Flame generated by the burning of a candle.

Another candle flame

A flame is often defined as the visible (light-emitting) part of a fire. Fire is the heat and light energy released during a Chemical reaction, in particular a combustion reaction. Physically, it is caused by a highly exothermic reaction (for example, combustion, a self-sustaining oxidation reaction) taking place in a thin zone. In Thermodynamics, the word exothermic "outside heating" describes a process or reaction that releases Energy usually in the form of Heat, but Combustion or burning is a complex sequence of Exothermic chemical reactions between a Fuel and an Oxidant accompanied by the production of Redox (shorthand for reduction-oxidation reaction describes all Chemical reactions in which atoms have their Oxidation number ( Oxidation state A chemical reaction is a process that always results in the interconversion of Chemical substances The substance or substances initially involved in a chemical reaction are called A flame generally emits light, by two different mechanisms which will be described below.

The color and temperature of a flame are dependent on the type of fuel involved in the combustion, as, for example, when a lighter is held to a candle. Temperature is a physical property of a system that underlies the common notions of hot and cold something that is hotter generally has the greater temperature Fuel is any material that is burned or altered in order to obtain energy A lighter is a portable device used to create a Flame. It consists of a metal or plastic container filled with lighter fluid (usually Naphtha or liquid Butane A candle is a Light source and sometimes a Heat source consisting of a solid block of Fuel and an embedded wick. The applied heat causes the fuel molecules in the wick to vaporize. In Chemistry, a molecule is defined as a sufficiently stable electrically neutral group of at least two Atoms in a definite arrangement held together by Evaporation is the process by which Molecules in a Liquid state (e In this state they can then readily react with oxygen in the air, which gives off enough heat in the subsequent exothermic reaction to vaporize yet more fuel, thus sustaining a consistent flame. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five In Physics, heat, symbolized by Q, is Energy transferred from one body or system to another due to a difference in Temperature In Thermodynamics, the word exothermic "outside heating" describes a process or reaction that releases Energy usually in the form of Heat, but The high temperature of the flame tears apart the vaporized fuel molecules, forming various incomplete combustion products and free radicals, and these products then react with each other and with the oxidizer involved in the reaction. In Chemistry, radicals (often referred to as free radicals) are atoms molecules or ions with Unpaired electrons on an otherwise Open shell Sufficient energy in the flame will excite the electrons in some of the transient reaction intermediates such as CH and C2, which results in the emission of visible light as these substances release their excess energy (see spectrum below for an explanation of which specific radical species produce which specific colors). In Physics and other Sciences energy (from the Greek grc ἐνέργεια - Energeia, "activity operation" from grc ἐνεργός The electron is a fundamental Subatomic particle that was identified and assigned the negative charge in 1897 by J Light, or visible light, is Electromagnetic radiation of a Wavelength that is visible to the Human eye (about 400–700 As the combustion temperature of a flame increases (if the flame contains small particles of unburnt carbon or other material), so does the average energy of the electromagnetic radiation given off by the flame (see blackbody). Electromagnetic radiation takes the form of self-propagating Waves in a Vacuum or in Matter. In Physics, a black body is an object that absorbs all light that falls on it

Other oxidizers besides oxygen can be used to produce a flame. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Hydrogen burning in chlorine produces a flame and in the process emits gaseous hydrogen chloride (HCl) as the combustion product. Hydrogen (ˈhaɪdrədʒən is the Chemical element with Atomic number 1 Chlorine (ˈklɔriːn from the Greek word 'χλωρóς' ( khlôros, meaning 'pale green' is the Chemical element with Atomic number 17 and ^[1] Another of many possible chemical combinations is hydrazine and nitrogen tetroxide which is hypergolic and commonly used in rocket engines. Hydrazine is a Chemical compound with the formula N2H4 It has an Ammonia -like odor and is derived from the same industrial chemistry Nitrogen tetroxide ( dinitrogen tetroxide or nitrogen peroxide) is the Chemical compound N2O4 A hypergolic propellant is either of the two Rocket propellants used in a hypergolic Rocket engine, which spontaneously ignite when they come into contact A rocket engine is a Jet engine that uses only Propellant mass for forming its high speed propulsive jet.

