The ZOETROPE was invented in the mid-1800’s, long before the development of the movie camera and animated cartoons, as a way of deriving motion from still pictures. Visitors are invited to look through the slits at the drawings and turn the crank at the side of the exhibit as fast as they can. (Turning the crank the other way causes the balls to appear to roll in the opposite direction.) As the cylinder rotates, the user sees a fragment of the picture on the far side of the cylinder. When the next slit passes the eye it reveals a slightly different part of the picture. Each image lingers in the viewer’s eye and brain long enough to merge with the next image. This phenomenon, called persistence of vision, creates the illusion of a continuously moving picture.