The document discusses sound and ultrasound. It defines the audible range of human hearing as 20 Hz to 20,000 Hz. Frequencies above 20,000 Hz are ultrasound, while frequencies below 20 Hz are infrasound. The ear detects sound waves that travel through the outer, middle, and inner ear to the brain. Sources of sound include vibrating strings and air columns, as seen in instruments like guitars and wind instruments. The Doppler effect causes changes in frequency or wavelength for an observer moving relative to a sound source. Ultrasound is used in nondestructive testing and medical imaging techniques like Doppler echocardiography. Infrasound sources include volcanic eruptions and wind flowing around ocean waves.

1. The SOUND

2. SoundSound
Audible range: about 20 Hz to 20,000 Hz;Audible range: about 20 Hz to 20,000 Hz;
upper limit decreases with ageupper limit decreases with age..
Ultrasound:
above 20,000 Hz;
see ultrasonic
camera focusing
below
Infrasound:
below 20 Hz

3. Approximate frequency rangesApproximate frequency ranges
corresponding to ultrasound, withcorresponding to ultrasound, with
rough guide of some applicationsrough guide of some applications

4.  Ultrasonic Testing (UT) is a
group of
nondestructive examination
(NDE) techniques that use short,
high-frequency ultrasonic waves
to identify flaws in a material.

5. The Ear and Its Response; LoudnessThe Ear and Its Response; Loudness
Outer earOuter ear: sound waves travel: sound waves travel
down the ear canal to the eardrum,down the ear canal to the eardrum,
which vibrates in responsewhich vibrates in response
Middle earMiddle ear: hammer, anvil, and: hammer, anvil, and
stirrup transfer vibrations to innerstirrup transfer vibrations to inner
earear
Inner earInner ear: cochlea transforms: cochlea transforms
vibrational energy to electricalvibrational energy to electrical
energy and sends signals to theenergy and sends signals to the
brainbrain

7. The strings on a guitar canThe strings on a guitar can
be effectively shortened bybe effectively shortened by
fingering, raising thefingering, raising the
fundamental pitch.fundamental pitch.
The pitch of a string of aThe pitch of a string of a
given length can also begiven length can also be
altered by using a string ofaltered by using a string of
different density.different density.
Sources of Sound: VibratingSources of Sound: Vibrating
Strings and Air ColumnsStrings and Air Columns

8. A piano uses both methodsA piano uses both methods
to cover its more than seven-to cover its more than seven-
octave range—the loweroctave range—the lower
strings (at left) are bothstrings (at left) are both
much longer and muchmuch longer and much
thicker than the higher ones.thicker than the higher ones.
Sources of Sound: VibratingSources of Sound: Vibrating
Strings and Air ColumnsStrings and Air Columns

9. A tube open at both ends (most wind instruments)A tube open at both ends (most wind instruments)
has pressure nodes, and therefore displacementhas pressure nodes, and therefore displacement
antinodes,antinodes, at the ends.at the ends.
Sources of Sound: VibratingSources of Sound: Vibrating
Strings and Air ColumnsStrings and Air Columns

10. Doppler EffectDoppler Effect
The Doppler effect occurs when a source ofThe Doppler effect occurs when a source of
sound is moving with respect to an observer.sound is moving with respect to an observer.
As can be seen in the previous image, a sourceAs can be seen in the previous image, a source
moving toward an observer has a higher frequencymoving toward an observer has a higher frequency
and shorter wavelength; the opposite is true whenand shorter wavelength; the opposite is true when
a source is moving away from an observer.a source is moving away from an observer.

11. The Doppler effectThe Doppler effect
 The The Doppler effectDoppler effect (or the (or the DopplerDoppler
shiftshift) is the change in frequency or ) is the change in frequency or
wavelenngth of a waver for an wavelenngth of a waver for an
observer, who is moving relative to observer, who is moving relative to
the wave sourcethe wave source
 It is named after the Austrian It is named after the Austrian
physicist physicist Christian DopplerChristian Doppler, who , who
described the phenomenon in 1842.described the phenomenon in 1842.

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Sound

13. And the change in the frequency:And the change in the frequency:
If the source is moving away from the observer:If the source is moving away from the observer:
Doppler EffectDoppler Effect

14. Color flow ultrasonographyColor flow ultrasonography
(Doppler) of a carotid artery(Doppler) of a carotid artery

15. Renal ultrasonography with usingRenal ultrasonography with using
duplex technique of a normal adultduplex technique of a normal adult
kidneykidney

16. Doppler echocardiographyDoppler echocardiography

18. THE CHARACTERISTICS
OF
A SOUND

19.  Fundamental frequency determinesFundamental frequency determines
thus have hearing the pitch, and athus have hearing the pitch, and a
set of harmonic components - theset of harmonic components - the
timbre of soundtimbre of sound. In the spectrum of. In the spectrum of
speech sounds are formants -speech sounds are formants -
stable groups of frequencystable groups of frequency
components corresponding tocomponents corresponding to
certain phonetic elements.certain phonetic elements.

20.  Energy characteristic of theEnergy characteristic of the
sound waves is thesound waves is the soundsound
intensityintensity - the energy carried by- the energy carried by
a sound wave through a unita sound wave through a unit
area perpendicular to thearea perpendicular to the
direction of wave propagation indirection of wave propagation in
a unit time. The intensity of thea unit time. The intensity of the
sound depends on the amplitudesound depends on the amplitude
of the sound pressure, as well asof the sound pressure, as well as
the properties of the mediumthe properties of the medium
itself and the shape of the wave.itself and the shape of the wave.

21.  Subjective soundSubjective sound
characteristics related tocharacteristics related to
its intensity, is theits intensity, is the
volumevolume, depending on the, depending on the
frequency.frequency.

22.  Ultrasound with a frequency over 25Ultrasound with a frequency over 25
kHz causes pain in birds.kHz causes pain in birds.
 This is useful for scaring gulls fromThis is useful for scaring gulls from
reservoirs of drinking water and fishreservoirs of drinking water and fish
from the trawlers.from the trawlers.

23.  1. volcanic eruptions1. volcanic eruptions
 2.Wind flowing around the2.Wind flowing around the
crests of the wavescrests of the waves
Sources of infrasound