The chemical kinetics occurring in the flame is very complex and involves typically a large number of chemical reactions and intermediate species, most of them radicals. Chemical kinetics, also known as reaction kinetics is the study of rates of chemical processes In Chemistry, radicals (often referred to as free radicals) are atoms molecules or ions with Unpaired electrons on an otherwise Open shell For instance, a well-known chemical kinetics scheme, GRI-Mech ^[2] , uses 53 species and 325 elementary reactions to describe combustion of natural gas. Natural gas is a Gaseous Fossil fuel consisting primarily of Methane but including significant quantities of Ethane, Propane,

There are different methods of distributing the required components of combustion to a flame. In a diffusion flame, oxygen and fuel diffuse into each other; where they meet the flame occurs. In Combustion, a diffusion flame is a Flame in which the Oxidizer combines with the Fuel by Diffusion. In a premixed flame, the oxygen and fuel are premixed beforehand, which results in a different type of flame. A premixed flame is a Flame in which the Oxidizer has been mixed with the Fuel before it reaches the flame front Candle flames (a diffusion flame) operate through evaporation of the fuel which rises in a laminar flow of hot gas which then mixes with surrounding oxygen and combusts. Evaporation is the process by which Molecules in a Liquid state (e Laminar flow, sometimes known as streamline flow occurs when a fluid flows in parallel layers with no disruption between the layers

Flame color

Different flame types of a Bunsen burner depend on oxygen supply. On the left a rich fuel with no premixed oxygen produces a yellow sooty diffusion flame; on the right a lean fully oxygen premixed flame produces no soot and the flame color is produced by molecular radicals, especially CH and C2 band emission. Spectral bands are part of optical spectra of polyatomic systems including condensed materials large molecules etc

Spectrum of the blue (premixed, i. e. , complete combustion) flame from a butane torch showing molecular radical band emission and Swan bands. Butane, also called n -butane, is the unbranched Alkane with four Carbon Atoms CH3CH2CH2CH3 In Chemistry, radicals (often referred to as free radicals) are atoms molecules or ions with Unpaired electrons on an otherwise Open shell Note that virtually all the light produced is in the blue to green region of the spectrum below about 565 nanometers, accounting for the bluish color of sootless hydrocarbon flames.

A flame test for sodium. A flame test is a procedure used in Chemistry to detect the presence of certain Metal ions based on each element's characteristic Emission spectrum Sodium (ˈsoʊdiəm is an element which has the symbol Na( Latin natrium, from Arabic natrun) atomic number 11 atomic mass 22 Note that the yellow color in this gas flame does not arise from the blackbody emission of soot particles (as the flame is clearly a blue premixed complete combustion flame) but instead comes from the spectral line emission of sodium atoms, specifically the very intense "sodium D lines". A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range compared

Flame color depends on several factors, the most important typically being blackbody radiation and spectral band emission, with both spectral line emission and spectral line absorption playing smaller roles. The Electromagnetic radiation emitted by a Black body. You may also be looking for Incandescence, the radiation from a body Spectral bands are part of optical spectra of polyatomic systems including condensed materials large molecules etc A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range compared In the most common type of flame, hydrocarbon flames, the most important factor determining color is oxygen supply and the extent of fuel-oxygen "pre-mixture", which determines the rate of combustion and thus the temperature and reaction paths, thereby producing different color hues. In Organic chemistry, a hydrocarbon is an Organic compound consisting entirely of Hydrogen and Carbon. In a laboratory under normal gravity conditions and with a closed oxygen valve, a Bunsen burner burns with yellow flame (also called a safety flame) at around 1,000°C. A laboratory (informally lab) is a facility that provides controlled conditions in which scientific Research, Experiments and Gravitation is a natural Phenomenon by which objects with Mass attract one another A Bunsen burner is a common piece of Laboratory equipment that produces a single open gas Flame, which is used for heating sterilization and combustion This is due to incandescence of very fine soot particles that are produced in the flame. Incandescence is the emission of Light (visible Electromagnetic radiation) from a hot body due to its temperature Soot (ˈsʊt is a general term that refers to the black impure carbon particles resulting from the incomplete combustion of a hydrocarbon With increasing oxygen supply, less blackbody-radiating soot is produced due to a more complete combustion and the reaction creates enough energy to excite and ionize gas molecules in the flame, leading to a blue appearance. Ionization is the physical process of converting an Atom or Molecule into an Ion by adding or removing charged particles such as Electrons The spectrum of a premixed (complete combustion) butane flame on the right shows that the blue color arises specifically due to emission of excited molecular radicals in the flame, which emit most of their light well below ~565 nanometers in the blue and green regions of the visible spectrum. Butane, also called n -butane, is the unbranched Alkane with four Carbon Atoms CH3CH2CH2CH3 In Chemistry, a molecule is defined as a sufficiently stable electrically neutral group of at least two Atoms in a definite arrangement held together by

