Shishu Sansaar | Science
|How Do We See Colors|
How Do We See Colors
You know that eyes do not see. Eyes are the camera, they take pictures of what we see and send it to brain. Then the brain analyze the picture and tells us what is it. Normally this camera can take colored pictures to send it to brain. How does this camera work?
The rods and cones are part of the retina of our eye, which has millions of teeny cells that detect the light and then send nerve impulses down a highway (called the optic nerve) to the brain. A human retina has 100 million rods, and 7 million cones, thus they can see 7 million colors. The rods tell your brain about black and white information so that you can see in the dark when the lights go out, and the cones send stronger levels of light trough which we can see colors around us.
There are three types of cones in humans - red, blue, and green, which send messages to the brain to decipher the color seen by the eye. Dogs have only two types of cones, so they can see blue/green as white. However, they have more rods than humans, so that they can see in the dark better than humans. They can also detect motion better than people.
Some people cannot see color which is called color vision deficiency or colorblindedness. Do you know which part of the eye does not work correctly if you are colorblind? That is right! It's the red, blue, and green cones. When humans are born, they are colorblind for about 4 months because their cones tae some time to develop, which is when the cones in the eye finally start to work.
If the cones do not work properly, then they may not be able to see red and green or blue and yellow, which mix together to make all of the other colors that we see. It does not mean that they cannot see the color at all, but that the blue or yellow looks grey or white.
See these pictures and know how many colors can you recognize?
Created by Sushma Gupta on January 15, 2002
Modified on 09/28/13