Fire is the rapid
oxidation
Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a ...
of a material (the
fuel) in the
exothermic chemical process of
combustion
Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combus ...
, releasing
heat
In thermodynamics, heat is defined as the form of energy crossing the boundary of a thermodynamic system by virtue of a temperature difference across the boundary. A thermodynamic system does not ''contain'' heat. Nevertheless, the term is ...
,
light
Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 te ...
, and various reaction
products
Product may refer to:
Business
* Product (business), an item that serves as a solution to a specific consumer problem.
* Product (project management), a deliverable or set of deliverables that contribute to a business solution
Mathematics
* Produ ...
.
At a certain point in the combustion reaction, called the ignition point, flames are produced. The ''
flame
A flame (from Latin '' flamma'') is the visible, gaseous part of a fire. It is caused by a highly exothermic chemical reaction taking place in a thin zone. When flames are hot enough to have ionized gaseous components of sufficient density they ...
'' is the visible portion of the fire. Flames consist primarily of carbon dioxide, water vapor, oxygen and nitrogen. If hot enough, the gases may become ionized to produce
plasma. Depending on the substances alight, and any impurities outside, the
color
Color (American English) or colour (British English) is the visual perceptual property deriving from the spectrum of light interacting with the photoreceptor cells of the eyes. Color categories and physical specifications of color are assoc ...
of the flame and the fire's
intensity will be different.
Fire in its most common form can result in
conflagration
A conflagration is a large fire. Conflagrations often damage human life, animal life, health, and/or property. A conflagration can begin accidentally, be naturally caused (wildfire), or intentionally created (arson). A very large fire can produc ...
, which has the potential to cause physical damage through
burning. Fire is an important process that affects ecological systems around the globe. The positive effects of fire include stimulating growth and maintaining various ecological systems.
Its negative effects include hazard to life and property, atmospheric pollution, and water contamination. If fire removes
protective vegetation, heavy
rain
Rain is water droplets that have condensed from atmospheric water vapor and then fall under gravity. Rain is a major component of the water cycle and is responsible for depositing most of the fresh water on the Earth. It provides water ...
fall may lead to an increase in
soil erosion by water. Also, when vegetation is burned, the
nitrogen
Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...
it contains is released into the atmosphere, unlike elements such as
potassium
Potassium is the chemical element with the symbol K (from Neo-Latin ''kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmosph ...
and
phosphorus
Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ear ...
which remain in the
ash
Ash or ashes are the solid remnants of fires. Specifically, ''ash'' refers to all non-aqueous, non- gaseous residues that remain after something burns. In analytical chemistry, to analyse the mineral and metal content of chemical samples, ash ...
and are quickly recycled into the soil. This loss of nitrogen caused by a fire produces a long-term reduction in the fertility of the soil, but this fecundity can potentially be recovered as molecular nitrogen in the atmosphere is "
fixed
Fixed may refer to:
* ''Fixed'' (EP), EP by Nine Inch Nails
* ''Fixed'', an upcoming 2D adult animated film directed by Genndy Tartakovsky
* Fixed (typeface), a collection of monospace bitmap fonts that is distributed with the X Window System
* ...
" and converted to
ammonia
Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous wa ...
by natural phenomena such as
lightning
Lightning is a naturally occurring electrostatic discharge during which two electrically charged regions, both in the atmosphere or with one on the ground, temporarily neutralize themselves, causing the instantaneous release of an avera ...
and by
leguminous
A legume () is a plant in the family Fabaceae (or Leguminosae), or the fruit or seed of such a plant. When used as a dry grain, the seed is also called a pulse. Legumes are grown agriculturally, primarily for human consumption, for livestock for ...
plants that are "nitrogen-fixing" such as
clover
Clover or trefoil are common names for plants of the genus ''Trifolium'' (from Latin ''tres'' 'three' + ''folium'' 'leaf'), consisting of about 300 species of flowering plants in the legume or pea family Fabaceae originating in Europe. The genus ...
,
pea
The pea is most commonly the small spherical seed or the seed-pod of the flowering plant species ''Pisum sativum''. Each pod contains several peas, which can be green or yellow. Botanically, pea pods are fruit, since they contain seeds and d ...
s, and
green beans.
Fire is one of the four
classical elements
Classical elements typically refer to earth, water, air, fire, and (later) aether which were proposed to explain the nature and complexity of all matter in terms of simpler substances. Ancient cultures in Greece, Tibet, and India had simi ...
and has been used by humans in
rituals
A ritual is a sequence of activities involving gestures, words, actions, or objects, performed according to a set sequence. Rituals may be prescribed by the traditions of a community, including a religious community. Rituals are characterized, b ...
, in agriculture for clearing land, for cooking, generating heat and light, for signaling, propulsion purposes,
smelting
Smelting is a process of applying heat to ore, to extract a base metal. It is a form of extractive metallurgy. It is used to extract many metals from their ores, including silver, iron, copper, and other base metals. Smelting uses heat and a ...
,
forging,
incineration
Incineration is a waste treatment process that involves the combustion of substances contained in waste materials. Industrial plants for waste incineration are commonly referred to as waste-to-energy facilities. Incineration and other high ...
of waste,
cremation
Cremation is a method of final disposition of a dead body through burning.
Cremation may serve as a funeral or post-funeral rite and as an alternative to burial. In some countries, including India and Nepal, cremation on an open-air pyre is ...
, and as a weapon or mode of destruction.
