fire

Fire is a rapid exothermic oxidation of a material that releases heat, light, and reaction products such as carbon dioxide and water. It occurs when a fuel combines with an oxidizer in the presence of sufficient heat. The traditional requirement of heat, fuel, and an oxidizer is known as the fire triangle; a fourth element, chemical chain reactions, is sometimes noted in modern explanations.

Flames are the visible portion of a fire, consisting of hot gases arising from the combustion process. Flame temperature and color depend on the fuel and the level of mixing with oxygen; typical flames range from roughly 600 to 1,800 degrees Celsius. Colors can vary due to soot or colored emissions from specific elements.

Fires progress through stages of ignition, growth, and decay. They spread by diffusion of hot gases and by flame fronts that preheat adjacent fuels. Key factors include fuel type, oxygen availability, confinement, and heat transfer by convection, conduction, and radiation. Suppression aims to remove heat, starve fuel, or reduce oxygen.

Fire serves many human needs, including cooking, space heating, metalworking, and energy generation. It also poses hazards such as burns, smoke inhalation, property damage, and environmental pollution. Wildfires can be driven by weather, vegetation dryness, and wind.

Humans have used fire for millennia, enabling cooking, tools, and industry, and it has shaped cultures and environments. Fire safety, prevention, and firefighting practices have evolved to reduce risks and improve control, with methods ranging from safety design and detection to suppression and evacuation.