# How Does a Benham disk work?

## How Does a Benham disk work?

When you gaze at one place on the spinning disk, you are looking at alternating flashes of black and white. When a white flash goes by, all three types of cones respond. But your eyes and brain see the color white only when all three types of cones are responding equally.

How do you make a Benham disk?

1. Get some cardboard and a toothpick.
2. Draw a circle (with a diameter of at least 4 inches) on the cardboard.
3. Cut out the circle carefully.
4. Poke a hole in the center of the circle with the toothpick.
5. Insert the toothpick into the hole.
6. Twist the toothpick to spin the spinner.

When spun quickly a Benham disk produces?

The effect is most commonly demonstrated with a device known as Benham’s top (also called Benham’s disk). When the top is spun, arcs of pale color are visible at different places on the disk that forms its upper surface. The effect can also be seen in stroboscopic lights when flashes are set at certain critical speeds.

### What happens to the colors when spinning the disc?

Results: When the disk is spun at high speed the colours disappear and the disk appears white. The faster the spinning the better the result is and the clearer the effect.

What is a Benham wheel?

Contribute To this Entry » An optical illusion consisting of a spinnable top marked in black with the pattern shown above. When the wheel is spun (especially slowly), the black broken lines appear as green, blue, and red colored bands. The effect depends on the color of lighting.

How does the Delboeuf illusion work?

The distance between the circles causes them to be perceived as separate and contrasting. The larger-circumference ring dwarfs the smaller central disc and causes it to be perceived as smaller. After a few minutes of looking at this illusion, the illusory effects diminish for human subjects.

#### How do you make a Newton?

To make a Newton disc, start by cutting out two circles of the same size from a piece of cardboard and a piece of paper and gluing them together. Next, divide the circle into 7 equal triangles and color each section a different color in this order: red, orange, yellow, green, blue, indigo, and violet.

What do you see when you spin a colour wheel?

Spinning the disc mixed all the different wavelengths of coloured light together, creating white light. The faster you move the disc, the more white light you see. This process is called colour addition.

Who created the Delboeuf illusion?

Joseph Remi Leopold Delboeuf
The illusion was named for the Belgian philosopher, mathematician, experimental psychologist, hypnotist, and psychophysicist Joseph Remi Leopold Delboeuf (1831–1896), who created it in 1865.