Why do we see colors?

Why do you see colors when you rub your eyes?

• whenever i rub my eyes i see colors. why. and sometimes for no apperent reason i see black dots y?

• Answer:

  It is perfectly normal to see colours. If you were to press hard onto the bone directly underneath the eye, you would probably see a rainbow effect. Newton actually did this in his attempt to "find God". The black dots might be caused by unwanted bits of dust and hair that have collected between the lens and the optic nerve and are perfectly normal but slightly annoying sometimes. They can be seen best if you look up at the sky in day time. Hope this has helped.