Children can use markers to draw designs like stripes or curves on the circles in two or more colors. Use the finger and thumb to twist the top and observe the color the eye perceives. Circle covers can also be cut from colored magazine pictures and fitted over the cardboard circle. Have students keep records of their experiments on the Color Prediction Form. The brain then combines these messages into a new color.
Students can even perceive colors from a combination of black and white lines on a top.
As shown in the video, the brain combines the slightly different views seen by each eye into one whole. Tell students to hold their pointer fingers in front of them so that the fingertips touch. Focus on something beyond them. They will see a short finger with nails on each end floating between their hands. Some movies have used filters to make flat images appear three-dimensional.