Sound

Sound

1. A medium in the form of a solid, liquid or gas is needed for the transmission of sound.

2. Sound can be described by pitch (frequency) and volume (amplitude).

3. Increasing the pitch = more waves on screen.

4. Increasing the volume = higher amplitude

5. Methods of Measuring Sound

   • Starting pistol, when see smoke start stopwatch, when hear bang, stop stopwatch.
   • Stand known distance from wall, fire pistol, when it comes back to you stop stopwatch.
     • Either divide the distance by 2 or half the time taken.
   • Electronic timer

6. Human range of hearing = 20 Hz to 20 000 Hz

7. Ultrasound = 20 000 Hz +

   • Uses
     • Cleaning delicate instruments
     • Scanning unborn children in mothers womb
     • detecting tumours
     • (SONAR) working out how deep water is
     • (SONAR) Checking for fish

8. Sound level is measured in decibels, dB.

9. Noise pollution, e.g. lawnmowers, crying

10. Prolonged exposure to loud noise = damage to hearing

    • Use ear-defenders to prevent

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