|Pennsylvania in February is not a multi-colored feast for the eyes, things we see outside merge from white through gray to black with the tedium relieved by a few small points of green where spring flowers
are just beginning their journey to the surface. Perhaps it's the best time
to consider the wide, wonderful world our sense of sight brings us.
Our discussion of sight begins by concentrating hard on USING our sight to look at things around us, especially looking closely at things we have only glanced at previously. Seeing the criss-cross pattern on the boombox speakers, the way separate window pane shapes make small boxes within larger boxes within the box shape of the window frame, all the lines that show the edges on a chair; these are among the interesting things we find to look at in the classroom.
We talk of colors, our favorites and our UNfavorites, and tell each other why we make those choices. We think of the information and feelings we get from color: a red face, a brown flower, a dark sky, a green banana, a purple bruise, a pink azalea, a blue sky, a red apple, and so on. With amazement we find that research shows our eyes are sensitive to only red, green and blue yet our brains convert those three signals to the thousands of different colors we recognize.
We consider the fairly common condition of color blindness, where sufferers cannot tell the difference between the colors red and green. So who ever decided traffic lights should use those colors?
Did you ever hear anyone tell about their MIND'S EYE, which they use to make pictures in their imagination? My own favorite mind's eye pictures involve redrock canyons and the Colorado River, how about yours?
OUR SEEING DETECTOR
Excellent web sites which illustrate and describe the action
of the eye can be found at:
As this information demonstrates, light rays enter the
eye through the cornea and are focused by the lens on the retina,
which contains rod cells for light detection and cone cells for color
and accuracy detection. In the retina the light information is converted
to electrical impulses which are sent, via the optic nerve, to the brain
for interpretation...and we see.
"Out of the Corner of My Eye ......"
Let some students spend a short time in dim light then compare their enlarged pupil size when they re-enter the bright light. Ask them if they noticed that in dim light we can see shapes well but have no color vision. Have they ever noticed how nocturnal animals, like owls or koalas, have greatly enlarged pupils?
Extract a promise of strict honesty (ha!) from a student, then have her stare straight ahead and indicate when she first detects, WITHOUT moving her eyes, a movement coming from behind and entering the edges of her field of vision. This demonstrates her LATERAL peripheral vision. Repeat the experiment with movement coming from above, then below. This gives her LONGITUDINAL peripheral vision. So humans, in addition to their accurate frontal vision can also notice many things out of the corners of their eyes.
Now we can discuss eye placement and peripheral vision in other animals. Predatory animals have eyes in the FRONT of their heads to focus clearly on and be able to target moving prey, whereas non-predators have eyes on the SIDES of their heads giving them wide peripheral vision to watch for enemies coming from behind as they are chomping on their stationary, vegetable diet.
If you ever startle a deer he will lift his head and be still. Do remember that although he seems to be looking away he can see you very well - he just has a DIFFERENT TYPE OF VISION best suited to his lifestyle, a built-in rear view mirror to watch for enemies behind him.
Listing and Grouping
Suggest some other verbs for looking and group them by feeling, for example: glaring, peering, gazing, staring, glancing, peeking, etc.
World Wide Web
Then go to the AMAZING ANIMAL SENSES website and find out the unusual seeing abilities of buzzards, pigeons, giant squid, sparrows, seahorses, penguins, octopi, four-eyed fish, starfish, flies, chameleons, scallops, falcons, scorpions, and the color blindness in deep sea fish.
WHAT IS IT?
I'm thinking of something that has an OCTAGONAL shape,
WORLD WIDE WEB LINKS
We relax at lesson's end by browsing through the following sight-related web sites.THE SIX MAGIC DOTS OF BRAILLE,
COLOR BLINDNESS (test pattern),
LINE DRAWING ILLUSIONS,
MAGIC EYE STEREOGRAM OF THE WEEK,
VENTURE'S STORY: LIFE AND TIMES OF A GUIDE DOG.
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