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A burning candle. Fire is the rapid oxidation of a material (the fuel) in the exothermic chemical process of combustion, releasing heat, light, and various reaction products. [1] [a] At a certain point in the combustion reaction, called the ignition point, flames are produced.
One may investigate different parts of a candle flame with the aid of a cold metal spoon: [4] the higher parts of the flame produce water vapor deposition, the result of combustion, the yellow parts in the middle produce soot, and the area near the candle wick produces unburned wax. Goldsmiths use higher parts of a flame with a metallic blow ...
The fire triangle or combustion triangle is a simple model for understanding the necessary ingredients for most fires. [1] The triangle illustrates the three elements a fire needs to ignite: heat, fuel, and an oxidizing agent (usually oxygen). [2] A fire naturally occurs when the elements are present and combined in the right mixture. [3]
There are two kinds of enthalpy of combustion, called high(er) and low(er) heat(ing) value, depending on how much the products are allowed to cool and whether compounds like H 2 O are allowed to condense. The high heat values are conventionally measured with a bomb calorimeter. Low heat values are calculated from high heat value test data.
Combustion does not always result in fire, because a flame is only visible when substances undergoing combustion vaporize, but when it does, a flame is a characteristic indicator of the reaction. While activation energy must be supplied to initiate combustion (e.g., using a lit match to light a fire), the heat from a flame may provide enough ...
In an adiabatic system (i.e. a system that does not exchange heat with the surroundings), an otherwise exothermic process results in an increase in temperature of the system. [11] In exothermic chemical reactions, the heat that is released by the reaction takes the form of electromagnetic energy or kinetic energy of molecules. [12]
Heat domes can act like large, unmovable bubbles, forcing any moisture to move up and over the bubble of heat. Thunderstorms that ignite on the fringe of the heat dome are known as ring of fire ...
"Rollover" or tongues of fire appear (known as "angel fingers" to firefighters) as gases reach their auto-ignition temperatures. There is a rapid build-up (or "spike") in temperature due to the compound effect of rapidly burning (i.e., deflagrating) gases and the thermal cycle they produce.