When you go to the movies the projector flashes thousands of pictures on to the screen to create the illusion of movement. Every second you watch a movie you see 72 separate pictures projected onto the screen – when your mind pieces these pictures together it is called persistence of vision.
You can learn more about persistence of vision by visiting the Notion of Motion exhibit that opens tomorrow. There will be an Aether Zoetrope, a device invented in the mid-1800′s that uses still pictures to create the illusion of movement.
Make your own illusion at home using an index card and a pencil. Cut 2 small squares. Draw a simple picture on both drawings with one difference. On my first square I drew a container with a red liquid inside. On the second square I drew the same container, but I showed the liquid spilling out the top.
Tape the squares around the end on the pencil.
Quickly flip the pencil back and forth. It looks like the liquid spills over the top of the container.