How Fire Works

If fire is nothing if not a chemical reaction. Yeah, I got so. Okay. Have you heard of the Winecoff Hotel? Yeah, but born and raised here, Yeah? Uh the Ellis Hotel? Was that the hotel fire? Yeah? Yeah, you know that. It's now the l Hotel. It's at the corner of Peach Tree and Ellis, nice refurbished hotel. Back in nine it was called the wine Cough Hotel and it was the site of the most disastrous casualty wise hotel fire in US history. In December d nineteen people died right

right here in a very sty four. Just under forty four years later, in Las Vegas, Nevada. The MGM Grand had a hotel fire. People died. Do you remember the MGM fire GM Grand fire? It was a big deal. Not at all you you. I'm surprised because I kind of remember, like seeing footage of that. When was this? Oh no, I don't remember. So both of these fires and all the loss of life associated with them were the direct result of hubris towards fire. The wine cough

their fire exits one stairwell for the whole building. I think it was like nineteen stories or something like that. Um, the MGM Grand, they they didn't put up like sixty dollars for a fire detection system in this one part of the hotel that would have saved everyone's lives. A part Hubrist, part financial shenanigans. Right, But isn't that kind of based on Hubrists. My point is is that if there's one thing that we shouldn't have, hubris towards its

fire agreed. We do. You think we might control fire thanks to Prometheus being given it by the gods, yea, But fire controls us when it really comes down to it. That's right. You gotta face off a tete a tete with fire. You're gonna lose buddy because you're combustible. Yeah. So also we should say here that this fire as um it should be a prequel to the how wildfires work and how um spontaneous human combustion works. Those two episodes are great. I agreed, this will seal up our

triumvirate and now we're gonna explain how fire works. Yeah. I do have a couple of quick stats. We're talking about. The deadly nature of fire does kill more people than any other force of nature. I couldn't find that any source for that, but I saw I was searching for it, and it brought up like a handful of plagiarized versions of this article on the internet. Yeah. Those are always fun, especially when it's your own. This one is not mine.

This is a Bill Harritt, Tom Harris, Tom Harris. Um. But I do have some stats in the US, at least in two thousand ten for residential building fires, over people died that year. And that's sort of in the wheelhouse that fluctuates between about thirty two hundred a year

from building fires. Uh, cooking is far and away the leading cause of the building fire and arsonist number two huh, which I would have thought like falling asleep with a cigarette would would be above arson um and then total in two thousand nine, and I guess this counts like any kind of fire in the US, they were close to thirty deaths that year, so that you know, that's a lot. Yeah, I mean that's more than um, I'm

sure killed by volcanoes in the US every year. I think, you know, that's just one or two people falling into kill aweya from getting too close. Have you seen that footage of that scientists going, Um, he's collecting some sort of I guess magma from an active volcano in Hawaii, and um, it was really nerve racking because he goes up,

takes a sample. He's climbing up the rim and then climbs back down and right when he steps away from it, the magma comes up over the rim exactly where he'd just been climbing like five minutes before, and so it would have like just just completely disintegrated him. I imagined, what did he say? I don't know, like, holy crap, did that Well? The guy who was filming it was like narrating like this is so stupid. Yeah, it's very cool.

I don't know what you'd search, but it's up there on the internet somewhere search WU and that should do it, so Chuck. The Greeks thought that fire was one of the four elements earth wire, water, wind and fire. Earth wind and fire and water and nash and young silly Greeks. Uh. The reason why that doesn't really hold up is because um, earth, fire, air, these are elements. They're matter, Yeah, they're made up of atoms.

Fire is the physical manifestation of matter changing form. It's pretty cool, like when you think of it that way. And we're going to describe how this happens, all right, I can tackle some of this. Chemistry is not my forte but it is a chemical reaction at its core between oxygen and um fuel, which I mean, we'll probably let's talk about like a camp fire. Let's go with wood. Wood fire is probably easiest way to describe it. But the wood is the fuel. The wood is the fuel.

Oxygen's found in the air, that's right. But for these things to uh make fire, you gotta have something called combustion, yeah, and which means you're gonna have to have some sort of a spark um. Well, actually not always, because as we find out, some things can combust without a spark. I think if they get hot enough, Like the heat is just so intense that it doesn't need any spark, right, But for wood, you have to get it up to um.

Uh it's ignition temperature, which is about three hundred degrees fahrenheit, which is where you're gonna start seeing some smoke because that is cellulose burning away. Uh. And it just occurred to me reading this today, like where there's smoke, there's fire. Not true, Yeah, because things can smoke without there being a fire. Yeah, actually a byproduct of fire. You know,

um doesn't smoke. So I guess in order to if you're one of the people that now says bottom of the totem pole or instead of top of the totem pole, then we can for they reinforce this obnoxious quality by encouraging you to say, where there's smoke, there is ignition temperature of a combustible fuel, there's volatile gases. It's nice

way to go chucked, all right? Thanks? So yeah, heat is heat decomposes fuel where will to say wood, And in the case of wood specifically, it decomposes the um volatile gases contained in the solid matter, Right, so these volatile gases start to heat up themselves, and while they're doing that, the cellulose, the solid stuff, is decomposing and turning into what's called char. Yeah, I got a little thing on cell cellulotional quest and then you can just

take it home. No man, because that's where I get confused. I'm confused to cellulose about of wood is cellulose, and that's what like, that's where you make paper, that's what you make paper from. That's what you make cellulosic ethanol from, too, and it's what you make cellophane out of. Cellophane is regenerated cellulose. So it's it's like it looks like plastic, but it's not. I had no idea. It is a

