The Eye
PIRA classification 6J
Grayed Demos are either not available or haven't been built yet. |
6J10. The Eye
PIRA # |
Demonstration Name |
Subsets |
Abstract |
6J10.10 |
eye model |
pira200 |
The standard take apart eye model. |
6J10.21 |
water flask model of the eye |
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A large flask filled with water, a little fluorescein, and some external lenses make a model of the eye in near and far sighted conditions. |
6J10.30 |
blind spot |
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Move a white cross toward a white spot on the blackboard while the students close one eye. |
6J10.40 |
inversion of image on retina |
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A small tube has three holes in a triangular pattern drilled in one end and a single hole in the other. Hold the triangular end near the eye and the pattern appears inverted. |
6J10.50 |
astigmatism |
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Look at a chart of radial black lines. |
6J10.55 |
eyeglasses |
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Project an image of concentric circles crossed by radial lines. Place a lens and then a correcting lens over the projection lens. |
6J10.60 |
chromatic aberration of the eye |
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A purple filter is mounted in front of a straight filament lamp. |
6J10.80 |
resolving power |
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The limit of resolving two filaments of an auto headlamp is 25 - 30 feet. ALSO - show slides of the "Navicula" made with green and UV light. Reference. |
6J10.81 |
resolving power |
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The camera zooms in on a vertical series of back illuminated double slits, each separated by half the distance of the preceding pair. |
6J10.85 |
Computer generated Sayce chart |
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A valuable background discussion on the resolution of the eye and a computer generated Sayce is shown. An external slit is used to stop down the eye pupil. |
6J10.90 |
locating images by parallax |
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An arrangement is shown for locating real and virtual images by parallax. |
6J11. Physiology
PIRA # |
Demonstration Name |
Subsets |
Abstract |
6J11.00 |
Physiology |
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6J11.10 |
retinal fatigue - color disc |
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6J11.10 |
retinal fatigue disc |
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A red light placed behind a rotating disc with a slot at the border of half black and half white appears different colors depending on the direction of rotation. |
6J11.10 |
retinal fatigue - color disk |
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A disk with a notch, half black, half white is spun in front of a red lamp. The lamp appears green or red depending on the direction that the disk spins. |
6J11.11 |
psychological colors |
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A black and white patterned disc appears colored when rotated. |
6J11.20 |
visual fatigue |
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6J11.20 |
visual fatigue |
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Stare at a bright spot and a complementary color appears when the spot is turned off. |
6J11.22 |
after image and judgement of size |
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The retinal fatigue image seems to change size. |
6J11.30 |
persistence of vision |
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6J11.30 |
persistence of vision |
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6J11.30 |
persistence of vision |
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A wheel with circles with phase shifted dots painted on the rim is spun in strobed light. |
6J11.32 |
colored fans |
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Paint a four bladed fan different colors and illuminate with a strobe. |
6J11.33 |
tubeless television |
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Wave a wand at the point a projected image is focused. |
6J11.35 |
integration of light pulses |
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If light intensity from a strobe that appears continuous at 3000 Hz is cut in half, it will appear continuous at about 1700 Hz. |
6J11.36 |
fluorescence of retina |
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Shine an UV source with a visible filter toward the class and notice the luminous haze that covers the field of view. |
6J11.37 |
jarring the eye |
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Stamp your foot while watching a free running oscilloscope. |
6J11.40 |
subjectivity of colors |
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A red spot projected on the wall looks orange or brown if it is surrounded by white or black. |
6J11.42 |
Mach disk |
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A spinning disk appears to have light and dark rings where it should be uniform. |
6J11.44 |
relative black and white |
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A bright light shining on a black screen looks the same as a filtered light shining on a white screen. |
6J11.46 |
most sensitive to green light |
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A stick moved up and down in a projected spectrum will appear to bend at the green light area. |
6J11.50 |
impossible triangles |
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6J11.50 |
impossible triangles |
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An optical illusion that depends on viewing angle. |
6J11.51 |
the square that ain't there |
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A cutout of a square in black paper has the illusion of being a white square on top of black paper. |
6J11.52 |
optical illusions |
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Compare the height to the width of a projected hat. |
6J11.55 |
perception |
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Many cases of optical perception are discussed along with some audio and misc. phenomena. |
6J11.60 |
depth perception - special case |
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Apparatus for demonstration of depth perception when due solely to the geometrical disparity of binocular vision. |
6J11.70 |
color blindness |
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6J11.70 |
color blindness |
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Use standard color-blindness slides or charts to test the students. |