Sound Vibrations

KEY IDEAS

  • Vibrations create sound waves
  • Altering the vibration can alter the sound
  • Sound waves are invisible but we can sometimes observe materials vibrating because of these waves
  • Sound waves can be visually represented on an oscilloscope

EXAMPLE QUESTIONS

  • Have you even seen objects vibrating because of sound?
  • How can you feel sound vibrations?
  • How are high notes different from low notes?
  • How can you make a quiet sound louder or a loud sound softer?

SOUNDS TRAVEL OUTWARDS

  • Sound vibrations travel in all direction away from the source of the sound in a manner similar to the ripples of water created when a stone is thrown into a pond.
  • Sounds however, travel in all direction s, not just outwards, but upwards and downwards as well.

ALTERING THE VIBRATION CAN ALTER THE SOUND

  • Changing the vibration affects the volume, pitch or tone of the sound produced.

SOUNDS ARE INVISIBLE

  • Although sound is invisible, we sometimes can see its effects when objects vibrate (in a large window, for example).
  • An instrument called an oscilloscope can be used to produce patterns that represent sounds.