Sound

Sound

1. Definition

   • form of energy
     • produced by vibration of
       • air
       • plates
       • membrane
       • string

2. Characteristics

   • depends on temperature of air
   • faster in hot air than cold air
   • fast thru liquid and gases
   • fastest thru solids
   • waves are longitudinal
     • move back and forth
     • cannot travel in vacuum
     • can be reflected and absorbed

3. Echo

   • repetition of sound
     • caused by reflection of sound waves
     • human ear can hear two sounds separately
       • original
       • reflected
       • if there is a time interval of one-tenth of a second
   • conditions
     • minimum distance
       • 17m
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