Spark (fire)
Encyclopedia
A spark is an incandescent
Incandescence
Incandescence is the emission of light from a hot body as a result of its temperature. The term derives from the Latin verb incandescere, to glow white....

 particle. Such sparks may be produced by pyrotechnics, by metalworking
Metalworking
Metalworking is the process of working with metals to create individual parts, assemblies, or large scale structures. The term covers a wide range of work from large ships and bridges to precise engine parts and delicate jewelry. It therefore includes a correspondingly wide range of skills,...

 or as a by-product of fire
Fire
Fire is the rapid oxidation of a material in the chemical process of combustion, releasing heat, light, and various reaction products. Slower oxidative processes like rusting or digestion are not included by this definition....

s, especially when burning wood
Wood fuel
Wood fuel is wood used as fuel. The burning of wood is currently the largest use of energy derived from a solid fuel biomass. Wood fuel can be used for cooking and heating, and occasionally for fueling steam engines and steam turbines that generate electricity. Wood fuel may be available as...

.

Pyrotechnics

In pyrotechnics
Pyrotechnics
Pyrotechnics is the science of using materials capable of undergoing self-contained and self-sustained exothermic chemical reactions for the production of heat, light, gas, smoke and/or sound...

, iron filings and metal alloys such as magnalium
Magnalium
Magnalium is an aluminium alloy with 1.5 to 2% magnesium and small amounts of copper, nickel, and tin. Some alloys, intended for particular uses at the cost of poor corrosion resistance, may consist of up to 50% magnesium...

 may be used to create sparks. In the case of iron, the presence of carbon
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...

 is required, as in carbon steel — about 0.7% is best for large sparks. The carbon burns explosively in the hot iron and this produces good, branching sparks. The color of sparks used in pyrotechnics is determined by the material that the sparks are made from, with the possibility of adding different chemical compounds to certain materials to further influence the color of the sparks. The duration of the existence of a spark is determined by the initial size of the particle, with a larger size leading to a longer-lasting spark.

Metals with low thermal conductivity
Thermal conductivity
In physics, thermal conductivity, k, is the property of a material's ability to conduct heat. It appears primarily in Fourier's Law for heat conduction....

 are especially good at producing sparks. Titanium
Titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....

 and zirconium
Zirconium
Zirconium is a chemical element with the symbol Zr and atomic number 40. The name of zirconium is taken from the mineral zircon. Its atomic mass is 91.224. It is a lustrous, grey-white, strong transition metal that resembles titanium...

 are especially good in this respect and so are now used in fireworks. Copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...

, on the other hand, has a high conductivity and so is poor at producing sparks. For this reason, alloys of copper such as beryllium bronze
Beryllium copper
Beryllium copper , also known as copper beryllium, beryllium bronze and spring copper, is a copper alloy with 0.5—3% beryllium and sometimes with other alloying elements. Beryllium copper combines high strength with non-magnetic and non-sparking qualities. It has excellent metalworking, forming...

 are used to make safety tools which will not spark so easily.

Flint and steel

Robert Hooke
Robert Hooke
Robert Hooke FRS was an English natural philosopher, architect and polymath.His adult life comprised three distinct periods: as a scientific inquirer lacking money; achieving great wealth and standing through his reputation for hard work and scrupulous honesty following the great fire of 1666, but...

 studied the sparks created by striking a piece of flint
Flint
Flint is a hard, sedimentary cryptocrystalline form of the mineral quartz, categorized as a variety of chert. It occurs chiefly as nodules and masses in sedimentary rocks, such as chalks and limestones. Inside the nodule, flint is usually dark grey, black, green, white, or brown in colour, and...

 and steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...

 together. He found that the sparks were usually particles of the steel which had become red hot and so melted into globules. These sparks can be used to ignite tinder
Tinder
Tinder is easily combustible material used to ignite fires by rudimentary methods. A small fire consisting of tinder is then used to ignite kindling. Anything that can be ignited by a match can be considered tinder; or by more rigorous definition, anything that begins to glow under a shower of...

 and so start a fire.

