Sound vibrations and waves presentation. Physics presentation "sound waves"

Description of the presentation by individual slides:

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Sound waves Completed by: Ruban Anastasia Gabova Valeria, a student of grade 11A, checked by: Glushkova T.A. Physics teacher

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Sound Like any wave, sound is characterized by amplitude and frequency spectrum. An ordinary person is able to hear sound vibrations in the frequency range from 16-20 Hz to 15-20 kHz. Sound below the range of human audibility is called infrasound; higher: up to 1 GHz, - ultrasound, from 1 GHz - hypersound. The loudness of a sound depends in a complex way on the effective sound pressure, frequency and shape of vibrations, and the pitch of a sound depends not only on the frequency, but also on the magnitude of the sound pressure. Sound is a physical phenomenon that is the propagation of mechanical vibrations in the form of elastic waves in a solid, liquid or gaseous medium. In a narrow sense, sound refers to these vibrations, considered in connection with how they are perceived by the senses of animals and humans.

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Sound waves in gases and liquids can only be longitudinal, since these media are elastic only with respect to compression (tension) deformations. In solids, sound waves can be both longitudinal and transverse, since solids have elasticity with respect to compression (tension) and shear deformations. Sound in gases Sound in liquids

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Sound intensity Sound intensity (or sound intensity) is a quantity determined by the time-average energy transferred by a sound wave per unit time through a unit area perpendicular to the direction of propagation of the wave: The sensitivity of the human ear is different for different frequencies. In order to cause a sound sensation, the wave must have a certain minimum intensity, but if this intensity exceeds a certain limit, then the sound is not heard and causes only a painful sensation. Thus, for each vibration frequency there is a minimum (hearing threshold) and a maximum (pain threshold) sound intensity that can cause sound perception. I=W/(St)

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Level of sound intensity Many thousands of teenagers pay for their passion for loud music, especially fashionable nowadays, with acquired hearing loss. Sound Hearing threshold vdb Barely audible sound 0 Whisper near the ear 25-30 Speech of medium volume 60-70 Very loud speech (screaming) 90 Roar of an airliner taking off 120 At rock and pop music concerts in the center of the hall 106-108 At rock and pop music concerts in the center of the hall scenes 120

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The impact of sound waves The Swiss scientist Hans Jenni studied the effect of sound on inorganic matter, including water. Under the influence of sound, a drop of water, vibrating, took the shape of a three-dimensional star or a double tetrahedron in circles. The higher the vibration frequency, the more complex the forms. But as soon as the sound died down, the most beautiful formations again became shaped like a drop of water.

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Japanese scientist Professor Emoto Masaru conducted experiments on the effects of various music, prayers, obscene expressions, positive and negative statements on water. Emoto Masaru's experiments showed that the result of the influence of spiritual and classical music, prayers and words carrying positive energy is the formation of snowflakes of amazing beauty in ordinary water.

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On the contrary, when exposed to obscene expressions and words carrying negative energy, a crystalline structure did not form at all in ordinary water, and the previously well-formed crystalline structure of the water was destroyed. The structure of water copies the energy-informational field in which it is located, and we are 90% water. The positive or negative energy of the sounds of speech or a piece of music affects the entire body, right down to the cell structure.

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Russian scientists under the leadership of P.P. Garyaeva and the staff of the Institute of General Genetics proved that DNA perceives human speech. If a person uses obscene expressions in his speech, his chromosomes begin to change their structure, a kind of negative program begins to be developed in the DNA molecules, which can be called a “self-destruction program,” and this is passed on to the person’s descendants. Scientists have recorded: a swear word causes a mutagenic effect similar to radiation with a power of a thousand roentgens!

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On the contrary, high-frequency sounds in a range favorable to humans have a beneficial effect on us, increasing energy levels, causing joy and good mood. High-frequency sounds activate brain activity, improve memory, stimulate thinking processes, while at the same time relieving muscle tension and balancing your body in a different way. After studying music written by various composers, French otolaryngologist Alfred Tomatis found that Mozart's music contains the most high-frequency sounds that recharge and activate the brain. It is very useful to listen to the voices of birds and the sounds of nature. An extended speech range (from 60 to 6000 Hz) is also important because speech represents complex signals that, in addition to the fundamental tones, also contain many harmonics that are multiples of them in frequency. Our native Russian language is very promising in this sense, because it includes both very low and very high frequencies. The area of ​​American and English is much narrower.

