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For more information, please see full course syllabus of AP Physics B
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  • Sound waves are longitudinal.
  • In a sound wave in air there is a succession of compressions (or condensations) and rarefactions.
  • For humans, audible sound has frequencies between 20 Hz and 20 kHz.
  • In air, at 0 °C, the speed of sound is 331 m/s. At other temperatures, it is (331 m/s)*SQRT (T/273), where T is the absolute temperature in Kelvin.
  • Sound waves carry energy. The amount of energy transported is the power P. The sound intensity is the power that passes perpendicularly through a surface divided by the area of the surface.


Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.

  • Intro 0:00
  • Longitudinal Sound Wave 0:12
    • Tube Filled With Gas and Piston at One End
    • Compression or Condensation
    • Moving the Piston Back
    • Rarefraction
    • Wavelength
  • Frequency 13:07
    • Diaphragm of a Large Speaker
    • Audible Wave Human Being
    • Frequency Less Than 20 Khz Infrasonic Wave
    • Larger Than 20 Khz Ultrasonic Wave
  • Pressure as a Sound Wave 18:30
    • Sound Wave Propagation in Tube
  • Speed of Sound 25:10
    • Speed of Sound in Gas
    • Speed of Sound at 0 Degrees
    • Speed of Sound in Liquid
    • Speed of Sound in Solid
  • Sound Intensity 46:29
    • Energy Produced/Sec
  • Decibels 51:10
    • Sound Level or Intensity Level
    • Threshold of Hearing
  • Extra Example 1: Eardrum
  • Extra Example 2: Sound Detector
  • Extra Example 3: Lightning and Thunder