Types of Mechanical Waves

There are several different areas in which there can be qualitatively different types of waves.  The table below lists most of these Areas, and lists the choices available in those areas.
The "Other Choices?" column indicates whether there are more choices than the examples listed here; this will say "Continuum" if the choices describe the extremes with a continuum of choices in between.

Area Choices Other Choices? Links
Wave motion
  • Traveling Waves: waves crests move, transporting energy
  • Standing Waves: wave crests remain stationary
Continuum Standing as combination of traveling, AVI file or MOV file
Medium motion
  • Longitudunal (AKA Compression): medium pieces move parallel to wave motion or to extent of wave.
  • Transverse: medium pieces move perpendicular to wave motion.
  • Circular Transverse: medium pieces move in circles around wave motion direction.
  • Circular Longitudinal: medium pieces move in circles with the motion direction in the plane of the circles.  This is what water waves are.
  • Torsional: medium pieces oscillate in arcs around wave motion direction.
Yes Animations
( page by Dan Russell of Penn State)
Spatial Extent of Wave
  • Continuous (AKA Wave Train):  no beginning or end.  Obviously, real life can only approximate this.
  • Pulse (AKA Shock Wave): Only a single wave crest.
  • Packet: A limited number of wave crests with an amplitude that is biggest in the center and approaches zero away from the center.
Continuum Use this applet (from PhET) to make your own
Extent of Medium
  • One Dimensional:  Positions in the medium can be specified by using only a single number.  Pieces of the medium MAY move in directions other than along the medium.
  • Two Dimensional:  Positions in the medium can be specified by using only two numbers.  At the interface between two substances, 2D waves MAY involve motion of those substances some distance away from the interface.
  • Three Dimensional: Positions in the medium require three numbers to be specified.  Wave propagation can occur in any direction.
 No

Examples

1D: Ropes, long springs

2D: Water surface waves, Drum heads, Plasmons

3D: Sound (in air or any medium), Light