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Application of sound waves Ultrasonic waves have found more applications in many areas of human activity: in industry, in medicine, in everyday life, ultrasound was used for drilling oil wells, etc. Until now, high-frequency sound waves have been used in medicine only to diagnose the condition of internal organs. Now they are becoming a precision surgeon's instrument. With their help, you can “weld” and destroy tumors without anesthesia, without a single cut of living tissue.

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Slide captions:

Sound sources. Sound characteristics.

Sound is mechanical waves perceived by the human hearing organs that cause sound sensations. Sound sources can be any body that vibrates at a sound frequency (from 16 to 20,000 Hz).

A sound wave is a longitudinal wave, so it can propagate in solid, liquid and gaseous media.

Children A person aged 20 years A person aged 35 years A person aged 50 years Hz 16-22000 16-20000 16-15000 16-12000 Cricket Grasshopper Frog Dolphin Hz 2-4000 10-100000 50-30000 400-200000 Range of audible sounds.

Humans do not perceive infrasound, although they can feel its impact due to resonance. The frequency of infrasound oscillations is less than 16 per second, i.e. below the threshold of audibility.

The concept of ultrasound Ultrasound is high-frequency mechanical vibrations of particles of a solid, liquid or gaseous medium, inaudible to the human ear. The frequency of ultrasonic vibrations is above 20,000 per second, i.e. above the threshold of audibility.

Ultrasound and infrasound Ultrasound and infrasound are as widespread in nature as waves in the sound range. They are emitted and used for their “negotiations” by dolphins, bats and some other creatures.

Sound sources Natural (murmur of a stream, bird voices, light splash of water) Artificial (tuning fork, string, bell, membrane, etc.)

For the existence of sound you need: 1. Source of sound 2. Environment 3. Hearing aid 4. Frequency 16–20000 Hz 5. Intensity

: Sound wave receivers: Natural - ear. Its sensitivity depends on the frequency of the sound wave: the lower the frequency of the wave, the less sensitive the ear. Exceptional selectivity: the conductor captures the sounds of individual instruments. Artificial - microphone. It converts mechanical sound vibrations into electrical ones.

Propagation of sound Sound propagates in any elastic medium - solid, liquid and gaseous, but cannot propagate in space where there is no substance (for example, in a vacuum).

From the history of the discovery of the speed of sound. The speed of sound in air was first determined in 1708 by the English scientist William Durham. At two points, the distance between which was known, cannons were fired. At both points, the time intervals between the appearance of fire from a shot and the moment when the sound of a shot was heard were measured. Speed ​​of sound in air 340 m/s

Physical characteristics of sound Objective: - sound pressure (pressure exerted by a sound wave on an obstacle standing in front of it); - sound spectrum - decomposition of a complex sound wave into its component frequencies; - intensity of the sound wave.

Subjective: - Volume - Pitch - Timbre

The pitch of sound is a characteristic that is determined by the frequency of vibrations. The higher the frequency of the body that produces vibrations, the higher the sound will be. Timbre is the color of sound. Timbre is the difference between two identical sounds performed by different musical instruments. The volume of the sound depends on the amplitude of the vibrations.

Volume of sound The volume of sound depends on the amplitude of the vibrations: the greater the amplitude of the vibrations, the louder the sound. Loudness is a subjective quality of auditory sensation that allows sounds to be ranked on a scale from soft to loud. The unit of sound loudness is called sleep.

Timbre. The quality of musical sound, its peculiar “coloring” is characterized by timbre. Here are some characteristics of timbre: thick, deep, masculine, harsh, velvety, matte, shiny, light, heavy, rich. The timbre depends on the material from which the instrument is made and on the shape of the instrument.

Sound vibrations occurring according to the harmonic law are perceived by humans as a musical sound, or tone.

