Data Bases • Custom Term Papers • Free Term Papers • Free Research Papers • Free Essays • Free Book Reports • Plagiarism? Links • Top 100 Term Paper Sites • Top 25 Essay Sites • Top 50 Essay Sites • Search 97,000 Papers @ DirectEssays.com • Search 101,000 Papers @ ExampleEssays.com • Search 90,000 Papers @ MegaEssays.com Free Essays • Term Paper Sites • Chuck III's Free Essays • Free College Essays • TermPaperSites.com • My Term Papers • Get Free Essays • Essay World • Planet Papers	Search Lots of Essays Back to Subjects - Mathematics Optical Illusions Optical Illusions What is an optical illusion? An optical illusion is like a “magic picture”. An optical illusion fools your brain into thinking something about a picture that isn’t necessarily true. To understand optical illusions, it is helpful to understand how the The colored circle on your eye is called the iris. The smaller black circle within the iris is called the pupil. The pupil lets light into the eye. When you look at an image, light is reflected off the image and through the pupil of your eye to a lens behind the iris. The lens projects the image upside down and backwards to the retina in at the back of the eyeball. The upside down and backwards picture is then carried to your brain by nerves in the retina. Once the picture is in your brain, it is turned right side up so it can be seen correctly and so the brain can understand what you are seeing. An optical illusion is a special picture made to fool the eye. The optical illusion doesn’t make sense, so when the nerves carry the image to the brain the brain has a hard time comprehending the image. When a person sees an optical illusion, they often have to look more than once so their brain There are several different types of optical illusions. In figure A, the side lines make it appear as if the central lines are not equal in length, when in fact, they are. The side lines lead the eye either outwardly or inwardly. This is called Muller-Lyer illusion. In figure B, the three concentric circles with bites taken out of them is an example of closure. Even though there is no triangle drawn in this picture, the mind unconsciously completes the triangle that seems to be formed by the bites taken out of the circles. The Necker Cube, figure C, seems to “flip-flop”, creating the image that the dot is in the front of the cube and then the cube “flip-flops”, and then the dot is in the back of the cube. In the Ponzo illusion, figure E, the circle with the tangents looks larger than the other circle. The farther distance between the tangent lines and the second circle, creates the illusion that the second circle is smaller. In The figure-and-ground illusion, figure F, you might see a white vase against a black background. You might also see two black silhouettes against a white background. This illusion shows object reversibility as well as the Necker Cube. In the Zollner illusion, figure L, the short lines intersecting the vertical lines create the illusion that the long vertical lines are not parallel. It has been said that some optical illusions, such as the “flip-flop” of the Necker Cube, are easier for younger people to see, and more difficult for mature people to see. None the less, whether you’re young or old, optical illusions are Bibliography: Word Count: 494
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