The Ear

Modified: 2026-08-05 3:04 PM CDST

• The ear's job is to transduce sound energy into neural impulses.
  • Remember that sound consists of pressure waves in a medium.
    • The medium can affect the speed of the sound travelling through it, although sound is relatively slow regardless of the medium.

• Let's look at some examples of the interaction of media and sound.
• You may have inhaled helium and then spoken.
  • When you did that, your voice sounded squeaky and high pitched.
  • Why?
  • Your voice changed because you were pushing helium instead of air through your vocal apparatus.
  • Because of helium's physical properties your voice changed.
• Another example is how sound travels through sea water.
  • Sea water conducts sound about 17 times faster than air does.
    • So, sounds can be heard for long distances under the ocean.
    • Submarines try to be silent as possible for that reason.
    • The movie, "The Hunt for Red October," featured a sonar operator as one of its main characters.
    • In that movie the Soviets had developed a new, quieter underwater propulsion system.
    • The sonar operator detected it as a new and different sound.
  • In real life, the Toshiba company of Japan sold some machining equipment to the former Soviet Union a few years ago.
  • The U.S. government was upset because that machinery could be used to manufacture quieter submarine propellers.
• Finally, do you remember the first time you heard yourself on on a recording?
  • You probably said, "That's not my voice."
  • But it was.
  • You are the only one that hears your voice both from vibrations in the air and from vibrations in the bones of your head.
  • Everyone else only hears the vibrations of your voice in the air.
  • That is why singers recording a record use earphones.
  • They want to hear how they sound to everyone else, not how they sound to themselves.

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