What is the loudest sound of and in everyone’s impression? Some might say it’s the whistle of a ship, or the sound of a dance hall stereo, or the sound of firecrackers during the New Year.
"I'm afraid the New Year's Eve firecrackers are too noisy..."
This is indeed a loud sound that we can hear in our daily lives, but it is still far behind the limit of sound .
So, why is the maximum sound value
Do you really understand "sound"?
The generation and spread of sound
The generation of sound is caused by the vibration of objects . We can clearly see some vibrations, such as plucked strings, but some vibrations are very weak and difficult to observe. . But no matter what, once the vibration of the object stops, the sound will stop.
Of course, human hearing is not very powerful in nature. We can only hear sounds with frequencies between 20 and 20,000hz. . This frequency refers to the number of times an object vibrates in one second. However, no matter how fast the object vibrates, sound still needs medium to propagate , and the propagation speed is different in different media.
Sound propagation will also be affected by the medium
Generally speaking, the speed of restless waves is greater in solids than in liquids than in gases, but in a vacuum environment like the universe, sound cannot propagate .
So the signals people receive in the universe will definitely not be sounds. In other words, the entire universe is actually silent . Even the explosion of star death is a silent "fireworks show" ".
The broad and quiet universe
Fortunately, there is air everywhere on the earth. Air can be used as a medium for transmitting sound, allowing humans to hear sounds . Otherwise, imagine living in a silent environment, it must be very frustrating. Furthermore, sound is also important for communication.
In addition, sound has many characteristics such as loudness, pitch, timbre, etc. The maximum sound we are talking about today is 194 decibels, which actually refers to the loudness of the sound .
Sound loudness is a measure of how loud a sound is.
This loudness is often determined by the amplitude and the distance between the person and the sound source.. For example, if you stand next to a volcano crater and hear the sound produced by its eruption for tens of kilometers, There is a clear difference in the sounds heard outside.
So, why is there an upper limit of 194 decibels for sound? What will happen if the sound exceeds this upper limit?
The sound will become weaker and weaker during the propagation process.
The upper limit of the sound is 194 decibels.
We introduced above that the sound must rely on the medium to propagate, which leads to it having an extreme value. Because the more strongly the particles in the air vibrate, the higher the decibel value of the sound will be, but when it reaches the limit of 194 decibels, the energy will explode and form a "vacuum condition" .
As we all know, sound cannot propagate in a vacuum , so this is the upper limit of sound.
It seems that there is indeed an upper limit for sound
If you still can't understand it, you might as well consider it from the situation that air is compressed. Because air cannot be infinitely compressed by , so the decibel is with an upper limit.
But it should be noted that the 194 decibels mentioned here in refers to the maximum sound under standard atmospheric pressure. In other environments, the sound can reach greater decibels.
The standard atmospheric pressure is about 101.325kPa
Many people may say that regardless of the decibel limit, we should have never heard such a loud sound.In fact, it is normal for us to be curious about the sound of 194 decibels under the earth's standard atmospheric pressure, but our ears cannot bear such a sound, because when the decibel value of the sound is greater than
So I want to hear the sound of 194 decibels, should be deaf before hearing .
Sound decibel diagram
So, when the sound exceeds the limit of 194 decibels, what kind of terrifying thing will it become?
You can first recall the classic clip in "Kung Fu". When the charter woman performed the lion's roar skill, we saw the horror of the sound. When the sound in the air exceeds the energy limit, it will change from sound to shock wave .
Picture of the charterer performing the Lion's Roar Kung Fu
This kind of shock wave is mainly caused by the energy pushing the air outwards. In the process of pushing away, a vacuum part will be formed in the center part. Once the sound limit exceeds 194 decibels, this kind of shock wave will appear, , and there is gas compressed to the limit at the edge of the shock wave.
Imagine, when the gas is squeezed from a loose state into a very dense "solid"-like existence, sound waves become a weapon , and everything on the road it passes will be impacted. It is worth mentioning that the shock wave is not only as impactful as a newly sharpened knife, but also because the air is compressed to a certain extent, the molecules getting closer and closer rub more intensely, making the temperature of the shock wave also Improved .
Concept map of shock wave
Therefore, it is very easy for a shock wave that exceeds the limit to "kill". Moreover, the shock wave killing of sound also depends on the distance between and . If it is far away, it is fine, but if it is close, it may be "cut" and smashed directly.
For example, the atomic bomb dropped by the United States on Japan before. The huge shock wave generated after the explosion directly leveled the nearby places several kilometers away..
The ruins of Nagasaki, Japan
And after the volcanic eruption in Indonesia in the 19th century, the loudest sound ever detected by humans was produced.Not only did it directly blow up a nearby island, it even spread to More than 160 kilometers away, the loudness of the sound can still reach more than
It is reported that many residents living nearby at that time were injured by this powerful sound wave. This injury was not limited to eardrums and even the internal organs in the body were injured to varying degrees .
Concept map of the eruption of Tambora volcano in Indonesia
In addition, volcanic eruptions will also produce infrasound waves . Although this kind of infrasound wave with a frequency less than 20 Hz cannot be heard by humans, it is not easy to attenuate and absorb, so that can circle the earth several times is like an excellent "marathon runner".
Some people may say that it’s a good thing we can’t hear infrasound waves, otherwise we wouldn’t be disturbed to death by the “looping” infrasound waves.
Although infrasound waves cannot be heard, but infrasound waves of certain frequencies will resonate with human organs, and in severe cases, they can still cause death .
Infrasound waves of a certain intensity will stimulate the human nervous system
So, don’t underestimate the power of volcanic eruptions. In addition to the visible volcanic ash, the sound waves that can only be felt when you are close, and the infrasound waves that surround you from multiple angles. These are all It's the "invisible killer".
For example, the Tonga volcano erupted in early 2022. Eight and a half hours after the eruption, the Kunming infrasound array, 10,151 kilometers away from the volcano eruption location, recorded super strong infrasound signals, with a propagation speed of approximately
Tonga volcano eruption picture
It is worth mentioning that in addition to such natural disasters or man-made explosions that can make loud noises, many animals in nature also have the ability to "roar".
Loud animals
First of all, let’s talk about an animal that is small but has strong decibels, that is tiger gun shrimp .
But don’t get me wrong, this guy doesn’t make sounds with his mouth, but uses his claws to shoot water jets to create a bubble. When this bubble bursts, it can generate a shock wave greater than 200 decibels, killing certain creatures within 2 meters .
Tiger gun shrimp with its own "bullets"
The second one is Blue whale, which likes to sing in the sea . Sometimes their sound can even reach 188 decibels. If you happen to be next to a blue whale, you may be directly hit by it. The sound shattered.
Fortunately, whales only sing in the ocean. We who live on land do not often face "deafening".
The sound of the blue whale can be transmitted up to 1,600 kilometers away
Finally, there is the cicada that screams in the trees every summer. I believe that many people have cicadas chirping in the summer in their childhood memories.
Although everyone now says that it represents a memory, I still feel irritated by the harsh chirping of cicadas. According to scientists' observations, the sound of cicadas can sometimes reach more than 100 decibels , which is no less intense than when the speakers in KTV play music.
Male cicadas produce sounds through the vocal organs in their abdomen
In general, nature does have an open mind, and so many creatures with different characteristics live here together. Moreover, everyone seemed to be separated by some kind of "barrier" and generally did not disturb each other. And it seems that even the universe is aware of this, so it has turned the cosmic space into a vacuum, helping us to shield us from the loud noises made by stellar activities.
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-