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Listen here (Brain and senses)

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					Brain   and   senses

Listen here                                                How well can
                                                           you hear?
When you shout you send out                                Your hearing range is from
 invisible sound waves through                             the highest to the lowest
   the air. Your ears pick up                              notes that you can hear.
       the waves and transmit                                      Adults have quite a
         the sound to your brain.                                  small range compared
                                                                   to other animals.

                  The speed of sound                               Children hear higher
                                                                   notes than adults. Your
                  We don’t notice the slight                       range shrinks with age.
                  delay between someone’s
                                                                   Cats, dogs, and rabbits
                          lips moving and                          can hear much higher
                            the sound actually                     notes than people.
                             reaching our ears.                    Bats have excellent
                               It’s too fast!                      hearing. Their range is
                                                                   five times as large as ours.


                                                                     h t he
                                                                 roug
                                                Sound travels th
                                       Headphones feed
                                       different sounds
                                       into each ear so
                                       you feel as if
                                       you’re surrounded
                                       by instruments.




                                                           Why two ears?
                                                           Sounds normally reach one ear
                                                           first and then the other. This
                                                           helps our brains work out
                                                           where sounds are coming from
                                                           and how far away they are.
44
                          Why do we have ear wax?
                                                                                     Listen here

         Outer ear                                                                   A little help
                                                                                     Partially deaf
         What we call the ear is                                                     people may use
         really just the part that                                                   hearing aids.
         we can see. Sounds are                                                      These make the
                                                                                     sounds entering
            collected here, and                                                      the ear louder
              funnelled inwards.                                                     and easier to
                                                                                     hear.



                              Middle ear
                              Sounds arriving here from the
                              outer ear cause the eardrum to
                              vibrate and set off movements
                              in three tiny little bones.
                                                                                           Cochlea
              Ou




                                                        Bones
                                      Ear canal
                te




                     ea
                 r




                          r

air to
         your ear.




                                                                                                            ar
                                                                  M


                                                                      dd
                                                                   i




                                                                                                     re
                                                                         le   ear                       e
                                                                                                 I nn
                                                                Ear drum



Inner ear
The bones moving cause
vibrations in the liquid
deep inside the ear.
                                                                              Tiny hairs are
Tiny hairs in your                                                            moved by sounds.
inner ear pick up these
vibrations in the liquid                                                   Signals travel
around them. The hairs                                                     along these nerves
                                                                           to the brain.
are attached to nerves,
which connect to your brain.
          To protect the skin lining the ear canal, trap dust, and repel insects.                            45

				
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posted:10/10/2012
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