Examples of Luminescence Simply Explained

• Chemoluminescence - This process creates light through a chemical reaction. Common applications are glow sticks (cyalume sticks) and the forensic application for locating blood using luminol.
• Crystalloluminescence - Light is made during crystallization and it is theorized that the light comes from small fractures in the crystal.
• Electroluminescence - This occurs when an electromagnetic field is applied to solid or gaseous material. This excites the molecules and the substance glows. LEDs, or light-emitting diodes, are found in flat panel televisions and computer monitors.
• Fluorescence - Fluorescent materials absorb light and then they glow for a certain time. In fluorescent light bulbs an electrical current runs through mercury vapor producing electrons that hit material that is painted on the inside of the bulb.
• Phosphorescence - Phosphorescent materials also glow in the dark; but, their glow lasts longer than fluorescence, making them good for glow in the dark applications. Clocks and watches have phosphorescent paint on them.
• Photoluminescence - This is a process where a substance absorbs photons and then re-emits them. The electromagnetic energy is absorbed at a certain wavelength and is emitted at a different wavelength which is most commonly longer.
• Radioluminescence - Light from this process is made from using radiation or high energy particles to bombard a substance. This is used in medical physics and radar screens.
• Sonoluminescence - This produces light from bubbles that are hitting one another when sound waves passed through the liquid. The sound waves cause bubbles which emit light when popped.
• Thermoluminescence - Light comes from using heat to release of electrons that were trapped in a substance. This process is used in archaeological dating.
• Triboluminescence - In this process, the light coming from the substance is made by friction, like rubbing, crushing, or scratching. The friction pulls apart chemical bonds, thus causing electrical charges.

Bioluminescence is a type of chemoluminescence that is used by living creatures. For example:

• Angler fish - These fish use bioluminescent lures to trap prey. The light comes from bacteria that used bioluminescence to communicate.
• Comb jellies - These glow all over and when a chunk is bitten off by an enemy, the chunk continues to glow, making that creature more visible to predators.
• Deep sea creatures including fish, crustaceans, and squid like the hatchetfish - These creatures can adjust their light output to eliminate their shadow.
• Earthworms - Some secrete a substance that glows that is thought to startle any predators.
• Fireflies - These insects have a chemical reaction in their bodies that converts lucifern into another form and that reaction produces light. They are also called lightning bugs.
• Fungi - There are over 70 species that are bioluminescent. The green glow may attract bugs to help spread spores, may attract the bugs' predators, or may have no particular function.
• Glow worms - These are the larval stage of gnats and these larvae produce sticky lines to catch prey. Then they secrete a glowing substance to attract the prey.
• Loose jaw dragonfish - These fish send out a red light from under their eyes that is essentially night vision.
• Plankton - Also called dinoflagellates, some plankton use their light as a startle mechanism. This may attract larger fish to attack the plankton's predator.
• Sea cucumbers - These have skin that is sticky and glows. It rubs off on their predators, making them more susceptible to other predators.
• Sea worms - Five species of sea worms launch capsules filled with liquid that break open and bioluminescence for a few seconds. This is done to distract predators.

So now you have seen both luminescence and bioluminescence.