Physics - Chapter 17

• Sound - A longitudinal traveling wave that carries energy in the form of mechanical oscillations of the medium.

  In order for the sound waves to carry, you must have a medium for the waves to travel through
• Hearing - the perception of sound
• Pitch - perception of frequency
• Vw (speed of sound) = f x wavelength
• Threshold of human hearing - 1E-12 W/m^2
• Intensity - The power per unit area carried by the wave

  I = P/a

  units: W/m^2
• Doppler effect - the change in the frequency of a wave in relation to an observer who is moving relative to the source of the wave.
• Vw on top, stationary observer. (-) motion towards observer (+) motion away
• Vw on bottom. (-) motion away from observer (+) motion towards the observer
• first overtone - 3f
• Sounds below 20Hz are infrasound
• Sounds above 20,000 Hz are ultrasound
• Loudness - the perception of intensity
• Timbre - Number and relative intensity of multiple frequencies
• Note - basic unit of music with specific names, combined to generate tunes
• tone - number and relative intensity of multiple frequencies
• Decibel scale - used to measure sound intensity