Pure tone The branches of a tuning fork perform harmonic (sinusoidal) oscillations. Such oscillations have only one strictly defined frequency. Harmonic vibrations are the simplest type of vibration. The sound of a tuning fork is a pure tone. A pure tone is the sound of a source that vibrates harmonics at the same frequency.

Noise is loud sounds of different frequencies merged into a discordant sound.

Read more physics and happiness will smile on you!

Sound waves. Sound speed

Sound is mechanical waves perceived by the human hearing organs that cause sound sensations.

Sound sources can be any body that vibrates at a sound frequency (from 16 to 20,000 Hz).

Range of audible sounds.

Children

16-22000

Man aged 20

Man aged 35

16-20000

Man aged 50

16-15000

16-12000

Cricket

Grasshopper

10-100000

Frog

50-30000

Dolphin

400-200000

Humans do not perceive infrasound, although they can feel its impact due to resonance.

The frequency of infrasound oscillations is less than 16 per second, i.e. below the threshold of audibility.

The concept of ultrasound

Ultrasound- high-frequency mechanical vibrations of particles of a solid, liquid or gaseous medium, inaudible to the human ear. The frequency of ultrasonic vibrations is above 20,000 per second, i.e. above the threshold of audibility.

Ultrasound and infrasound

Ultrasound and infrasound are as widespread in nature as sound waves. They are emitted and used for their “negotiations” by dolphins, bats and some other creatures.

Sound sources

Natural

Artificial

(tuning fork, string, bell, membrane, etc.)

For sound to exist, it is necessary :

1. Sound source

2. Wednesday

3. Hearing aid

4. Frequency 16–20000 Hz

5. Intensity

Sound wave receivers:

Natural – ear. Its sensitivity depends on the frequency of the sound wave: the lower the frequency of the wave, the less sensitive the ear. Exceptional selectivity: the conductor captures the sounds of individual instruments.

Artificial – microphone. It converts mechanical sound vibrations into electrical ones.

Sound propagation

Sound propagates in any elastic medium - solid, liquid and gaseous, but cannot propagate in space where there is no substance (for example, in a vacuum)

From the history of the discovery of the speed of sound .

The speed of sound in air was first determined in 1708 by the English scientist William Durham. At two points, the distance between which was known, cannons were fired. At both points, the time intervals between the appearance of fire from a shot and the moment when the sound of a shot was heard were measured. Speed ​​of sound in air 340 m/s

Pitch, timbre and volume of sound

part 2

Physical characteristics of sound

Objective:

Sound pressure (pressure exerted by a sound wave on an obstacle in front of it);

Sound spectrum - decomposition of a complex sound wave into its component frequencies;

Sound wave intensity.

Subjective:

- Volume

- Height

- Timbre

Pitch – a characteristic that is determined by the frequency of oscillations . The higher the frequency of the body that produces vibrations, the higher the sound will be.

Timbre called sound color .

Timbre is the difference between two identical sounds performed by different musical instruments.

Volume sound depends on the amplitude of vibrations .

Sound volume

The volume of sound depends on the amplitude of the vibrations: the greater the amplitude of the vibrations, the louder the sound.

Loudness is a subjective quality of auditory sensation that allows sounds to be ranked on a scale from soft to loud.

The unit of sound loudness is called sleep.

Timbre.

The quality of musical sound, its peculiar “coloring” is characterized by timbre. Here are some characteristics of timbre: thick, deep, masculine, harsh, velvety, matte, shiny, light, heavy, rich.

The timbre depends on the material from which the instrument is made and on the shape of the instrument.

Pure tone

A pure tone is the sound of a source that vibrates harmonics at the same frequency.

The branches of the tuning fork perform harmonic (sinusoidal) oscillations. Such oscillations have only one strictly defined frequency. Harmonic vibrations are the simplest type of vibration. The sound of a tuning fork is in a clear tone .

Noise - These are loud sounds of different frequencies, merged into a discordant sound.

Read more

physics

and happiness

will smile at you!

