Fundamentals of sound

Fundamentals of Sound

From musical boxes to iPods

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Sound travels to your ear

The air vibrates but does not travel from the alarm to the ear.

Sound

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Whales sing to each other.

Sound travels through water.

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Telephones -- Are like a sound system

The electrical signal is amplified

A microphone changes sound to an electrical signal.

A loudspeaker changes the electrical signal to sound.

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Telephones -- The message travels through miles of

wires as an electrical signal.

microphone

loudspeaker

electrical signal

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Radio signal

Mobile phones use radio

Sound - electrical signal - radio signal - electrical signal - sound In one phone the sound is changed into an electrical signal then into a radio signal.

Sound - electrical signal - radio signal - electrical signal - sound

In the second phone the radio signal is changed into an electrical signal then into sound.

Mobile phone beacons

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What is this?

What sound does she make?

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What are these?

What sound do they make?

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What sound does this make?

How does it make the sound?

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Bells

What sounds will they make?

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Size matters!

Large things make

___________ sounds

Small things make

___________ sounds

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New words:

High pitch = high frequency

Low pitch = low frequency

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What have we learned? Vibrating objects make sounds

Sound needs a medium through which to travel – air, water, string - - -

The medium vibrates but does not travel with the sound

Large vibrations make loud sounds- small vibrations make quiet sounds

Large objects make low frequency sounds- small objects make high frequency sounds

In strings the frequency of the sound depends on the length, thickness, and tension.

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Can you spot the baby?

Sound has lots of uses

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Ultrasound is very, very high frequency sound.

It is used to see inside people - to see

babies before they are born

if a heart is working well

blood flow