In colonial America, flint and steel were used to light fires when easier methods failed. Scorched linen
Linen
Linen is a textile made from the fibers of the flax plant, Linum usitatissimum. Linen is labor-intensive to manufacture, but when it is made into garments, it is valued for its exceptional coolness and freshness in hot weather....

 was commonly used as tinder to catch the spark and start the fire but producing a good spark could take much time. A spinning steel wheel provided a good stream of sparks when it engaged the flint and a tinderbox designed to do this was known as a mill.

In a modern lighter
Lighter
A lighter is a portable device used to generate a flame. It consists of a metal or plastic container filled with a flammable fluid or pressurized liquid gas, a means of ignition, and some provision for extinguishing the flame.- History :...

 or firesteel
Firesteel
A Fire striker is a piece of high-carbon steel used for striking a spark, usually kept in a tinderbox together with flint and tinder.-Usage:...

, iron is mixed with cerium
Cerium
Cerium is a chemical element with the symbol Ce and atomic number 58. It is a soft, silvery, ductile metal which easily oxidizes in air. Cerium was named after the dwarf planet . Cerium is the most abundant of the rare earth elements, making up about 0.0046% of the Earth's crust by weight...

 and other rare earths
Rare earth element
As defined by IUPAC, rare earth elements or rare earth metals are a set of seventeen chemical elements in the periodic table, specifically the fifteen lanthanides plus scandium and yttrium...

 to form the alloy ferrocerium
Ferrocerium
Ferrocerium is a man-made metallic material that has the ability to give off a large number of hot sparks at temperatures at when scraped against a rough surface , such as ridged steel...

. This readily produces sparks when scraped and burns hotter than steel would. This higher temperature is needed to ignite the vapour of the lighter fluid
Butane
Butane is a gas with the formula C4H10 that is an alkane with four carbon atoms. The term may refer to any of two structural isomers, or to a mixture of them: in the IUPAC nomenclature, however, butane refers only to the unbranched n-butane isomer; the other one being called "methylpropane" or...

.

Metal working

Molten metal sparks can be created when metal is heated by processes such as Bessemer conversion
Bessemer process
The Bessemer process was the first inexpensive industrial process for the mass-production of steel from molten pig iron. The process is named after its inventor, Henry Bessemer, who took out a patent on the process in 1855. The process was independently discovered in 1851 by William Kelly...

 of iron to steel or arc welding
Arc welding
Arc welding is a type of welding that uses a welding power supply to create an electric arc between an electrode and the base material to melt the metals at the welding point. They can use either direct or alternating current, and consumable or non-consumable electrodes...

.

Arc welding uses a low voltage and high current electric arc between an electrode and the base material to melt the metals at the welding point, which often creates sparks. To reduce the risk of burns, welders wear heavy leather gloves and long sleeve jackets to avoid exposure to extreme heat, flames, and sparks. In spot welding, metal surfaces that are held in contact are joined by the heat from resistance to electric current flow. It is common for a spray of sparks in the form of molten metal droplets to be ejected from the parts being joined. or the resistance heating of spot welding
Spot welding
Spot welding is a process in which contacting metal surfaces are joined by the heat obtained from resistance to electric current flow. Work-pieces are held together under pressure exerted by electrodes. Typically the sheets are in the thickness range...

.

Fires and spark arrestors

Fire
Fire
Fire is the rapid oxidation of a material in the chemical process of combustion, releasing heat, light, and various reaction products. Slower oxidative processes like rusting or digestion are not included by this definition....

s may produce sparks as updrafts carry particles of the burning fuel aloft. This was a great problem with steam locomotive
Steam locomotive
A steam locomotive is a railway locomotive that produces its power through a steam engine. These locomotives are fueled by burning some combustible material, usually coal, wood or oil, to produce steam in a boiler, which drives the steam engine...

s as the sparks might set fire to the adjacent landscape or even to the train itself, especially if the engine burned wood rather than coal
Coal
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...

