Michael Bach's Optical Illusions and Visual Phenomena

Michael Bach collection of optical illusions are fun and educational.

Abstract geometric pattern
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Michael Bach's Optical Illusions and Visual Phenomena website showcases some of the best optical illusions on the Web and explains how and why they work. Dr. Michael Bach is a vision researcher and electrophysiologist who has been collecting and studying optical illusions and the science of vision for many years.

The site is wonderfully interactive and often gives buttons that help the user control their experience.

There are even hints to help with especially tricky visuals. With more than a hundred illusions and puzzles, this is an excellent resource for exploring optical illusions.

When you first visit the site, you'll likely find a pair of eyes drifting about the screen, following your mouse pointer. This is cute and amusing, but if it becomes distracting you can turn them off. Look in the upper left corner of the page for the button "eyes off." Click it and the floating eyes will disappear.

The Optical Illusions and Their Explanations

Explanations of the optical illusions don't shy away from discussing scientific principles at work in them. This offers great learning opportunities for kids as well as adults. Of course, kids—and adults—may find the technical explanations difficult to understand, but this doesn't take away from enjoying the optical illusions themselves.

Also, viewers may struggle to see what is described in some of the illusions.

There are hints to help with especially tricky visuals, but if you're not able to see them you shouldn't interpret this as a failing or indicator that something is wrong with your vision. As Bach states:

Don’t let it irk you if you don’t see all the phenomena described. For many illusions, there is a percentage of people with perfectly normal vision who just don’t see it, often for reasons currently unknown.

The optical illusions are broken down into several categories:

  • Motion & Time
  • Luminance & Contrast
  • Color
  • Geometric and Angle Illusions
  • Space, 3D & Size Constancy
  • Cognitive/Gestalt Effects
  • Specialities with Faces

The site is wonderfully interactive and often gives buttons that help the user control their experience. For example, the Reverse Phi Illusion lets you adjust the delay between frames of a short video of a snowboard, or stop it completely and restart it.

New optical illusions are added to the website from time to time, and if you look on the right sidebar, toward the bottom (scrolling down), you can see new additions and the dates they were added. Also on the right sidebar is a list of recognitions and awards for the website.

This is one of those websites you can easily spend a good chunk of time on without even realizing it. The optical illusions are fascinating, brainteasing, and they should prove to be a lot of fun to explore with your kids.