Light and SightBig Goal: At least 85% mastery of every unit- because we are smart, because education takes us places, and because we control how far we go.

Daily Goal: We will identify the structures within the eye and investigate how and what these structures allow us to see.

Homework: Gist, turn in any missing work, revise any work below 77%, get your progress report signed. Quiz on light waves on Friday.

Our eyes do some pretty incredible things…Your eye muscles move 100,000 time every day! If your legs moved that much, you’d end up traveling 50 miles.

The eye muscles have a special protein that keeps them from experiencing fatigue from moving so quickly. If you looked at someone’s eyes, you’ll notice that they never really stay still. Eyes are always moving.

Eyes process light in interesting ways. Take a look at these optical illusions. By the end of this unit, you will know what parts of the eye control how we see and why we see things the way that we do.

Keep staring at the black dot. After a whilethe gray haze around it will appear to shrink.

Count the black dots! :o)

How many legs does this elephant have?

Do you see a musician or a girl's face?

Science Starter:1. Find the farthest spot in the room, and stare at

it. 2. Close one eye, hold up your index finger, and

bring your finger as close to your eye as you can until you loose clear focus. When you loose focus, stop, and keep your finger right where it starts to get blurry.

3. Keep your finger where it is, and look just to the side of it at the spot in the room where you looked in step 1.

4. Without looking away from that spot in the room, observe your finger.

Analyze and HypothesizeScience Starter: **Write this down and answer it**What does your finger (the nearby object) look like when you are focusing on the wall (the distant object)?_________________________________________________When you focus on your finger, what does the spot on the wall look like?_________________________________________________What might be happening in your eye to cause this change ?__________________________________________________________________________________________________

EYE see!» Eyes are natural tools for humans. » Our eyes transmit light, _________(bend) light,

and respond to different wavelengths of light.

» Our eyes are just like lenses!

Access Prior Knowledge; Generate Ideas

What are some things that use lenses?___________________________________How do you think a lens works?______________________________________________________________________

I spy the parts of an eye

Cornea1. Light enters the eye

through the__________.

2. The cornea acts as a convex (or u-shaped) lens and does most of the ______________in the eye.

The cornea is a transparent (see through) membrane that covers the eye.

**ADD THIS TO YOUR GLOSSARY**

For visual learners:--- Visible light waves

Cornea

Test your learning:» Think back to what we learned last week. What

does the word refract mean? (You may look at your notes.)

» What happens to light waves when something refracts them?

(Hint: Think about the pen in the jar of water)

The iris and the pupil3. After passing through the cornea, the light continues through the _________and then through the__________.

**WRITE THIS DOWN**

**WRITE THIS IN YOUR GLOSSARY**

Iris - the colored part of your eye that is underneath the cornea; it opens and closes to change the size of the pupil

Pupil – the circular opening in your eye that controls how much light enters

IRIS PUPIL

Let’s put our irises and our pupils to the test!

1. When I say go, cover both of your eyes with your hands so that as little light as possible gets through. Keep your eyes open under your hands.

2. I will time us for 1 and ½ minutes. Don’t take your hands off of your eyes.

3. With your hands still over your eyes, turn to the person next to you.

4. When I say go, take your hands off, and look at the black, middle part of your neighbor’s eyes – their pupils.

Analyze Your Observation» What did you notice about your neighbor’s

pupils? How did they change?________________________________________» Why do you think they changed this way?________________________________________

» What parts of the eye were changing?________________________________________

The LensLENS

light

4. After passing through the iris, the light passes through the _________________.

Lens – is a part of the eye underneath the iris; it is convex (u-shaped) on both sides and refracts light to help us focus on near or far objectsThe lens was working when we looked at the spot on the wall and at our finger. Tiny muscles contract (or tighten) and relax to control how much ___________________occurs.

**WRITE THIS DOWN**

**WRITE THIS IN YOUR GLOSSARY*

The Retina

RETINA

5. The light passes through the lens and hits the ____________.

**WRITE THIS DOWN**

Retina – an area in the back of your eye that contains specialized cells whose job it is to respond to light; these cells send signals to brain about the image

**WRITE THIS IN YOUR GLOSSARY**

When the image hits the _________, it is upside down. Your brain flips it around and interprets it so that we see things the right way up.

Fun Fact!

The Optic Nerve

OPTIC NERVE

**WRITE THIS DOWN**6. When light hits the retina, the cells send signals to the brain through the ___________. The brain interprets these signals as _____________.

**WRITE THIS IN YOUR GLOSSARY**

Optic Nerve – the pathway for signals from the cells in the retina to the brain