The Ear

D. Crowley, 2008

The Ear

• To be able to label the ear, and to know the function of each part

Hearing• How do we hear?

• Ears change sound energy into electrical signals, which are sent to your brain

• Vibrating sound waves travel through the air, into the ear, making the eardrum vibrate

• These vibrations then reach the cochlea, where they are changed to electrical impulses which travel to the brain

• The eardrum vibrates the inner ear bones (anvil, hammer, and stirrup)

Hearing

Hearing

1. Sound waves are collected by the ear lobe (pinna)

2. The waves travel along the ear canal 3. The waves make

the ear drum vibrate

4. The small bones of the inner ear amplify the vibrations

5. The cochlea turns these into electrical signals

6. The auditory nerve takes the signals to the brain

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Using the worksheet label, and make the key notes, for how the ear works

Hearing• Complete the hearing

worksheet, adding the key words which are missing, explaining how we hear

Hearing

How We Hear

Something vibrates to produce a sound. Sound travels through the air to the ear.

When the vibrations reach the eardrum they are transferred to the small bones, called the hammer, anvil and stirrup.

The bones pass the vibrations to the cochlea. This contains tiny hairs which change the vibrations to electrical signals, called impulses.

The auditory nerve takes the signals to the brain. We hear the sound when the message reaches the brain.

How Much• We hear a range of sounds from low pitch to high pitch –

this is the audible range

• The audible range is roughly between 20 Hz and 20,000 Hz (but different people have different audible ranges)

• Many animals have a much wider range of hearing, such as dogs, dolphins and bats…

Damaging• The ear is very delicate (thin membranes and tiny bones which

can be damaged easily)

• Think of as many ways as you can which can cause damage to our ears

• Your task is to produce a leaflet either listing the ways we can damage our hearing, or ways in which we can protect our hearing

• It needs to be aimed at pupils you age – so think what is likely to affect your hearing!

DamagingConsider

• Ear getting blocked by wax (stops ear drum vibrating)• Loud bangs / accidents / infections can damage the ear drum

(although it may repair itself)• Middle ear can get infected (antibiotics may help)• As people age the tiny bones in the inner ear can fuse

together, preventing amplification of the vibrations so hearing worsens

• Nerve cells in the cochlea sometimes fail, so the messages are not sent to the brain

• Cochlea can be affected by loud noise (constant loud noises can causes hearing loss, and there is no treatment for this)

Tinnitus

Inner ear cells (these vibrate, changing sound vibrations to electrical impulses

Tinnitus - noises 'in the ears' and/or 'in the head' with no external source

Levels• Constant loud noises can

be extremely damaging to your hearing

• Persistent levels above 90dB can result in hearing damage

• Levels can be measured in decibels – more than 130dB will causes pain

• Above 140dB even short exposure can results in hearing loss