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Magnifying Glass

            In those old detective movies, before all those high tech instruments had been developed, the detective always has a magnifying glass to inspect the crime scene.  Perhaps you have wondered how a magnifying glass actually works.  It just seems like a piece of glass attached to a handle, but then windows are glass, and when we look through them the outside does not seem to be magnified.  This is because the glass in a magnifying glass is acting as a lens.  It is actually curved sLightly to form a convex lens, while the glass in our windows are plane glass. 

            The magnifying glass is not projecting an image onto anything; it is merely bending the Light rays from the object so that the object will appear larger.  The magnifying glass is an example of a Case 6 situation, of which the object is between the center of the lens and F, and the image is magnified, virtual and upright, and on the same side.  This is why a magnifying glass only works when it is close enough to the object (because the object must be between the center and F).

lenses4.gif" width="105" height="160"> Magnifying Glass Credits: Karen Wu