What exactly are fire and electricity?

[sam1123]

I can't help but try and link them with states of matter and I get all confused. I'm sure it's something to do with electrons and energy transfer but I'm getting very confused. What exactly are they!?

[John Cuthber]

Fire is a process by which fuel is oxidised and gives out heat.

Electricity is a phenomenon where a variety of effects are brought about by the movement of electrons.

Neither is a form of matter, so states of matter don't apply.

[MigL]

Isn't a red-ox reaction also a movement/transfer of electrons, John ?

[sam1123]

But what exactly is it if it is not solid, liquid or gas? Also my title was meant to be what ARE electricity and fire, sorry for the poor grammar!

[Essay]

But what exactly is it if it is not solid, liquid or gas? Also my title was meant to be what ARE electricity and fire, sorry for the poor grammar!

 

Fire is just the light given off by smoke (and ignitable gases), when that smoke and gas combine with oxygen. That's why burning is called oxidation. And that is why the flames are shaped fairly closely to the shape of the "licks" of smoke, and hot rising gas plumes. Flashover is an example of excess smoke suddenly combining with oxygen and igniting (lighting up) in flame.

But "fire" itself, is only the light given off when electrons rearrange themselves--as oxygen combines with those atoms in the smoke and other gases expanding out from any heated fuel.

The smoke and gases (from the heated fuel) are rich in carbon and hydrogen, and so form CO2 & H2O after combining most completely with oxygen.

===

And with sparks, I think it is also the light we are seeing, as electrons settle back down, after getting excited (insert joke here).

~

Edited July 4, 2013 by Essay

[John Cuthber]

Fire is still a process- like building or cooking or metalwork.

[pwagen]

Fire is still a process- like building or cooking or metalwork.

Would the answer be different if the question was "what are flames"?

[sam1123]

 

 

Fire is just the light given off by smoke (and ignitable gases), when that smoke and gas combine with oxygen. That's why burning is called oxidation. And that is why the flames are shaped fairly closely to the shape of the "licks" of smoke, and hot rising gas plumes. Flashover is an example of excess smoke suddenly combining with oxygen and igniting (lighting up) in flame.

But "fire" itself, is only the light given off when electrons rearrange themselves--as oxygen combines with those atoms in the smoke and other gases expanding out from any heated fuel.

The smoke and gases (from the heated fuel) are rich in carbon and hydrogen, and so form CO2 & H2O after combining most completely with oxygen.

===

And with sparks, I think it is also the light we are seeing, as electrons settle back down, after getting excited (insert joke here).

~

 

 

Ahhh I see, I thought that electricity was the movement of electrons; so it's the radiation of light from moving electrons in combustion that causes the flames to appear as a result of intense light? Are they (fire and electricity) both forms of non-ionising radiation?

Also thanks to whoever changed my title!

Edited July 4, 2013 by sam1123

[Essay]

Ahhh I see, I thought that electricity was the movement of electrons; so it's the radiation of light from moving electrons in combustion that causes the flames to appear as a result of intense light? Are they (fire and electricity) both forms of non-ionising radiation?

 

Also thanks to whoever changed my title!

 

I don't think there is much that relates electricity with fire. Nor did I mean to say electricity is "relaxing" electrons, but just that the light you see (associated with some electricity) is from "relaxing" electrons.

Electricity should still be thought of as "flowing" electrons (or electron holes). I'm no expert on electricity, so I should probably have kept my first answer to that "what is flame" part of the question.

Please don't confuse electricity and light, based on that mention of "sparks" above. But at least you have a better notion about flames now, as the light you see coming from the (oxidative) chemical reaction, right?

~ Cheers

Edited July 4, 2013 by Essay

[sam1123]

ah yeah okay, so the electricity is a flow of free electrons, and fire is the light we see given off from a chemical as a conversion of energy states, from chemical to light?

[John Cuthber]

Do you really think fire is just light?

Do you not realise that, for example, fire spreads?