Physical properties
Chemistry
![Combustion reaction of methane](https://upload.wikimedia.org/wikipedia/commons/7/7c/Combustion_reaction_of_methane.jpg)
Fire is a chemical process in which a
fuel and an
oxidizing agent
An oxidizing agent (also known as an oxidant, oxidizer, electron recipient, or electron acceptor) is a substance in a redox chemical reaction that gains or " accepts"/"receives" an electron from a (called the , , or ). In other words, an oxi ...
react, yielding
carbon dioxide
Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is trans ...
and
water
Water (chemical formula ) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living ...
.
This process, known as a
combustion reaction, does not proceed directly and involves
intermediates.
Although the oxidizing agent is typically
oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...
, other compounds are able to fulfill the role. For instance,
chlorine trifluoride
Chlorine trifluoride is an interhalogen compound with the formula ClF3. This colorless, poisonous, corrosive, and extremely reactive gas condenses to a pale-greenish yellow liquid, the form in which it is most often sold (pressurized at room temp ...
is able to ignite
sand
Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class o ...
.
Fires start when a
flammable or a combustible material, in combination with a sufficient quantity of an
oxidizer
An oxidizing agent (also known as an oxidant, oxidizer, electron recipient, or electron acceptor) is a substance in a redox chemical reaction that gains or " accepts"/"receives" an electron from a (called the , , or ). In other words, an oxid ...
such as oxygen gas or another oxygen-rich compound (though non-oxygen oxidizers exist), is exposed to a source of heat or ambient
temperature
Temperature is a physical quantity that expresses quantitatively the perceptions of hotness and coldness. Temperature is measurement, measured with a thermometer.
Thermometers are calibrated in various Conversion of units of temperature, temp ...
above the
flash point for the
fuel/oxidizer mix, and is able to sustain a rate of rapid oxidation that produces a
chain reaction
A chain reaction is a sequence of reactions where a reactive product or by-product causes additional reactions to take place. In a chain reaction, positive feedback leads to a self-amplifying chain of events.
Chain reactions are one way that sys ...
. This is commonly called the
fire tetrahedron
The fire triangle or combustion triangle is a simple model for understanding the necessary ingredients for most fires.
The triangle illustrates the three elements a fire needs to ignite: heat, fuel, and an oxidizing agent (usually oxygen). A fi ...
. Fire cannot exist without all of these elements in place and in the right proportions. For example, a flammable liquid will start burning only if the fuel and oxygen are in the right proportions. Some fuel-oxygen mixes may require a
catalyst
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...
, a substance that is not consumed, when added, in any
chemical
A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be separated into its constituent elements by physical separation methods, i.e., w ...
reaction during combustion, but which enables the reactants to combust more readily.
Once ignited, a chain reaction must take place whereby fires can sustain their own heat by the further release of heat energy in the process of combustion and may propagate, provided there is a continuous supply of an oxidizer and fuel.
If the oxidizer is oxygen from the surrounding air, the presence of a force of
gravity
In physics, gravity () is a fundamental interaction which causes mutual attraction between all things with mass or energy. Gravity is, by far, the weakest of the four fundamental interactions, approximately 1038 times weaker than the stro ...
, or of some similar force caused by acceleration, is necessary to produce
convection
Convection is single or multiphase fluid flow that occurs spontaneously due to the combined effects of material property heterogeneity and body forces on a fluid, most commonly density and gravity (see buoyancy). When the cause of the conve ...
, which removes combustion products and brings a supply of oxygen to the fire. Without gravity, a fire rapidly surrounds itself with its own combustion products and non-oxidizing gases from the air, which exclude oxygen and
extinguish the fire. Because of this, the risk of fire in a
spacecraft
A spacecraft is a vehicle or machine designed to fly in outer space. A type of artificial satellite, spacecraft are used for a variety of purposes, including communications, Earth observation, meteorology, navigation, space colonization, p ...
is small when it is
coasting in inertial flight. This does not apply if oxygen is supplied to the fire by some process other than thermal convection.
![Fire tetrahedron](https://upload.wikimedia.org/wikipedia/commons/9/99/Fire_tetrahedron.svg)
Fire can be
extinguished by removing any one of the elements of the fire tetrahedron. Consider a natural gas flame, such as from a stove-top burner. The fire can be extinguished by any of the following:
* turning off the gas supply, which removes the fuel source;
* covering the flame completely, which smothers the flame as the combustion both uses the available oxidizer (the oxygen in the air) and displaces it from the area around the flame with CO
2;
* application of water, which removes heat from the fire faster than the fire can produce it (similarly, blowing hard on a flame will displace the heat of the currently burning gas from its fuel source, to the same end), or
* application of a retardant chemical such as
Halon to the flame, which retards the chemical reaction itself until the rate of combustion is too slow to maintain the chain reaction.
In contrast, fire is intensified by increasing the overall rate of combustion. Methods to do this include balancing the input of fuel and oxidizer to
stoichiometric
Stoichiometry refers to the relationship between the quantities of reactants and products before, during, and following chemical reactions.
Stoichiometry is founded on the law of conservation of mass where the total mass of the reactants equ ...
proportions, increasing fuel and oxidizer input in this balanced mix, increasing the ambient temperature so the fire's own heat is better able to sustain combustion, or providing a catalyst, a non-reactant medium in which the fuel and oxidizer can more readily react.
