To Do And Notice

Stare at the center of the disk for about 15 seconds. Stare at the palm of your hand. Notice that your palm seems to be turning in the opposite direction from the way you turned the wheel.


What's Going On?

When you stare at a moving pattern, your eyes and brain get used to seeing movement. When you look at something that's standing still, your eyes see movement in the opposite direction. The common name for this illusion is the waterfall effect. If you stare at a waterfall for some time and then look at the nearby rocks, the rocks may look like they are moving upward.


What else can I do?

The Depth Spinner exhibit also demonstrates a similar phenomenon

What if the animation is playing too slow to see the effect?

Results of this experiment may vary depending on your computer's processing speed, the amount of RAM allocated to your browser and the colordepth your monitor is set to.


You can increase animation performance by:
  • Switching your monitor's color depth to 256 colors
  • Closing other open applications
  • Allocating more RAM to your web browser


The Squirming Palm is also available as a downloadable application for the Mac OS. Squirming Palm 2.0 Beta for the Mac OS (928k hqx)


©1998 The Exploratorium