Objectives
Today we will explore the phenomena of “persistence of vision”, and make a replica 19th Century toy illustrating the principle. Students should also understand that these devices were precursors to the invention of the movie film camera.
What is Persistence of Vision?
Concept
Animation has a rich history, dating from prehistoric cave paintings through to today’s high tech 3D animation simulating real life; this is credited to a phenomenon called “persistence of vision”.
Animation history begins with a simple mechanical toy called the “Thaumatrope”. This optical toy was in wide circulation in Europe and America in the 19th Century. The toy was very simple - a paper disc attached to two pieces of string. Each side of the disk had a drawing, a classic being one side a bird, the other a cage. The disk was twirled by twisting the strings between the fingers. This produced an effect of blending the two images together; the bird was in the cage.
This perceptual phenomenon is known as the “persistence of vision”.
Our eyes hold on to images for slightly longer than they are actually projected. Rather than a blur we perceive the images as a continuous picture. This phenomenon is used to its greatest effect in television and films, where rapid sequences of still images give the illusion of movement.
Tasks
Build a Thaumatrope. Use a piece of heavy cardboard to produce some paper discs. Use a hole punch to make two holes on opposite sides of the disc. Thread some string though the holes and the Thaumatrope is complete. Recreate the bird in a cage effect, or try something else. Experiment with photographs cut out from magazines, on one side of the disc stick the photograph of a celebrity, on the other draw in glasses, a beard, hat or whatever comes to mind. The image above shows a completed Thaumatrope.
