When there is a thunderstorm, people will hear thunder. Do you know why it thundered

In thunderstorm weather, people will hear thunder and know that friction will thunder. Junior high school physics involves this problem. For example, when track and field athletes start together, there are always different points to reach the finish line. We remove the different speeds of athletes, that is, the differences in speed. Similarly, when it rains, lightning and thunder occur at the same time, but the speed of light is much faster than the speed of sound. In vacuum, the speed of light is 3× 108 m/s, while in air, it is slightly smaller, which can also be approximately considered as 3×108m/s. This speed is equivalent to seven and a half times around the equator in one second, while the speed of sound in air is usually 340m/s. When you see lightning, start timing and measure the time.

By using the formula S=V, you can estimate the distance to lightning. Similarly, after firing, you can estimate the distance from the firing point to the explosion point by recording the time between the flash and the explosion. But this method doesn't work in space. You may have seen the science fiction of the Earth Guard fighting against alien invaders in space. When the spaceship was hit and exploded, it was a fantasy to see the flash first and then hear the explosion. Because the propagation of light does not need a medium, and the propagation of sound does need a medium, and vacuum cannot spread sound, so if it really explodes in space, you can only see the flash, but you can't hear the sound of explosion.

As we all know, astronauts on the moon must have face-to-face conversations by radio, because there is no air on the moon and human voices cannot spread. So in a thunderstorm, thunder and lightning happen at the same time. But because light travels very fast. The propagation speed of light in air is slower than that in vacuum, but it is nearly 30 km/s faster. The speed of sound is much slower. The speed at which sound travels in the air is 340 meters per second. Therefore, even if it thunders far away, the light of lightning will reach our eyes in an instant, and we won't feel the time it takes. Thunder travels much slower and takes a long time to reach our ears from a distance.

We can judge how far thunder is from us by the time difference between lightning and thunder. If we see lightning and hear thunder rumbling five seconds later, the lightning is about 1, 700 meters away. Pay special attention to the discharge phenomenon in the atmosphere when it thunders. Lightning is very dangerous. Don't stay outdoors when it thunders in summer Don't hide under the tree, lest you be struck by lightning.