Light and Sight

We see objects that produce their own light due to the light being detected by our eyes. We view all other objects because light reflected from the objects enters into our eyes.



















































How we detect light


Visible light is the part of the electromagnetic spectrum that can be detected by our eyes. Our eye gathers light to form the images that we see.
Muscles around the lens change the thickness of the lens so that objects at different distances can be seen in focus. The light that forms the real image is detected  by receptors in the retina called rods and cones. Rods can detect very dim light. Cones detect colors in bright light.

How our eyes work

1. light is refracted as it passes through the cornea, a membrane that shields and protects the eye
2. Light then passes through the pupil, the opening in the eye
3. The iris controls the size of the pupil This is the colored part of the eye
4. The lens of the eye is convex and refracts light to focus a real image on the back of the eye
5. The retina is the back surface of the eye. Light is detected by receptors in the retina called rods and cones
6. Nerves attached to the rods and cones carry information to the brain about the light that strikes the retina