Make an optical illusion

This optical illusion lets you turn two pictures into one.

What you need:

  • white cardboard
  • pencils and colouring pens
  • scissors
  • glue/sellotape


  • Cut out two shapes from a sheet of white cardboard.
  • Draw whatever you want, but we tried some fish on one piece and the tank on the other.
  • Glue or sellotape a pencil in between the two pictures.
  • Hold the pencil between your palms and rub your hands to make the picture spin around.



The Science bit

The fish should look like they are inside the tank.

This is the same concept used for making cartoons, still pictures are moved very quickly to create an illusion of movement.

Author: Emma Vanstone

Science Sparks, is a site dedicated to making Science fun for kids. I’d love you to follow me on my Google Profile+.

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  1. This is an old favourite. When the flicker rate is high enough, the brain starts to blend the two images so we see the bird in the cage. Wonderful. How sad it would be if this were not so. Seeing a movie would become a series of still images.
    Ross Mannell (teacher)

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  2. Kids love this one! Thanks for sharing. Saw you at For the Kids Fridays.

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    • So glad you liked it! x

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    • Thank you. x

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  3. You have such fascinating ideas! Thank you for sharing this on The Sunday Showcase!

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  4. thanks for bringing back memories of childhood science projects! my boys will LOVE this one, and I’m quite sure will run to school with it! thanks so much for sharing on Craft Schooling Sunday!

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