doctor doctor I feel like watching Operation Ouch you can watch them now on the free BBC iPlayer app
please welcome to the lab Ozzy Ossicles
are you ready to watch? yes. are you ready to do this experiment
it's Ozzy Ossicles don't worry it's me I have made a very simplified model of the human middle
and inner ear so imagine there's a big ear out here and that catches the sound waves and directs
them down the ear canal towards the eardrum or tympanic membrane when the sound waves hit the
eardrum they make it wobble when the eardrum wobbles it moves the ossicles the three bones
in your middle ear the malleus wobbles and hits the incus next the incus wabbles and
makes the stapes wobble and then the stapes moves against the cochlea which turns the sound into an
electrical signal and sends it to your brain okay zoned let's see it in action why don't we start
with a quiet sound here we go so if we imagine a sound wave arriving at the tympanic membrane
the air molecules which are represented by these pink ping pong balls start to vibrate back and
forth and they tap on the tympanic membrane passing a small amount of energy between the
bones and the stapes Taps lightly on the cochlea so there's no damage let's see what happens when
a sound wave with more energy hits the eardrum let's fire up some big sound waves down the ear
canal now the eardrum is moving more and that's moving the ossicles more so more energy is being
passed along and now the stapes is hitting the cochlear even harder and sometimes it's hitting
it so hard I'm worried it might be about to damage it but you have an amazing job Chris
which will help prevent damage because you are the acoustic reflex here we go let's make a
louder noise I'm holding two red strings this one is the tensor tympani and this one is the
stapedius and their muscles attached to two of the ossicles and I'm pulling them tight
stopping them moving so less energy gets moved from the eardrum through to the cochlear so
there's less risk of damage Chris this is working brilliantly your acoustic reflex does an amazing
amazing job brilliant work Chris but sometimes sounds can be so loud it's too much energy for
your acoustic reflex to cope with and it can damage the cochlear Chris it's time to unleash
are you sure about this sound absolutely sure Chris but first I need to modify the
stapes here's an operation you must perform head to wherever you download
your apps download the free BBC iPlayer app now and watch brand new Operation Ouch
pins balloon spells disaster exactly Chris time to crank it up to 11. it's gonna go
and that is why you have to be careful around loud noises prolonged exposure can damage your
cochlear now it's not going to explode like that but if you're ever told to wear ear Defenders or
headphones specially designed for children make sure you wear them but then you can rock out
so we've shown you that sound travels in waves Quiet Sounds have waves with a low Peak and
carry small amounts of energy and loud sounds have waves with tall Peaks that carry lots of
energy too much energy can damage your cochlear and that you have two amazing bits of body kit
called the tensor tympani and stapedius muscles and they help prevent too much energy being passed
by your ossicles to your cochlear reducing the risk of loud noises damaging it well all
this has put me in the mood for playing with my favourite blue giant balloon if you'll excuse me
where did I put it I love that balloon I wonder where it could be
ouch I think I've got a fever BBC iPlayer app fever I've just downloaded it for
free to watch brand new Operation Ouch whenever I want and you should do it too