Both can be demonstrated by using a bowl on a table. Place a marble in the bottom of the bowl so that it is not moving. This is called the original position. If the marble is given a light push in one direction, it will try to return to the center of the bowl. This is called a statically stable system. This was the goal of the early airplane designers; that the airplane would try to return to its original position after a disturbance such as a wind gust.

Push that same marble again and watch how long it takes to come to rest in the bottom of the bowl. Again, airplane designers are concerned with how long it would take for a plane to return to its original position after being pushed from its course.

If the bowl is turned over, and the marble placed gently on the top, any slight touch will cause the marble to roll off the bowl. It will not return to its original position! This is called a statically unstable system. Statically unstable airplanes need constant attention to control them. This is not static or dynamic.