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Teachers’ notes – Hearing sound
Synopsis
In this activity, learners consider how and why they are able to hear a range of familiar
sounds. They watch a video clip of granules of sugar moving on a stretched skin as a result of
a sound source and consider how this might relate to the ear and hearing. Learners consider
what they know about the ear and the way it helps people hear sounds and how and where
information about the ear might be gathered. After presenting their findings, learners plan and
make a model to show how the ear works. They compare the ears of different animals using
photographs and find out and consider how humans improve the way they hear and maximise
hearing potential. Finally, learners plan an investigation to find out how distance affects the
loudness of sounds that we hear.
Curriculum links
Interdependence of organisms:
1. the names, positions, functions and relative sizes of a human’s main organs
How things work
4. how different sounds are produced and the way that sound travels
Skills
Communication: 1, 2 & 3
Enquiry – Planning: 2, 3, 4, 5, 6 & 7
Enquiry – Developing: 1, 2, 3, 4, 5, 6 & 7
Enquiry – Reflecting: 2, 3, 4, 5 & 6
Activities
Tab 1
Learners are asked to consider what sounds they can hear in
their local environment. They are encouraged to go on a
‘listening walk’ and to record and identify sounds they hear. It is
also suggested they sit in silence and consider what they hear
and how difficult it is to identify different sounds.
Encourage learners to record a range of sounds from their local
environment. These can be used as a stimulus in class for other
learners to identify the sounds and to support discussion. Remind
learners about the health and safety issues relating to being out
on their own.
Tab 2
Learners listen to familiar sounds and consider where they might
hear these sounds, how they are able to hear these sounds, how
the sounds travel and what they travel through to reach the
listener.
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1. Football crowd, 2. Aeroplane, 3. Electric drill, 4.
Cockerel crowing, 5. Hair dryer, 6. Baby crying, 7. Wind chimes,
8. Train, 9 Wind, 10. Road traffic, 11 Pop music, 12. Car alarm.
Tab 3
A piece of balloon rubber is stretched across the top of a glass
beaker. Granules of sugar are placed onto the stretched balloon.
A child claps their hands in close proximity to the beaker but not
touching it. This set up is shown to learners as a video clip. They
observe the video and consider what they see happening.
Teacher’s notes:
The child clapping produces a sound wave that travels through
the air. The force of the sound wave makes the stretched rubber
skin begin to vibrate which results in the granules of sugar
moving around. This provides evidence that sound travels
through the air.
Tab 4
Learners consider what they know about the ear and the way it
helps people hear sounds. They are asked to record their ideas
using – what I definitely know, what I think I know and what I
would like to know. Encourage the learners to express their
own ideas and opinions as a stimulus for discussion. Learner’s
alternative viewpoints will be essential to move learning forward
at this stage.
Tab 5
Learners consider how to find answers to questions raised on tab
3. How and where will information about the ear be gathered?
They use ‘Just a minute’ to present what they have learned about
the ear.
Rollover questions are provided to support discussion.
Encourage learners to think beyond the ‘internet’ for where they
might locate information. Ask them to explain where and how
their information was located and to analyse which information
sources provided what they needed and which were the most
reliable and so on.
Tab 6
3 in 1 Plan – Develop – Reflect tab structure. Learners plan and
make a model to show how the ear works.
Teacher’s notes:
Generally, the ear can be thought of as consisting of three main
parts – the outer, middle and inner ear.
The outer ear has two parts:
i) the visible cartilage covered in skin called the ‘pinna’. This part
protects the eardrum (tympanic membrane) and collects sound
waves. It is what we can see on both sides of the head and refer
to as the ‘ears’. It also collects sound waves so that they move
through the ear to the eardrum.
ii) the auditory ear canal called the ‘meatus’. This is the channel
the sound waves move through on the way to the eardrum after
being collected by the pinna. ‘Cerumen’ commonly known as ear
wax is secreted in the ear canal. The wax protects the ear canal
and helps keep it clean, though an excessive build up of wax can
damage the eardrum and reduce sound transmission.
The middle ear:
This refers to a space filled with air called the ‘tympanic cavity’
that is separated from the outer ear by the eardrum. Within this
cavity are three small connected bones that vibrate in response
to the vibrations of the eardrum. The bones are called the
‘malleus’, ‘incus’ and the ‘stapes’ but due to their shapes are
commonly known as the ‘hammer’, ‘anvil’ and ‘stirrup’. The main
function of this chain of bones is to amplify sound. The
‘Eustachian tube’ connects the middle ear to the back of the nose
and throat. This tube opens when we swallow or yawn and
serves to ensure that air pressure is the same on both sides of
the eardrum. A pressure difference results in the blocked feeling
sometimes experienced when in an aeroplane or driving to a
higher altitude. When the tube opens you might experience a
popping sensation as the pressure becomes equal again.
The inner ear:
This is the most complex part of the hearing system and is
located in a very small space of hard temporal bone and is not
accessible by examination. It consists of three closely related
parts:
i) the cochlea is a shell shaped spiral tube that contains the
sensory organ of hearing and is directly responsible for hearing.
It contains three fluid filled compartments that convert sound
vibrations into nerve impulses which are transmitted to the brain
via the acoustic nerve.
ii &iii) three semicircular canals and the vestibule or ‘labyrinth’
serve to maintain balance and equilibrium. When the head
changes position the movement of the fluids in these canals
provides the brain with the information to identify the extent and
direction of movement so that balance is maintained.
Tab 7
Learners compare the ears of different animals. They consider
whether all animals have ears and gather more information about
hearing in a range of animals.
Teacher’s notes:
All mammals have outer ears. Many mammals that live in very
hot climates have large ears that help to dissipate heat from their
bodies. Birds and reptiles have no visible outer ear but do have a
middle and inner ear. Insects do not have ears as such though
most can detect sound – either through some form of ‘tympanum’
or the movement of small hairs on the legs or body.
1. bat
2. mouse
3. polar bear
4. rabbit
5. elephant
6. owl.
Tab 8
Learners consider and find out how we can improve the way we
hear/maximise our hearing potential – position etc. Six
photographs showing different things people do to improve
hearing are provided for the learners to think about and discuss.
Rollovers encourage them to explore string and funnel
telephones – though exploration of any method of enhancing
hearing should be encouraged.
Teacher’s notes:
There are six photographs shown on this tab. One image shows
a person shouting and another shows someone using a
‘megaphone’. In essence both of these images show that
increasing the loudness of a sound helps the listener as louder
sounds are easier to hear. They travel a greater distance and
have a greater volume. One image shows an electronic hearing
aid that typically fits in or behind the ear and is designed to
amplify and modulate sound waves. This is a more modern take
on the ‘ear trumpet’ shown in another photograph – simply a
funnel designed to collect more sound energy and direct it to the
eardrum. This effect is simply adapted in another more familiar
image of putting a cupped hand to the ear- a method commonly
used by many people of all ages. The final photograph shows
two children using ‘string telephones’. When someone talks into
one cup the bottom of it will vibrate very quickly. The vibrations
travel through the string and start to vibrate the bottom of the
second cup, producing further sound waves that travel to the
listener, letting them hear what was said.
Tab 9
3 in 1 Plan – Develop – Reflect tab structure. Learners plan an
investigation to find out how distance affects the loudness of
sounds that we hear.