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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