WHAT IS NON PERIODIC CHANGE
*Tornado, Volcanic eruption, Tsunami, etc. (by that I mean most of the natural disasters)
Any motion whose characteristics don't repeat at regular intervals.
-- The motion of a car driving several blocks on a busy downtown street.
-- The motion of my dog on a walk around the block.
-- The motion of fingers as they type on a keyboard.
-- The motion of fingers as they play a song on a keyboard.