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AIR LENSES IN WATER








EQUIPMENT

    redball.gif (326 bytes) Plexiglas Water Tank
   
redball.gif (326 bytes) Air Lenses
   
redball.gif (326 bytes) 6 Volt Lamp
 


NARRATIVE
            The purpose of this demonstration is to show the dependence of refraction on the difference of indices of refraction of two media.

            Fill the water tank with a dye solution. There are three lenses needed for this demonstration. One lens is a solid converging lense, another is a concave air lens, and the third is a convex air lens. These lenses are constructed by encasing air between two thin convex or concave pieces of glass. Insert the solid lens between the light source and the tank. Notice the focal length. Now insert the lens in water. The lens is less"effective" in water. Perform the same operation with the air lenses. The concave lens has no effect in air but acts as a converging lens in water. The convex air lens has the opposite effect.