Sét là một hiện tượng thiên nhiên, được hình thành trong những điều kiện khí tượng nhất định nào đó. Khi có sự phân chia điện tích trong các đám mây, những ion dương gặp ion âm sẽ tạo ra tia sét, truyền trong không khí hoặc đẩy xuống đất, gây nên hiện tượng sét đánh.
Lightning is a very dangerous problem for property and human life. Currently, humans have not found a way to prevent electrical discharges in the atmosphere between clouds and between clouds and land, but have found ways to avoid the effects caused by lightning.
With a safe lightning protection system for buildings or structures, people will feel secure when lightning strikes. Many companies have also applied and launched lightning protection systems and solutions to improve people's lives. However, the important issue is how to build the most effective and safe lightning protection system?
Lightning does not go in a certain direction. Sometimes the flash precedes the lightning (the speed of light is always faster than the speed of sound) in one place, but when the lightning strikes again in another place. Therefore, it is necessary to take timely measures to avoid lightning and its harmful effects.
Trước hết, khi nghe dự báo thời tiết có mưa hay giông bão, cần lên kế hoạch để đề phòng sét. Tại khu vực làm việc, cần để ý trước các nơi có thể trú mưa và tránh sét an toàn; đồng thời phải tính được thời gian từ chỗ làm việc đến nơi an toàn.
Usually, a thunderstorm comes very quickly, within 15 minutes, and moves at a speed of 40 km/h. Therefore, if you are in an unsafe place, it is necessary to pay attention to the signs of thunderstorms such as dark clouds, cold air, and wind.
Next, it is necessary to apply the rule of sight and hearing. When lightning occurs, first we see a flash of lightning, and then there is a thunderclap. If you calculate the time from the moment the lightning flashes until the thunder is heard, divide that number of seconds by 3, you can determine the distance to the place where the lightning occurred.
For example, counting 3 seconds, lightning is 3 divided by 1 km from the standing position. Remember, if the time between seeing lightning and hearing thunder is less than 30 seconds, it means we are already in the "sight" of lightning and must be careful. If this time is less than 20 seconds, move to a safer place. Always pay attention to the danger of hearing the first thunderclap, as lightning can strike 15-20km away from where it rains.
