home Auditorium 7 Interesting facts about sound physics. The most interesting facts about sound. Why does a person hear the sound of a sea wave in a shell?

Interesting facts about sound physics. The most interesting facts about sound. Why does a person hear the sound of a sea wave in a shell?

All of humanity’s ideas about sound are obtained by observing the surrounding world, nature and conducting experiments. In ancient times, primitive man, watching the leaves on a tree, saw how they swayed from the wind and rustled, making a sound when they interacted with each other. And if you knock on a tree with a stick you get one sound, but on another tree it sounds different.

Using stones you can get the same sounds, but different ones. Some sounds, such as the sound of a wave, were liked by primitive people, and some, such as thunder or the cry of an animal, were frightening. Now it is difficult to reliably state how everything happened and how much time it took for classification, but by observing young children it is easy to track how the process of cognition and assimilation of sounds occurs.

Sound and its perception is method of information transfer. Any sound causes a person to react. This happens unnoticed by the person himself if the sounds are familiar and constant. Some people, in order to increase attention, specifically concentrate on sound and analyze it, building logical chains and receiving more information.

A quiet, measured, ringing sound is quite pleasant and comfortable for a person, but a low hum causes anxiety. High notes in a person's voice or in a song attract attention, but are not so pleasant to listen to. It has been scientifically determined that sound is measured in decibels and arises from any movement of any objects, organisms and particles in airspace or any other environment.

A person perceives, catches and hears some sounds, while others cannot be recognized and perceived, and therefore cannot be heard. This determines the range, that is, the area of human perception. This value is approximately in the middle of the scale of all existing sounds known on the planet. Infrared sounds are considered the lowest, and ultrasound is considered the highest. Conducting experiments with sound, humanity has identified unusual and interesting facts, namely:

The main function of sound waves - to propagate in any environment except vacuum, and to bounce off obstacles - is actively used by humanity as echolocation. A lot of instruments for determining distance, density and even color are based precisely on this principle. All animals use sound waves in the ultrasonic range to one degree or another, even fish. In bats, dolphins, and butterflies, this phenomenon is simply vital and allows them to navigate the world around them.

Interesting facts about waves.

Waves are mainly formed by the wind blowing over water. The size of the waves depends on the strength of the wind, how long it blows, and the distance the wind blows. Strong winds blowing over long water surfaces generate large waves.

Waves are formed when the wind pushes water on the surface in front of it, and gravity forces the water to stay in place, as if pushing it back. Under the influence of these two forces, the waves move up and down. (The tops of the waves are called crests, and the bases are called troughs.)

Rippling water, although it looks like it is moving, in fact, other than moving up and down, it doesn't really move much. The drops that make up the wave, driven by wind energy, move as if in a circle, and the top of such a circle is the crest of the wave.

A seagull sitting on a wave will rise and fall with the wave, but will not move forward towards the shore.

However, when waves reach the coastline, their movement is affected by the shallow ocean floor, and in such cases the waves are said to "break" on the shore. Here the water moves forward with a certain force, rolling onto the shore or hitting the rocks. Wave crests that break into white foam are called whitecaps.

In general, waves on the surface of water, be it the sea or the ocean, are formed for various reasons. The most common waves on the surface of the sea are wind and tidal waves. Wind ones are formed under the influence of wind already from 0.7 m/sec. onto the surface of the water, creating ripples 3-4 mm high and 45-50 mm long.

The wind movement near the surface of the water is not stable, so the air breaks up into separate horizontal vortices, which in turn create pulsating pressure above the water, leading to the formation of capillary waves.

The stronger and longer the impact of the wind, the faster the transition from a capillary wave to a gravity wave will occur. But under the influence of the attraction of the Moon and the Sun, tidal waves arise.

During a storm, waves exert pressure from 3 to 30 thousand kilograms per 1 square centimeter. Surf waves sometimes throw rock fragments weighing up to 13 tons to a height of 20 meters.

