Colourful sections

What can you do here
Look at the pattern on the still disc. Start spinning it. Slowly increase the spinning speed. What are you seeing? Experiment by rotating the disc with various angular velocities. Pay attention to what you are seeing while blinking.

How does it work
When the rotation speed is low, you can see blurred colourful streaks. The explanation of this phenomenon is thought to be similar to the one regarding Benham’s top. When the wheel rotates fast, you will see a uniform grey surface. This color results from mixing yellow and blue. From time to time blue-and-yellow flashes (fragments of the disc) can be visible during blinks.

Interesting facts
During every blink eyelids moisten the surface of the eye and remove dust or germs. On average, people blink once or twice every 10 seconds and every blink takes one third of a second. Thus, during a 12-hour period we spend around 25 minutes blinking.