Flame
![Candle-light-animated](https://upload.wikimedia.org/wikipedia/commons/2/2a/Candle-light-animated.gif)
A flame is a mixture of reacting gases and solids emitting visible,
infrared
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
, and sometimes
ultraviolet
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiation ...
light, the
frequency spectrum
The power spectrum S_(f) of a time series x(t) describes the distribution of power into frequency components composing that signal. According to Fourier analysis, any physical signal can be decomposed into a number of discrete frequencies, ...
of which depends on the chemical composition of the burning material and intermediate reaction products. In many cases, such as the burning of
organic matter, for example wood, or the incomplete
combustion
Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combus ...
of gas,
incandescent
Incandescence is the emission of electromagnetic radiation (including visible light) from a hot body as a result of its high temperature. The term derives from the Latin verb ''incandescere,'' to glow white. A common use of incandescence is ...
solid particles called
soot
Soot ( ) is a mass of impure carbon particles resulting from the incomplete combustion of hydrocarbons. It is more properly restricted to the product of the gas-phase combustion process but is commonly extended to include the residual pyrolysed ...
produce the familiar red-orange glow of "fire". This light has a
continuous spectrum. Complete combustion of gas has a dim blue color due to the emission of single-wavelength radiation from various electron transitions in the excited molecules formed in the flame. Usually oxygen is involved, but
hydrogen
Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic ...
burning in
chlorine
Chlorine is a chemical element with the symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine i ...
also produces a flame, producing
hydrogen chloride
The compound hydrogen chloride has the chemical formula and as such is a hydrogen halide. At room temperature, it is a colourless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric water vapor. Hydrogen chloride ga ...
(HCl). Other possible combinations producing flames, amongst many, are
fluorine and
hydrogen
Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic ...
, and
hydrazine and
nitrogen tetroxide
Dinitrogen tetroxide, commonly referred to as nitrogen tetroxide (NTO), and occasionally (usually among ex-USSR/Russia rocket engineers) as amyl, is the chemical compound N2O4. It is a useful reagent in chemical synthesis. It forms an equilibrium ...
. Hydrogen and hydrazine/
UDMH
Unsymmetrical dimethylhydrazine (UDMH; 1,1-dimethylhydrazine, НДМГ or codenamed Geptil) is a chemical compound with the formula H2NN(CH3)2 that is used as a rocket propellant. It is a colorless liquid, with a sharp, fishy, ammonia-like smell ...
flames are similarly pale blue, while burning
boron and its compounds, evaluated in mid-20th century as a
high energy fuel for
jet and
rocket engine
A rocket engine uses stored rocket propellants as the reaction mass for forming a high-speed propulsive jet of fluid, usually high-temperature gas. Rocket engines are reaction engines, producing thrust by ejecting mass rearward, in accorda ...
s, emits intense green flame, leading to its informal nickname of "Green Dragon".
The glow of a flame is complex.
Black-body radiation is emitted from soot, gas, and fuel particles, though the soot particles are too small to behave like perfect blackbodies. There is also
photon
A photon () is an elementary particle that is a quantum of the electromagnetic field, including electromagnetic radiation such as light and radio waves, and the force carrier for the electromagnetic force. Photons are massless, so they a ...
emission by de-excited
atom
Every atom is composed of a nucleus and one or more electrons bound to the nucleus. The nucleus is made of one or more protons and a number of neutrons. Only the most common variety of hydrogen has no neutrons.
Every solid, liquid, gas, ...
s and
molecule
A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioche ...
s in the gases. Much of the radiation is emitted in the visible and infrared bands. The color depends on temperature for the black-body radiation, and on chemical makeup for the
emission spectra. The dominant color in a flame changes with temperature. The photo of the forest fire in Canada is an excellent example of this variation. Near the ground, where most burning is occurring, the fire is white, the hottest color possible for organic material in general, or yellow. Above the yellow region, the color changes to orange, which is cooler, then red, which is cooler still. Above the red region, combustion no longer occurs, and the uncombusted carbon particles are visible as black
smoke
Smoke is a suspension of airborne particulates and gases emitted when a material undergoes combustion or pyrolysis, together with the quantity of air that is entrained or otherwise mixed into the mass. It is commonly an unwanted by-produc ...
.
![Space Fire](https://upload.wikimedia.org/wikipedia/commons/7/74/Space_Fire.jpg)
The common distribution of a flame under normal gravity conditions depends on
convection
Convection is single or multiphase fluid flow that occurs spontaneously due to the combined effects of material property heterogeneity and body forces on a fluid, most commonly density and gravity (see buoyancy). When the cause of the conve ...
, as soot tends to rise to the top of a general flame, as in a
candle
A candle is an ignitable wick embedded in wax, or another flammable solid substance such as tallow, that provides light, and in some cases, a fragrance. A candle can also provide heat or a method of keeping time.
A person who makes candle ...
in normal gravity conditions, making it yellow. In
micro gravity or zero gravity, such as an environment in
outer space
Outer space, commonly shortened to space, is the expanse that exists beyond Earth and its atmosphere and between celestial bodies. Outer space is not completely empty—it is a near-perfect vacuum containing a low density of particles, pred ...