Along the western coast of France alone, the energy of one wave impact corresponds to a power of 75 million kilowatts. Scientists are thinking about how to subordinate this power to man. In France, it is planned to build a giant tidal hydroelectric power station with a dam 18 kilometers long. The capacity of this power plant is expected to be increased to 12 million kilowatts.

Interestingly, as a result of the construction of a tidal hydroelectric power station, it is believed that the Earth will slow down its rotation on its axis by one day every 2 thousand years.

It is curious that at great depths in the ocean waves up to 100 meters high occur, but on the surface of the water these waves are invisible.

The highest tsunamis (the Japanese name for huge sea waves that accompany coastal earthquakes or earthquakes somewhere in the open ocean) are observed in the Pacific Ocean.

Their height reaches 30 meters. Tsunamis penetrate about a kilometer deep into the coast. The Japanese, Aleutian, Hawaiian, Philippine, Kuril Islands and partly Kamchatka are susceptible to their invasion.

There are interesting facts about sound as a physical phenomenon perceived by humans through the organs of hearing.

Sounds for humans contain important information received from the surrounding world. In medicine, for example, it is widely used.

Interesting facts about sound do not reach modern people, remaining somewhere on the pages of school textbooks and children's encyclopedias.

One of the most interesting topics in physics is the properties and capabilities of sound waves.

Facts about the properties and capabilities of sound waves

For example, here is an interesting fact: we are accustomed to thinking that deaf people are those who do not hear sounds. But everything is not quite like that; the deaf perceive them quite well and may even have an ear for music. An example of this is the famous great composer, Beethoven, who used a simple invention to recognize sound.

Ludwig van Beethoven

It is known that the great composer, who wrote more than 240 works, of which nine completed symphonies, five piano concertos and 18 string quartets, lost his hearing at the age of 45. So, after 45 years, Beethoven put the end of a stick to the piano, while taking the other end in his teeth. Thus, the sound was transmitted by vibration through the bone balls of the teeth and skull and reached the innermost ear, which was healthy.

For a similar experiment, you can take a mechanical wristwatch between your teeth and cover your ears. The ticking of the clock will turn into loud blows, so strong will it seem. It's amazing that practically deaf and completely deaf people can talk on the phone using vibration detection. They press the tube not to the concha of the ear, but to the temporal bone. People with hearing impairments can also be excellent dancers, since vibrations penetrate into the inner ear not only through the shell, but also through all the bones of the skeleton, to the feet through the floor.

Fun fact with infrasound

The topic of infrasound waves contains many interesting facts. Infrasound refers to vibrations lower than a frequency of 16 Hz. These waves are perfectly transmitted through water, so many marine animals communicate with their help, perfectly navigating at low depths and wide expanses of water. Infrasound can even travel hundreds of kilometers. Scientists are passionately conducting research on the influence of infrasound on humans.

There is a very famous case in history related to infrasound.

Robert Wood

Once in the nineteenth century, a play about the Middle Ages was staged in some theater, and therefore the then famous physicist R. Wood (1868-1955) received an order for a huge organ pipe, about forty meters long. Such a long pipe was needed to produce very low sounds, almost imperceptible to the human ear. The sound wave in a forty-meter pipe is approximately 8 Hz.

But during the performance, an embarrassment occurred: the infrasound that the instrument produced was not audible, but at the same time it began to echo the alpha waves of brain activity, and it worked. Few people knew then that this alpha rhythm, created artificially, would have such an effect on people: the audience began to panic and they all ran away without even finishing watching the performance.

More bizarre facts

Interesting and creepy facts:

In airless space, sound waves do not travel because there is nothing to push them away from.
flies don't hear sound
Animals with large ears hear better than animals with small ears.
A fox's hearing is so good that it can hear the squeak of a mouse 100 meters away. She can even catch the sound of a mouse scratching underground!
echo occurs when sound waves bounce off an object rather than being absorbed
if you scream continuously for 8 years, 7 months and 6 days, you will produce enough sound energy to heat a cup of coffee
The loudest natural sound on earth is a volcanic eruption

Now that you have learned all these amazing and interesting facts about sound, you know about the huge role of sound in our lives, and can ruin our lives.