[Essay]

ah yeah okay, so the ... fire is the light we see given off from a chemical as a conversion of energy states, from chemical to light?

...and @JohnC

 

I wouldn't say it quite the same way. That sounds like a conversion from chemicals into light, but that isn't what your getting at, I hope.

Some "chemical" energy can be converted into "light" energy, but other changes in "chemical" energy (especially heat) occur during chemical reactions. In other words, the chemical isn't turning into light, but rather some chemical reactions may "release" some light.

===

Not all chemical reactions give off light, but they all involve changes in "chemical" (heat) energy. "Fires" can burn and spread, while just smoldering without flames, which illustrates a slower and more incomplete chemical reaction (still oxidation) that only glows with red-IR light.

But a flame occurs when enough hot fuel (smoke) is mixed well enough with oxygen (as the smoke rises and diffuses) to permit "complete" oxidation (a chemical reaction that gives off a brighter light, along with more heat, rapidly)--a flame. So the "flame" is shaped by the area in space filled with (very rapidly) oxidizing smoke.

===

Depending on whether the flame smoke is more carbon-rich or hydrogen-rich, you can get a different colored (yellow/blue) flame, or parts within the flame, as the smoke/fuel oxidizes. Other elements also produce unique colors when oxidized (reacted/combined with oxygen), which forms the basis of certain spectroscopes.

~

Assuming this is right and correctly expressed, does that make more sense... or make it more complex?

p.s. "Chemical reactions" involve the exchange and rearrangement of electrons (which sometimes produces light), between and within atoms; so in a sense, chemical reactions involve a "flow" of electrons slightly similar to electricity.

But I wouldn't try to understand one as an analogy for the other; though you possibly could define electricity as an ongoing chemical reaction that propagates contiguously... though you probably shouldn't....

Edited July 6, 2013 by Essay

[sam1123]

Do you really think fire is just light?

Do you not realise that, for example, fire spreads?

 

Well know I don't think it's that, I'm not sure what it is so that's why i asked the question

 

...and @JohnC

 

I wouldn't say it quite the same way. That sounds like a conversion from chemicals into light, but that isn't what your getting at, I hope.

Some "chemical" energy can be converted into "light" energy, but other changes in "chemical" energy (especially heat) occur during chemical reactions. In other words, the chemical isn't turning into light, but rather some chemical reactions may "release" some light.

===

Not all chemical reactions give off light, but they all involve changes in "chemical" (heat) energy. "Fires" can burn and spread, while just smoldering without flames, which illustrates a slower and more incomplete chemical reaction (still oxidation) that only glows with red-IR light.

But a flame occurs when enough hot fuel (smoke) is mixed well enough with oxygen (as the smoke rises and diffuses) to permit "complete" oxidation (a chemical reaction that gives off a brighter light, along with more heat, rapidly)--a flame. So the "flame" is shaped by the area in space filled with (very rapidly) oxidizing smoke.

===

Depending on whether the flame smoke is more carbon-rich or hydrogen-rich, you can get a different colored (yellow/blue) flame, or parts within the flame, as the smoke/fuel oxidizes. Other elements also produce unique colors when oxidized (reacted/combined with oxygen), which forms the basis of certain spectroscopes.

~

Assuming this is right and correctly expressed, does that make more sense... or make it more complex?

p.s. "Chemical reactions" involve the exchange and rearrangement of electrons (which sometimes produces light), between and within atoms; so in a sense, chemical reactions involve a "flow" of electrons slightly similar to electricity.

But I wouldn't try to understand one as an analogy for the other; though you possibly could define electricity as an ongoing chemical reaction that propagates contiguously... though you probably shouldn't....

 

 

 

Thanks for your helpful answer. I've been doing a little bit of reading and I'm seeing fire defined as a body of superheated gas, is that correct? Which forms when oxygen mixes with a fuel?

[howlingmadpanda]

Both are simply an excitation of particles, fire being a given chemical reaction creating heat and thus exciting the particles around it, electricity being the excitation of electrons or as commonly meant a flow of electrons.

