6A40.40 - Refraction - Variable Index of Refraction - Mirage

See paragraph one in the procedure section
Code Number:
Demo Title:
Refraction - Variable Index of Refraction - Mirage
Variable Index of Refraction
Area of Study:
Optics tank, laser, jack stands, cork pad, stirring rods, front surface mirror, and sugar water.

Mix up 5 liters of saturated sugar water.  Pour 2 liters of that solution into the bottom of the tank.  With the remainder of the stock make 1500 ml solutions that are 75%, 50%, 25%, and 10% saturated.  Float the cork pad on the 2 liter saturated solution in the tank and pour the 75% saturated solution over the cork pad then repeat this procedure with the other three solutions.  Shine a laser in the flat end of the tank and you should see the laser beam bend toward the bottom of the tank.  For an added effect you may place a front surface mirror at the point where the laser beam hits the bottom of the tank.  This will give you another curved beam reflected outward.  

A variation on this demo is to carefully pour Ethyl Alcohol on top of a layer of water.  In this case the beam will curve upward instead of downward. 

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Disclaimer: These demonstrations are provided only for illustrative use by persons affiliated with The University of Iowa and only under the direction of a trained instructor or physicist.  The University of Iowa is not responsible for demonstrations performed by those using their own equipment or who choose to use this reference material for their own purpose.  The demonstrations included here are within the public domain and can be found in materials contained in libraries, bookstores, and through electronic sources.  Performing all or any portion of any of these demonstrations, with or without revisions not depicted here entails inherent risks.  These risks include, without limitation, bodily injury (and possibly death), including risks to health that may be temporary or permanent and that may exacerbate a pre-existing medical condition; and property loss or damage.  Anyone performing any part of these demonstrations, even with revisions, knowingly and voluntarily assumes all risks associated with them.