Sounds are the very first thing a person encounters when he is born. And the very last thing he hears when leaving the world. And between the first and the second a whole life passes. And all of it is built on noise, tones, clanking, rumble, music, in general, a complete cacophony of sounds.

Here are ten of the most interesting facts about them.

1. Their level is measured in decibels (dB). The maximum threshold for human hearing (when pain begins) is an intensity of 120-130 decibels. And death occurs at 200.

2. Sound and noise are not the same thing . Although it seems so to ordinary people. However, for specialists there is a big difference between these two terms. Sound is vibrations perceived by the senses of animals and humans. And noise is a disorderly mixture of sounds.

3. Our voice in the recording is different because we hear “with the wrong ear.” It sounds strange, but it's true. But the whole point is that when we speak, we perceive our voice in two ways - through the external (auditory canal, eardrum and middle ear) and internal (through tissues).heads, which enhance the low frequencies of the voice).

And when listening from the side, only the external channel is used.

4. Some people may hear the sound of their eyeballs rotating . And also your breathing. This is due to

a defect of the inner ear, when its sensitivity is increased above normal.

5. The sound of the sea that we hear through the sea shell , in fact, just the sound of blood flowing through our vessels. The same noise can be heard by placing a regular cup to your ear. Try it!

6. Deaf people can still hear. Just one example of this: the famous composerBeethoven, as you know, was deaf, but could creategreatworks. How? He listened... with his teeth! The composer placed the end of the cane against the piano, and clamped the other end in his teeth - this way the sound reached the inner ear, which was absolutely healthy for the composer, unlike the outer ear.

7. Sound can turn into light . This phenomenon is called “sonoluminescence”. It occurs if a resonator is lowered into water, creating a spherical ultrasonic wave. In the rarefaction phase of the wave, due to the very low pressure, a cavitation bubble appears, which grows for some time, and then quickly collapses in the compression phase. At this moment, a blue light appears in the center of the bubble.

8. "A" is the most common sound in the world . It is found in all languages of our planet. And in total there are about 6.5-7 thousand of them in the world. The most commonly spoken languages are Chinese, Spanish, Hindi, English, Russian, Portuguese and Arabic.

9. It is considered normal when a person hears soft spoken speech from a distance of at least 5-6 meters (if these are low tones). Or at 20 meters with elevated tones. If you have trouble hearing what they say from a distance of 2-3 meters, you should check with an audiologist.

10. We may not notice that we are losing our hearing. . Because the process, as a rule, does not occur simultaneously, but gradually. Moreover, at first the situation can still be corrected, but the person does not notice that “something is wrong” with him. And when an irreversible process occurs, nothing can be done.

