Glow sticks were invented about 25 years ago. They are an alternative light source that does not require a bulb or a battery to work. Light sticks actually form there "glow" from a chemical reaction. Two chemicals are in a vial inside the stick. When the stick is snapped then shaken, the chemicals mix together and create protons which are particles of light. The wide variety of glow stick colors is made by using different chemicals of fluorescent dye. Glow sticks do not heat up when they glow, so this makes them very safe to handle. They make great party prizes and decorations for all night time party's, not to mention they are great for kids to play with at night.