Definition

         "Any motion that repeats itself identically at regular intervals, in which the restoring force is proportional to the displacement".

 Equation:X= displacement from the initial position.

 

This is an example of a Harmonic Motion model. The model shows that it repeats itself in the form of a wave. When the wave has a low part, it is a trough. When it's at a high point, it's a crescent. From one crescent to the next identical crescent is a wavelength. A compressional wave, which must travel through a medium like air or water, repeats this constant pattern.

This was provided by wikipedia at http://en.wikipedia.org/wiki/Image:Simple_harmonic_motion_animation.gif