Chapter 21 - The Nature of Sound

•Sound is produced by ________________ which are thecomplete _____________________ motion of an object•Sound travels as __________________ waves, where theparticles vibrate back and forth _________________________that the wave travels. •Sound waves travel ________________________ from theirsource, but the ____________ through which they pass does ________ travel. The particles in the media just ____________ back and forth.

vibrationsback and forth

longitudinalalong the path

in all directionsmedium

NOT vibrate

•Sound waves require a ___________. Usually this is ____ but sound waves also travel through ___________,____________, and __________.Sound cannot travel in a _________.

medium air

waterglass metal

vacuum

Properties of Sound • The speed of sound through any ___________ is ___________ unless the properties of the medium change.

medium constant

1. The ____________ the medium, the ____________ thespeed of sound. Why? ____________________________________________________________________________

cooler slower The particles in cool materials moveslower and therefore transmit energy more slowly.

This is a picture of a jet breaking the sound barrier (traveling faster than the speed of sound).

•Pitch - how _______ or _________ you perceive a sound to be. This depends on the __________________ of a wave (the _____________ of waves produced in a given time, expressed in____________).

high lowfrequency

numberhertz (Hz)

When an object goes faster than the speedof sound, it breaks the ________ ________,causing ________ ___________ which we hear as a __________ ________.

sound barriershock wavessonic boom

Humans can hear sound frequencies between ____________and _____________ Hz. Sounds below 20 Hz are ____________and sound above 20,000 Hz are ______________. Most humanscannot hear sounds in these ranges.

2020,000 infrasonic

ultrasonic

•The Doppler Effect - the ________________ change in the ________________ of a sound caused by ____________ of either the _____________ or the _____________ of the sound.

apparentfrequency motion

listener source

•Loudness is how_______ or __________ a sound is, and dependson the amount of _____________ transferred, which affects the_______________ particles in the medium move from their ______position.

A. The _________________ is the maximum distance the_______________in a wave vibrate from their ________position. The ____________ the amplitude, the __________the sound.B. Loudness is measured in ______________. The humanear can hear from ______ and feels pain at ________.

loud softenergy

distance rest

amplitudeparticles rest

larger louder

decibels (dB)0 dB 120 dB

•An ________________ can convert sound waves into a graphicrepresentation showing ________________ and _______________of the wave.

oscilloscopeamplitude frequency

low amplitude high amplitudehigh frequency

low frequency

same frequency

Interactions of Sound Waves•Reflection - _____________________________________________________________________________________________This is called an _________. The amount of reflection depends on the reflecting _____________. Waves reflect best off of__________, _____________ surfaces.

The bouncing back of sound waves after strikinga barrier

echosurface

smooth hard

•Interference - _______________________________________A. Constructive interference - _____________________________________________________________________________________________________________________B. Destructive interference - ______________________________________________________________________________________________________________________

The result of 2 or more waves overlapping As the compressions of onewave overlap the compressions of another wave, thesound will be louder because the amplitude is increased. As the compressions of onewave overlap the rarefractions of another wave, thesound will be softer because the amplitude is decreased.

C. Standing waves - _____________________________________________________________________________

Interference in which portionsof the wave are at rest and others have large amplitude.

Resonance - __________________________________________________________________________________________

An object vibrating at or near the resonant frequencyof another object causes the second object to vibrate

Resonant frequencies - _____________________________________________________________________________________

The frequencies at which standing wavesare made

Sound quality - ___________________________________________________________________________________________

the result of several pitches blending togetherthrough interference

NoiseSound of speech

Chapter 21 - The Nature of Sound

•Sound is produced by ________________ which are thecomplete _____________________ motion of an object•Sound travels as __________________ waves, where theparticles vibrate back and forth _________________________that the wave travels. •Sound waves travel ________________________ from theirsource, but the ____________ through which they pass does ________ travel. The particles in the media just ____________ back and forth.

•Sound waves require a ___________. Usually this is ____ but sound waves also travel through ___________,____________, and __________.Sound cannot travel in a _________.

Properties of Sound • The speed of sound through any ___________ is ___________ unless the properties of the medium change.

1. The ____________ the medium, the ____________ thespeed of sound. Why? ____________________________________________________________________________

This is a picture of a jet breaking the sound barrier (traveling faster than the speed of sound).

•Pitch - how _______ or _________ you perceive a sound to be. This depends on the __________________ of a wave (the _____________ of waves produced in a given time, expressed in____________).

When an object goes faster than the speedof sound, it breaks the ________ ________,causing ________ ___________ which we hear as a __________ ________.

Humans can hear sound frequencies between ____________and _____________ Hz. Sounds below 20 Hz are ____________and sound above 20,000 Hz are ______________. Most humanscannot hear sounds in these ranges.

•The Doppler Effect - the ________________ change in the ________________ of a sound caused by ____________ of either the _____________ or the _____________ of the sound.

•Loudness is how_______ or __________ a sound is, and dependson the amount of _____________ transferred, which affects the_______________ particles in the medium move from their ______position.

A. The _________________ is the maximum distance the_______________in a wave vibrate from their ________position. The ____________ the amplitude, the __________the sound.B. Loudness is measured in ______________. The humanear can hear from ______ and feels pain at ________.

•An ________________ can convert sound waves into a graphicrepresentation showing ________________ and _______________of the wave.

low amplitude high amplitudehigh frequency

low frequency

same frequency

Interactions of Sound Waves•Reflection - _____________________________________________________________________________________________This is called an _________. The amount of reflection depends on the reflecting _____________. Waves reflect best off of__________, _____________ surfaces.

•Interference - _______________________________________A. Constructive interference - _____________________________________________________________________________________________________________________B. Destructive interference - ______________________________________________________________________________________________________________________

.

C. Standing waves - _____________________________________________________________________________

Resonance - __________________________________________________________________________________________

Resonant frequencies - _____________________________________________________________________________________

Sound quality - ___________________________________________________________________________________________

NoiseSound of speech