Spectroscopy is a way to identify substances by exposing them to electromagnetic radiation (light). Light is given off when electrons jump from one place to another within an atom. Each atom has a unique arrangement of electrons. Each atom emits a unique mixture of different colored lights. As I was looking at the illuminated incandescent bulb through the spectrometer purple, red, and green were the colors that appeared. Wavelength measures in nano meters. The observed spectrum extend from 700 to 550 nano meters. Spectroscopy is important, because it shows the chemicals within a light bulb to the naked through a spectrometer.