8l sound and hearing

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8L Sound and hearing

Making sounds

Hearing and deafness


Too loud!


Making sounds



8L Sound words

1 vibration

2 pitch

3 loudness

4 sound

5 amplify

A how high or low it sounds to the listener

B vibrations that can be heard

C to make sound louder

D how loud or quiet it sounds to the listener

E a backwards and forwards movement which transmits sound

Match the words to the definitions.

E a backwards and forwards movement which transmits sound

A how high or low it sounds to the listener

D how loud or quiet it sounds to the listener

B vibrations that can be heard

C to make sound louder


8L Describing waves

What does a large amplitude tell you about the sound?

What does a large number of waves (frequency) tell you about the sound?

What unit is used to measure frequency?


8L Sound pictures

Match the description to the oscilloscope pattern:

1. Low-pitched sound, very loud

2. Loud, high-pitched sound

3. Medium sound with medium pitch

4. Quiet, high-pitched sound

A B C D

D

C

B

A


8L Sound speeds

Concorde was the first passenger jet to travel faster than the speed of sound. But how fast is that?

The speed of sound:

In air = 330 metres per second

In water = 1500 metres per second

In steel = 6000 metres per second

Why did native American trackers put their ear to the ground if they wanted to listen for their prey?


1. I can increase the pitch of a note on a guitar by...

a) plucking the string harder

b) tightening the string

c) holding the guitar tighter.

2. I play the lowest notes on an electric guitar by...

a) not pressing on the strings on the fretboard

b) touching the strings very gently

c) turning the volume down on the amplifier.

8L Rock legends?


3. Hitting the strings hard on a guitar will...

a) make the note louder

b) make the note higher pitched

c) hurt my fingers.

4. The sound from an electric guitar dies away when...

a) the string stops moving

b) the guitarist stops plucking the strings

c) the strings are magnetised.

8L Rock legends?


5. A drummer can change the pitch of the drum by...

a) changing the tightness of the drum skin

b) hitting the skin harder

c) using different drumsticks.

6. A drummer grabs hold of a vibrating cymbal to...

a) stop it making a sound

b) change the pitch of the sound

c) stop it falling off the stage.

8L Rock legends?


8L What is sound?

Sound is created by something vibrating. Imagine the surface of a drum.

As the skin wobbles it pushes on the air next to it and squeezes it to make a little area of high pressure.


8L What is sound?

Then the skin moves the other way and creates an area of low pressure.

If this happens over and over again you get areas of high and low pressure being made.

These areas pass through the air and to our ears where we detect them as sound.


8L Match signals to patterns of particles

We can see these areas of high pressure with a microphone and an oscilloscope.


8L The frequency range

Make a list of these in order of frequency, starting with the lowest.

A The note middle C in the middle of a piano keyboard

B Bottom string on a bass guitar

C Typical whistle for a dog

D Rumble from an earthquake

E The highest note sung by a human being

D Rumble from an earthquake

B Bottom string on a bass guitar

A The note middle C in the middle of a piano keyboard

E The highest note sung by a human being

C Typical whistle for a dog


Match the oscilloscope traces to the source of the sound.

1. A flute playing a single clear note

2. A dog whistle

3. A milk bottle dropped onto a floor

4. A rumble of thunder

A B C D

B

C

D

A

8L I’ll name that tune in...


1. The softer you hit a drum, the quieter the sound.

2. Louder sounds are higher pitched.

3. Bigger vibrations make louder sounds.

4. Hollow objects make sounds louder.

5. Carpets and curtains make sounds louder.

8L Sound as a … sound?

True or false?

TRUE

FALSE

TRUE

TRUE

FALSE


1. High sounds have a low frequency.

2. Dogs can hear higher pitched sounds than humans can.

3. Some sounds can make you deaf.

4. Hard surfaces reflect sound.

5. Sound travels faster in water than steel.

8L Sound as a … sound?

True or false?

FALSE

TRUE

TRUE

TRUE

FALSE


Hearing and deafness

8l Sound and hearing


8L The human ear


8L Hear this!

Which parts can move?

Which part carries a nerve signal?

Which part is made of bone?

ear flap (pinna)

sound waveseardrum

cochlea

bones of middle ear nerves

to brain


8L Batty!

Insect-eating bats use sounds with a frequency of 80 000 Hz (or 80 kHz) to ‘see’ their prey.

The bat sends out a sound and then listens for the echo as it bounces back from the insect.

The bat compares the sound it hears from both ears to work out the direction the insect is in.

What would happen to a bat if it went deaf in one ear?


Too loud!



8L Measuring loudness

Why do we need a way to measure the loudness of sound?

What unit is used to measure sound?

I’ve asked you to turn that rubbish down!

It’s too loud. You’ll damage your ears.

It’s not as loud as you have the television.

I’ve already turned it down – and it’s not rubbish!


8L Hear this!

8l sound and hearing

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