Fluorescence

Some materials glow in amazing colors when you shine a special ultraviolet light on them. This glow is called fluorescence. The material absorbs invisible UV light and gives off visible light that you can see. Highlighter pens, white T-shirts, and some minerals are all fluorescent.

How Fluorescence Works

Ultraviolet light has more energy than visible light. When UV light hits a fluorescent material, the material absorbs the energy. The atoms in the material get excited and then release the energy as visible light. The color of the glow depends on the material. This all happens in a tiny fraction of a second.

Fluorescence in Nature and Technology

Some animals are fluorescent. Certain scorpions, jellyfish, and coral glow under UV light. Fluorescent dyes are used in highlighter pens and safety vests. Fluorescent lights in buildings use this principle to produce light efficiently. Laundry detergent contains fluorescent chemicals that make white clothes look brighter.

Fun Facts

• Scorpions glow bright blue-green under ultraviolet light, though scientists are not sure why.
• Some bananas glow blue under UV light because of a chemical in their skin.
• Fluorescent lights use about 75 percent less energy than incandescent light bulbs.

Did You Know?

The word fluorescence comes from the mineral fluorite, which was one of the first materials found to glow under ultraviolet light. Some fluorite crystals glow a brilliant blue-violet color!