Science, Tech, Math › Science Fluorescence Definition Chemistry Glossary Definition of Fluorescence Share Flipboard Email Print Fluorescent lights are coated with phoshors that absorb energy and release it as visible light. Verena Andrea Philipp / EyeEm / Getty Images Science Chemistry Chemical Laws Basics Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry in Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate by Anne Marie Helmenstine, Ph.D. Updated July 28, 2018 Fluorescence is luminescence that occurs where the energy is supplied by electromagnetic radiation, usually ultraviolet light. The energy source kicks an electron of an atom from a lower energy state into an "excited" higher energy state; then the electron releases the energy in the form of light (luminescence) when it falls back to a lower energy state. Fluorescence Examples: fluorescent lights, the red glow of rubies in sunlight, phosphors in television screens Continue Reading