Make a spectrometer.  Demostrate how light is affected by color or how objects of a certain color appear when bathed in light of another color.  Our high-energy diffraction grating is 100X more effecient that acetate gratings, producing a spectrum bright enought ot see in a lighted classroom.  The sinusoidal shape, embossed in polyster plastic, places most light in the first order images and produces a 23.5 dispersion angle and groove sepratong of 19,050 lines per inch (750 lines per mm) for a wavelength of 550nm.