12 April 2023

SoundSound

Target:

To understand what we have to do to an object in order to produce a sound

Instrument What makes the soundHarpViolaDrumsGuitarBeeCymbals

The objects in the pictures are producing sounds. How does each object produce the sound?

Next

Return Sound 1 Sound 2

Previous

Press buttons to hear the sounds again.

The objects in the pictures are producing sounds. How does each object produce the sound?

Next

Return Sound 1 Sound 2

Previous

Press buttons to hear the sounds again.

The objects in the pictures are producing sounds. How does each object produce the sound?

Next

Return Sound 1 Sound 2

Previous

Press buttons to hear the sounds again.

Instrument What makes the soundHarp Vibrating stringViola Vibrating stringDrums Vibrating skinGuitar Vibrating card in loudspeakerBee Vibrating wingsCymbals Vibrating metal disc

How sound travels…As we know, sound waves are formed when something vibrates. But how does the sound reach our ears?

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

Air molecules

Studying sound

Signal generators can produce signals over a range of frequencies and of varying amplitudes.

Loudspeakers convert the signal from the signal generator into sound waves.

The oscilloscope allows us to study the frequency and loudness of a sound.

PITCH OF THE NOTE

The frequency indicates the pitch of a note. High pitch notes have a short wave length.

Low pitched note High pitched note

Pitch (or frequency)

A high pitch sound. A low pitch sound.

The shorter/longer the wavelength of the wave on the trace; the lower/higher the frequency of the sound.

The more waves you can see, the higher the pitch/frequency.

Oscilloscope traces

Which trace represents the highest pitched sound?

A B

‘A’ is the highest pitched sound because it has the shortest wavelength/most number of waves visible.

FREQUENCY

• The frequency is the number of sound waves in one second.

• It is measured in Hertz

• Symbol = (Hz)

Sound : What can I hear?

Increase the frequency of the signal provided by a signal generator whilst keeping the volume the same.

The lowest frequency I can hear is ________ Hz

The highest frequency I can hear is __________ Hz

20

20 000

Sound : We are not all the same.

You have just found your hearing range - could everyone hear exactly the same frequencies as you?

We all have slightly different hearing ranges but almost 1 in 5 people suffer some sort of hearing loss. This changes with age. A baby has a wider range than an older person.

Temporary hearing loss may be caused by ear infections and colds and hearing recovers.

Permanent hearing loss and deafness can be present at birth or occur if the ear is damaged or diseased.

Sound : Are we all the same?

Hearing is tested using an audiometer and the results are shown on an audiogram.

0

10

20

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0 2000 4000 6000 8000

Frequency of sound [Hz]

optimalhearing

impairedhearing

Heari

ng

Loss

[d

B]

GOOD HEARING

POOR HEARING

Sound : Hearing Ranges

0 1 10

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1,0

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Frequency [Hz]

Moths

Elephants

Mice

Humans

Pigeons

Bats

Hearing Ranges of Animals

An

imal

Which animal can hear the lowest frequency?

pigeons

Which animal can hear the highest frequency?

moths

human

cat dog bat dolphin

elephant

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200

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75

50

25

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Frequency

of

sound in k

Hz

The hearing ranges of different animals.