1. Sound waves and the Ear

2. Sound Sound travels in waves. We “hear” vibrations of molecules.

3. Speed of Sound Depends on what it is traveling through. Air  340 m/s Liquids  1400 m/s Solids  5500 m/s Why? The more dense = more particles to pass on energy

4. Frequency Human hearing is between 16Hz-20 000Hz (20 kHz) Dogs can hear up to 80 000 Hz and bats up to 120 000 Hz Hearing test http://www.youtube.com/watch?v=4G60hM1W_mk

5. The Decibel Scale A relative scale measuring the intensity or amplitude of noise Above 100 dB will do damage to the ear. Above 120 dB – pain and immediate loss of hearing

6. Source Intensity Level Instant Perforation of Eardrum 160 dB Military Jet Takeoff140 dB Threshold of Pain130 dB Front Rows of Rock Concert110 dB Walkman at Maximum Level100 dB Large Orchestra 98 dB Vacuum Cleaner 80 dB Busy Street Traffic70 dB Normal Conversation60 dB Whisper 20 dB Rustling Leaves10 dB Threshold of Hearing (TOH)0 dB

7. The Ear

9. Pinna or Auricle Auditory canal Outer Ear

10. Pinna or Auricle Only visible part of ear Shaped like a funnel *picks up sound vibrations

11. Outer Ear Auditory Canal 2.5 cm long *carries sound vibrations to ear drum Lined with fine hairs and glands that secrete wax –> *prevents foreign particles from entering ear (ex. dust)

12. Pinna or Auricle Auditory canal Outer Ear Tympanic Membrane Ossicles Eustachian tube

13. Middle Ear Tympanic Membrane (eardrum) Thin flexible membrane About 1 cm in diameter *moves with sound vibrations

14. Middle Ear Ossicles 3 small bones Amplify the sound waves by 20%

15. Middle Ear Eustachian Tube Connects middle ear to pharynx Equalizes pressure during swallowing

16. Pinna or Auricle Auditory canal Outer Ear Tympanic Membrane Ossicles Eustachian tube Semi-circular canals Cochlea Vestibule

17. Inner Ear Semi-circular canals Filled with liquid *BALANCE when moving*

18. Inner Ear Vestibule Links semi-circular canals to the cochlea Balance when not moving

19. Inner Ear Cochlea Liquid filled Walls covered with hairs (auditory nerve cells) Hairs transform vibrations into a nerve impulse

21. Pinna or Auricle Auditory canal Outer Ear Tympanic Membrane Ossicles Eustachian tube Semi-circular canals Cochlea Vestibule Auditory Nerve

22. Sends information (nerve impulses) to the brain

23. Video clips Intro – parts - http://www.youtube.com/watch?v=ahCbGjasm_E&feature=related Stomp - http://www.youtube.com/watch?v=KY7_TIktQFs&feature=PlayList&p=FE42A62D04D5C9 B7&playnext=1&playnext_from=PL&index=6 http://www.youtube.com/watch?v=KY7_TIktQFs&feature=PlayList&p=FE42A62D04D5C9 B7&playnext=1&playnext_from=PL&index=6 Hearing loss and hair cells - http://www.youtube.com/watch?v=MGj- cdn2M9o&feature=PlayList&p=FE42A62D04D5C9B7&playnext=2&playnext_from=PL&in dex=7