges in the cloud: the negative accumulates in the lower part, while the positive accumulates in the upper part. When the negative charge grows enough to overcome the electrical resistance of the air - which happens at about 18.000 volts -, a flow of electrons begins to descend from the cloud zigzagging towards the earth (lightning). The proximity of electrons causes positive charges to accumulate on the earth, which use any conductive object in the area to ascend: buildings, trees or people. And the deployment begins pyrotechnic, a kind of short to the beast. In less than a thousandth of a second, the current reaches about 10.000 to 200.000 amps. Although the actual flow of particles is descending, the point of contact between the cloud stream and the ground jet rises to 80.000 km / h. This kickback contributes with more electrons and heats the air to about 50.000ºC. Every meter of hot air in the lightning channel shines as much as a million 100-watt bulbs. This brightness of the counterattack ascending is the lightning, only that it seems to us as if it were descending.
And the thunder?
Thunder occurs when lightning instantly heats up 30.000 ° C the air through which it moves. This air, which is at a very hot temperature, increases in volume and expands at high speed. When you encounter a mass of cold air from the surroundings, its temperature drops sharply and contracts. These expansion and contraction movements generate shock waves that cause thunder noise.
Normally, the noise of thunder is usually heard a few seconds after seeing the lightning. Some argue that it is possible to determine the distance at which lightning strikes by counting the seconds between lightning and thunder, because light moves faster than sound. The speed of light is 300.000Km / s, while the speed of sound is 0.340Km / s.
However, some people say that the sound of thunder does not propagate through sound waves, but through shock waves, which move at a non-constant speed of 12-14 km / s, forty times greater than that of sound . This theory calls into question the effectiveness of this method to calculate the distance at which the rays fall.
The lightning produces explosive waves that propagate through the air and cause an initial click. When this sound is loud and sharp, it can be deduced that the lightning has occurred very close to us. On the contrary, when the ray has been given well before the sound perception, deaf discharges are heard that change intensity. This indicates that we are located at a greater distance from the discharge point.