Longitudinal waves

• Longitudinal wave in a slinky

  • Regions where coils become closer are called compressions (C)
  • Regions where coils are further apart are called rarefactions (R)
• Sound propagates in the medium as a series of compressions and rarefactions
• Propagation of disturbance in a slinky

  Compared to sound propagation in the medium
• Longitudinal waves

  • Individual particles of the medium move in a direction parallel to the direction of propagation of the disturbance
  • Particles do not move from one place to another but simply oscillate back and forth about their position of rest
• Sound waves are longitudinal waves
• Transverse wave

  • Particles do not oscillate along the direction of wave propagation but oscillate up and down about their mean position as the wave travels
  • Individual particles of the medium move about their mean positions in a direction perpendicular to the direction of wave propagation
• Transverse wave

  • Waves on the water surface when a pebble is dropped in a pond
• Light is a transverse wave, but the oscillations are not of the medium particles or their pressure or density - it is not a mechanical wave</b>