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Text content of presentation slides: Sound wavesSpeed ​​of sound We are surrounded by a world of sounds: musical instruments, human voices, noise of transport, sounds of birds and animals What is sound? Sound is elastic longitudinal waves that cause auditory sensations in humans. Sound sources are physical bodies that vibrate, i.e. tremble or vibrate at a frequency of 20 to 20,000 times per second. There are both natural and artificial sources of sound. One of the artificial sources of sound is a tuning fork. ●The pitch of the sound depends on the frequency of vibration. Frequency is measured in Hz (Hertz)●Loudness depends on the amplitude of oscillations in the sound wave. The unit of sound loudness is taken as a unit of sound. Sound volume is 1B (1 Bel) In practice, loudness is measured in decibels (dB). 1 dB = 0.1B. How will the volume of a sound change if the amplitude of its source oscillations is reduced? The volume of sound will decrease. Does sound travel in all media? In water. In the air. In solids. There is no sound in a vacuum! Conclusion: Sound propagates in any elastic medium - solid, liquid and gaseous, but cannot propagate in space where there is no substance. New material. Sound waves are commonly called waves perceived by the human ear. The audio frequency range is approximately 20 Hz to 20 kHz. In what range is the human ear capable of perceiving elastic waves? The human ear is capable of perceiving elastic waves with a frequency of approximately 20 Hz to 20 kHz. Animals perceive waves of other frequencies as sound. What is the speed of sound? It is known that during a thunderstorm we first see a flash of lightning and only after a while we hear the rumble of thunder. This delay occurs because the speed of sound in air is much less than the speed of light coming from lightning. Speed ​​of sound in air: The speed of sound in air was first measured in 1636 by the French scientist M. Mersenne. At a temperature of 20°C it is equal to 343 m/s, i.e. 1235 km/h. The speed of sound depends on the temperature of the environment: with an increase in air temperature it increases, and with a decrease it decreases. At 0°C, the speed of sound in air is 331 m/s. Sound travels at different speeds in different gases. The greater the mass of gas molecules, the lower the speed of sound in it. Thus, at a temperature of 0 °C, the speed of sound in hydrogen is 1284 m/s, in helium - 965 m/s, and in oxygen - 316 m/s. In warm air, the speed of sound is greater than in cold air, which leads to a change in the direction of sound propagation. What is the speed of sound in water? The speed of sound in water was measured in 1826. J. Colladon and J. Sturm. The experiment was carried out on Lake Geneva in Switzerland. On one boat they set fire to gunpowder and at the same time struck a bell lowered into the water. The sound of this bell, using a special horn, also lowered into the water, was captured on another boat, which was located at a distance of 14 km from the first. Based on the time interval between the flash of light and the arrival of the sound signal, the speed of sound in water was determined. At a temperature of 8 °C it is approximately equal to 1440 m/s. Different speeds of sound for different substances: (table in the textbook, page 130) Substance Speed ​​of sound, m/s Air (at) 343.1 Hydrogen 1284 Water 1483 (at) Iron 5850 Sea water 1530 Rubber 1800 Formulas for finding the speed of sound. – speed (m/s) - wavelength (m)ⱴ- frequency (Hz) S– distance (m) t – time (s) T- period (s) The human ear is a very sensitive device. With age, due to loss of elasticity eardrum, people's hearing deteriorates. Useful information Causes of hearing impairment: Working near powerful aircraft, noisy factory floors. Frequent visits to discos and excessive passion for audio players. The noisiest city in the world is Tokyo. Noise pollution of the environment is one of the pressing problems today. Industrial enterprises and airfields are built on the outskirts of the city, and they also use noise reduction devices.

Sound
wavesMOU Sukhovskaya secondary school
Physics teacher -
Puchkova Svetlana Alexandrovna

The purpose of the lesson is to show the connection between physics and biology, expand the concept of “sound waves,” and talk about sounds in nature.

Lesson progressIntroduction
Sound waves: human audible, infrasound, ultrasound, hypersound
Acoustic signals
Acoustic properties of different habitats
Ultrasound Applications
Consolidation

Echo - the constant answer
nature to questions that
we ask her Echo - the constant answer
nature to questions that
we ask her

Usually, when they talk about the sounds made by animals, they first of all talk about birds, since most often we hear their voices. As for other living organisms, many consider them almost mute. Although in fact this is not the case, we simply cannot always hear them; the sound connection between them is carried out at a height inaccessible to our hearing.

