Materials: Computer and School Network
Time Allotment: 3 Class Days
The purpose of this activity is to explore a variety of refraction effects and to make an attempt to explain them using some simple refraction principles and some ray diagramming.
Consider the following thought experiment (which corresponds to an experience which you may have had).
Ben Laborin has just completed the graveyard shift (11 pm to 7 am) at the local factory. On his drive home he becomes tired and momentarily falls asleep. His car gradually veers to the side of the road. Finally, his right front tire passes from the blacktop road onto the gravel XXX. His car suddenly begins to turn further to the right. The sudden noise of a tire on gravel and the sudden change in direction of the car awakes Ben and he naturally responds by jerking the steering wheel to the left and returning to the blacktop road.
In the above analogy, Ben Laborin's car changed speed and direction as it passed from one surface (blacktop) to another surface (gravel). The above analogy can be extended to understanding the behavior of light as it passes from one material to another. Ray Zuvlite takes a laser pen and shines the beam at a 45-degree angle from air towards the water-filled fish tank.
Obtain a clear drinking glass and a pencil or pen. Fill the glass three-fourths full of water. Place the pencil in the water in an upright position. Place the water at eye level (or better yet, your eyes at water level). Slowly move the pencil from side to side, observing the appearance of the pencil both above and below the water.
Write a paragraph in which you define refraction in simple terms, explain when refraction takes place, explain why refraction takes place, state a general rule for predicting the direction which a light ray will refract, and explain the value of such a rule in explaining a refraction phenomenon (other than the one discussed in this lab). Do a bang-up job!
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This page created by Tom Henderson and last updated on 8/25/97.