Flame temperatures of common items include a blow torch at 1,300°C, a candle at 1,400°C [1], or a much hotter oxyacetylene combustion at 3,000°C. The meaning of " blowtorch " varies between Britain and the USA A candle is a Light source and sometimes a Heat source consisting of a solid block of Fuel and an embedded wick. Concerning a. " for the verdict on this matter --> Oxy-fuel welding (commonly called oxyacetylene welding, oxy welding Cyanogen produces an ever-hotter flame with a temperature of over 4525°C (8180°F) when it burns in oxygen. Cyanogen is the Chemical compound with the formula ( C[[nitrogen N]]2 ^[3]

Generally speaking, the coolest part of a diffusion (incomplete combustion) flame will be red, transitioning to orange, yellow, and white the temperature increases as evidenced by changes in the blackbody radiation spectrum. The Electromagnetic radiation emitted by a Black body. You may also be looking for Incandescence, the radiation from a body For a given flame's region, the closer to white on this scale, the hotter that section of the flame is. The transitions are often apparent in TV pictures of fires, in which the color emitted closest to the fuel is white, with an orange section above it, and reddish flames the highest of all. Beyond the red the temperature is too low to sustain combustion, and black soot escapes. A blue-colored flame only emerges when the amount of soot decreases and the blue emissions from excited molecular radicals become dominant, though the blue can often be seen near the base of candles where airborne soot is less concentrated.

Flames in microgravity

In zero gravity, convection does not carry the hot combustion products away from the fuel source, resulting in a spherical flame front. Weightlessness is a phenomenon experienced by people during Free-fall.

In the year 2000 the National Aeronautics and Space Administration (NASA) of the United States discovered that gravity also plays an indirect role in flame formation and composition. The National Aeronautics and Space Administration ( NASA, ˈnæsə is an agency of the United States government, responsible for the nation's public space program The United States of America —commonly referred to as the Gravitation is a natural Phenomenon by which objects with Mass attract one another ^[4] The common distribution of a flame under normal gravity conditions depends on convection, as soot tends to rise to the top of a flame (such as in a candle in normal gravity conditions), making it yellow. In microgravity or zero gravity, such as an outer space environment, convection no longer occurs and the flame becomes spherical, with a tendency to become bluer and more efficient. Weightlessness is a phenomenon experienced by people during Free-fall. Outer space, often simply called space, comprises the relatively empty regions of the Universe outside the escape velocities of Celestial bodies. Convection in the most general terms refers to the movement of molecules within Fluids (i There are several possible explanations for this difference, of which the most likely is the hypothesis that the temperature is sufficiently evenly distributed that soot is not formed and complete combustion occurs. ^[5] Experiments by NASA reveal that diffusion flames in microgravity allow more soot to be completely oxidized after they are produced than do diffusion flames on Earth, because of a series of mechanisms that behave differently in microgravity when compared to normal gravity conditions. The National Aeronautics and Space Administration ( NASA, ˈnæsə is an agency of the United States government, responsible for the nation's public space program In Combustion, a diffusion flame is a Flame in which the Oxidizer combines with the Fuel by Diffusion. EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 ^[6][7] These discoveries have potential applications in applied science and industry, especially concerning fuel efficiency. For the song by 311, see Grassroots. Applied science is the application of knowledge from one or more natural scientific For other uses of this term see Industry (disambiguation An industry (from Latin industrius, "diligent industrious" Fuel efficiency, in its basic sense is the same as Thermal efficiency, meaning the efficiency of a process that converts chemical potential energy contained in a carrier A video of a microgravity flame in the NASA Glenn 5 s drop facility is at [2].

References