, convection no longer occurs, and the flame becomes spherical, with a tendency to become more blue and more efficient (although it may go out if not moved steadily, as the CO
2 from combustion does not disperse as readily in micro gravity, and tends to smother the flame). There are several possible explanations for this difference, of which the most likely is that the temperature is sufficiently evenly distributed that soot is not formed and complete combustion occurs. Experiments by
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the US federal government responsible for the civil List of government space agencies, space program ...
reveal that
diffusion flame
In combustion, a diffusion flame is a flame in which the oxidizer and fuel are separated before burning. Contrary to its name, a diffusion flame involves both diffusion and convection processes. The name diffusion flame was first suggested by S. ...
s in micro gravity allow more soot to be completely oxidized after they are produced than diffusion flames on Earth, because of a series of mechanisms that behave differently in micro gravity when compared to normal gravity conditions. These discoveries have potential applications in
applied science and
industry
Industry may refer to:
Economics
* Industry (economics), a generally categorized branch of economic activity
* Industry (manufacturing), a specific branch of economic activity, typically in factories with machinery
* The wider industrial sector ...
, especially concerning
fuel efficiency.
In
combustion engines, various steps are taken to eliminate a flame. The method depends mainly on whether the fuel is oil, wood, or a high-energy fuel such as
jet fuel.
Typical adiabatic temperatures
The adiabatic flame temperature of a given fuel and oxidizer pair is that at which the gases achieve stable combustion.
*
Oxy
Oxy may refer to:
Arts, entertainment, and media
* Oxy, a fictional character from the Molecularium Project
* Oxy, abbreviation for the Oxyrhynchus Papyri
Brands and enterprises
* Oxy, a line of skin care products from Mentholatum
* OXY, Ticker ...
–
dicyanoacetylene
Dicyanoacetylene, also called carbon subnitride or but-2-ynedinitrile (IUPAC), is a compound of carbon and nitrogen with chemical formula . It has a linear molecular structure, (often abbreviated as ), with alternating triple and single covalen ...
*
Oxy
Oxy may refer to:
Arts, entertainment, and media
* Oxy, a fictional character from the Molecularium Project
* Oxy, abbreviation for the Oxyrhynchus Papyri
Brands and enterprises
* Oxy, a line of skin care products from Mentholatum
* OXY, Ticker ...
–
acetylene
*
Oxyhydrogen
Oxyhydrogen is a mixture of hydrogen (H2) and oxygen (O2) gases. This gaseous mixture is used for torches to process refractory materials and was the first
gaseous mixture used for welding. Theoretically, a ratio of 2:1 hydrogen:oxygen is enough ...
*
Air
The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing f ...
–
acetylene
*
Blowtorch
A blowtorch, also referred to as a blowlamp, is an ambient air fuel-burning gas lamp used for applying flame and heat to various applications, usually metalworking.
Early blowtorches used liquid fuel, carried in a refillable reservoir attach ...
(air–
MAPP gas
MAPP gas was a trademarked name, belonging to The Linde Group, a division of the former global chemical giant Union Carbide, for a fuel gas based on a stabilized mixture of methylacetylene (propyne), propadiene and propane. The name comes from ...
)
*
Bunsen burner
A Bunsen burner, named after Robert Bunsen, is a kind of ambient air gas burner used as laboratory equipment; it produces a single open gas flame, and is used for heating, sterilization, and combustion.
The gas can be natural gas (which is ma ...
(air–
natural gas
Natural gas (also called fossil gas or simply gas) is a naturally occurring mixture of gaseous hydrocarbons consisting primarily of methane in addition to various smaller amounts of other higher alkanes. Low levels of trace gases like carbo ...
)
*
Candle
A candle is an ignitable wick embedded in wax, or another flammable solid substance such as tallow, that provides light, and in some cases, a fragrance. A candle can also provide heat or a method of keeping time.
A person who makes candle ...
(air–
paraffin Paraffin may refer to:
Substances
* Paraffin wax, a white or colorless soft solid that is used as a lubricant and for other applications
* Liquid paraffin (drug), a very highly refined mineral oil used in cosmetics and for medical purposes
* Alkan ...
)
Fire science & ecology
Every natural ecosystem has its own
fire regime
A fire regime is the pattern, frequency, and intensity of the bushfires and wildfires that prevail in an area over long periods of time. It is an integral part of fire ecology, and renewal for certain types of ecosystems. A fire regime describes th ...
, and the organisms in those ecosystems are adapted to or dependent upon that fire regime. Fire creates a mosaic of different
habitat
In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...
patches, each at a different stage of
succession. Different species of plants, animals, and microbes specialize in exploiting a particular stage, and by creating these different types of patches, fire allows a greater number of species to exist within a landscape.
Fire science is a branch of
physical science
Physical science is a branch of natural science that studies non-living systems, in contrast to life science. It in turn has many branches, each referred to as a "physical science", together called the "physical sciences".
Definition
Phy ...
which includes fire behavior, dynamics, and
combustion
Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combus ...
. Applications of fire science include
fire protection
Fire protection is the study and practice of mitigating the unwanted effects of potentially destructive fires. It involves the study of the behaviour, compartmentalisation, suppression and investigation of fire and its related emergencies, as we ...
,
fire investigation
Fire investigation, sometimes referred to as origin and cause investigation, is the analysis of fire-related incidents. After firefighters extinguish a fire, an investigation is launched to determine the origin and cause of the fire or explosion ...
, and
wildfire
A wildfire, forest fire, bushfire, wildland fire or rural fire is an unplanned, uncontrolled and unpredictable fire in an area of combustible vegetation. Depending on the type of vegetation present, a wildfire may be more specifically identi ...
management.