End of form

Physics 9th grade

Lesson topic: Mechanics. Oscillations and waves. Sound waves

We continue to study mechanics. We are in Chapter 7, “Oscillations and Waves.” Paragraph 7, which today is about sound waves.Sound waves - these are special waves that cause vibrations in the environment, which are perceived by our organ of hearing - the ear. The branch of physics that deals with these waves is called acoustics. The profession of people who are popularly called listeners is called acousticians. A sound wave is a wave propagating in an elastic medium, it is a longitudinal wave, and when it propagates in an elastic medium, we alternate between compression and discharge. It is transmitted over time over a distance. Sound waves include vibrations that occur at a frequency of 20 Hz and 20 thousand Hz. I wrote that this range will be called audible sound. These wavelengths correspond in the environment we talked about, air at t = 20 °C corresponds to 17 m wavelength and 20 thousand Hz frequency - 17 mm. There are also ranges that acousticians deal with - infrasonic and ultrasonic. Infrasonic are those that have a frequency of less than 20 Hz. And ultrasonic ones are those that have a frequency of more than 20 thousand Hz. Every educated person should be familiar with the frequency range of sound waves and know that if he goes for an ultrasound, the picture on the computer screen will be constructed with a frequency of more than 20 thousand Hz. Infrasound is also an important wave that is used to vibrate the surface (for example, to destroy some large objects). We launch infrasound into the soil - and the soil breaks up. Where is this used? For example, in diamond mines, where they take ore that contains diamond components and crush it into small particles to find these diamond inclusions. This means that the speed of sound depends on environmental conditions and temperature. I specifically wrote down these important discrepancies that occur with the wave if we take a different medium or increase the temperature. Look, in air the speed of sound at t=0 °C is V= 331 m/s, at t=1 °C the speed increases by 1.7 s. If you are a researcher, then this knowledge may be useful to you. You may even come up with some kind of temperature sensor that will record or measure temperature differences by changing the speed of sound in the medium. I said: the denser the medium, the more serious the interaction between the particles of the medium, the faster the wave propagates. In the last paragraph we discussed this using the example of dry air and humid air. Look, the speed in water is V = 1400 m/s. Sound, if we spread it (knock on a tuning fork, for example, or on a piece of iron with some object in water and air), then the speed of propagation increases almost 4 times. By water, information will reach 4 times faster than by air. And in steel it’s even faster, look, V = 5000 m/s = 5 km/s. So that you remember this, I specially wrote such a beacon - Ilya Muromets. You know from the epics that Ilya Muromets used (and all the heroes, and ordinary Russian people and the boys of RVS Gaidar) used a very interesting method of detecting an object that is still far away, approaching, but located still far away. The sound that it makes when moving is a train or enemy cavalry, this cavalry is not yet visible or heard. Ilya Muromets, with his ear to the ground, can hear her. Why? Because sound is transmitted over solid ground at a higher speed, which means it will reach Ilya Muromets’ ear faster and he will be able to prepare to meet the enemy. The most interesting sound waves are musical sounds and non-musical noises. What objects can create sound waves? If we take a wave source and an elastic medium, if we make the sound source oscillate harmoniously, then we will have a wonderful sound wave, which will be called musical sound. You know these sources of sound waves: for example, the strings of a guitar or the strings of a piano. This may be a sound wave that is created in the air gap of a pipe (for example, an organ or pipe, some kind of wind instrument). From music lessons you know the notes: do, re, mi, fa, sol, la, si. In acoustics they are called tones. They are designated by the following letters. The most amazing thing is that all objects that can emit tones, they will all have characteristics. How are they different? They differ in wavelength and frequency. If these sound waves are not created by harmoniously sounding bodies or are not connected into some kind of common orchestral piece, then such a quantity of sounds will be called noise. A chaotic mixture of sounds is noise. The concept of noise is everyday, it is physical, it is very similar, and therefore we introduce it as a separate important object of consideration.

Let's move on to quantitative estimates of sound waves. What are the characteristics of musical sound waves? These characteristics apply exclusively to harmonic musical vibrations. So,sound volume . How is sound volume determined? Here I have drawn the propagation of a sound wave in time or the oscillations of the source of the sound wave. It is located here and begins to vibrate, while vibrating harmoniously, causing a musical sound. At the same time, if we did not add a lot of sound to the system (we quietly hit a piano note, for example), then there will be a quiet sound. If we loudly raise our hand high, we cause this sound by hitting the key, we get a loud sound. What does this depend on? In my opinion, everyone understands that everything will depend on the amplitude of vibration of the sound source. A quiet sound has a smaller vibration amplitude than a loud sound A T < А gr.

The next important characteristic of musical sound and any other sound isheight . What does the pitch of sound depend on? The height depends on the frequency. We can make the source oscillate frequently, or we can make it oscillate not very quickly, and perform fewer oscillations per unit of time. Look how I drew this mathematically on the board. The first low sound vibrates like this. Here is a time sweep. Vibrations occur here; you can make the string vibrate like this. We will describe the oscillations in this way. At the same time, it is virtual, something that does not exist, but exists only in our consciousness, a development in time, we have drawn it this way.

