Fluorescence

In black light, some posters glow eerily.  This cool effect is due to fluorescence (5).  Fluorescence’s emission of light is due to the de-excitation of electrons. A form of energy such as thermal energy is applied.  The electrons in the molecules become excited and move up one or more energy levels.  The spin on the electron remains constant.  This new electron is very unstable and quickly emits a photon to return to ground state.  This photon is often at a wavelength we can see (8).  What makes a fluorescent object glow, however, is that the objects next to it do not have fluorescent properties.  A fluorescent molecule takes a thermal or other non-visible source of energy and re-emits it at a different wavelength visible to the eye.  Because a significant greater amount of light is being emitted by a fluorescent object than a non-fluorescent object, it appears to be glowing.  The fluorescent materials are able to take non-visible energy and use it to emit more light.  The non-fluorescent object can only emit the relatively small amount of visible light in the room (5). Harnessing non-visible energy, fluorescence is a way for an electron to emit light.