3 Sound

you can see waves with an oscilloscope

An oscilloscope can be used to look at waves like sound waves. It makes longitudinal waves look like transverse ones - which makes them easier to understand.

When the waves are bunched up close together the oscilloscope is showing a high frequency sound - or a high note.
Low notes (low frequency sounds) are more spread out.
If the waves are tall (big amplitude) on the oscilloscope then the sound is loud ... quiet sounds have a small amplitude.

Sound waves of a very high frequency cannot be heard but they can be used to scan unborn children still inside the mother.

Ultrasonic waves can also be used to dislodge dirt from delicate objects like jewellry - cleaning them.

These special, high frequency, sound waves are called ultrasonic waves.

Now answer these questions:

  1. What sort of wave is a sound wave ?
  2. What instrument lets you 'see' sound waves ?
  3. High notes are what ?
  4. Low notes are what ?
  5. If the amplitude of a sound wave is altered - what changes ?
  6. If the frequency of a sound wave is altered - what changes ?
  7. Very high frequency sounds are sometimes called what ?
  8. Can ultrasonic waves travel through skin ?
  9. Why is ultrasound useful in hospitals ?
  10. What can ultrasonic waves do to jewellry ?

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