Lightning and thunder come at the same time, so why do we see lightning first and then hear thunder? On this question, perhaps many people know that the reason is that light is faster than sound, but why is light faster than sound? Let's start at the beginning.
Our most common is the discharge in the cloud, which generally occurs in the troposphere, that is, from the surface upwards, up to about 11 km or so, and the hot spots in the troposphere are, the higher the height, the lower the temperature.
The cause of lightning is not fully understood, and the most widely accepted claim is as follows:
Cumulonimbus clouds are the hotbed of lightning, Cumulonimbus clouds generally reach a height of more than 10,000 meters, we know that the tropospheric high altitude temperature is very low, in fact, ice crystals above 5 km will form. When the raindrops in the Cumulonimbus cloud are frozen, the positively charged ions will be concentrated in the cold places inside the raindrops, and the negatively charged ions will be concentrated in the warmer places in the raindrops, which is a situation that has been confirmed by the experiment.
Therefore, the raindrops are colder on the outside and positively charged, and the raindrops are warmer and negatively charged inside.
As the raindrops further freeze into ice crystals, they eventually crack, at which point the positively charged shell on the outside of the raindrops breaks into fragments and moves upwards as the air currents move upwards, while the heavier raindrop cores carry negative electricity to the bottom of the cloud.
When the difference in charge within the cloud accumulates to about millions or even hundreds of millions of volts, discharge occurs between clouds, between clouds, and between clouds. It's as if a capacitor is broken down because the voltage is too high.
The breakdown instantaneously produces lightning, the air around the lightning is heated to about 33,000 degrees Celsius in less than 1 second, and the air is rapidly heated, producing an explosive expansion of the air, which in turn produces sound waves, which is thunder.
It can be seen that thunder and lightning are produced at the same time.
Thunder and lightning are essentially sound and light, and the propagation speed of light (lightning) is much greater than the propagation speed of sound (thunder). Specifically, the speed of light is about 300,000 kilometers per second, and the speed of sound is about 343 meters per second, that is, light is roughly 1 million times faster than sound.
If light and sound race, circling the earth at the same time, it only takes about 0.134 seconds for light, while for sound, it takes about 32 hours.
With this feature, we can simply estimate how far lightning is from us.
If the lightning is 1000 meters away from the person, when the person sees the lightning, it will take about 3 seconds before the thunder is heard. As soon as you see the lightning, you immediately silently count the seconds in your heart, and then the corresponding distance for one second is about 333 meters, and after calculating the results, the students who are afraid of thunder may be able to rest assured.
Light is 1 million times faster than sound, generally "100,000 Whys" explained here, it stops, if this reason is taken as a problem, is there a deeper principle behind it?
Light waves are electromagnetic waves, while sound is mechanical waves. The difference between these two waves determines the difference in their propagation speed.
First of all, electromagnetic waves, light waves as electromagnetic waves with wavelengths between 380 and 800 nanometers, are themselves high-frequency electromagnetic fields radiated from atoms and molecules, this process belongs to nuclear reactions, with extremely high energy, so it does not need a medium to propagate.
Sound, as a mechanical wave, is essentially generated by the vibration of an object, similar to dominoes, so it must rely on the medium to propagate. Once there is no medium, such as when people go into space, sound cannot be heard.
Light waves rely on electromagnetic fields to propagate, and the generation of light waves requires extremely high energy, in contrast, the vibration energy of objects is much lower, and it is also inseparable from the medium, the above difference makes light faster than sound speed.
Back to the question: Why see lightning first and then hear thunder? Do you have a deeper understanding?
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