Glow-in-the-dark materials are substances that can absorb light and then re-emit it, creating a glowing effect in the dark. This phenomenon occurs due to a process called phosphorescence, where energy from light is stored and gradually released over time. Common examples of glow-in-the-dark items include toys, stickers, and watch dials. These materials typically contain phosphors, which are compounds that exhibit this glowing property. When exposed to a light source, such as sunlight or artificial light, they charge up and can glow for several hours after the light source is removed. Glow-in-the-dark products are often used for safety, decoration, and fun.