Fossil record
Human control
Early human control
![Des8](https://upload.wikimedia.org/wikipedia/commons/5/50/Des8.jpg)
The ability to
control fire was a dramatic change in the habits of early humans.
Making fire
Fire making, fire lighting or fire craft is the process of artificially starting a fire. It requires completing the fire triangle, usually by heating tinder above its autoignition temperature.
Fire is an essential tool for human survival an ...
to generate heat and light made it possible for people to
cook
Cook or The Cook may refer to:
Food preparation
* Cooking, the preparation of food
* Cook (domestic worker), a household staff member who prepares food
* Cook (professional), an individual who prepares food for consumption in the food industry
* ...
food, simultaneously increasing the variety and availability of nutrients and reducing disease by killing organisms in the food. The heat produced would also help people stay warm in cold weather, enabling them to live in cooler climates. Fire also kept nocturnal predators at bay. Evidence of cooked food is found from , Although there is some evidence that fire may have been used in a controlled fashion about 1 million years ago, other sources put the date at 400,000 years ago.
Evidence becomes widespread around 50 to 100 thousand years ago, suggesting regular use from this time; interestingly, resistance to
air pollution
Air pollution is the contamination of air due to the presence of substances in the atmosphere that are harmful to the health of humans and other living beings, or cause damage to the climate or to materials. There are many different typ ...
started to evolve in human populations at a similar point in time.
[ The use of fire became progressively more sophisticated, as it was used to create charcoal and to control wildlife from 'tens of thousands' of years ago.][
Fire has also been used for centuries as a method of torture and execution, as evidenced by ]death by burning
Death by burning (also known as immolation) is an execution and murder method involving combustion or exposure to extreme heat. It has a long history as a form of public capital punishment, and many societies have employed it as a punishment f ...
as well as torture devices such as the iron boot, which could be filled with water, oil
An oil is any nonpolar chemical substance that is composed primarily of hydrocarbons and is hydrophobic (does not mix with water) & lipophilic (mixes with other oils). Oils are usually flammable and surface active. Most oils are unsaturated ...
, or even lead
Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cu ...
and then heated over an open fire to the agony of the wearer.
By the Neolithic Revolution, during the introduction of grain-based agriculture, people all over the world used fire as a tool in landscape management. These fires were typically controlled burns or "cool fires", as opposed to uncontrolled "hot fires", which damage the soil. Hot fires destroy plants and animals, and endanger communities. This is especially a problem in the forests of today where traditional burning is prevented in order to encourage the growth of timber crops. Cool fires are generally conducted in the spring and autumn. They clear undergrowth, burning up biomass that could trigger a hot fire should it get too dense. They provide a greater variety of environments, which encourages game and plant diversity. For humans, they make dense, impassable forests traversable. Another human use for fire in regards to landscape management is its use to clear land for agriculture. Slash-and-burn agriculture is still common across much of tropical Africa, Asia and South America. "For small farmers, it is a convenient way to clear overgrown areas and release nutrients from standing vegetation back into the soil", said Miguel Pinedo-Vasquez, an ecologist at th
Earth Institute’s Center for Environmental Research and Conservation
However, this useful strategy is also problematic. Growing population, fragmentation of forests and warming climate are making the earth's surface more prone to ever-larger escaped fires. These harm ecosystems and human infrastructure, cause health problems, and send up spirals of carbon and soot that may encourage even more warming of the atmosphere – and thus feed back into more fires. Globally today, as much as 5 million square kilometres – an area more than half the size of the United States – burns in a given year.
Later human control
There are numerous modern applications of fire. In its broadest sense, fire is used by nearly every human being on earth in a controlled setting every day. Users of internal combustion
An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combust ...
vehicles employ fire every time they drive. Thermal power station
A power station, also referred to as a power plant and sometimes generating station or generating plant, is an industrial facility for the generation of electric power. Power stations are generally connected to an electrical grid.
Many ...
s provide electricity
Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as describ ...
for a large percentage of humanity by igniting fuels such as coal
Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen.
Coal is formed when ...
, oil
An oil is any nonpolar chemical substance that is composed primarily of hydrocarbons and is hydrophobic (does not mix with water) & lipophilic (mixes with other oils). Oils are usually flammable and surface active. Most oils are unsaturated ...
or natural gas
Natural gas (also called fossil gas or simply gas) is a naturally occurring mixture of gaseous hydrocarbons consisting primarily of methane in addition to various smaller amounts of other higher alkanes. Low levels of trace gases like carbo ...
, then using the resultant heat to boil water into steam, which then drives turbine
A turbine ( or ) (from the Greek , ''tyrbē'', or Latin ''turbo'', meaning vortex) is a rotary mechanical device that extracts energy from a fluid flow and converts it into useful work. The work produced by a turbine can be used for generating ...
s.
The use of fire in warfare
War is an intense armed conflict between states, governments, societies, or paramilitary groups such as mercenaries, insurgents, and militias. It is generally characterized by extreme violence, destruction, and mortality, using regul ...
has a long history
History (derived ) is the systematic study and the documentation of the human activity. The time period of event before the invention of writing systems is considered prehistory. "History" is an umbrella term comprising past events as well ...
. Fire was the basis of all early thermal weapons
Early thermal weapons, which used heat or burning action to destroy or damage enemy personnel, fortifications or territories, were employed in warfare during the classical and medieval periods (approximately the 8th century BC until the mid-16th ...
