Sound

Sound

1. EAR : helps us to hear and keep our balance

   • Outer Ear : Vibrations from the medium travel to the ear. The vibrations are funnelled through the ear canal. Vibrating air sets up vibrations in ear canal.
   • Middle Ear : War drum transmits vibrations to small bones called ossicles, causing them to vibrate.
   • Inner Ear : The cochlea vibrates. These vibrations are detected by the hair lining which are then detected by the hair lining which are then detected by the auditory nerve where impulses are sent to the brain

2. Longitudinal wave

   • Light travels much faster than sound

3. happens due to the medium's vibrations

   • since a medium needs to vibrate, sound travel's the fastest in a solid -> liquid -> gas. Sound does not travel through a vacuum
   • violin : rubbing a bowl against strings or by plucking them
   • piano: hammer hits a specific string

4. Decibel scale (dB)

   • measures intensity of sound
     • high intensity sounds can cause damage to the hair lining of our ears. The hair lining cannot be regenerated over time.
       • Protecting the ears is very important. One should: Try to limit exposure; Buy quieter products; Regularly see a professional; Buy noise cancelling headphones if the need arises

5. Waves properties

   • Amplitude : maximum displacement of a wave from the equilibrium
   • Wavelength: length of 1 wave cycle
   • Frequency: number of waves in 1 second. Unit : Hertz
   • Period or Periodic Time: time taken to complete 1 wave. Unit : seconds

6. Importance of Sound

   • Humans
     • Signals
     • echoes
       • to determine the depth of the sea
   • Animals
     • snakes
     • bats

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