CD-ROM Spectroscope: A Simple and Inexpensive Tool for Classroom Demonstrations on Chemical Spectroscopy

Abstract

Construction of a handy spectroscope using a compact disk (CD) or a CD-ROM and its application to the observation of emission and absorption spectra are described. Using this simple cardboard-made spectroscope, one can readily observe line emission spectra of fluorescent lamps, gas discharge tubes, etc. The spectroscope is also used to observe the absorption spectra of colored solutions; the absorption bands are observed as distinct black bands on the rainbow-colored continuous spectrum of an incandescent lamp. The results for the aqueous solution of potassium permanganate, the methanol and ethanol solutions of cobalt chloride, and Fe(III)-thiocyanate complex are described. These results clearly show the general rule that a colored solution absorbs the complementary color of the color of the solution. Thus, the CD-ROM spectroscope is a useful tool in primary and secondary schools to teach what color is and what spectra are. Furthermore, it can be used effectively in introductory courses in colleges and un...