. Homer
Homer (; grc, Ὅμηρος , ''Hómēros'') (born ) was a Greek poet who is credited as the author of the ''Iliad'' and the ''Odyssey'', two epic poems that are foundational works of ancient Greek literature. Homer is considered one of the ...
detailed the use of fire by Greek soldiers who hid in a wooden horse to burn Troy
Troy ( el, Τροία and Latin: Troia, Hittite: 𒋫𒊒𒄿𒊭 ''Truwiša'') or Ilion ( el, Ίλιον and Latin: Ilium, Hittite: 𒃾𒇻𒊭 ''Wiluša'') was an ancient city located at Hisarlik in present-day Turkey, south-west of Ç ...
during the Trojan war
In Greek mythology, the Trojan War was waged against the city of Troy by the Achaeans (Greeks) after Paris of Troy took Helen from her husband Menelaus, king of Sparta. The war is one of the most important events in Greek mythology and ...
. Later the Byzantine
The Byzantine Empire, also referred to as the Eastern Roman Empire or Byzantium, was the continuation of the Roman Empire primarily in its eastern provinces during Late Antiquity and the Middle Ages, when its capital city was Constantinopl ...
fleet used Greek fire to attack ships and men. In the First World War
World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...
, the first modern flamethrowers were used by infantry, and were successfully mounted on armoured vehicles in the Second World War. In the latter war, incendiary bombs
Incendiary weapons, incendiary devices, incendiary munitions, or incendiary bombs are weapons designed to start fires or destroy sensitive equipment using fire (and sometimes used as anti-personnel weaponry), that use materials such as napalm, th ...
were used by Axis
An axis (plural ''axes'') is an imaginary line around which an object rotates or is symmetrical. Axis may also refer to:
Mathematics
* Axis of rotation: see rotation around a fixed axis
* Axis (mathematics), a designator for a Cartesian-coordinat ...
and Allies alike, notably on Tokyo, Rotterdam, London, Hamburg and, notoriously, at Dresden
Dresden (, ; Upper Saxon: ''Dräsdn''; wen, label= Upper Sorbian, Drježdźany) is the capital city of the German state of Saxony and its second most populous city, after Leipzig. It is the 12th most populous city of Germany, the fourth ...
; in the latter two cases firestorm
A firestorm is a conflagration which attains such intensity that it creates and sustains its own wind system. It is most commonly a natural phenomenon, created during some of the largest bushfires and wildfires. Although the term has been used ...
s were deliberately caused in which a ring of fire surrounding each city was drawn inward by an updraft caused by a central cluster of fires. The United States Army Air Force also extensively used incendiaries against Japanese targets in the latter months of the war, devastating entire cities constructed primarily of wood and paper houses. The use of napalm
Napalm is an incendiary mixture of a gelling agent and a volatile petrochemical (usually gasoline (petrol) or diesel fuel). The name is a portmanteau of two of the constituents of the original thickening and gelling agents: coprecipitated alu ...
was employed in July 1944, towards the end of the Second World War
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposi ...
; although its use did not gain public attention until the Vietnam War
The Vietnam War (also known by other names) was a conflict in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. It was the second of the Indochina Wars and was officially fought between North Vietnam a ...
. Molotov cocktail
A Molotov cocktail (among several other names – ''see other names'') is a hand thrown incendiary weapon constructed from a frangible container filled with flammable substances equipped with a fuse (typically a glass bottle filled with fla ...
s were also used.
Productive use for energy
Setting fuel aflame releases usable energy. Wood
Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin ...
was a prehistoric fuel, and is still viable today. The use of fossil fuels, such as petroleum
Petroleum, also known as crude oil, or simply oil, is a naturally occurring yellowish-black liquid mixture of mainly hydrocarbons, and is found in geological formations. The name ''petroleum'' covers both naturally occurring unprocessed crud ...
, natural gas
Natural gas (also called fossil gas or simply gas) is a naturally occurring mixture of gaseous hydrocarbons consisting primarily of methane in addition to various smaller amounts of other higher alkanes. Low levels of trace gases like carbo ...
, and coal
Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen.
Coal is formed when ...
, in power plants
A power station, also referred to as a power plant and sometimes generating station or generating plant, is an industrial facility for the generation of electric power. Power stations are generally connected to an electrical grid.
Many pow ...
supplies the vast majority of the world's electricity today; the International Energy Agency states that nearly 80% of the world's power came from these sources in 2002. The fire in a power station
A power station, also referred to as a power plant and sometimes generating station or generating plant, is an industrial facility for the generation of electric power. Power stations are generally connected to an electrical grid.
Many ...
is used to heat water, creating steam that drives turbine
A turbine ( or ) (from the Greek , ''tyrbē'', or Latin ''turbo'', meaning vortex) is a rotary mechanical device that extracts energy from a fluid flow and converts it into useful work. The work produced by a turbine can be used for generating ...
s. The turbines then spin an electric generator to produce electricity. Fire is also used to provide mechanical work
In physics, work is the energy transferred to or from an object via the application of force along a displacement. In its simplest form, for a constant force aligned with the direction of motion, the work equals the product of the force stre ...
directly, in both external
External may refer to:
* External (mathematics), a concept in abstract algebra
* Externality
In economics, an externality or external cost is an indirect cost or benefit to an uninvolved third party that arises as an effect of another party' ...
and internal combustion engine
An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal c ...
s.
The unburnable solid remains of a combustible material left after a fire is called ''clinker'' if its melting point
The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depen ...
is below the flame temperature, so that it fuses and then solidifies as it cools, and ''ash'' if its melting point is above the flame temperature.
