2047? Youxin City? Livenstead College? Ripple and Acoustics Building? 107 Lecture Hall

In the large lecture hall with bright and clean windows, all kinds of teaching furnishings are in compliance with the regulations, and the teachers and students are in a relatively good mood. It seems that this is a lecture that will have very good feedback effects.

Professor: "Although Classmate Li Bo's previous question caused everyone to burst into laughter, in fact, thinking deeply, Classmate Li's question was very good. Of course he understood the naivety of this question, and it was precisely after Classmate Li's naivety that he thought about some micro aspects.

Small energy reflections.”

Professor: "Actually, I can't give a comprehensive answer to this question for Li, but I will report it to the association, or if there are the latest research results in the world, the teacher will tell the students immediately. That is, the propagation of sound must go through a medium.

So in the absence of a medium, can sound still propagate? Is it possible for it to propagate? Of course, the students immediately thought of vacuum. Extensive physics research shows that sound is still difficult to propagate in a vacuum.

, and what hinders their spread is not simply the absence of a medium.”

Professor: "This is actually what Li Bo just said. What blocks the sound has been isolated at the beginning. And what isolates it can be understood as no subsequent medium, or it can be understood as the energy feedback of the vacuum that does not allow the sound to be heard.

Sound can enter, and everyone understands that there is no place in the universe that is completely empty, but we still cannot understand the meaning of their existence."

In the lecture hall, a female student in the back row tried hard to raise her hand and wanted to ask a question. The honest and simple professor smiled and said, "What's the problem, Mr. Alvin?"

Alvin, the gentle-looking girl immediately stood up and asked excitedly: "Professor, professor, that is to say, most of the sounds we know do not have the power to enter the structure of some unknown energy bodies, like you said

, although vacuum does not exist as a medium, it itself also exists."

After listening to this question, the professor nodded with great satisfaction, then pressed his hand slightly to indicate that he should sit down, and then continued: "If the issues of existence and energy are brought to our class, although I, teacher, have also dabbled in it,

But some of them are too far, so I can only use them as examples to explain to you. But the question and summary of classmate Ai Wen are just right, that is, we think that all space and energy do not have any matter, but they are exactly the same.

The existence itself is an unchanging fact, and there must be a medium that can circulate, even if it is void, even if it is chaos."

Professor: "This goes back to Li Bo's question just now. According to the current teacher's answer, the sounds we know are not of sufficient quantity and quality to spread in unknown areas."

Professor: "Of course, this is just a temporary explanation based on my current knowledge. The specific reasons have to wait for the explanation of the general theory of physics by the World Physics Research Council. Don't worry yet."

Professor: "Okay, let's start today's lesson, which is the nature of sound and the chain reactions of other substances and media caused by pressure waves."

While the professor was speaking, he used the controller in his hand to open the spherical projection demonstration behind him, which contained various types of data analysis and preparations for the simulation state.

Students in the lecture hall can also use the computers on their desks to synchronize with the projection sphere on the podium.

The middle-aged professor who seemed to have won the trust of his classmates continued: "You can look at the podium or your own computer projector. When the sound is emitted, the sphere first represents air. I first set it to more normal air.

Then students can intuitively see the impact and vibration of sound in the air."

Professor: "Sound is a pressure wave, or the wave comes from an effective movement of the sound source that causes a chain reaction of the associated quantities. When playing a musical instrument, beating a reverberable physical substance or striking a physical plane unit, they

The vibration of the medium will cause it. A single example is the rhythmic vibration of air molecules, which causes the density of the surrounding air to change, forming longitudinal waves of alternating density and density, which generates sound waves. This phenomenon will continue until the vibration disappears. "

Professor: "Sound is a type of wave. Frequency and amplitude have become important attributes, or one of the attributes, to describe waves. Our current physics research can only define it in this way. The size of frequency is different from what we usually call

corresponds to the pitch, while the amplitude affects the size of the sound.”

Professor: "Look at my new demonstration. Sound can be decomposed into a superposition of sine waves of different frequencies and different intensities. This transformation or decomposition process is currently called Fourier transform. Therefore, general sounds always contain certain frequencies.

The range of sound frequencies that the human ear can hear is between 20 and 20,000 Hz. Waves above this range are called ultrasonic waves, while those below this range are currently called infrasound waves."

Professor: "Speaking of some animals in nature, such as dogs and bats, they can hear sounds up to 160,000 Hz. What is even more strange is that whales and elephants can produce sounds with frequencies in the 15 to 35 Hz range."

Professor: "From this, some smart students here will think that the use of sounds does not have to be very advanced or very low, it is enough to achieve their purpose or express their intention. Scientific research over the years has shown that the perception of different creatures in this world

There are different differences. Sound and smell are very obvious symbols, and we humans don’t know what it was like before. But so far, we can have deep research on sound and have very developed creations, but the human body must try its best to

May avoid harm from those unusual sounds.”

At this time, the particularly inquisitive classmate Li Bo raised his hand again. When the professor saw him, he smiled, reached out and pointed in his direction and said, "Go ahead, Classmate Li."

Li Bo immediately stood up happily: "Professor, what you are saying is that sound is widely used by living things, but it is stronger than all living things on the earth. We can only use it, right?"

Professor: "Yes, although it is currently unclear to what extent extraterrestrial civilizations have reached and whether they identify with our plane or space, the source of the sound is believed to be after the explosion at the core of the universe, and their existence is much further away based on current understanding.

Far beyond our space and all our knowledge.”

Professor: "Everyone knows clearly from the cosmic physics class that the greater the mass and the stronger the gravity of the planet, the slower their time will be, and the sound is erupting from the core into the endless void. Their huge volume and

The reactions involved are not something we can imagine. The sounds of the earth are only formed by its own movement, and we can use them just now, but whether they originate from the beginning of the universe remains to be verified."

Li Bo: "Professor, then the formation of our earth was naturally accompanied by sound."

Professor: "Of course, when there are physical vibrations and movements, ripples and fluctuations will naturally occur. While our creatures are infinitely adapting to the environment, we have learned to use these fluctuations to express the intentions in our thoughts, so that we or our companions can

To achieve the purpose of execution, the creature itself can also spontaneously instinct or imitate natural vocalizations."
Chapter completed!