Every time you see something, rods and cones are at work. These light-catching cells sit at the back of your eyes and help you see in dim light and in color.
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At the very back of your eye is a thin layer called the retina. It's packed with light-catching cells called rods and cones, named for their shapes.
The very center of your retina is packed with cones. That's the spot you use to see the sharpest details, like the words you are reading now!
Rods work even in very dim light. But they can't tell colors apart. That's why everything looks gray-ish at night.
Cones need brighter light, and they see color. There are three kinds. One kind is best at red light, one at green, and one at blue. Your brain mixes their messages to make all the colors you see.
Scroll up to the 3D model and press Dim light, then Bright light. Watch which cells light up.
With a grown-up, sit in a nearly dark room with some crayons. Can you tell their colors? Turn on the light and check!
When light hits a rod or cone, it turns the light into a tiny signal. The signal passes through other nerve cells and travels along the optic nerve to your brain. Your brain puts it all together into a picture.
Where the optic nerve leaves your eye, there are no rods or cones at all. Each eye has a small blind spot there! You don't notice it because your brain fills in the gap.
By Peekaboo Kidz. A fun video for kids.
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