what's fire made of?

Question

I know oxygen is needed to have fire, and fire is red, hot, but what is fire exactly?

Answer 1

"fire" is a chemical reaction, it is not made up of any elements or cells. the chemical reaction of fire is caused by the heating of molecules with flamability.

Answer 2

Typically, fire comes from a chemical reaction between oxygen in the atmosphere and some sort of fuel (wood or gasoline, for example). Of course, wood and gasoline don't spontaneously catch on fire just because they're surrounded by oxygen. For the combustion reaction to happen, you have to heat the fuel to its ignition temperature.

Here's the sequence of events in a typical wood fire:

Something heats the wood to a very high temperature. The heat can come from lots of different things -- a match, focused light, friction, lightning, something else that is already burning...

When the wood reaches about 300 degrees Fahrenheit (150 degrees Celsius), the heat decomposes some of the cellulose material that makes up the wood.

Some of the decomposed material is released as volatile gases. We know these gases as smoke. Smoke is compounds of hydrogen, carbon and oxygen. The rest of the material forms char, which is nearly pure carbon, and ash, which is all of the unburnable minerals in the wood (calcium, potassium, and so on). The char is what you buy when you buy charcoal. Charcoal is wood that has been heated to remove nearly all of the volatile gases and leave behind the carbon. That is why a charcoal fire burns with no smoke.

Answer 3

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

Answer 4

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.

Answer 5

A fire means a release of heat and light accompanied by flames as a result of some chemical changes.

Answer 6

Fire is made of a triangle (the triangle of fire). The three sides are : Heat, Fuel and Oxygen. You need all 3 to make fire. Hope this helps x

Answer 7

They are just luminescent gases. Something as high energy as combustion pushes electrons into an excited state (an orbital higher than their ground state). When the electrons decay, they give off that energy as light which is visible to your eye. It is not completely unlike glow sticks. With them, the excitation of the electrons occurs through a chemical reaction with a much lower thermal barrier than combustion.

Answer 8

Gas atoms, some molecules and very small particles emitting light, due to fluorescence and thermal emission.

All fire isn't red. A natural gas flame (CH4, methane) will burn blue in the right environment.

Answer 9

The explanations of fire in most standard reference works, not to put too fine a point on it, suck. The Encyclopaedia Britannica, for example, takes the following ineffectual stab: "rapid burning of combustible material with the evolution of heat and usually accompanied by flame." No wonder people have lost faith in science. Time to let a professional show how it's done. We'll start by reviewing the defects of the EB definition.

(1) Rapid burning. OK, fire burns rapidly. Slow combustion, also known as oxidation, includes such nonfiery processes as rusting and digestion. However, to say that fire involves burning is to embark on a circular definition: What is fire? When something burns. What is burning? When something is on fire. We need to address the matter in more basic terms.

(2) Combustible materials. Redundant. If a material is capable of rapid burning, by definition it's combustible. Also, "materials" is needlessly vague. One specific material, oxygen, is always involved.

(3) Evolution of heat. I don't know what this is supposed to mean either.

(4) Usually accompanied by flame. "Usually accompanied by" my ****. Flame is the quintessential pyrolytic phenomenon, not a mere by-product.

Now for a proper definition, devised by myself: "Fire is the rapid combination of oxygen with fuel in the presence of heat, typically characterized by flame, a body of incandescent gas that contains and sustains the reaction and emits light and heat." Let's go through this bit by bit:

(1) Rapid combination of oxygen with fuel in the presence of heat. Oxygen, fuel, and heat are the essential ingredients of fire.

(2) Typically characterized by flame. The pup qualifier "typically" allows me to sidestep the issue of apparently nonflaming fires, like you get with burning charcoal. I suspect charcoal fires do create flame--you just can't see it due to the lack of impurities or incompletely burned fuel in the plume. (You can't see a fuel fire at an Indy or CART race either, because the cars run on clean-burning methanol.) But that's a matter we can leave for another day.

(3) Body of incandescent gas. Flame defined. Most encyclopedia and dictionary definitions blow past this entirely, allowing persons such as yourself to imagine that fire is "pure energy" or similar nonsense. We say "body" because the gas has a characteristic structure and composition. We say "incandescent" because (a) it sounds scientific, (b) it means "luminous with intense heat," precisely what we are attempting to convey, and (c) if the Teeming Millions are going to learn one vocabulary word today, by God "incandescent" should be it.

(4) Contains and sustains the reaction. Flame isn't just the result of fire; it is the fire. What's more, without the flame's heat the fire would go out.

(5) Emits light and heat. Duh. However, we mustn't overlook the obvious.

Now to your other questions:

Is fire purely energy? Clearly not. The dancing flames are glowing gas--your suspicions confirmed.
Can fire be ionized? Is it affected by magnetism? Not so's you'd notice. You're thinking of plasma, which is ionized (and thus electromagnetically reactive) gas, often described as the fourth state of matter. You see it in welding arcs, lightning bolts, and the sun. Ordinary fire isn't plasma.
Is fire affected by gravity? Of course--gas has mass. Flame is shaped by convection, a function of gravity (hot air rises). In low- or zero-G environments, fire looks way different: a candle flame on the space shuttle isn't yellow and tapered but blue and nearly spherical.
So there you have it. One step closer to a better world.

--CECIL ADAMS

Answer 10

Fuel (gasoline, paper, etc.), oxygen (open air is fine), and heat (usually from pressure or friction) make fire.

Answer 11

fire is intense heat & light, some ionized atoms and molecules too.
The energy is released by chemical reaction is utilized to
excite and de-excite atoms and molecules. the emmited light
is thus dependent on the temperature and nature of substance
being burnt.