A match is a simple chemical tool designed to produce fire reliably on demand. This device converts mechanical friction into a stable, self-sustaining flame through a precise sequence of controlled, exothermic chemical reactions.
The Chemical Difference Between Safety and Strike-Anywhere Matches
The fundamental difference between match types lies in the placement of the primary igniting chemical. Safety matches separate the reactive components, igniting only when struck against a specific surface. The match head contains the oxidizer, typically potassium chlorate, and the primary fuel, often a sulfur compound like antimony trisulfide. The striking surface contains the igniter, red phosphorus, mixed with a friction agent like powdered glass. Strike-anywhere matches, conversely, contain all necessary ingredients directly on the match head. Their head includes the oxidizer alongside a highly reactive phosphorus compound, such as phosphorus sesquisulfide (\(\text{P}_4\text{S}_3\)), allowing them to ignite on nearly any rough surface.
The Mechanics of Initial Ignition
Ignition begins when striking the match converts kinetic energy into thermal energy through friction. Powdered glass, mixed into the striking surface, increases roughness, maximizing this heat. For a safety match, this initial heat converts a minute amount of red phosphorus on the striking strip into white phosphorus. White phosphorus has an exceptionally low ignition temperature, causing it to spontaneously ignite upon contact with air. This flash of combustion generates a significant spike in local temperature, triggering the main reaction. The heat rapidly decomposes the potassium chlorate oxidizer in the match head, releasing a burst of oxygen gas (\(\text{O}_2\)). This oxygen then reacts with the fuel compounds in the match head, creating the first sustained, high-temperature flame.
How the Flame Sustains Itself
The initial reaction immediately ignites the secondary fuel compound, such as sulfur or antimony trisulfide, which burns more slowly. This secondary combustion transfers heat to the bulk of the matchstick. The wooden splint is often impregnated with paraffin wax, which serves as a highly flammable bridge fuel. The heat from the burning head and the wax causes the wood to undergo pyrolysis, where the cellulose breaks down into volatile, flammable gases. These gases combust to create the flame that continues to burn until the fuel source is depleted. Furthermore, the wooden stick is typically treated with a chemical like ammonium phosphate to prevent the wood from glowing or smoldering once the flame has been extinguished.