A safety match head contains oxidizer (like KClO₃), fuel (sulfur), and binder. The striking surface contains red phosphorus, glass powder, and binder. Striking the head against the surface creates friction, which generates heat. This heat energy is sufficient to convert a tiny amount of red phosphorus on the strip into the highly reactive white phosphorus, which ignites instantly in air. This initial ignition then provides the heat to decompose the potassium chlorate in the match head, releasing oxygen, which oxidizes the sulfur, causing the main flame.