| LONG PATH DIFFRACTION
illustrates the wave nature of light by making visible the interference
patterns caused when light bends around an object. Normally, these
patterns are too small to see. Because laser light is monochromatic
(one color) and coherent (all the light waves travel together),
the interference patterns are very clear. Visitors can hold various
objects in the path of the laser light and see their fringed shadows
on the screen.