manual

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White is made up of all seven colors of the rainbow.
rods cones
section of the retina
When the disk is still, the seven
colors of the rainbow arrive at the
eye and they are transmitted by cells
(cones) from the retina to the brain.
Cones recognize colors and
transmit them to the brain. Rods
detect black and white.
When the disk is spinning, as the image of
each color arrives at the eye, they overlap
with each other. The brain then blends all the
colors together. As you saw in the last
experiment, all the colors blended
together creates white light. So,
you perceive the spinning disk to
be white.