 Welcome back to Kids Fun Science. My name is Ken. Today's experiment is the black-and-white disc illusion. As always, adult supervision is required. What you need for this experiment is a printout of a black-and-white template that I have in the description, a CD, a marble, a piece of foam, and a hot glue gun. To set up this experiment, you need to go to the link in the description and print out that template and then cut it out and then glue it on top of the CD like this right there, any kind of glue stick. And then take a hot glue gun and put on a piece of marble on the bottom and secure the marble on the bottom and then take a piece of foam or a bottle cap and secure it with a hot glue gun on the top and then you're ready. Now we know the disc is black and white so when you give it a spin, you're actually going to stare at it and you're going to see multiple different colors. Here I see a little bit of a blue and a red and a slight, very tiny little bit of green and it will change per person and I'll explain the science behind it as I continue to spin it. So the science behind this is some information. The wheel is called the Benham's top and it's created an illusion of color when black and white patterns are rapidly changed. It is named after the toy maker Charles Benham who in 1895 created the top painted with a pattern shown above. When you spin the disc and stare at the illusion, you may see arcs of subtile colors. These are called fetchner colors and appear out of nowhere. But incredibly different people see different colors and some might not see anything at all. Many people see greens and yellows and a few see reds. I see blues, reds and greens. Exactly this is why the case that has baffled scientists for decades. The faster you spin the disc, the more obvious the color effect and reversing the disc a different way is even a different way to see different colors. One theory why people see different colors is that the receptors in the human eye respond different rates of red, green and blue. The retina in the eye is composed of two types of receptors, sensitive to light, cones and rods. Cones are a very important color vision and seen in bright light. There are three different types of cones, each of which is most sensitive to a particular wavelength of light. Please put in the comments below the different colors of light you saw when the spinning disc. I hope you enjoyed this video. Remember to click thumbs up or to share it if you liked this video and thanks for watching.