Lesson 1 – The Electromagnetic Spectrum

Electromagnetic (EM) radiation flows all around us, and takes many forms. Though all radiation moves at the speed of light, it is classified by the length of its waves or the frequency of its vibrations. Only a narrow range of wavelengths (colors) can be seen by humans: this is called the visible (Vis) spectrum. However, radiation with wavelengths both shorter and longer than the visible rainbow interacts in similar ways with common materials like glass, metal, ceramic, and polymer. This region that spans from short ultraviolet (UV) rays to long infrared (IR) radiation is known as the optical spectrum. The science of light, optics, involves material interactions with radiation from the UV through the Vis into the IR.