Transcript The Ear - Noadswood Science

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
•
The eardrum vibrates the inner
ear bones (anvil, hammer, and
stirrup)
•
These vibrations then reach the
cochlea, where they are changed
to electrical impulses which travel
to the brain
Hearing
Hearing
4. The small bones of
the inner ear amplify
the vibrations
1. Sound waves are
collected by the ear
lobe (pinna)
6. The auditory nerve
takes the signals to the
brain
6
4
1
2
2. The waves travel
along the ear
canal
3
3. The waves make
the ear drum
vibrate
5
5. The cochlea
turns these into
electrical signals
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!
Damaging
Consider
• 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
Tinnitus - noises 'in the ears' and/or 'in the head' with no external source
Inner ear cells (these vibrate, changing sound vibrations to electrical impulses
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