How Do Glow Sticks Work? The History and Mechanics of Chemiluminescence
Glow sticks have been a fascinating accessory, for both young and old for almost 4 decades. They come in different shapes, colors, and sizes and are commonly known as a fun gimmick for the audience at music events, to create an engaging atmosphere. However, besides their purpose of entertainment, glow sticks can be used in many practical ways as well. In fact, the US Department of Defense is the biggest consumer of glow sticks today.
The Inventors of Glow Sticks
The history of glow sticks began in the United States during the 1960s, when chemist Dr. Edwin Chandross discovered an active luminescence-producing combination by experimenting with hydrogen peroxide and chloride. Unfortunately, Dr. Chandross never patented his discovery and so in 1976 scientists Vincent J. Esposito, Steven M. Little, and John H. Lyon were the lucky men to be listed as the inventors of the “Chemical Light”.
More than Just Fun
These chemical lights were initially intended as a fun party gag, but soon they became of great use in other fields. Motorists e.g. can use glow sticks as a reliable light source if their vehicle breaks down or is involved in an accident. On the one hand the glow stick serves as a mark to make the car visible for passing drivers; on the other hand the glow stick is a great tool to check on the engine or other car parts. Since glow sticks last longer and are more durable than the batteries in a flashlight, they are a safer choice for any emergency case preparations. Glow sticks are also used by anglers when they pursue their hobby in the early morning hours or late at night. The light stick works as a float, which marks the position of the fishing pole in the water. Golfers took advantage of the idea to create the “ultimate golf ball”, which glows up to twelve hours and allows the athletes to putt in the dark. The US Department of Defense equips its soldiers with glow sticks as emergency lighting and also as marker aids and consumes about 20 million light sticks per year. Likewise, the concept of glow sticks is used for lifeboats to surround the boat with a highly visible radiance.
How do Glow Sticks Work?
Most chemical reaction release energy in the form of warmth. The chemical reaction in a glow stick however produces energy in the form of light. This process is called chemiluminescence, including the Latin word “lumen” (English: “light”). The glow stick itself is made of polyethylene, a thermoplastic synthetic material that can be melted to a liquid and remolded as it returns to a solid state. This is not part of the actual chemical reaction. The container consists of two separate chambers filled with two different chemical liquids. The inner chamber is a thin glass tube that swims in the chemical the exterior chamber is filled with. Now as you bend the glow stick, the glass tube breaks and releases the internal chemical which then reacts with the outer chemical to produce a bright light. The long-lasting reaction is based on the oxidative release of nitrogen from luminol by the reaction of hydrogen peroxide and sodium hydroxide. These two chemicals are in the glass tube. Heat is not produced in this reaction, which makes the glow stick a convenient replacement for light bulbs that can get so hot that they burn your fingers. Chemists call the product of this chemical reaction therefor “cold light”. To get more color variations, dyes that stimulate the luminol flourescence are added to the liquids. Sadly, glow sticks cannot be used more than once.
The effect of chemiluminescence can be found in many organisms in nature, here called bioluminescence. One example for this is the firefly that uses cells that contain a chemical called luciferin and make an enzyme called luciferase, which produce their charming light. The bioluminescence often occurs in the deep sea in certain jellyfish or the famous lantern fish. The bioluminescence does also not produce heat, only light.