The Science of Chem Light
What is fun to snap, hear crack, and watch glow? Glow sticks! A glow stick, also known as chem light, is a self-contained chemical light source that has been around since the 1960s. Although not popular until the 1980s, scientists first started investigating chemiluminescence (the science of chem light) after being fascinated by the bioluminescent light produced by fireflies. Oddly enough, the basic chemistry was discovered by accident in a janitor’s closet when chemist Edwin A. Chandross noted a weak light after exposing a xanthone derivative, prepared with oxalyl chloride, to hydrogen peroxide and anthracene dye.
How do all of these chemicals make a glow stick glow?
Inside a glow stick, there are separated chemicals that react to create light when the barriers are snapped and the chemicals mix into one. The outer plastic tube of the glow stick holds a solution of oxalate ester and an electron-rich dye. The inner chemical is a hydrogen peroxide solution encased in a glass tube. The cracking sound you hear when you snap a glow stick is the glass tube breaking. After the glass tube is broken, the hydrogen peroxide is released and the chemicals mix. This causes a chemical reaction that results in the stored energy inside the tube released as light. Modifying the chemical formula can result in different colors, level of brightness, and duration of the illumination. Temperature has a significant impact on glow stick chemistry as well, with cooler temps extending the reaction and heat intensifying but shortening the duration.
Standard glowsticks will radiate a luminous glow for 8 to 12 hours. In ideal conditions, some types will glow for over 24 hours. The 24-hour glow sticks are ideal for camping and emergencies, while the standard glow sticks are most popular for kids and adults and can bring a fun excitement to many events.
Are they safe?
Being so popular with kids, many people may wonder if glow sticks are safe. In short, yes, the chemical contents inside of a glow stick are non-toxic and non-flammable. Generally, people should not require medical attention if they are exposed to the chemicals inside a glow stick (1). That said, it is best to err on the side of caution. Read the product warning labels thoroughly and follow the recommended guidelines provided by the manufacturer.
The science of chem light is both fun and illuminating! Now the next time you snap a glow stick, you can enlighten those around you with your knowledge of glow stick chemistry! Enjoy some sciency-fun this Halloween with chem light colors to brighten your night.