Fire management
Deftly controlling a fire to optimize its size, shape, and intensity is generally called ''fire management'', and the more advanced forms of it, as traditionally (and sometimes still) practiced by skilled cooks, blacksmith
A blacksmith is a metalsmith who creates objects primarily from wrought iron or steel, but sometimes from other metals, by forging the metal, using tools to hammer, bend, and cut (cf. tinsmith). Blacksmiths produce objects such as gates, gr ...
s, ironmaster
An ironmaster is the manager, and usually owner, of a forge or blast furnace for the processing of iron. It is a term mainly associated with the period of the Industrial Revolution, especially in Great Britain.
The ironmaster was usually a large ...
s, and others, are highly skill
A skill is the learned ability to act with determined results with good execution often within a given amount of time, energy, or both. Skills can often be divided into domain-general and domain-specific skills. For example, in the domain of w ...
ed activities. They include knowledge about selecting which types of wood, charcoal, or mineral coal to burn; how to arrange the fuel; how to stoke the fire both in early phases and in maintenance phases; how to modulate the amount of heat, flames, and smoke as suited to the desired application; how best to bank a fire to be revived later; how to choose, design, or modify woodstoves, coalstoves, bakery ovens, and industrial furnaces; and so on. Detailed expositions of fire management are available in various books about blacksmithing, about skilled camping
Camping is an outdoor activity involving overnight stays away from home, either without shelter or using basic shelter such as a tent, or a recreational vehicle. Typically, participants leave developed areas to spend time outdoors in more na ...
or military scouting, and about the domestic arts in previous centuries.
Protection and prevention
Wildfire prevention programs around the world may employ techniques such as ''wildland fire use'' and ''prescribed or controlled burns''.[''Federal Fire and Aviation Operations Action Plan'', 4.] ''Wildland fire use'' refers to any fire of natural causes that is monitored but allowed to burn. ''Controlled burns'' are fires ignited by government agencies under less dangerous weather conditions.
Fire fighting
Firefighting is the act of extinguishing or preventing the spread of unwanted fires from threatening human lives and destroying property and the environment. A person who engages in firefighting is known as a firefighter.
Firefighters typicall ...
services are provided in most developed areas to extinguish or contain uncontrolled fires. Trained firefighters use fire apparatus
A firefighting apparatus describes any vehicle that has been customized for use during firefighting operations. These vehicles are highly customized depending on their needs and the duty they will be performing. These duties can include firefighti ...
, water supply resources such as water main
A water distribution system is a part of water supply network with components that carry potable water from a centralized treatment plant or wells to consumers to satisfy residential, commercial, industrial and fire fighting requirements.
Definit ...
s and fire hydrant
A fire hydrant, waterplug, or firecock (archaic) is a connection point by which firefighters can tap into a water supply. It is a component of active fire protection. Underground fire hydrants have been used in Europe and Asia since at least t ...
s or they might use A and B class foam depending on what is feeding the fire.
Fire prevention is intended to reduce sources of ignition. Fire prevention also includes education to teach people how to avoid causing fires. Buildings, especially schools and tall buildings, often conduct fire drill
A fire drill is a method of practicing how a building would be evacuated in the event of a fire or other emergencies. In most cases, the building's existing fire alarm system is activated and the building is evacuated by means of the nearest a ...
s to inform and prepare citizens on how to react to a building fire. Purposely starting destructive fires constitutes arson and is a crime in most jurisdictions.
Model building code
A building code (also building control or building regulations) is a set of rules that specify the standards for constructed objects such as buildings and non-building structures. Buildings must conform to the code to obtain planning permiss ...
s require passive fire protection
Passive fire protection (PFP) is components or systems of a building or structure that slows or impedes the spread of the effects of fire or smoke without system activation, and usually without movement. Examples of passive systems include floo ...
and active fire protection
Active fire protection (AFP) is an integral part of fire protection. AFP is characterized by items and/or systems, which require a certain amount of motion and response in order to work, contrary to passive fire protection.
Categories of active fi ...
systems to minimize damage resulting from a fire. The most common form of active fire protection is fire sprinkler
A fire sprinkler or sprinkler head is the component of a fire sprinkler system that discharges water when the effects of a fire have been detected, such as when a predetermined temperature has been exceeded. Fire sprinklers are extensively use ...
s. To maximize passive fire protection of buildings, building materials and furnishings in most developed countries are tested for fire-resistance, combustibility and flammability
A combustible material is something that can burn (i.e., ''combust'') in air. A combustible material is flammable if it ignites easily at ambient temperatures. In other words, a combustible material ignites with some effort and a flammable mat ...
. Upholstery
Upholstery is the work of providing furniture, especially seats, with padding, springs, webbing, and fabric or leather covers. The word also refers to the materials used to upholster something.
''Upholstery'' comes from the Middle English w ...
, carpeting
Fitted carpet, also wall-to-wall carpet, is a carpet intended to cover a floor entirely. Carpet over 4 meters in length is usually installed with the use of a power-stretcher (tubed or tubeless).
Fitted carpets were originally woven to the dimen ...
and plastics used in vehicles and vessels are also tested.
Where fire prevention and fire protection have failed to prevent damage, fire insurance can mitigate the financial impact.
See also
* Aodh (given name)
Aodh ( , , ; sga, Áed) is an Irish and Scottish Gaelic male given name, originally meaning "fire".The modern word ''aodh'' meaning 'inflammation' or as a phrase with the Irish word for 'itch' (''tochas''), giving ''aodh thochais'', 'burning itc ...
