# Can fire be explained through just Physics?

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Hey guys,

So I learned from my Physics teacher that many things even explosions are just high velocity oxygen particles.

So he told me when a grenade explodes, it the high vel oxygen that kills you.

So I want to know then,,,

What particles are part of a fire

and

How do those particles move that causes a fire?

------------------------

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Hey guys,

So I learned from my Physics teacher that many things even explosions are just high velocity oxygen particles.

So he told me when a grenade explodes, it the high vel oxygen that kills you.

So I want to know then,,,

What particles are part of a fire

and

How do those particles move that causes a fire?

------------------------

I have to question the high-velocity oxygen explanation. There's ~4x as much high-velocity nitrogen. The explosion causes a blast wave in air. There may also be shrapnel.

Here's Richard Feynman explaining what fire is

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So I learned from my Physics teacher that many things even explosions are just high velocity oxygen particles.

So he told me when a grenade explodes, it the high vel oxygen that kills you.

It's called shock wave

It's unlikely that exactly shock wave in air from exploding grenade will kill you. Rather fragments.

"Fragmentation grenades are common in armies. They are weapons that are designed to disperse lethal fragments on detonation. "

Underwater reverse.

"The Mk 40 kills or otherwise incapacitates the target by creating a lethal shockwave underwater"

So I want to know then,,,

What particles are part of a fire

f.e. H2O, CO2 and typically other oxides of exploding material, or not fully burned intermediate compounds.

Edited by Sensei
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Hey guys,

So I learned from my Physics teacher that many things even explosions are just high velocity oxygen particles.

So he told me when a grenade explodes, it the high vel oxygen that kills you.

So I want to know then,,,

What particles are part of a fire

and

How do those particles move that causes a fire?

------------------------

Easily explained. It's more of a chemical reaction than an equation, I guess. If I had to put the process of combustion and flammation into precise terms it'd be along the lines of Saying that fire is the word we us to describe the rapid oxidation of a material...And that it occurs in the exothermic chemical process of combustion. During this combustion heat, light, and various reaction products are emitted, or released.

Any fire requires a fuel source and a combustible substance to be ignited and then burned. The ignition is the catalyst and the burning is the actual chemical reaction you call fire. Particulate matter during the burning and combustion process would always be emitted or released in an outward fashion. Hest always causes this sort of motion, from expansion at the milder end of the spectrum, as in a piece of metal expanding when heated, due to it's molecules moving apart, to explosion on the more drastic, powerful end of the spectrum.

http://science.howstuffworks.com/environmental/earth/geophysics/fire1.htm

Edited by Velocity_Boy
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Easily explained. It's more of a chemical reaction than an equation, I guess. If I had to put the process of combustion and flammation into precise terms it'd be along the lines of...Saying that first is the word we us to describe the rapid oxidation of a material...And that it occurs in the exothermic chemical process of combustion. During this combustion heat, light, and various reaction products are emitted, or released.

Any fire requires a fuel source and a combustible substance to be ignited and then burned. The ignition is the catalyst and the burning is the actual chemical reaction you call fire. Particulate matter during the burning and combustion process would always be emitted or released in an outward fashion. Hest always causes this sort of motion, from expansion at the milder end of the spectrum, as in a piece of metal expanding when heated, due to it's molecules moving apart, to explosion on the more drastic, powerful end of the spectrum.

You don't need a grenade for some fun spectacular burning and fuels.

You can set fire to an iron rod if you heat it hard enough and then it will burn fiercely enough to cut through concrete and steel.

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You can set fire to an iron rod if you heat it hard enough and then it will burn fiercely enough to cut through concrete and steel.

It's iron tube, and through that tube there is blasted pure Oxygen from container.

Edited by Sensei
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It's true that the thermite process now encompasses a wide variety of fuels.

https://en.wikipedia.org/wiki/Thermite

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........And this link will also explain everything you want to know about the chemical process of combustion and fire.

http://science.howstuffworks.com/environmental/earth/geophysics/fire1.htm

Hey guys,

So I learned from my Physics teacher that many things even explosions are just high velocity oxygen particles.

So he told me when a grenade explodes, it the high vel oxygen that kills you.

So I want to know then,,,

What particles are part of a fire

and

How do those particles move that causes a fire?

------------------------

Your teacher has obviously never been close to combat, nor seen the first hand results of a grenade attack. His claim about the hi vel oxygen is idiotic. Wish I'd been sitting in that classroom! LOL

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Hey guys,

After hearing what my teacher said i wanted to create a story where "magic" in that universe is based off of physics.