Why do we need
Are ears given by nature?

Are all the sounds
can we hear?

About sounds...

The speed of sound in air was first measured in 1836 by the Frenchman M. Marsenne. At a temperature of 200 C, it was 343 m/s. In air, the speed of sound was first measured in 1836 by the Frenchman M. Marsenne. At a temperature of 200 C it was 343 m/s.
The speed of a bullet from a Kalashnikov assault rifle is 825 m/s, i.e. the bullet overtakes the sound of the shot and reaches the victim before the sound arrives.

Information:

Acoustics (from the Greek akusticos - “auditory”) - the study of sounds. Acoustics (from the Greek akusticos - “auditory”) - the study of sounds.
There are “audible” and “inaudible” sounds.
In ordinary understanding, sound is what the human ear perceives.
Not only people hear sounds, but also animals, and even plants react to sounds to one degree or another.

Currently
sound can be divided
in frequency for the next
four
main range

Slide No. 10

sound,
audible
human ultrasound

hypersound

infrasound

109 < <1013 Гц

16< < 20 000 Гц

Slide No. 11

Fish, cats and whales perceive it well. Fish, cats and whales perceive it well.

Infrasound

Slide No. 12

Whales have very fine hearing and are able to detect a wide range of sound waves. Whales have very fine hearing and are able to detect a wide range of sound waves.
Echolocation allows a whale to determine how big an object is, how far away it is, and in what direction it is moving.

Slide No. 13

The Pallas's cat, living in the steppe, and the velvet cat, living in vast open spaces, must hear their prey from afar. The Pallas's cat, living in the steppe, and the velvet cat, living in vast open spaces, must hear their prey from afar.
Therefore, in these two breeds of cats, the ears are widely spaced and are designed in such a way that they work like a good antenna: they pick up the weakest sounds, amplify them and transmit them to the eardrum.

Slide No. 14

The Japanese keep this fish in their home aquariums, which can predict a natural disaster in a few hours. The Japanese keep this fish in their home aquariums, which can predict a natural disaster in a few hours.

Gambusia

Pisces react an hour before an earthquake. If the earthquake is not very strong, they gather in a dense flock, press their bodies against each other and stand with their noses to the epicenter, literally pointing at it. And when there is a strong earthquake, the fish jump out of the aquarium.

Slide No. 15

Bats, dolphins, and dogs perceive it well. Bats, dolphins, and dogs perceive it well.

Ultrasound

Student message

Slide No. 16

Bats are able to perceive the echo from their signal at a pressure 10,000 times less than the emitted signals.Bats are able to perceive the echo from their signal at a pressure 10,000 times less than the emitted signals.

The bats
when probing
spaces emit and
receive impulses
frequency from 30 to 150 kHz.
At a distance of 5-10 cm from the animal’s head
ultrasonic pressure reaches 60 mbar
(1 bar=100 kPa).

Volatile
mouse

Slide No. 17

The place where sounds arise is the larynx, in which a high-pressure zone is created before the “release” of the signal. The place where sounds arise is the larynx, in which a high-pressure zone is created before the “release” of the signal.

Bats rely on their acoustic memory.
During familiarization flights, when traditional ultrasonic ranging is used, the animals remember the “sound picture” of the space.

Slide No. 18

To receive information about the presence of fish or objects, the bottlenose dolphin (a species of dolphin) emits a series of short signals, perceived by humans as clicks.
Limits of hearing
dolphins' perceptions
extend
from 75 to 180 kHzDolphins

Slide No. 19

Dolphins make more than 700 ultrasonic clicking sounds per second. Sound Stream
returns
through a certain
time interval
in the form of an echo and suggests
dolphins distance
to the nearest
school of fish.

Slide No. 20

There are approximately 1018 different insects on earth. They all differ in the number of wing beats, which means the wavelength they generate is different. Fish primarily use organs whose main function is not directly related to the generation of sounds (these are fins, swim bladder). Acoustic signals

Slide No. 21

mosquitoes do about mosquitoes do about
1000 wing flaps
per second

bumblebees - about 200

butterflies - 5-10 strokes per second

bees flying light - 400-500
strokes per second
bees with a burden - about 200 times per second

Slide number 22

Studies have shown that if you talk to a plant, they grow better. Research has shown that if you talk to a plant, they grow better.
The sound waves of our voice cause plant cells to vibrate.

