Word of the Month: Fluorescence

David Zapatka

Ever wonder what makes your freshly-washed clothes glow in the sunlight? Have you ever been intrigued by the unnaturally-bright colors in the highlighters we use to highlight text? Have you ever looked at the light traveling through a tube in a light fixture and wonder how that works? Think fluorescence, this month’s word of the month.

Fluorescence – noun flo͝o(ə)ˈresəns,flôrˈesəns/ the visible or invisible radiation emitted by certain substances as a result of incident radiation of a shorter wavelength such as X-rays or ultraviolet light; the property of absorbing light of short wavelength and emitting light of longer wavelength.

First Known Use: 1852; Origin and etymology – Mid 19th Century English from fluorspar (which fluoresces), on the pattern of opalescence.

Examples of fluorescence in a sentence: “It is remarkable for its fluorescence, which in the opinion of some authorities, adds to its beauty.” “Human beginnings, the human kingdom, was evolved as a fluorescence of the mineral, vegetable and animal kingdoms.”

Fluorescence used in scientific and philosophic writing:

Fluorescence is a term to describe the emission of light by a substance that has absorbed light. The substance becomes excited and unstable when light is absorbed and tries to go back to its ground state by emitting energy in the form of light. In most cases, the emitted light has a longer wavelength. – Logos Biosystem

Because ultraviolet light has the ability to cause chemical reactions and excite fluorescence in materials, it has a huge number of useful applications in electronic communications. – Towards an Age of Light Part 1, World Goodwill, Lucis Trust

Fluorescence is all around us. In the form of light given off by excited molecules in their return to their ground state, fluorescence is seen in light bulbs, the ink from highlighters, the spice turmeric due to its main component, curcumin, and laundry detergent. For your naked eye to see some of these examples, a source of UV light may be needed. Fluorescence is very useful to chemists studying the property and identity of molecules, hydrologists studying trace amounts of pollutants in water and biologists tracking death as it passes through the cells of a body.

The next time you want to compliment a friend on the beautiful, bright clothes she’s wearing, you can thank the fluorescence caused by the laundry detergent she uses. Want to do something really cool? Scuba dive with a UV dive light to witness the spectacular phenomena known as coral fluorescence. What was already beautiful will become absolutely stunning in bright, vivid colors.

Please submit any experiences with fluorescence you would like to share, any thoughts on this month’s column or any word you may like to share, along with your insights and comments, to [email protected]