The reason why we see lightning first and then hear thunder in thunderstorm weather.

In thunderstorm weather, we first see lightning and then hear thunder, because light travels much faster than sound.

Thunderstorms often occur in summer, and when it rains, lightning and thunder are earth-shattering. We know that when the electric field between the positive and negative charge areas in a thunderstorm cloud is large enough, the two charges will be neutralized to generate sparks, and strong light will be generated during the spark discharge, which is lightning.

In thunderstorm clouds, lightning and thunder occur at the same time. During lightning, the temperature in the convective cloud can reach about 1000℃, the gas will expand rapidly, the cloud droplets and rainwater will vaporize rapidly, and then cool rapidly after lightning. When the air vibrates strongly, it will produce huge thunder. People always see lightning first and then hear thunder, because light travels much faster than sound.

According to the propagation speed, the propagation speed of sound in the air is 340 meters per second; Light waves travel in the air at a speed of 300,000 kilometers per second. It can be seen that the propagation speed of light wave in air is much faster than that of sound. So we see lightning first, and then we hear thunder. Sometimes the thunder drags on for a long time, which is caused by the thunder reflected back and forth from clouds, peaks and ground.

Similarities and differences between sound and light;

Sound and light are waves, that is, waves. They all have the characteristics of waves, such as refraction, reflection, diffraction, interference, polarization, Doppler effect, standing wave, * * * vibration and so on. In addition, the mathematical expression describing wave function has many similarities with the research method of wave. This is the similarity between the two.

The difference between them is that sound is mechanical wave, which needs vibration source and medium. Sound is the propagation of mechanical vibration in the medium. The frequency of sound is related to the vibration source, and the wave speed of sound is related to the medium. When the sound source stops vibrating, the sound stops propagating, and there will be no sound in the vacuum.

Light wave is an electromagnetic wave, and its frequency is a changing magnetic field excited by a changing electric field, which excites the changing electric field to propagate in space.