The wandering wheel

What you can do here
Look closely at the pattern on the wheel and start spinning it gradually increasing the speed. What can you see? Experiment by rotating the disk with various angular velocities in both directions.

How it works
A slowly spinning wheel looks like it has a circle moving along the circumference. When the speed is high, black-and-white details blur into grey. The eye cannot catch fast colour changes and the images transmitted to the brain are indistinct. Linear speed is the lowest at the centre of the wheel. That’s why you can distinguish black lines against the white background in this region.

Interesting facts
The French artist Marcel Duchamp (1887-1968) used stereoscopy (an illusion of depth) in 1935 in spinning cardboard wheels called Rotoreliefs. Another of his works are presented in our exhibition as The Crater.