Striking a match starts a chemical reaction. There are two types of matches: safety matches and "strike anywhere" matches. A safety match can only light when someone strikes it against the striking surface on the side of the match box. A "strike anywhere" match can be lit by striking the match on anything solid. A "striking surface" is made of sand, powdered glass, and a chemical called "red phosphorus." The head of a safety match is made of sulfur, glass powder, and an oxidizing agent. An oxidizing agent is a chemical that takes electrons from another chemical. When a match is struck on the striking surface of its box, the friction caused by the glass powder rubbing together produces enough heat to turn a very small amount of the red phosphorus into white phosphorus, which catches fire in air. A "strike anywhere" match works in a similar way, but instead of phosphorus being on a striking surface, it is added to the head of the match. You can tell the difference between the two types of matches by looking at the colors of the match heads. A safety head is only one color, but a "strike anywhere" match is two colors: one for the phosphorus, and one for the oxidizing agent.