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I made this presentation to support a hearing impaired student in my class. The idea is to talk about what sound is, how we hear and about hearing impairments.

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  1. 1. What is sound and howdo we hear it?How are sounds made?How does sound get from the source to your ears?
  2. 2. Sound is a type of energy made by vibrations.When any object vibrates, it causes movementin the air particles. These particles bump into theparticles close to them, which makes themvibrate too causing them to bump into more airparticles. This movement, called sound waves,keeps going until they run out of energy. If yourear is within range of the vibrations, you hearthe sound.
  3. 3. What is sound? Watch this movie tofind out!Click this link if video does not play
  4. 4. The main points from the movie were:- When sounds travel we are actually hearing how the vibrations affectthe air molecules- Molecules squeezing and stretching through the air are what we call sound waves.- Sound travels slower than light. That is why we see lightening before we hearThunder in a storm.-Air molecules in a long tube vibrate more slowly, producing a lower pitch.Air molecules in a short tube vibrate more quickly, producing a higher pitch.-Pitch is measured by the number of vibrations per second. The faster the vibrations,the higher the pitch.
  5. 5. • Sound waves travel through the air and enter the ear causing the ear drum to vibrate.• The vibrations are processed in the ear in the cochlear, which sends messages toour brain, and our brain interprets these as sound.• If sound intensity is too great, or happens for a long period of time, the cells will dieat the beginning of the cochlear.• High frequency sounds are heard by the beginning of the cochlear, and lowFrequency sounds are heard by the end of the cochlear.• This is why many older peoplecannot hear high frequencysounds as well.Just like Mr Murphy!• Sound is measured in decibels. A quiet library is about 40 decibels, while a loudrock band would be about 150 decibels.I can’tstand loudmusic!!
  6. 6. How do we hear sounds?1. Ear canal2. ear drum3. Hammer4. anvil5. Stirrup8. Cochlea (inner ear)9. The nerve of hearingSound wavesEnter the earcanalThe ear drum vibrates and then the hammer, anvil and stirrupvibrate sending the vibrations to the cochlea (inner ear).The little hairs in thecochlea move and theychange the vibrationsinto a signal. This signalis then sent tothe brain through thenerve of hearing like amessage.The brain interpretsthis message for us –and that is how we hear!
  7. 7. Protect your hearingDon’t listen to very loud sounds for longperiods of time.The most significant singlecause of hearing loss inAustralia is exposure toloud noise. 37% of hearingloss is due to excessivenoise exposure.
  8. 8. A hearing loss can result ifthere’s a problem at any pointin the hearing pathway –in the outer, middle or innerears, or in the complex auditorynerve pathway to the brain. - present when you are born- Acquired later, through illness ,accident, exposure to chemicals or drugs- Caused by a blockage or damage to theInner or outer ear, cochlea or auditory(Hearing nerve)Click here for more information on hearing loss in Australia
  9. 9. Click here for more info on frequency and intensity of familiar sounds.
  10. 10. SoundwavesSee soundwaves in action!
  11. 11. One in six people inAustralia has ahearning loss. Withthe ageing of theAustralian population,hearing loss isprojected to increaseto one in fourAustralians by 2050.
  12. 12. Let’s make some sound with :- A plastic cup- A paperclip- Some wool- Some damp paper towelCan you make theSound of a farmyardanimal usingthese things????Click here for the link to the experiment
  13. 13. How does it work?The cup and string demonstration isis an example of how a soundingboard works. The vibrations from thestring would be almost silent withoutthe cup, but when you add the cup, itspreads the vibrations and amplifiesthem (makes them louder.) Pianosand music boxes use wood to act as asounding board to make theinstrument louder.
  14. 14. 5. Why does a flute have a higher pitch than a bass clarinet?Task: Write down the answers to the following questions.1. If someone asked you “What is sound?” how would you explain it?2. In a thunderstorm, why do we see lightening before we hear thunder?3.What is the unit of measurement for sound?4. James listens to his ipod on full volume every day. How will this damage his hearing?6. What are some causes of hearing loss?
  15. 15. A bone conductor is ahearing aidthat allows you tohear without soundgoing through youreardrums.
  16. 16. How It WorksInvented by Beethoven – Perfected by Audio BoneHow It WorksIt is how we normally hearWe all hear sounds through both our bones and our ear drums.Most sounds are heard by our ear drums.The ear drum converts the sound waves to vibrations and transmits them to thecochlea(or inner ear). But in some cases vibrations are heard directly by the innerear – bypassing your ear drums. In fact, this is one of the ways you hear your ownvoice. This is also how whales hear.Invented by BeethovenBone conduction was discovered by Ludwig van Beethoven,the famous 18th century composer who was almost deaf. Beethoven found a wayto hear music through his jawbone by biting a rod attached to his piano.Ludwig Van Beethoven 1770-1827Click here for more information about bone conductor hearing aids