How we did it:
- pencil - or marker
- colored pencils
- glue stick
Gather your materials.
Cut two circles out of a piece of cardstock.
Draw a fishbowl in the center of one.
Draw a fish in the center of the other one.
Glue the back sides of the drawings together so that the fishbowl is upright and the fish is upside down.
Thread a piece of string through a needle and make a hole on one side of the circle. Then, pull the string through and tie it.
Repeat step 6 on the other side of the circle.
Hold one string in each hand. Then, quickly twirl the string back and forth between your fingers. What do you observe? Try making other images too - like a flying rocket ship!
When you slowly twirl the thaumatrope, you see the fish, and then the bowl. But if you twirl it fast enough, the images blend together and the fish looks like it’s back in its home!
This happens because of an effect called persistence of vision. When something changes or moves really fast, it looks like part of it stays, or persists. Persistence of vision is why your fingers blur together if you wave them in front of your face, and why embers look like they streak away from a crackling fire.
Vision persists because your brain is fast, but not super-fast. Your brain takes time to process the messages that your eyes send to it when they see something. So if the thing you’re looking at changes faster than your brain can process it, your brain blurs and blends it all together. That’s how the fish gets in the bowl!