Transcript File

10/04/2016
Sound and Hearing
Speed of sound
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The speed of sound in air is around 330 m/s. What happens
when sound travels through different materials?
Speed of
sound
(in m/s)
Material
Conclusion – the denser the material, the
faster sound travels through it
Making Sounds
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A sound is made when an object or material VIBRATES.
Take, for example, a guitar.
To make a sound with a guitar a string has to
vibrate. We can raise the pitch of the sound
on a guitar by doing three things:
1) _________ the length of the string
2) _________ the string
3) Using a _________ string
We can make the sound louder by ________ the string harder
Words – tightening, thinner, decreasing, plucking
Using an oscilloscope
1) Quiet sound, low frequency:
2) Quiet sound, high frequency:
3) Loud sound, low frequency:
4) Loud sound, high frequency:
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How sound travels…
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As we know, sound waves are formed when something vibrates.
But how does the sound reach our ears?
Air molecules
1) An object
makes a
sound by
vibrating
2) The vibrations pass
through air by making
air molecules vibrate
3) These
vibrations are
picked up by
the ear
How does the ear work?
1) Sound waves
are “funnelled”
into the ear by
the pinna
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5) The electrical
signals are then
sent to the brain
4) These
vibrations are
turned into
electrical
2) These
vibrations
3) These vibrations make signals in the
cochlea
make the ear the ear bones vibrate
drum vibrate