When hearing is painful - cgrahamphysics.files.wordpress.com

When hearing is painful Can we damage our ears?

© cgrahamphysics.com 2016

What is the link?


Have you ever wondered…

…what we learned from dolphins and use in submarines today?


Objectives:

• To describe what noise is and how it can be measured

• Explain some different types of hearing loss

Key words

• decibel – The unit for measuring the loudness of sound (dB)

• Noise – unpleasant sound

• Noise pollution – constant unpleasant sound

• Threshold of hearing – The quietest sound that can be heard


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

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

Does everyone have the same hearing range?

Hearing Ranges and Hearing Loss


Hearing range can be tested using a pitch sweep, in which

the frequency of a sound wave is gradually increased.

This can be created using a signal generator and loudspeaker.

What range of frequencies can you hear?

What is the hearing range of a healthy young person?

Humans can only hear sounds of certain frequencies.

The range of frequencies a person can hear is called

their hearing range.

20 Hz to 20,000 Hz © cgrahamphysics.com 2016

100,000

10,000

1,000

100

10

1

0

human dog elephant bat mouse dolphin

•Which animals hear the lowest and the highest frequencies?

•Which animal has the largest hearing range?

frequency

(Hz)


The decibel scale

O dB is silence

130 dB is the

loudest you can hear

without pain

Above 140 dB you

get permanent ear

damage


160

140

120

100

80

60

40

20

0

permanent

ear damage

can just

be heard

aircraft

overhead

decibels

circular saw

at 2m

quiet

countryside

pin being

dropped

loud

bell

personal stereo

The Decibel Scale


Noise Noise is any unwanted sound louder than 85-90

decibels. Which of these are noisy?

Yes

Yes

Yes

Yes


Have you ever wondered… Dolphins use ultrasound to find their way.

They use sound to “see”.


What is the submarine doing?

Why does it need to do this?


The ear drum…

What will sounds with a high frequency do to the ear drum?

Make it vibrate very quickly

What will sounds with a large amplitude do to the ear drum?

Make it vibrate a larger distance


Hearing problems

Hearing problems are mainly:

Burst ear drums Wax Broken ossicles


Ear gets blocked by wax

Accidents or loud bangs can damage the eardrum

Middle ear can get infected

Older peoples bones may fuse

Nerve cells in the cochlea degrade with time

Loud noise may damage the cochlea

This can be treated with antibiotics

This might repair itself

This prevents vibration

There is no cure for this

Signals are not sent to the brain

A doctor can wash this out

How might our ears become damaged?


Label the parts of the ear BF ear drum has torn

EG middle ear bones have been damaged

DG Never has been damaged

CF ear canal is blocked

AG hairs in cochlea are damaged © cgrahamphysics.com 2016

Ordering volumes


The units for measuring the loudness of a sound are ________ . We cannot hear any sounds quieter than ________ dB.

When leaves rustle, they have a loudness of ________ dB. People usually talk with a loudness of ________ dB.

Loud noises can ________ our ears and make us deaf. A very loud noise can break the ________.

The cochlea can also be damaged by ________ noise. There are laws to protect people who work in noisy

________. The loudest sound allowed is 90 dB. This is the same loudness as a ________ ________.

________ ________ and explosions are louder than this.

decibel

zero

20

40

damage

Ear drum

loud

places

Road drill

Sirens, thunder


Reducing noise


Understanding Checkpoint:

1) If your eardrum breaks you will be deaf forever 2) People use their ears in the same way bats do 3) Antibiotics can treat some hearing problems 4) The ear bones are in the middle of the ear


Homework, Write a leaflet or design a poster to: • Encourage clubbers to wear ear plugs to

stop damage to their hearing

OR

• Inform patients in a Doctor’s surgery about hearing damage and some advice. Think about what type of people or jobs you might need to consider.


When hearing is painful - cgrahamphysics.files.wordpress.com

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