Transcript How fast does sound travel?

Understanding Sound & Hearing
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VOCABULARY
Tempranic Membrane ( eardrum)
Cochlea ( inner ear – magnifies sound )
Auditory Nerve ( converts to electric signal)
Sound Waves & Compression Waves
Decibel ( dB ) Power & Intensity
Hertz ( unit of sound measure )
To hear sound, your ear has to
do three basic things:
･Direct the sound waves into the hearing
part of the ear
･Sense the fluctuations in air pressure
･Translate these fluctuations into an
electrical signal
 Diagram - Human Ear
Ear Vs Mic (electric Signals)
 Inner Ear
 Amplification
System Via
Cochlea - Fluid
22 x more then
Ear Drum
The Amazing Ear
The Inner Ear To Electric Signals
How Sound Moves
 An object produces sound when it vibrates in matter,
such as earth, a liquid, water, gas, or typically air.
 Most of the time, we hear sounds traveling through
the air in our atmosphere.
 When something vibrates in the atmosphere, it moves
the air particles around it.
 Those air particles in turn move the air particles
around them, carrying the pulse of the vibration
through the air.
Sound Waves - Compression
Underwater Earthquake
Speed Of Sound
Fifteen Football Fields Per Second
1,236 kilometers per hour
(768 mph)
Speed Of Sound
How fast does sound travel?
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Sound moves about 1500 meters per second in seawater.
( slightly less than a mile )
Thats approximately 15 football fields end-to-end in one second!!
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Approximately a mile per second
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(Sound moves much more slowly in
only 3 football fields a second).
air, at about 340 meters per second,
Sound Waves
Vocabulary _ Part Two
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Crest
Trough
Wavelength
Waveform
Diaphragm
Foley Artist
Sound Waves Vs Ocean Waves
Crests, Troughs & Wavelengths
Sound Waves Cont..
Audio Waveforms In Final Cut
DIAPHRAGMS & MICS
 Different types of microphone have different
ways of converting energy but they all share
one thing in common:
The diaphragm.
 This is a thin piece of material (such as
paper, plastic or aluminum) which vibrates
when it is struck by sound waves.
Microphones convert energy from one form to anotheracoustical energy (sound waves) into electrical energy
(the audio signal).
 Typical Microphone
SOUND>MIC ( Diaphragm)>Signal dB
How Microphones Work
Cross Section - Typical Mic
Brief Summary
 Sounds are vibrations caused by the movement of
air molecules through air, water, earth ( matter ).
• These vibrations enter the ear, press against the
ear drum ( tempranic membrane) and then enter
the middle and inner ear where they are amplified
up to 20x.
• The ear converts these vibrations into
“ELECTRICAL SIGNALS” for the Brain.
• MICROPHONES convert sound waves into
electrical signals for recording devices.
Careers As A Foley Artist
Who Was Jack Foley
SOUND / FOLEY PROJECT
( see teacher web page to print)