[Essay]

 

I'm seeing fire defined as a body of superheated gas, is that correct? Which forms when oxygen mixes with a fuel?

The fire, is what "forms when oxygen mixes [chemically] with a fuel" Just to clarify, the superheated gas doesn't form "when oxygen mixes with a fuel." ...[unless that is how they define "superheated"]

 

Yes, that is right.

A superheated volume or body of gas (a hot plume) that combines (chemically) with oxygen is fire; and the light we see is from the gas molecules combining (reacting) with oxygen molecules... within that flame-shaped plume of superheated gas... as electrons move around within those reacting molecules or atoms of gas.

===

You could have a plume of superheated gas, where if enough oxygen was NOT available, the superheated gas would NOT ignite to become a flame. It would just remain a volume of superheated gas that did not emit any light (nor emit the extra heat that would normally be generated when reacting with oxygen).

Fire spreads because the extra heat, from the ignited superheated gas (flame), causes nearby fuel to suddenly become a superheated gas. If enough oxygen is available, the new superheated gas will also ignite and release extra heat, which causes more nearby fuel to suddenly become a superheated gas... repeating the cycle. So the fire spreads, if enough oxygen continues to be available as newly superheated gas is generated.

If you hold a match next to a piece of wood, some of the wood will continue heating up until it turns into a volume of superheated gas (hot smoke). Once that curly lick of smoke (superheated gas plume) ignites and burns, it heats adjacent wood until that wood suddenly vaporizes into smoke. That smoke helps repeat the cycle, while oxygen is available.

~

 

Both are simply an excitation of particles, fire being a given chemical reaction creating heat and thus exciting the particles around it, electricity being the excitation of electrons or as commonly meant a flow of electrons.

 

Right, and the light that we see from electrons relaxing, after they are exited by mixing chemically, is what we see as fire. So the shape of the flame is the shape of the (body of) chemically reacting gases.

 

~

Edited July 14, 2013 by Essay

[michel123456]

Anyway the 2 processes are related

 

http://www.plasma-universe.com/Image:Electric-candle-flame.jpg

[sam1123]

The fire, is what "forms when oxygen mixes [chemically] with a fuel" Just to clarify, the superheated gas doesn't form "when oxygen mixes with a fuel." ...[unless that is how they define "superheated"]

 

Yes, that is right.

A superheated volume or body of gas (a hot plume) that combines (chemically) with oxygen is fire; and the light we see is from the gas molecules combining (reacting) with oxygen molecules... within that flame-shaped plume of superheated gas... as electrons move around within those reacting molecules or atoms of gas.

===

You could have a plume of superheated gas, where if enough oxygen was NOT available, the superheated gas would NOT ignite to become a flame. It would just remain a volume of superheated gas that did not emit any light (nor emit the extra heat that would normally be generated when reacting with oxygen).

Fire spreads because the extra heat, from the ignited superheated gas (flame), causes nearby fuel to suddenly become a superheated gas. If enough oxygen is available, the new superheated gas will also ignite and release extra heat, which causes more nearby fuel to suddenly become a superheated gas... repeating the cycle. So the fire spreads, if enough oxygen continues to be available as newly superheated gas is generated.

If you hold a match next to a piece of wood, some of the wood will continue heating up until it turns into a volume of superheated gas (hot smoke). Once that curly lick of smoke (superheated gas plume) ignites and burns, it heats adjacent wood until that wood suddenly vaporizes into smoke. That smoke helps repeat the cycle, while oxygen is available.

~

 

 

Right, and the light that we see from electrons relaxing, after they are exited by mixing chemically, is what we see as fire. So the shape of the flame is the shape of the (body of) chemically reacting gases.

 

~

 

 

Anyway the 2 processes are related

 

http://www.plasma-universe.com/Image:Electric-candle-flame.jpg

 

Thank you Essay, very coherent and detailed answer, very helpful! And thank you for the really cool picture michel!