1. The Human Eye
6th Grade Science

2. Parts of the Eye Sclera Eyelid Lens Eyelashes Orbital Muscles Iris
Aqueous Humor
Cornea
Vitreous Humor
Optic Nerve
Pupil
Eye Socket

3. Fun Fact: Eyelids display expression and emotions that are an important part of our individuality.
Eyelid & Eyelashes
The eyelids protect the eyes from the environment, injury and light.
They also spread tears evenly over the eye.
Eyelashes protect the eye from debris and are sensitive to being touched (reflexive), providing a warning that an object is near the eye.

4. Sclera Commonly known as "the white of the eye.“
Fun Fact: As we age, the sclera tends to become more yellow.
Commonly known as "the white of the eye.“
A tough, opaque tissue that serves as the eye's protective outer coat.
Six tiny muscles connect to it around the eye and control the eye's movements.
The optic nerve is attached to the sclera at the very back of the eye.

5. Cornea
Fun Fact: The cornea is extremely sensitive - there are more nerve endings in the cornea than anywhere else in the body. 
The cornea is the transparent, dome-shaped window covering the front of the eye.
Add note: aqueous humor a clear gel that fills the space between the cornea and the pupil and makes the “dome”

6. Iris Circular band that controls how much light enters the eye
Fun Fact: The color, texture, and patterns of each person's iris are as unique as a fingerprint.
Iris
Circular band that controls how much light enters the eye
Located just behind the cornea
The colored part of your eye.
Activity: Using a mirror, examine your eyes with the lights off and then with the lights on. What do you notice?

7. Lens Located just behind the iris.
Fun Fact:  With age, the lens gradually hardens, taking away the ability to focus far away and close up.
Located just behind the iris.
Its purpose is to focus (bend) light onto the retina. 

8. Fun Fact: Doctors often look at the reaction of pupils to light to determine a person's neurological function.
Pupil
Hole in the center of the iris which allows light to pass through

9. Why do optometrist dilate (to make bigger) your eyes?

10. Retina Layer of tissue that lines the back of the eye
Fun Fact: There are approximately 6 million cones and 125 million rods.
Retina
Layer of tissue that lines the back of the eye
Has millions of sensors called cones and rods, which capture light rays and convert them into electrical impulses
Rods: allow us to see black, white, & shades of grey
Cones: allow us to see red, blue, and green colors
They work together so we can see many shades of colors

11. Vitreous Humor
the clear gel that fills the space between the lens and the retina of the eyeball - gives the eye its shape

12. Orbital Muscles Allow eyes to move
Humans are the only animal who can “roll” their eyes

13. Optic Nerve
Fun Fact: Doctors have yet to find a way to transplant an eyeball. The optic nerve that connects the eye to the brain is too sensitive to reconstruct successfully.
The optic nerve transmits electrical signals from the retina to the brain.
It connects to the back of the eye
Add: Forms the

14. How do we see? 1. Light enters the eye through the cornea.
2. Light continues through the pupil which is controlled by the iris.
3. Light passes through the lens which refracts (bends) the light causing the picture to be upside down.
4. The upside down picture travels to the retina.
5. The optic nerve sends signals to the brain, which interprets the images right side up.

15. Coloring the Eye: Optic Nerve = Brown (add the words “blind spot”)
Blood Vessels = Trace in Red
Retina = Do NOT color, but finish the upside down smiley FACE (add circle, hair, color it, etc.)
Pupil = Yellow ring
Lens = LIGHT Blue
Ligament attached to Lens = Orange
Iris = The color of YOUR eyes
Muscle attached to Iris = Red
Eyelids = Skin tone add top & bottom lashes

16. Bill Nye : Eyeball video

17. Eye Fun Facts
Owls can see a mouse moving over 150 feet away with light no brighter than a candle.
The reason cat's and dog's (and cow’s) eyes glow at night is because of silver mirrors in the back of their eyes called the tapetum. This makes it easier for them to see at night.
An ostrich has eyes that are two inches across. Each eye weighs more than their brain.
A chameleon's eyes can look in opposite directions at the same time.
One in every twelve males is color blind
A new-born baby sees the world upside down because it takes some time for the baby's brain to learn to turn the picture right-side up.
And……

18. The average blink lasts for about 1/10th of a second.
While it takes some time for most parts of your body to warm up to their full potential, your eyes are on their “A game” 24/7.
Eyes heal quickly. With proper care, it only takes about 48 hours for the eye to repair a corneal scratch.
Seeing is such a big part of everyday life that it requires about half of the brain to get involved.
Newborns don’t produce tears. They make crying sounds, but the tears don’t start flowing until they are about 4-13 weeks old.
Around the world, about 39 million people are blind and roughly 6 times that many have some kind of vision impairment.

19. You blink about 12 times every minute
You blink about 12 times every minute. Each time you blink, you shut your eyes for 0.3 seconds, which means your eyes are closed at least 30 minutes a day just from blinking.
Your eyes are about 1 inch across and weigh about 0.25 ounce.
Some people are born with two differently colored eyes. This condition is heterochromia.
Each of your eyes has a small blind spot in the back of the retina where the optic nerve attaches. You don’t notice the hole in your vision because your eyes work together to fill in each other’s blind spot.
Out of all the muscles in your body, the muscles that control your eyes are the most active.