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displaying 1 - 10 of 15 lessons
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Color Perception

This lesson provides a tutorial in color perception and the physiology of color sensitive cells in the eye. It includes three classroom activites for exploring color vision:

  1. a game testing peripheral color vision
  2. a demonstration of mixing colored light...
Average: 4.1 (7 votes)
8-Nov-2018 guy photoreceptor response
Zoetropes, Phenakistoscopes and Other Animation Toys

A lesson on zeotropes, phenakistoscopes and other vintage animation technologies, with explanations and attached printouts for making your own version.


Average: 2.9 (13 votes)
22-May-2017 guy zoetrope
Positive Afterimages

This lesson contains a short explanation of positive afterimages and some suggestions on how best to see them.

When light shines on the retina, chemical and electrical signals are sent to the brain, providing the basis for our sense of vision. When the light is turned...

Average: 4 (20 votes)
8-Jun-2016 guy
Motion-induced Blindness Illusions

Motion induced blindness illusions use apparent background motion to make static portions of the visual field temporarily disappear from view. They produce an effect that seems similar to the blind spot in the eye, or the disappearance of images in Cheshire cat illusions,...

Average: 3.4 (90 votes)
25-May-2016 guy motion blindness illusion
Anatomy of the Eye

This lesson provides an overview of the anatomy of the eye and suggests several simple activites for exploration, including

  • observing pupil response to variations in light
  • verifying the inverted image on the retina
  • comparing central and peripheral...
Average: 3.8 (4 votes)
25-May-2016 guy diagram of eye
Lilac Chaser Illusion

The Lilac Chaser illusion is a creation by Jeremy Hinton that relates to the effects of desensitization (and afterimages), motion-induced blindness, and beta movement (perceiving motion from static images). It makes a great follow-up activity after a lesson on negative...

Average: 3.8 (19 votes)
25-May-2016 guy Lila Chaser
Smoke Ring Machines and Dolphin Bubbles

Smoke rings offer wonderful lessons in fluid dynamics. Use them to initiate discussions on fluid flow, air pressure, and Bernoulli's principle. This lesson contains instructions for how to build your own smoke ring machine out of an empty soda bottle, and outlines the...

Average: 4 (10 votes)
25-May-2016 guy vortex chamber
Seeing Blood Vessels in the Eye

Describes a technique for seeing the shadows of blood vessels in your eye. Provides a great opportunity for discussing the anatomy of the eye. Requires a dark place.

For more examples of optical illusions caused by visual desensitization, check out our summary...

Average: 4 (6 votes)
3-Jun-2015 guy retina shadows
Cheshire Cat Illusions

Cheshire cat illusions are images that fade slowly away as you stare at them. They result from desensitization in the eye (and brain) when you view them without moving your eyes. This lesson explains the mechanism behind the disappearance, and provides several examples of...

Average: 3.6 (7 votes)
3-Jun-2015 guy Cheshire cat
Yang and Yin - negative afterimages

This lesson provides a tutorial on the mechanism behind negative afterimages, and includes three afterimage illusions for demonstration. Lecture slides are attached with all images.

For more examples of optical illusions caused by visual desensitization, check out our...

Average: 3.7 (6 votes)
3-Jun-2015 guy Mona Lisa negative