• 2 pieces of white paper

• Pencil

• Scissors

• Ruler

1. Create 24 sections, each 2 inches x 3 inches, so you’ll have 24 small pages.
2. Draw on the right half of each page. Make each image slightly different from the one before it. Try this example with 3 repeating images.

3. Place your pages in order.
4. Hold the stack tightly in your left hand and flip the pages with your right hand. Enjoy your illusion and try it with different repeating images!
5. Does the speed at which you flip the pages impact what you see?
6. Why does the image appear to be moving? Your moving picture combines after-images and the rate at which the eye refreshes the image it sends to the brain to create an optical illusion of movement! M. C. Escher would be proud!

You have just duplicated one of the earliest forms of animation. By quickly flipping the pages, the new image is superimposed on the old image and you "see" a single moving image.

To find this experiment and many more please download the Lighten Up! Discovering the Science of Light book, developed through a partnership with the Optical Society of America’s Foundation (OSAF) and the Girl Scouts of the USA.