Recently, the owner of a cattle farm in Hainan has not had a good life. The sudden thunderstorm caused 42 cows he farmed to be killed by lightning strikes, and the loss of this wave was about 700,000, which can be said to be a cattle tragedy. However, judging from the scene, the terrain of the cattle farm is gentle, and there are no telephone poles and tall trees around, so there is little possibility of triggering and gathering strong electric currents. Under normal circumstances, lightning strikes down and hits at most one or two cows, so why did 42 cows die?
Herds are kept in captivity in the barn, unlike wild cattle, which can roam the mountains, they all gather in one place and are close to each other. When lightning strikes the first cow in the herd, the current will run to the second cow next to it, and then the third cow will also conduct electricity. This situation is like a well-arranged domino, as long as the first card is pushed, the back cards will also fall one by one. So in the photos of the scene of the incident, we can see that the dead cows are all gathered in an area, close to each other.
But not all dead cows are next to each other. There are also cattle that fall at a certain distance from the cattle. It is reasonable to say that if you are far away from the cattle, you will not be conducted, so why are these lonely cattle still dead? In addition to lightning, there is a natural phenomenon called ground current. What is the ground current?
If you think about it, is the probability that lightning strikes down from the sky and can hit a person accurately, is it similar to buying a lottery ticket and finding yourself winning the lottery? It's just that it's a reverse jackpot. The data also shows that only 3% to 5% of the people who are killed by lightning every year are directly hit by lightning. Therefore, everyone usually says that do not do things that lack virtue, you will be struck by lightning, after all, this kind of event with a very low probability is more like the tool used by the legendary thunder and lightning mother to accurately punish bad people. The remaining dead are actually dying of ground current.
Ground current, as the name suggests, is the current of lightning diffusion to the surface. When the lightning strikes down, it cannot penetrate the ground, but will be centered on the landing point, spreading out in a network along the surface of the ground, and can extend tens of meters as far as possible. As long as you are in the range of ground current, it is very dangerous, although the thunder does not fall on the human body accurately, but the ground is full of electricity, and the human body is a conductor, when the person stands on the ground, it may be conducted. From an early age, we are taught that when thunder strikes, we cannot hide under a big tree, because the trunk rooted in the ground will direct the current of the ground to the human body.
This is also because the resistance of both humans and animals is smaller than that of the earth. Therefore, when the ground current encounters people and animals, it will definitely choose a route with lower resistance and easier to walk. The ground current is mesh-like, and its voltage will gradually decrease as it radiates outward from the center. When a person stands on a mesh graph of ground currents, the voltage in the area where his two feet are located is also different. After he walks, with each step, the voltage he is subjected to changes, this thing is called step voltage. The farther away the two feet are, the greater the voltage gap generated, such as the left foot in the high voltage area, the right foot in the low voltage area, at this time, the voltage will exceed the human body's bearing limit.
Therefore, in thunderstorm weather, even if we want to walk, we can't take a big stride, we have to walk carefully. But domestic animals do not have this consciousness, and cattle and sheep are much larger than humans, and the strides will be larger. The stride current on them will be more violent, and if they don't take a few steps, they will be electrocuted. The 42 cattle in The Hainan cattle farm have died a lot, but this is not an exception, and tens of thousands of various livestock die every year from ground current and step voltage.
Although the situation of humans is different from that of animals, it does not mean that people will be fine if they take a small step in thunderstorms. It is not a last resort, and it is safest not to go out in thunderstorms. If you suddenly encounter a thunderstorm during the process of going out, you can hide in the car if you have the conditions. If there is no place to hide, find a place where there is no tall object that can detonate, do not stand straight, reduce the height of the body as much as possible, you can bend down or crouch down, and at the same time put your legs together to avoid dangerous stride currents.
Fortunately, in modern society, many buildings have installed lightning rods, people generally do not stay in the wilderness, and fewer and fewer people have died from lightning strikes. But we should still keep in mind these lightning protection knowledge, take precautions, and put our own life safety in mind.