Plants exposed to classical music and jazz grow dense, healthy leaves and well-developed roots.
Under the influence of rock, their roots develop so poorly that the plants begin to die.

Plants

Slide No. 23

Why are they buzzing? Why are they buzzing?
Hummingbirds flap their wings so fast that they generate a high-pitched buzzing sound.

Slide No. 24

The habitat of animals influences the formation of their characteristics of the sound alarm system. The habitat of animals influences the formation of their characteristics of the sound alarm system.

Acoustic properties
different habitats

Slide No. 25

In the desert and steppe, the air during the day is characterized by low humidity and high temperature. Under such conditions, the transmission of sounds with a frequency higher than
1 kHz, since these frequencies are highly absorbed.
At a relative air humidity of 20%, the attenuation of sound with a frequency of 3 kHz is 14 dB per 100 m.

Slide No. 26

The propagation of sound in a forest or dense grass is affected by the density and height of the vegetation cover.
Thus, when a sound with a frequency of 10 kHz passes over dense tall grass, the attenuation is 0.6 dB per 1 meter, while when it propagates over the ground with sparse short grass, it is only 0.18 dB per 1 meter. On the propagation of sound in a forest or in dense grass, the density and height of the vegetation cover is affected.
Thus, when a sound with a frequency of 10 kHz passes over dense tall grass, the attenuation is 0.6 dB per 1 meter, while when it propagates over the ground with sparse short grass, the attenuation is only 0.18 dB per 1 meter.

Slide No. 27

EarthquakesEarthquakes
Tsunami

Animals predict:

Message
student

Slide No. 28

People simply do not notice some of the phenomena that precede an earthquake, but animals that are closer to nature can sense them and show concern. Horses neigh and run away, dogs howl, and fish begin to jump out of the water. Animals that normally hide in holes, such as snakes and rats, suddenly emerge from their holes: chimpanzees in zoos become restless and spend more time on the ground. People simply do not notice some of the events that precede an earthquake, but animals that are closer to nature may feel them and show concern. Horses neigh and run away, dogs howl, and fish begin to jump out of the water. Animals that normally hide in holes, such as snakes and rats, suddenly emerge from their holes: chimpanzees in zoos become restless and spend more time on the ground.

Slide No. 29

There was a very famous case in Leninakan: two hours before the earthquake, a dog - a husky - pulled its owner out of the house onto the street, although it had recently returned from a walk. When the owner of the husky called the police, he was laughed at. I called the city executive committee - the same reaction. He ordered all the neighbors to leave the house and took his family out. Those people were saved, but tens of thousands died. There was a very famous case in Leninakan: two hours before the earthquake, a dog - a husky - pulled its owner out of the house onto the street, although it had recently returned from a walk. When the owner of the husky called the police, he was laughed at. I called the city executive committee - the same reaction. He ordered all the neighbors to leave the house and took his family out. Those people were saved, but tens of thousands died

Slide No. 30

I live in Irkutsk. This is a seismic zone. In 1998, my cat behaved very strangely before the earthquake. She hid under the bed, meowed loudly, and ran after everyone like a tail. I was afraid... Soon the tremors began. I live in Irkutsk. This is a seismic zone. In 1998, my cat behaved very strangely before the earthquake. She hid under the bed, meowed loudly, and ran after everyone like a tail. I was afraid... Soon the tremors began.

Slide No. 31

If earthquakes occur under the ocean, they can create a giant wave over 30 m high.
Such a wave is called a tsunami.

Slide No. 32

Tsunamis are giant waves.
When they get into shallow water, they slow down, but their height increases sharply.

Slide No. 33

EcholocationEcholocation
Ultrasonic flaw detection
Ultrasound

Application
ultrasound

Slide No. 34

Echo is also used in ultrasound scanning, which allows you to look inside the human body. Bones, muscles and fat reflect sound waves differently. The computer uses this information and creates an image of the desired organ.