Weird Science - Persistence of Vision

Honolulu (HawaiiNewsNow) - Dr. V and Taizo are at the children at the Shriner's Hospital for Children.  The experiment today involves fish and a fish bowl and a bird and a bird cage.

Dr. V Show: Persistence of Vision

 Things you will need

  • thin piece of cardboard
  • hole punch
  • pencil
  • scissors
  • glue
  • rubber bands

The Experiment:

In this experiment, you will be making a thaumatrope. Cut out two discs of equal size. On one of the discs, draw a picture, try drawing a bird. On the other disc, draw an empty cage. Then glue the two discs together, making sure that the bird is facing right side up and the cage is upside down when you glue them together. Punch holes evenly on each side of the glued discs on the far left and far right sides of the image. Attach a rubber band into each of the holes. Twist the rubber band in between your thumb and finger, what do you see?

How does it work?

Before cartoons and movies, people used to enjoy simple animation with a thaumatrope. The reason you are able to see two images merge into one in this experiment is because when you see an image it stays on your eye for approximately 1/25 of a second. The image stays on your eye because the brain needs to process it. This phenomenon is knows as persistence of vision and is why when you spin the Thaumatrope disc you can see the two images long enough to become one. This is also why, you don't see all black when you blink.