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Unformatted text preview: Lesson 27: Refraction Refraction is when waves change the direction they are traveling when they go from one medium to another. Have you ever looked at something like a pencil or pen sitting in a cup of water? It probably looked something like Illustration 1 . Notice how the pen looks like it is bent and bigger in the water something must be happening to the visible light as it travels through two different substances water and air. If someone is standing in a swimming pool, the light traveling through the water from the persons feet does the same thing as it changes medium and travels into the air. This bending often makes it look like a person is short in the water. The way the waves move changes by moving to a different medium. Since Ptolemys time (about 100AD) people knew about refraction, but they didnt know why it happened, or how to predict and calculate it. In the year 1600 a Dutch mathematician named Willebrord Snell was playing around with numbers and figured out a formula that fit what everyone was measuring in their labs. This meant that Snell had a mathematical formula that fit the empirical evidence collected in labs. The Law of Refraction (AKA Snells Law ) in its basic form allows us to do calculations of how a beam will bend when it moves from one medium to another. In its full form, it also lets you do calculations involving wavelength and velocity of EMR in different media....
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This note was uploaded on 12/02/2011 for the course PHYSICS 235 taught by Professor Staff during the Fall '08 term at Rutgers.
- Fall '08