Sound Waves

Sound Waves

1. PROPERTIES

   • loudness (amp) - loud and quiet
   • pitch(frequency) - high and low
   • quality (wave form/shape) - simple and complex
   • ALWAYS LONGITUDINAL
     • made of
       • compressions
         • Constructive
         • high pressure
         • speakers= pushed out
       • rarefractions
         • depression
         • destructive
         • low pressure
         • speakers= pushed in

2. FUNTIONS

   • transmit energy through a medium
   • go thru, around, and reflect off of things
   • hav constructive and destructive interference
   • similar to mechanical waves

3. TUNING FORKS

   • always vibrate at a specific frequency

4. OSILISCOPE

5. PRESSURE/TIME GRAPH

   • shows how pressure changes over a period of time

6. Definition

   • sound made by changes in pressure

7. SOUND INTENSITY

   • measure of the amount of sound reaching an area (1m2) in 1 s
   • exact measurement verses perception(loudness)
   • pW/m2
   • sound intensity level - to the power of 10
     • measured in the Bel (B)
       • or the decibel (dB)
     • intensity increases by factor of 10 = increases by 1B
   • conversions
     • 1B = 10pW/m2

8. VELOCITY OF SOUND IN AIR

9. HUMAN HEARING

   • 20 - 20 000 Hz range
   • dogs - 50 - 50 000 Hz range
   • infrasonic
   • ultrasonic
   • supersonic
   • subsonic