1. Vision dominates the human senses. We always believe what we see first
Vision dominates the human senses. We always believe what we see first. But how do we see?
Look around the classroom and describe what you see. BE SPECIFIC!!!

2. 1. Cornea: the clear outer covering of the eye, behind which is a fluid.
2. Iris: A colored circular muscle that opens and closes, forming larger and smaller circles to control the amount of light getting into the eye.
3. Lens: The part of the eye that focuses an image on the retina. (very much like a camera lens)
4. Pupil: the opening in the eye.
FUN FACTS:
The pupils of the eye get smaller if we are disgusted.
The pupils of the eye get larger when we see something we really like.
The pupils of the eye also get larger when someone is afraid.

3. 5. Retina: The back of the eye, which contains millions of receptors for light. 6. Blind Spot: The portion of the retina though which the optic nerve exits and where there are no receptors for light waves. (We cannot see anything when light waves hit this point.

5. For the image above: With your right eye closed, stare at the circle
For the image above: With your right eye closed, stare at the circle. Move the paper away from your face then back to your face again. You should be able to find a position where the + disappears.

6. For the image above, close your right eye
For the image above, close your right eye. With your left eye, look at the red circle. Slowly move your head closer to the image. At a certain distance, the line will not look broken!!

7. 7. Rod: A visual receptor most sensitive to the violet – purple wave-lengths; very sensitive for night vision; “sees” only black and white.
8. Cone: A visual receptor that responds during daylight; “sees” color.
9. Color Blindness: The inability to perceive certain colors, such as red and green.
10. Afterimage: Image that remains after stimulation of the retina has ended. (Example: Green / Yellow American Flag)

8. To demonstrate and afterimage for yourself, focus your eyes on the “+” in the middle of the flag. Stare at it for one minute. Now quickly move your eyes to the white paper below. You should see the flag appear in red, white and blue.

9. ARE YOU COLOR BLIND?