HOW
DO PEOPLE HEAR
Kyle
Shalanda
Sound
Our
ears 
take
sounds 
and change them into nerve messages. The nerve messages travel to the brain
.
The brain tells us the sounds
we hear.
Parts
of the Ear
Sound
waves are funneled down the trumpet shaped outer ear to a sheet of skin
called the eardrum. This works like a door, keeping the dirty outside world
away from the sensitive inner ear.
The
middle ear has three tiny bones that connect the eardrum to the inner ear.
The
inner ear is a coiled tube filled with liquid and lined with tiny hairs
of varying lengths. Each sound wave makes some of the hairs vibrate. The
brain can tell what kind of sound has been heard from the way the hairs
vibrate.
A
sound always has meaning.
For example when the telephone rings it tells you there will be someone
waiting to talk to you.
Sounds
are just as important to animals, especially when they want to go courting
or to stake out their territory.
Croaking
for company
How
does a male find a female in a forest? This frog from Australia has the
answer. It takes a deep breath, swells out a pouch in its throat until
it is almost doubled in size, and then uses it as a sounding board to make
a deep croaking sound that can be heard for a long way.
Each
frog has a different size of pouch and this means that its sounding board
gives a special not. In a similar way people have different shaped mouths
which help give each voice its own sound.
Bleating
for comfort
Sheep
bleat gently to tell their lambs where they are and that all is well.
If
a fox or some other sign of danger appears in the distance the bleat changes
note and says: "Take care."
The crow with two meanings
As soon as it is light
the rooster begins to crow. But the "cock-a-doodle-doo" is not a chicken's
form of yawn as it wakes up. The rooster is making important signals to
other chickens. The cry says to female chickens: "Come here, there is a
friendly welcome." At the same time it gives this signal to other males;
"Watch it guys this is my patch."
HOT
LINKS
animal
sounds
a
description of the ear
the
virtual zoo
