Fire
See also: Fire (homonymy)
The fire is the production of a flame by an exothermic reaction of Oxydation called Combustion.
In a general way, the term “fire” often indicates a producing phenomenon of the light and/or the heat, which it comes from a combustion or not.
Chemistry and physique of fire
See also: Combustion
Combustion is a chemical reaction releasing of heat (exothermic) and the light. It can take place only if three factors are joined together: two chemical compounds (a Combustible and a Combustive ) and a source of energy (energy of activation), which one calls the triangle of fire.
Under the effect of the energy of activation (in particular of heat), the fuel breaks up (Pyrolyse), the product of this decomposition is a gas which reacts with the combustive one (in general the Dioxygène of the Air).
The light comes from two sources:
- on the one hand exchanges of electrons between the compounds during the chemical reaction;
- in addition the radiation which any body carried at high temperature emits (radiation of the black Corps).
Fire and the Man
Domestication by the man
The domestication of fire by Homo erectus marked a turning in the Préhistoire, the human being being distinguished then from the other animal species. It is attested from approximately - 450.000 years, in particular in the sites of Terra Amata close to Nice, of Carry out-Dregan to Plouhinec in Brittany, of Bilzingsleben in Germany or of Vértesszőlős in HungaryThe control of fire inspired by many myths, of which that of Prométhée. At the time contemporary, several works of fiction have depicts the importance of fire for the prehistoric groups, in particular the film the War of Fire of Jean-Jacques Annaud.
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Symbolization
In Chinese philosophy, it belongs to the five elements with metal, water, wood and the ground.At the Alchemists in occident, it belongs to the four basic inert elements composing each matter with the air, water and the ground.
Fire is naturally associated with the Sun, which is also a source of heat and of light (it is known now that of a combustion but of a nuclear Fusion it is not a question). It is also often associated with the Volcan S, such as for example the fire of the forging mill of Héphaistos/Vulcan. It is also associated with the Four elements (with the Eau, the Air and the Ground).
From its power quasi unlimited and destroying when it is not controlled, fire however continues to be fears by the men, which confers a very ambivalent role to him. Sometimes, it is associated with the divine power, from where a great number of ritual, passed or current, around fire (see will infra ). But it is also often associated with the forces of the Mal; in the Christian tradition, the Enfer is often represented like the kingdom of the eternal flames.
This ambivalence finds in the moral and legal aspects fire; sometimes it could be regarded as the instrument of a transcendent justice (the Bûcher was a current penal judgment with the Moyen-âge, and even exists very locally at the time contemporary; whereas the Immolation is regarded by certain as a supreme act of sacrifice vis-a-vis the justice of the men, including in modern societies, as in Czechoslovakia in 1969); sometimes its use rigorously is controlled, and sometimes seriously sanctioned (the Incendie was one of the greatest crimes with Athens).
Fire-worship
Fire is divinisé in many cultures and was the object of the worship of a great number of people.
Persia
At the old ones, the Perse S looked at the fire-worship like the fundamental part of their religion and the ceremonies of this worship are recalled with detail in the Zend-Avesta . Persians greeted every morning the rising sun, symbol of the purest fire. They looked at fire like the guard of the States and preserved in particular sanctuaries the crowned fire which was to never die out. Behram, wire of Ormuzd and one of the 28 Ized S, was the genius of fire. At the 19th century, at the Persan current ones, the Guèbres, which lived especially in the Kerman and the Guzzerat, had preserved all the ceremonies of old Persians with regard to fire.
Greece and Rome
In the Greek Mythology, it stolen with the gods and was brought to the Men by Prométhée.
The inextinguishable fire of the Greeks, which burned unceasingly with Athens and Delphes, the worship of Vulcan, fire that with Rome the priestesses maintained Vesta, still point out the deification of fire, idolatry common of the remainder to all the people of pelagic race .
Judaism
The Juif S light a Hanoukkia (candlestick with nine branches) at the time of the festival of Hanoucca.
Christianity
The use of Cierge S is generalized in the church S Catholique S and orthodoxe in order to mark liturgical times, or in Offrande with Saint S. the flame symbolizes also the Holy Spirit.
A certain number of pagan practices using fire were recovered in popular Christianity (the fires of the Saint Jean, the Chandelle S of St Lucia in Sweden, etc…).
Asia (Hindouisme, Buddhism…)
The Hindu S and the Bouddhiste S make burn various Offrande S within the framework of their worship. They practice also the Crémation Défunt S.
Uses
Fire is a natural phenomenon; in nature, it can result from the Foudre or Fermentation (production of flammable gases and heat). Its domestication by the Man - capacity to preserve it (the maintenance of the Hearth being reserved for the Woman in the traditional companies), then to recreate it at will - allowed many progress:
- Cuisson of food, which makes it possible to kill out of the germs and to consume inedible food if not;
- warming during the cold periods (winter), lighting the night;
- hardening of the Outil S out of wood, which improves their effectiveness;
- Metallurgy, and in a general way of the chemical and physical conversions taking place at high temperature;
- horse-power: Steam engine, then Thermal engine.
Risks
The produced fire of the Heat and the Smoked , takes Dioxygène, and tends to be spread without control in Incendie.
For the human ones, the risk is triple:
- risk of Burn, by heat: burn of the skin in contact with the flame or of a hot object, but also burn of the air Routes by gas inhalation and Smoked S heats;
- Asphyxiation: as indicated above, fire takes dioxygene of the air and thus prevents breathing; it produces hot gases which displace air (in particular Carbon dioxide CO2), which accentuates this phenomenon;
- Poisoning: fire can produce pollutant gases; more the current is the Carbon monoxide (CO), in particular in the event of lack of dioxygene (combustion is not complete).
Fire also causes the destruction of objects or plants, and can thus put in danger the wellbeing of a population, her capacity to be nourished, place themselves, the operation of its economy. It can present a risk for the Biodiversité, by destroying animal species and vegetable.
See too
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