Glowing in the Dark

• Things appear to glow in the dark because of a certain chemical property that they have, which allows them to release light consistently over a period of time. Fluorescent objects do not glow in the dark, and they can only be seen when a light is shined on them. Phosphorescent objects glow in the dark and emit small photons of light. The chemical reaction within glow sticks renders them as a phosphorescent object, where a dye's reaction to a chemical solution within the glow stick creates a constant release of photons.
  
  

History of the Glow Stick

• In 1968, Edwin Chandross was a chemist at Bell Labs, and he sought to create an alternative to flashlights, flares and overhead lights that were used by a variety of professions, such as miners, scuba divers and construction workers. He designed the structure of a glow stick, which uses an ampule located inside a plastic tube. His initial ideas yielded a few early prototypes of the glow stick, and a lot of scientists sought to refine Chandross' design. Eventually, Richard Taylor Van Zandt applied for and received a patent for what he called the "Chemical Light Device," which resembles the modern day glow stick.
  
  

How Glow Sticks Work

• Glow sticks begin to glow when you pinch or press the outer plastic casing together. This causes the inner glass ampule to break. When it does so, it releases chemicals that mix with the dye that is outside of the ampule. The chemical reaction resulting from these two mixing together is called chemoluminescence. Once the reaction starts, there is no way to reverse it. Putting the glow sticks in the freezer, however, can slow the reaction, making it take longer before the light fades.
  
  

Components of a Glow Stick

• There are four main parts of a glow stick: the outer plastic layer, a layer of liquid, a glass ampule and liquid within the ampule. When you hold a glow stick, you only touch the plastic layer. The liquid within the layer of plastic is typically dye, and you can see it move up and down as you tilt the glow stick. The glass ampule is an oval tube that encases a variety of chemicals, such as sodium carbonate, ammonium carbonate, copper sulfate pentahydrate, hydrogen peroxide and a little hydrogen dioxide.