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Revision as of 05:59, 23 November 2008 by 68.72.103.228 (talk) (→Chemistry)(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff) For other uses, see Fire (disambiguation).
Fire is the heat and light energy released during a chemical reaction (in particular, a combustion reaction). Depending on the substances alight, and any impurities outside, the color of the flame and the fire's intensity might vary. Fire in its most common form can result in conflagration, and has the potential to cause physical damage through burning.
CHRISTIAN AND TENZIN
Controlling fire
The ability to control fire was a major change in the habits of early humans. Making fire to generate heat and light made it possible for people to cook food, increasing the variety and availability of nutrients. Fire also kept nocturnal predators at bay. Archaeology indicates that ancestors or relatives of modern humans might have controlled fire as early as 790,000 years ago. The Cradle of Humankind site has evidence for controlled fire from 1 to 1.8 million years ago.
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" that 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 fall. 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.
The first technical application of the fire may have been the extracting and treating of metals. 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 vehicles employ fire every time they drive. Thermal power stations provide electricity for a large percentage of humanity.
The use of fire in warfare has a long history. Hunter-gatherer groups around the world have been noted as using grass and forest fires to injure their enemies and destroy their ability to find food, so it can be assumed that fire has been used in warfare for as long as humans have had the knowledge to control it. Homer detailed the use of fire by Greek commandos who hid in a wooden horse to burn Troy during the Trojan war. Later the Byzantine fleet used Greek fire to attack ships and men. In the First World War, 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 were used by Axis and Allies alike, notably on Rotterdam, London, Hamburg and, notoriously, at Dresden, in the latter two cases firestorms 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. In the Second World War, the use of napalm and molotov cocktails was popularized, though the former did not gain public attention until the Vietnam War. More recently many villages were burned during the Rwandan Genocide.
Fire fuel
Setting fuel aflame releases usable energy. Wood was a prehistoric fuel, and is still viable today. The use of fossil fuels, such as petroleum, natural gas and coal, in power plants supplies the vast majority of the world's electricity today; the International Energy Agency states that nearly 80% of the world's power comes from these sources. The fire in a power station is used to heat water, creating steam that drives turbines. The turbines then spin an electric generator to produce power.
The unburnable solid remains of a combustible material left after a fire is called clinker if its melting point 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. Incomplete combustion of a carbonaceous fuel can result in the production of soot.
Fire protection and prevention
Main article: Fire protection
Fire fighting services are provided in most developed areas to extinguish or contain uncontrolled fires. Trained firefighters use Fire apparatus, water supply resources such as water mains and fire hydrants or they might use A and B class foam depending on what is feeding the fire. An array of other equipment to combat the spread of fires.
Fire prevention is intended to reduce sources of ignition, and is partially focused on programs to educate people from starting fires. Buildings, especially schools and tall buildings, often conduct fire drills to inform and prepare citizens on how to react to a building fire. Purposely starting destructive fires constitutes arson and is a criminal offense in most jurisdictions.
Model building codes require passive fire protection and active fire protection systems to minimize damage resulting from a fire. The most common form of active fire protection is fire sprinklers. To maximize passive fire protection of buildings, building materials and furnishings in most developed countries are tested for fire-resistance, combustibility and flammability. Upholstery, carpeting and plastics used in vehicles and vessels are also tested.
Practical uses
Fire is or has been used:
- For light, heat (for cooking, survival and comfort), and protection
- As a weapon of warfare, especially during ancient and medieval times.
- For fire-stick farming
- For cremation
- For welding
- For celebration (such as, birthday candles)
- For religious observances
- For back-burning in fighting fires
- For controlled burn-offs for preventing wildfires
- For burn-offs to clear land for agriculture or for promoting new growth
- For recreational use as a campfire or bonfire
See also
- Active fire protection
- A list of articles relating to fire
- A list of articles relating to firefighting
- A list of articles relating to specific fires
- A list of sources of light
- ATF Fire Research Laboratory
- Colored fire - common and cheap chemicals by which to color a fire
- Endothermic
- Explosion, Rust, Digestion and composting are different kinds of combustion.
- Fire door
- Fire damage
- Fire lookout tower and/or Fire lookout
- Fireproofing
- Fire protection
- Fire protection engineering
- Firestop
- Firestop pillow
- Fire pit
- Fire test
- Fire whirl
- Fire worship
- Flame test - using flame colors to identify common metals
- Intumescent
- Life safety code
- Lightning
- Making fire
- Passive fire protection
- Plasma
- Pyromania
- Pyrokinesis
- Rubens' Tube
- Smoke
- Volcano
References
- "UNESCO - Fossil Hominid Sites of Sterkfontein, Swartkrans, Kromdraai, and Environs"
- "Share of Total Primary Energy Supply", 2002; International Energy Agency
- Fire & Life Safety Education, Manitoba Office of the Fire Commissioner
External links
- How Fire Works at HowStuffWorks
- What exactly is fire? (from The Straight Dope)
- On Fire, an Adobe Flash-based science tutorial from the NOVA (TV series)
- Early human fire mastery revealed BBC article on archaeological discoveries
- Flames in microgravity
- Spiral flames in microgravity
- moebuildingcontrol.co.uk - UK Guidance on fire safety codes and fire engineering
- Smokey Bear- Prevent Wildfires
- Fun Uses with Fire with a Rubens' Tube