So in order to boil water,

the people there would manipulate the molecules (in this case water molecules) with a "verse" and thus cause boiling

by increasing the speed of the water molecules.

___
But say these magicians wanted to create fire from thin air like we see in so many movies.

My question is, what would they need?

Assuming that they control any kind of molecule through their "verses"

Can they just increase the speed of the air molecules around them and make fire, etc

Like I just cant get my head around how they would do something like make fire from thin air like that by controlling the molecules

which is what physics mostly showed me, which = speed of molecules runs the world.

_________________________________________________

Or perhaps they could have the materials necessary

So maybe having

Ingredients)

-a piece of wood in hand

-and the oxygen in the air

And then would manipulating the molecules of the wood and oxygen be more likely to create a fire?

(And if we hide the wood under his sleeve would it seem like the fire came from out of thin air?)

Edited by gene098
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Fire is an outburst of heat. It creates a shock wave of vibrating particles that causes much injury. As the shock wave is basically a spherical wave travelling at about 332 m/s, it has a lot of momentum that results in injury.

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Fire is an outburst of heat. It creates a shock wave of vibrating particles that causes much injury. As the shock wave is basically a spherical wave travelling at about 332 m/s, it has a lot of momentum that results in injury.

This is misleading. I am presently sitting in front of a fire. The result is pleasant and comforting, nor am I experiencing any injury. At the same time the TV set is sending out a series of shockwaves. The only injury they are creating is a sense of outrage at the antics of politicians as reported on the news.

@gene098, the point made by several other posters needs to be emphasised, as you seem to be missing it. The primary thing about fire is that it is a chemical reaction that, in terrestrial conditions, is generally an exothermic oxidation reaction. i.e. one or more chemicals combine with oxygen, giving off heat in the process. The secondary thing about fire is that, since heat is involved, the particles move faster in a vibration mode. The shock waves that occur in an explosion involve particles moving faster. momentarily, in a linear fashion.

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This is misleading. I am presently sitting in front of a fire. The result is pleasant and comforting, nor am I experiencing any injury. At the same time the TV set is sending out a series of shockwaves. The only injury they are creating is a sense of outrage at the antics of politicians as reported on the news.

@gene098, the point made by several other posters needs to be emphasised, as you seem to be missing it. The primary thing about fire is that it is a chemical reaction that, in terrestrial conditions, is generally an exothermic oxidation reaction. i.e. one or more chemicals combine with oxygen, giving off heat in the process. The secondary thing about fire is that, since heat is involved, the particles move faster in a vibration mode. The shock waves that occur in an explosion involve particles moving faster. momentarily, in a linear fashion.

So the physics of faster moving particles in fire

Is primarily a result of chemistry, in which the combination of particles creates the heat, so fire is a byproduct in a sense and the heat which is also a byproduct is where physics comes in.

But then how does the chemical reactions occur in the first place?

Wouldnt physics be needed here?

Say if an individual had the ability to manipulate any kind of molecule(The means is that it is through a mechanism in the brain, as this is for a story I am building)

Then with wood and oxygen, essentially he would

Cause the chemical reaction to occur

By manipulating the molecules of oxygen and one or more other chemicals right?

and thus fire is created?

So would having a stick of wood handy be what he needs to create the reaction, if in fact he has the ability to manipulate molecules?

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Anything that oxidizes, really. You're replacing the heat source for ignition with psychically slamming the atoms together, essentially.

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If he can manipulate molecules, he could extract fuel from food or even from the CO2 in the air. He could then release combustible molecules through the skin in his hand.

Alternatively, he could heat up the air until it begins to glow and contain the hot air to avoid dissipation. This is unlikely to look like flames, but more like eg a glowing sphere.

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If he can manipulate molecules, he could extract fuel from food or even from the CO2 in the air. He could then release combustible molecules through the skin in his hand.

Alternatively, he could heat up the air until it begins to glow and contain the hot air to avoid dissipation. This is unlikely to look like flames, but more like eg a glowing sphere.

Right! I have heard that the speed heat or the speed of the molecules/ temp creates colors like fire is oragney red and humans also glow but we are lower temp and glow in infrared.

__________________________________________________

When you say extract fuel, do you mean specifically CH2?

So we could put a cap on possibly when and where he can make fire/ what the right conditions are

_______________________________________________

So I would like to ask if you could review the steps and see if it makes sense....

And when you say "release the combustible molecules through the skin in his hand"

do you mean he would....