For me, the wavelength of one fits into such a period of time. For the second wave, I deliberately made the amplitude the same so that the volume of the sound would be the same. It turns out that if we manage to make two vibrations with a sound source in the same time, then the sound will be high. Therefore, an interesting conclusion can be drawn. If a person sings in a bass voice, then his sound source (these vocal cords) vibrates several times slower than that of a person who, for example, is a woman who sings soprano. Her vocal cords vibrate more often, which is why they more often cause pockets of compression and discharge in the propagation of the wave. There is another interesting characteristic of sound waves that physicists do not study. Thistimbre . You know and easily distinguish the same piece of music performed on a balalaika or cello. How are these sounds different or how is this performance different? At the beginning of the experiment, we asked people who produce sounds to make them of approximately the same amplitude. The sound volume should be the same. This is true in an orchestra; if there is no need to highlight any instrument, everyone plays approximately the same, at the same strength. So the timbre of a balalaika and a cello is different, because if we drew the sound that is extracted from one instrument from another, we would draw it using diagrams, it would not be any different. But you can easily distinguish these instruments by their sound. Another example of why timbre is important. Two singers who graduate from the same music university, conservatory, with the same teachers, studied equally well with straight A's. For some reason, one becomes an outstanding performer, while the other is dissatisfied with his career all his life, trying to do something better. In fact, this is determined solely by their instrument, which causes vocal vibrations in the environment, i.e. their voices differ in timbre. If the timbre of the voice is such that it evokes some strong emotions in all other people (for example, the simplest emotion is goosebumps), if even such a physical change in the environment when transmitted from the singer to your ears causes this vibration in you changes in the skin, you can safely assume that this person is a genius. Thank you for your attention.

1. Their level is measured in decibels (dB). The maximum threshold for human hearing (when pain begins) is an intensity of 120–130 decibels. And death occurs at 200.

A normal conversation is approximately 45–55 dB.
Sounds in the office - 55–65 dB.
Noise on the street - 70–80 dB.
Motorcycle with muffler - from 85 dB.
A jet plane produces a noise level of 130 dB when taking off.
And the rocket is from 145 dB.

2. Sound and noise are not the same thing. Although it seems so to ordinary people. However, for specialists there is a big difference between these two terms. Sound is vibrations perceived by the senses of animals and humans. And noise is a disorderly mixture of sounds.

3. Our voice in the recording is different, because we hear “with the wrong ear.” It sounds strange, but it's true. The thing is that when we speak, we perceive our voice in two ways - through the external (auditory canal, eardrum and middle ear) and internal (through the tissues of the head, which enhance the low frequencies of the voice).

And when listening from the side, only the external channel is used.

4. Some people may hear the sound of their eyeballs rotating. And also your breathing. This occurs due to a defect in the inner ear, when its sensitivity is increased beyond normal.

5. The sound of the sea, which we hear through the sea shell, in fact, it’s just the sound of blood flowing through our vessels. The same noise can be heard by placing a regular cup to your ear. Try it!

6. Deaf people can still hear. Just one example of this: the famous composer Beethoven, as you know, was deaf, but could create great works. How? He listened... with his teeth! The composer placed the end of the cane against the piano, and clamped the other end in his teeth - this way the sound reached the inner ear, which was absolutely healthy for the composer, unlike the outer ear.

7. Sound can turn into light. This phenomenon is called “sonoluminescence”. It occurs if a resonator is lowered into water, creating a spherical ultrasonic wave. In the rarefaction phase of the wave, due to the very low pressure, a cavitation bubble appears, which grows for some time, and then quickly collapses in the compression phase. At this moment, a blue light appears in the center of the bubble.

8. “A” is the most common sound in the world. It is found in all languages of our planet. And in total there are about 6.5–7 thousand of them in the world. The most commonly spoken languages are Chinese, Spanish, Hindi, English, Russian, Portuguese and Arabic.

9. It is considered normal when a person hears soft spoken speech. from a distance of at least 5–6 meters (if these are low tones). Or at 20 meters with elevated tones. If you have trouble hearing what they say from a distance of 2–3 meters, you should check with an audiologist.

10. We may not notice that we are losing our hearing. Because the process, as a rule, does not occur simultaneously, but gradually. Moreover, at first the situation can still be corrected, but the person does not notice that “something is wrong” with him. And when an irreversible process occurs, nothing can be done.

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