Glow sticks are plastic tubes filled with a chemical solution that emits light when activated. They work through a process called chemiluminescence, where a chemical reaction occurs when the stick is bent, mixing two substances inside. This reaction produces a bright glow, making glow sticks popular for parties, concerts, and outdoor events. These light sources come in various colors and sizes, often used for decoration or safety purposes. Glow sticks are also commonly found at music festivals and campsites, providing illumination without the need for batteries or electricity. They are safe to use, but the contents should not be ingested.