How Vision Works

Corrected short version (checked for grammar):

Vision is our ability to see. Light enters your eye through the pupil and passes through the lens. The back of the eye (the retina) receives the picture upside down. Nerves send it to the brain, and the brain turns it the right way up.

Now a simple, step-by-step explanation for a 7-year-old:

1. Light comes from things around you. Light bounces off toys, trees, and faces and goes into your eye through the pupil (the black round part in the middle).
2. The lens focuses the light. The light goes through the lens, which bends the light so the picture becomes clear.
3. The retina gets the picture upside down. The back of your eye, called the retina, catches the picture, but it is upside down there.
4. Nerves send the picture to the brain. A bundle of nerves (the optic nerve) carries the picture from the retina to your brain.
5. The brain turns the picture the right way up. Your brain flips the image so you see everything the correct way.

Short summary: light → pupil → lens → retina (upside down) → optic nerve → brain (right way up).