Job #2: The famous fishing pole paradox


   When you look at a stick in the water, it looks like it bends up as it enters the water.
  (Look at the stick in our demonstration fish tank. Does the part of the stick that is below water appear to bend upwards or downwards at the water surface?)
  You know, of course, that light bends toward the perpendicular when it goes into a medium of higher index of refraction.
  So, shouldn't the stick appear to bend downward?

  Using the diagram shown on this page, draw that particular ray from the bottom tip of the stick that enters the observer's eye. (You might have to do a little trial and error to find the route that this ray takes.)
  Then note the direction from which this light ray appears to be coming (toward the eye). This is the direction in which the bottom of the stick appears to be. And the apparent length (along that direction) of the portion of the stick that is below water, is about the same as the actual length of the portion of the stick that is below water.

Explain in a few words, or with a well labelled ray diagram, how the paradox is resolved. (No numerical work is necessary)

Your Explanation here








Back to Job #1: Sally and Kenny go Wading
On to Job #3: How a prism separates blue light from red light
On to Job #4: The World's First Camera, or, How the Human Eye Works
On to Job #5: The Telescope, or How the Dutch Lens Grinders Made Galileo Famous
On to the Telescope Lab: Take two lenses and make a telescope right there in the lab
Answers to "Job" problems
Back to Optics Main menu

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