At the right speed you see faint rings of color, often reddish on one side and bluish on the other, though the disk is only black and white.
Try this
- Try different Spin speed settings: the colors are strongest at a few turns per second.
- Tick Stop the top to see it is only black and white.
- Colors look different on different screens: the effect depends on the display and the room light.
Why it happens
No one has a complete explanation. The leading idea is that the different kinds of cone cells in your eye respond and recover at slightly different speeds, so the flashing black and white arcs stimulate them in a pattern your brain reads as color. These are called pattern-induced flicker colors. Charles Benham, an amateur scientist, described his "artificial spectrum top" in Nature in 1894.
Did you know?
The colors reverse order if you spin the top the other way, one of the clues that timing in the eye is involved.
References
- Benham C. (1894). The Artificial Spectrum Top. Nature, 51, 200. doi:10.1038/051200c0
- Background on Wikipedia
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Frequently asked questions
Why does a black and white top look colored?
Probably because the eye's color receptors respond at slightly different speeds to the flicker. It is still not fully explained.
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