* Bonfire
* ''The Chemical History of a Candle
''The Chemical History of a Candle'' was the title of a series of six lectures on the chemistry and physics of flames given by Michael Faraday at the Royal Institution in 1848, as part of the series of Christmas lectures for young people found ...
''
* Colored fire
* Control of fire by early humans
The control of fire by early humans was a critical technology enabling the evolution of humans. Fire provided a source of warmth and lighting, protection from predators (especially at night), a way to create more advanced hunting tools, and a ...
* Deflagration
* Fire (classical element)
* Fire investigation
Fire investigation, sometimes referred to as origin and cause investigation, is the analysis of fire-related incidents. After firefighters extinguish a fire, an investigation is launched to determine the origin and cause of the fire or explosion ...
* Fire lookout
A fire lookout (partly also called a fire watcher) is a person assigned the duty to look for fire from atop a building known as a fire lookout tower. These towers are used in remote areas, normally on mountain tops with high elevation and a ...
* Fire lookout tower
* Fire making
Fire making, fire lighting or fire craft is the process of artificially starting a fire. It requires completing the fire triangle, usually by heating tinder above its autoignition temperature.
Fire is an essential tool for human survival and ...
* Fire pit
A fire pit or a fire hole can vary from a pit dug in the ground to an elaborate gas burning structure of stone, brick, and metal. The defining feature of fire pits is that they are designed to contain fire and prevent it from spreading.
Some rece ...
* Fire safety
* Fire triangle
The fire triangle or combustion triangle is a simple model for understanding the necessary ingredients for most fires.
The triangle illustrates the three elements a fire needs to ignite: heat, fuel, and an oxidizing agent (usually oxygen). A fir ...
* Fire whirl
* Fire worship
* Flame test
A flame test is an analytical procedure used in chemistry to detect the presence of certain elements, primarily metal ions, based on each element's characteristic flame emission spectrum (which may be affected by the presence of chloride io ...
* Life Safety Code
* List of fires
This article is a list of notable fires.
Town and city fires
Building or structure fires
Transportation fires
Mining (including oil and natural gas drilling) fires
This is a partial list of fire due to mining: man-made structures to extra ...
* List of light sources
This is a list of sources of light, the visible part of the electromagnetic spectrum. Light sources produce photons from another energy source, such as heat, chemical reactions, or conversion of mass or a different frequency of electromagnetic ener ...
* Phlogiston theory
The phlogiston theory is a superseded scientific theory that postulated the existence of a fire-like element called phlogiston () contained within combustible bodies and released during combustion. The name comes from the Ancient Greek (''burni ...
* Piano burning
* Prometheus
In Greek mythology, Prometheus (; , , possibly meaning " forethought")Smith"Prometheus". is a Titan god of fire. Prometheus is best known for defying the gods by stealing fire from them and giving it to humanity in the form of technology, kn ...
, the Greek mythological figure who gave mankind fire
* Pyrokinesis
Pyrokinesis is the purported psychic ability allowing a person to create and control fire with the mind. As with other parapsychological phenomena, there is no conclusive evidence in support of the actual existence of pyrokinesis. Many alleged c ...
* Pyrolysis
The pyrolysis (or devolatilization) process is the thermal decomposition of materials at elevated temperatures, often in an inert atmosphere. It involves a change of chemical composition. The word is coined from the Greek-derived elements ''py ...
* Pyromania
Pyromania is an impulse control disorder in which individuals repeatedly fail to resist impulses to deliberately start fires, to relieve some tension or for instant gratification. The term ''pyromania'' comes from the Greek word (''pyr'', 'fi ...
* Self-immolation
The term self-immolation broadly refers to acts of altruistic suicide, otherwise the giving up of one's body in an act of sacrifice. However, it most often refers specifically to autocremation, the act of sacrificing oneself by setting oneself ...
References
Notes
Citations
Sources
* Haung, Kai (2009)
Population and Building Factors That Impact Residential Fire Rates in Large U.S. Cities. Applied Research Project
Texas State University.
*
* Kosman, Admiel (January 13, 2011)
"Sacred fire"
'' Haaretz''.
*
External links
How Fire Works
at HowStuffWorks
HowStuffWorks is an American commercial infotainment website founded by professor and author Marshall Brain, to provide its target audience an insight into the way many things work. The site uses various media to explain complex concepts, termin ...
What exactly is fire?
from The Straight Dope
"The Straight Dope" was a question-and-answer newspaper column written under the pseudonym Cecil Adams. Contributions were made by multiple authors, and it was illustrated (also pseudonymously) by Slug Signorino. It was first published in 1973 in ...
On Fire
an Adobe Flash
Adobe Flash (formerly Macromedia Flash and FutureSplash) is a multimedia software platform used for production of animations, rich web applications, desktop applications, mobile apps, mobile games, and embedded web browser video players. Fla ...
–based science tutorial from the ''NOVA'' (TV series)
"20 Things You Didn't Know About... Fire"
from ''Discover
Discover may refer to:
Art, entertainment, and media
* ''Discover'' (album), a Cactus Jack album
* ''Discover'' (magazine), an American science magazine
Businesses and brands
* DISCover, the ''Digital Interactive Systems Corporation''
* D ...
'' magazine
{{Authority control
Articles containing video clips
Cooking techniques