How lightning rods achieve lightning protection?

Lightning can be said to be a very common natural phenomenon in life. In order to avoid its harm to humans on the ground, lightning rods came into being, but do you know how lightning rods achieve lightning protection? What is the lightning protection principle of lightning rods? How much can a lightning rod protect? Why can a small "needle" solve the damage caused by lightning strikes?

How powerful is the lightning?

Thunder and lightning occur because the clouds form a discharge phenomenon to the earth. As the air temperature rises in the clouds, water vapor will condense into cloud clusters, and the upper and lower clouds will form convection. After the positive charge in the upper layer and the negative charge in the bottom layer are accumulated to a certain extent, a potential difference is formed, and then a violent discharge phenomenon occurs. The lightning discharge process will break down the air and form a discharge channel. Because the huge current passes through, the air heats up rapidly, causing the air volume to expand and explode. This is the sound of thunder. The most common form of lightning is linear lightning, which looks like tree roots criss-crossed in the sky. Do you know how powerful lightning is? There was a lightning accident in Georgia before. 550 sheep grazing on a hillside were killed instantly by a flash of lightning. Such a tragic scene left many netizens stunned. Although it sounds unbelievable, the power of thunder and lightning is actually so powerful, and even more than that. Because lightning is a discharge phenomenon between clouds and the earth, this kind of electricity is a kind of direct current, and the voltage is very high. It is said that when lightning is first discharged, the voltage is about 500 million volts. Generally, the power of a medium-strength lightning is equivalent to the output power of a small nuclear power plant.

How lightning rods achieve lightning protection?

With such a powerful lightning phenomenon, how does the lightning rod achieve lightning protection? When a thunderstorm occurs, the dotted clouds in the sky carry a lot of negative charges, which makes many tall buildings induce a lot of positive charges. As the highest point in the building, the lightning rod accumulates the largest number of positive charges, so the probability of it forming a path with the charged clouds is very high. And at the other end of the lightning rod, connect it to the ground, so that the current can be introduced into the ground at the moment of forming a path, so as to achieve the effect of lightning protection. Just like the lightning protection principle of lightning rods, in fact, it is not for lightning protection, on the contrary, it is "lightning". Therefore, in the published "Code for Design of Building Lightning Protection", the term "lightning rod" is no longer used and replaced. It's an air-termination pole.

How much can a lightning rod protect?

If you look closely, you will find that some buildings do not only have one lightning rod installed on the roof, but several. So what is the basis for this number? How much can a lightning rod protect? When architects calculate the number of lightning rods to be installed, there is a simple algorithm, that is, the rolling ball method, which means that a sphere with a certain radius is rolled on the roof surface. Where the sphere cannot touch, the lightning cannot damage it. Location, which is why the lightning rods we see are generally installed in the middle or around the roof of the building.

Lightning protection of the future

There are countless times of thunder and lightning phenomena every year around the world, some of which are enough to split the entire tree. If there are no lightning rods on the building, it is conceivable how many lightning and lightning will destroy the building in the world every year. Of course, in addition to destructiveness, lightning also has certain benefits. After all, it is a non-polluting energy source. Moreover, in thunder and lightning weather, a large amount of nitrogen and oxygen can be combined into nitrogen dioxide to dissolve in water and make it fall into the soil. Become fertile. After understanding how lightning rods achieve lightning protection, Chinese scientists will continue to research and develop lightning rods based on the lightning protection principle of lightning rods. Perhaps in the near future, our daily electricity consumption will also have lightning participation. , What do you think of this?

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