The major light source for Earth is the Sun. While the moon, water, and mirrors reflect light, they are not primary light sources themselves. Light enters the eye through the cornea and pupil, is focused by the lens onto the retina, and the retina's light-sensitive cells send visual information through the optic nerve to the brain's visual cortex for interpretation based on past experiences.

1. Light

2. Our major li
ght source:
the Sun

4. Natural vs. Man-made (artificial)

5. moon
water
mirror
These items are not light sources, instead they ar
e reflecting light from other sources.

6. light
source

7. Light coming from, (or reflecting off) obje
cts enters the eye through the cornea then t
he pupil.
It is focused clearly by the lens on to the
retina.
The light sensitive cells of the retina gath
er information about patterns of light and da
rk, colour and movement and send it through
the optic nerve.

8. Information entering the brain through th
e optic nerve, is then transmitted through
more nerve pathways to the visual cortex.
Here the patterns of light and dark, colo
ur and movement are interpreted.
The brain, based on past experience, can
then understand what it ‘sees’.

9. light
source

10. light
source
light
source