Jump to content

What is fire?


MAR

Recommended Posts

I was wondering this for a while so i finally decided to look it up and the answers i got where wildly facinating, so I decided to share.

 

Check it out.

 

"Fire is a phenomenon of combustion manifested in intense heat and light in the form of a glow or flames."

"Fire is not a state of matter: rather, it is an exothermic chemical reaction accompanied by intense heat released during a rapid oxidation of combustible material. Fire may be visible as the brilliant glow and flames and may produce smoke.

Fires start when a flammable or combustible material with adequate supply of oxygen or other oxidizer is subjected to enough heat. The common fire-causing sources of heat include a spark, another fire (such as an explosion, a fire in the oven or fireplace, or a lit match, lighter or cigarette) and sources of intense thermal radiation (such as sunlight, a flue, an incandescent light bulb or a radiant heater). Mechanical and electrical machinery may cause fire when combustible materials used on or located near the equipment are exposed to intense heat from Joule heating, friction or exhaust gas. Fires can sustain themselves by the further release of heat energy in the process of combustion and may propagate, provided there is continuous supply of oxygen and fuel. Fires may become uncontrolled and cause great damage to and destruction of human life, animals, plants and property.

Fire is extinguished when any of the elements of so-called fire triangleheat, oxygen or fuel—is removed. The unburnable solid remains of fire are called ash.

Flames can conduct electricity, as a small portion of any fire is ionized. This has been demonstrated in the laboratory and also in large wildfires that occur in the vicinity of power lines. This ability to conduct electricity is due to its partially plasmaic nature.

A flame is an exothermic, self-sustaining, oxidizing chemical reaction producing energy and glowing gas, of which a very small portion is plasma. It consists of reacting gases emitting visible and infrared light, the frequency spectrum of which is dependent on the chemical composition of the burning elements and intermediate reaction products.

In many cases such as burning organic matter like wood or incomplete combustion of gas, incandescent solid particles, soot produces the familiar red-orange 'fire' color light. This light has a continuous spectrum. Complete combustion of gas has a dim blue color due to the emission of single wavelength radiations from various electron transitions in the excited molecules formed in the flame. Usually oxygen is involved, but hydrogen burning in chlorine produces a flame as well, producing the toxic acid hydrogen chloride (HCl). Other possible combinations producing flames, amongst many more, are fluorine and hydrogen, or hydrazine and nitrogen tetroxide. Recent discoveries by the National Aeronautics and Space Administration (NASA) of the United States also has found that gravity plays a role. Modifying the gravity causes different flame types."

"The glow of a flame is somewhat 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 emission by de-excited atoms and molecules 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 chemical makeup for the emission spectra. The dominant color in a flame changes with temperature. The photo of the forest fire is an excellent example of this variation. Near the ground, where most burning is occurring, it is white, the hottest color possible for organic material in general, or yellow. Above the yellow region, the color changes to orange, which is somewhat 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.

The common distribution of a flame under normal gravity conditions depends on convection, as soot tends to rise to the top of a general flame, such as in a candle in normal gravity conditions, making it yellow. In microgravity or zero gravity, such as an environment in outer space, convection no longer occurs, and the flame becomes spherical, with a tendency to become more blue and more efficient. There are several possible explanations for this difference, of which the most likely one given is that the cause is the hypothesis that the temperature is evenly distributed enough that soot is not formed and complete combustion occurs. Experiments by NASA in microgravity reveal that diffusion flames in microgravity allow more soot to be completely oxidised after they are produced than diffusion flames on Earth, because of a series of mechanisms that behaved differently in microgravity when compared to normal gravity conditions. Premixed flames in microgravity burn at a much slower rate and more efficiently than even a candle on Earth, and last much longer. These discoveries have potential applications in applied science and industry, especially concerning fuel efficiency.

Fire ecology is the study of the interaction of living things with fire."

http://en.wikipedia.org/wiki/Fire

I dont expect all of you to care or read this, but I know there are some people out there that might.

Link to comment
Share on other sites

This forum is supported by the 12ozProphet Shop, so go buy a shirt and help support!
This forum is brought to you by the 12ozProphet Shop.
This forum is brought to you by the 12oz Shop.

took me years to rationalize what the visible form of fire is. I knew that it is the combusted oxidation of materials, but ive always wondered what the actual substance of fire was. bout three years ago it just sort of occured to me as i was looking at a neon light. not gonna repeat my revelation cus its pretty much whats in the first post...

.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...