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Chapter 16Chapter 16
Section 1Section 1
SoundSound
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1.1. SoundSound Caused from Caused from vibrationsvibrationsand travelsand travels
through the air or other mediums as athrough the air or other mediums as a
longitudinal wavel
ongitudinal wave..a. The louder the sound is thea. The louder the sound is the more definedmore defined
thethe compressionscom
pressionsandand rarefactionsrarefactionsbecome.become.
b. No mediums in space, therefore no sound inb. No mediums in space, therefore no sound in
space.space.
c. We can hearc. We can hear 20 to 20,000 Hz20 to 20,000 Hz..
d. ogs can hear up to !",### $% and cats upd. ogs can hear up to !",### $% and cats up
to 6",### $%.to 6",### $%.
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!.!. Intensity of SoundIntensity of Sound etermined b& how much etermined b& how much energ&ene
rg&isis
carried b& the sound wave.carried b& the sound wave.
a. 'ore energ& means morea. 'ore energ& means more amplitudeamplitude, and, and louderlouder
sound.sound.
b. (ntensit& is measured inb. (ntensit& is measured in decibelsdecibels..
)*ange is)*ange is 0 to 1200 to 120, above 1!# causes pain and, above 1!# causes pain and
hearing loss.hearing loss.
Sounds above120 decibels
cause permanent
hearing loss.
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+.+. InfrasonicInfrasonic Sounds Sounds below the !# $%below the !# $%we can hear. i.e.we can hear. i.e.
sounds from arms moving-sounds from arms moving-
.. UltrasonicUltrasonic Sounds Sounds above the !#,### $%above the !#,### $%we canwe can
hear. i.e. dog whistle-hear. i.e. dog whistle-
lephants can
communicate !ith
and hear
infrasonic sounds
Ultrasounds can be used
to produce pictures of
developing babies
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".". "itch"itch epends on epends on fre/uenc&fr
e/uenc&. (s a measure of. (s a measure ofhowhow highhi
ghor howor how lowlowa sound is.a sound is.
)$igh fre/uenc& means high pitch.)$igh fre/uenc& means high pitch.6.6. #usical Instruments#usical Instruments 0ll mae vibrations that 0ll mae vibrations that
cause sound.cause sound.
a.a. $imbre$imbre The /ualit& of sound. The /ualit& of sound.
b. 'ost instruments createb. 'ost instruments create different fre/uenciesdifferent fr
e/uenciesat theat the same timesame timethat blend together to createthat blend together to createtheirtheir uni/ue sounduni
/ue sound..
c.c. %undamental tone%undamental tone 2owest fre/uenc& 2owest fre/uenc&created.created.
d.d. &vertones&vertones 0ll the sounds higher than the 0ll the sounds higher than thefundamental tone.fundamental tone.
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e.e. ShorterShorterstrings,strings, thinnerthinnerstrings,strings, short columnsshort columnsof air, orof air, or
smallersmallerpercussion tops create higher pitches.percussion tops create higher pitches.
f.f. 2onger2on
gerororthicerthicerstrings,strings, longer columnslon
ger columnsof air orof air orlargerla
rger
percussion tops create lower pitches.percussion tops create lower pitches.
lectric guitar 'lto sa(ophone
Snare
drum
)ass guitar
)aritone sa(ophone
)ass drum
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3.3. SonarSonar 4ses 4ses reflected sound wavesreflected sound wavesand allows largeand allows large
distances to be measured accuratel&.distances to be measured accuratel&.
)))ats)atsuse sonar to catch insects5use sonar to catch insects5
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