The document explains the production and travel of sound, stating that sound is created by vibrating objects and requires a medium for propagation, as it cannot travel through a vacuum. It discusses how sound travels fastest through solids due to tightly packed particles, in contrast to its speed in liquids and gases. Additionally, it compares the speed of sound with the speed of light, noting that light does not need a medium to travel.

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Learning Objectives
• To be able to describe how sound is
produced & travels.
• To be bale to explain why the speed of
sound is different in different materials.
• To be able to contrast the speed of sound
& speed of light.

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What causes sound?
The tuning fork vibrates
and you hear a sound.
Sounds are made when an
object vibrates.
Take a tuning fork and strike
it against a block of wood.
What do you observe?
Sound travels because the vibrating
object makes nearby particles vibrate.
Sound needs a medium to travel through
– it cannot pass through a vacuum.

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Good vibrations!
What vibrates so that each of these objects makes sound?
harp strings
lute strings
drum skin

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How does sound travel through the air?

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Sound waves need particles to travel through
• (12) Sound Needs a Medium to Travel –
YouTube

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Sound needs a substance through which to travel because it
travels by making particles vibrate.
Sound in different materials
Which state of matter does sound travel fastest through?
The particles in a solid are closer together than in a gas,
and more tightly bound than in a liquid. This means
vibrations are more easily passed from particle to particle,
and so sound travels faster.
Sound waves travel fastest through solids.

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Speed of Sound

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Which of these travel faster than the speed of sound in air?
Breaking the sound barrier
The jet fighter and the
meteorite travel faster than
the speed of sound in air.
This is called Supersonic,
breaking the sound barrier
120
600
small aeroplane
jet fighter
cheetah
meteorite
Distance (m)
5
Time (s) Speed (m/s)
900
50
10,000
2
2.5
0.35
450
20
28,571.4

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Which comes first?

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Light does not need a medium to travel
through
Light travels to earth from the sun through outer
space/vacuum where there are no particles!!