1. Week 9: Seeing Light
CHAPTER 4, SECTION 4
Page 125 – 128

2. The Human Eye Your eyes allow you to _SENSE_ light.
You see objects when a process occurs that involves both your _EYES_ and your __BRAIN__.

3. Light Enters the Eye
The transparent front surface of the eye is called the _CORNEA_.
The _PUPIL_ is an opening through which light enters the inside of the eye.
To get more light the pupil becomes _LARGER_, in less light the pupil _SMALLER_.
The iris is a ring of _MUSCLE_ that contracts and expands the size of the pupil.
The _IRIS_ gives the eye color.

4. An Image Forms The lens in the eye is a _CONVEX_ lens.
The _RETINA_ is a layer of cells that lines the inside of the eyeball.
Light-sensitive cells are called _RODS_.
Rods allow you to see different amounts of _LIGHT_.
Cones allow you to see _COLOR_.
BrainPop- Eyes (3:46)

5. A Signal Goes to the Brain
The short, thick nerve that connects the eyeball to the brain is called the _OPTIC NERVE_.
The Optic Nerve begins at the _BLIND SPOT_.
Close your left eye and look at the circle. Move your head and you will find your blind spot by not seeing the +

6. Correcting Vision
To correct vision problems people wear _GLASSES_ and _CONTACTS_.
_CONCAVE_ lenses to correct nearsightedness.
__CONVEX_ lenses to correct farsightedness.
A nearsighted person can see objects _NEARBY_, but distance objects are __BLURRY__.
A farsighted person can see _FAR AWAY_ objects, but nearby objects are _BLURRY_.
BrainPop – Vision Problems (3:24)