In traveling wave, energy is propogated in a definite direction and with a definite speed.
 If we whip one end of a rope back and forth, a traveling wave moves down the rope.
 The intriguing feature of this wave is that all the actual motion is tranverse to the overall alignment of the rope.
Think of a wave formed by a crown in a stadium, in which each spectator successively moves his or her arms up and down in response to a neighbor's motion, propagating a wave around the stadium perpendicular to the direction of the arm motion,
The wave travels from one side of the stadium to the other side much faster than any spectator could.

Usage¡G
  Green line: displacement from the equilibrium point.
  Yellow line: velocity of the medium
  Red line : acceleration
  Move the mouse to change the observed points.