. To prevent this dangerous nuisance, a variety of spark arrestors were invented and fitted.

The chimneys and exhausts of other fuel-burning engines such as steam engine
Steam engine
A steam engine is a heat engine that performs mechanical work using steam as its working fluid.Steam engines are external combustion engines, where the working fluid is separate from the combustion products. Non-combustion heat sources such as solar power, nuclear power or geothermal energy may be...

s or internal combustion engine
Internal combustion engine
The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...

s might also have spark arrestors fitted if there would be a fire risk from their operation. For example, a trail bike might be fitted with a centrifugal arrestor, which will trap glowing hot pieces of soot
Soot
Soot is a general term that refers to impure carbon particles resulting from the incomplete combustion of a hydrocarbon. It is more properly restricted to the product of the gas-phase combustion process but is commonly extended to include the residual pyrolyzed fuel particles such as cenospheres,...

.

Symbolism

The significance of a spark as a source for a flame or a conflagration shows clearly, for example in the naming and motto of Lenin
Vladimir Lenin
Vladimir Ilyich Lenin was a Russian Marxist revolutionary and communist politician who led the October Revolution of 1917. As leader of the Bolsheviks, he headed the Soviet state during its initial years , as it fought to establish control of Russia in the Russian Civil War and worked to create a...

's newspaper Iskra
Iskra
Iskra was a political newspaper of Russian socialist emigrants established as the official organ of the Russian Social Democratic Labour Party. Initially, it was managed by Vladimir Lenin, moving as he moved. The first edition was published in Stuttgart on December 1, 1900. Other editions were...

[The Spark]. The spark metaphor has often been used in philosophy, since Stoicism
Stoicism
Stoicism is a school of Hellenistic philosophy founded in Athens by Zeno of Citium in the early . The Stoics taught that destructive emotions resulted from errors in judgment, and that a sage, or person of "moral and intellectual perfection," would not suffer such emotions.Stoics were concerned...

, and recently, after Jacques Lacan
Jacques Lacan
Jacques Marie Émile Lacan was a French psychoanalyst and psychiatrist who made prominent contributions to psychoanalysis and philosophy, and has been called "the most controversial psycho-analyst since Freud". Giving yearly seminars in Paris from 1953 to 1981, Lacan influenced France's...

, the “creative spark” has come to be considered as inherent to metaphor itself. Hasidic philosophy
Hasidic philosophy
Hasidic philosophy or Hasidus , alternatively transliterated as Hassidism, Chassidism, Chassidut etc. is the teachings, interpretations of Judaism, and mysticism articulated by the modern Hasidic movement...

 contains a doctrine of holy sparks (nitzotzot) from the kabbalism of Isaac Luria
Isaac Luria
Isaac Luria , also called Yitzhak Ben Shlomo Ashkenazi acronym "The Ari" "Ari-Hakadosh", or "Arizal", meaning "The Lion", was a foremost rabbi and Jewish mystic in the community of Safed in the Galilee region of Ottoman Palestine...

 in which there is a duty to gather the sundered light of creation.

In the Book of Job
Book of Job
The Book of Job , commonly referred to simply as Job, is one of the books of the Hebrew Bible. It relates the story of Job, his trials at the hands of Satan, his discussions with friends on the origins and nature of his suffering, his challenge to God, and finally a response from God. The book is a...

 (Job 5:7) it is written "Yet man is born unto trouble, as the sparks fly upward." The use by King James' translators of the word sparks here is a poetic one rather than a literal one. The sparks of fire are identified by some translators as the sons of Resheph
Resheph
Resheph was a Canaanite deity of plague and war. In Egyptian iconography Resheph is depicted wearing the crown of Upper Egypt surmounted in front by the head of a gazelle. He has links with Theban war god Montu and was thought of as a guardian deity in battle by many Egyptian pharaohs...

- a Canaanite deity of lightning and pestilence.
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