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 materials used for this effect include certain types of phosphors and zinc sulfide. These materials are often found in various products, such as toys, stickers, and paint. When exposed to light, they charge up and will glow for a period after the light source is removed. Glow-in-the-dark items are popular for decorative purposes and safety applications, helping to illuminate dark areas.