Steps

1) Take fuel/CH2 from air or food, wood,/fuel source

2) Then as @Delta1212 says he would ignite it by smashing the the oxygen in the air with the CH2 to act as ignition

3) And to maintain the fire he would just take CH2/fuel from air or other fuel source and he no longer needs to reignite/ step 2

because

"The dangerous thing about the chemical reactions in fire is the fact that they are self-perpetuating.

The heat of the flame itself keeps the fuel at the ignition temperature, so it continues to burn as long as there is fuel and oxygen around it. The flame heats any surrounding fuel so it releases gases as well. When the flame ignites the gases, the fire spreads."

4) And in addition he can control the heat temperature and thus color of fire

after the ignition

by increasing or decreasing the amount of times he slams the CH2 and air molecules (Becasue its the reaction of the molecules of CH2 and air that releases heat

Edited by gene098
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Right! I have heard that the speed heat or the speed of the molecules/ temp creates colors like fire is oragney red and humans also glow but we are lower temp and glow in infrared.

A blackbody will emit a spectrum of EM radiation depending on its temperature (the power varies as T^4), with the peak wavelength also depending on the temperature. That Wien's displacement law.

https://en.wikipedia.org/wiki/Wien%27s_displacement_law

The peak shifts to shorter wavelengths as you get hotter. For something at room temperature or that of a human body, this peak is out around 10 microns. If you heat something up several hundred degrees, you start getting visible light ‚ the emission will look red, then orange, then yellow and then white, each being hotter.

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Anything that oxidizes, really. You're replacing the heat source for ignition with psychically slamming the atoms together, essentially.

Anything that oxidizes?

Doesnt it have to be specifically CH2, that reacts with Oxygen to get the fire?

Edited by gene098
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Anything that oxidizes?

Doesnt it have to be specifically CH2, that reacts with Oxygen to get the fire?

Carbon can react with the oxygen and give you CO2. That's a common one. But anything that adds an oxygen (oxidizes) will work.

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Anything that oxidizes?

Doesnt it have to be specifically CH2, that reacts with Oxygen to get the fire?

CH2 barely exists.

https://en.wikipedia.org/wiki/Methylene_(compound)

Sulphur burns in air. On the other hand, you can burn iron is sulphur vapour.

Sodium (and lots of other metals) will burn in chlorine,.

Practically everything burns in fluorine.

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CH2 barely exists.

https://en.wikipedia.org/wiki/Methylene_(compound)

Sulphur burns in air. On the other hand, you can burn iron is sulphur vapour.

Sodium (and lots of other metals) will burn in chlorine,.

Practically everything burns in fluorine.

So is fire kinda like the evaporation version of solid materials?(and obviously the water from the solid would leave and evaporate)

So Ignition temp is like the solid version, of Boiling temp (for liquid)

Ex)

So water goes from Solid(ice)>Liquid>Boil temp>Gas(evap)

so solid materials would go from

Solid>Ignition temp>Fire

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!

Moderator Note

Branch regarding the Ethics involved in the development by Scientists of weapons and the investigation of violence by empirical means has been split off into a new thread in the correct forum - Ethics

EudecioGabriel - if you have a question which is a branch from the original question then please open a new thread - Do Not ask different questions in the the same thread; we consider this hijacking and if you continue the staff will take action.

No need to respond to this moderation note within the thread

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!

Moderator Note

Branch regarding the Ethics involved in the development by Scientists of weapons and the investigation of violence by empirical means has been split off into a new thread in the correct forum - Ethics

EudecioGabriel - if you have a question which is a branch from the original question then please open a new thread - Do Not ask different questions in the the same thread; we consider this hijacking and if you continue the staff will take action.

No need to respond to this moderation note within the thread

May I ask if you have a recollection of what was posted?

As of right now I cant recall it

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CH2 barely exists.

https://en.wikipedia.org/wiki/Methylene_(compound)

Sulphur burns in air. On the other hand, you can burn iron is sulphur vapour.

Sodium (and lots of other metals) will burn in chlorine,.

Practically everything burns in fluorine.

Hi John,

Im not sure if you saw it or not but

So is fire kinda like the evaporation version of solid materials?(and obviously the water from the solid would leave and evaporate)

So Ignition temp is like the solid version, of Boiling temp (for liquid)

Ex)

So water goes from Solid(ice)>Liquid>Boil temp>Gas(evap)

so solid materials would go from

Solid>Ignition temp>Fire

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There are different phases. Dry Ice is the solid state of CO2 for example, but there's no dry ice in wood. You can see that there must be something happening between the oxygen in the air and the carbon in the wood to produce carbon dioxide.

Edited by Endy0816

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