man made as I'm sorry, it's a natural polymer. Plastic is manmade obviously, So cellophane is nothing more than regenerated paper in a way. Wow, like they had some other stuff to it. But that's why it's biodegradable. And I always wonder why, like supposedly cellophane is biodegradable. It's like

that's impossible. It's plastic, but it's not plastic. There's this old telephone and from like the fifties maybe, and it's like good things coming twos and it's like this, this pair of twins wrapped in cellophane and they're just like kind of looking around. But yeah, you can imagine they only have them in there for a few seconds before they snout the picture. I did not know that about cellophane. Back to the podcast right there, and I don't know

about that. Hats off to you, all right back to you. I know what the fact of the podcast is. You're gonna save it for when it comes. We can't save it, okay, okay. So um, you've got the cellulose, the solid matter of wood separating now from the volatile um gases that are starting to lift off. That's smoke, right, Okay, the wood, the solid matter is starting to turn into char um.

And that is basically if you if you burn would if you heat it up and you separate the gases, which are the smoke, what remains is carbon and what what charcoal is is charred wood that's had the volatile gases burned out of it, which is why when you have a charcoal fire, you don't have smoke, yeah, or not much at least, Yeah, because the gases have already

been burned off. Yeah, and charcoal too. That got that kind of got me on charcoal filtering because these charcoal is a filter, and I think that is a scrubber

two on smoke stacks. And uh, if you're like I did some of those survival articles at one point, and one of the things you can do to purify water is take your char from your fire, put it in like you know, cool it down obviously, and then put it in, then put it in like a hanky, and then running creek water through that to collect it underneath. That's awesome. And uh, and there's like real charcoal filters too.

But apparently charcoal has a quality because once it's pure carbon like that, it um has a knack for filtering out things like impurities like chlorine and letting other stuff get through. So that's why it's used as a filter. Yeah, because essentially what you're making is a carbon filter. Yeah, charcoal is like basically pure carbon with all the impurities burned off. Yeah, those impurities burned off as smoke. They're volatile gases, So that's pretty neat. Yeah, that's pretty awesome.

Little survival tip man, you're killing it today. Well now that this is when I go to sleep though. Okay, So, um, the third component of burned wood. You've got the volatile gases smoke, you have the char, the charcoal which is carbon, and then you have ash, which is unburnable minerals like um, calcium or phosphorus. I believe. Yeah. And if you like you ever cook with briquettes, charcoal briquettes, you're gonna get a lot more ash with that because it has a

lot of more like byproducts in it. Then if you use like real wood charcoal, right, but they're not gonna smoke, They're just not gonna burn. You're just gonna be left over, like you can't get rid of it. You can pounded into oblivion, but it's still there. Yeah. But if you use the real wood coal then char, then you'll notice you don't get a lot of that stuff. Oh is that right? Yeah? Okay, but the brackettes aren't as nasty synthetic briquettes. No, they're made from char and like binding

agents and stuff like that. And saw that. No. I actually used to hear that like, oh, you can't cook with briquettes are so nasty, But they're really I look into it. It's not super nasty. I mean you probably should cook somewhere in between nasty and super nasty. Yeah, well it's not It's not as bad as I thought. I thought it was like a bunch of chemical agents and glue and cement. And that's not the case I got. It's not the hot dogs of King materials. That's the

corn dog. Okay, um, okay, So we've got the components, right um. As these volatile um gases continue to heat up um to about five degrees fahrenheit two d six degrees celsius, they the molecules break apart, and when they break apart, they go to combine with oxygen oxidation. Right um. And the same thing happens with the carbon in the wood,

but this takes place in place much more slowly. But one of the the stars of this chemical reaction, this change of breaking down to these molecules and then the recombining into other things like carbon dioxide, carbon monoxide. Water. Isn't that weird that fire produces water? Um, That's why sometimes you have steam coming from a fire. Right um. The star of all this chemical reactions, all these chemical reactions,

is heat is produced. He the energy is released, which allows us to cook and be comfortable and feel secure and all the good stuff that comes with fire. And because of the heat that's released as these things are heated up, um, it is sustainable. That means the fire is sustainable so long as there's fuel and there's oxygen present. Yeah. That was the kind of creepy part. And not creepy, but it's self perpetuating, like that flame is gonna heat up any fuel near it to the point where it

can release those gases to recombine with oxygen. It's pretty elegant and think about it. Yeah, another big star of fire besides heat is light and part of that is from the same um the carbon atoms right, yeah, that are combining, that are being torn apart, the molecules that UM form up the char breaking down in their constituent carbon atoms when they combine with oxygen, right recombine, Yeah,

I think that would make carbon monoxide. But as they change UM, they they're electrons will go up, an energy level will change orbit and when they come back down they admit they release some of that energy that they have and they release it in the form of photons. They produce light UM and yeah, it's it's heat producing light. Like we talked about bioluminescence, where basically you heat up a filament in a light bulb and it glows. That's the same thing with the fires, the same based on

the same principle, which is incandescence. Pretty awesome, and depending on the temperature, Uh, different colored light is going to be produced. Yeah, Like, uh, you remember the buns and burners back in chemistry class and how the buns and burners have little slots on the side that you can vary the amount of like oxygen getting in there. You know, there's the little flickering orange flame of a buns and burner. Then if you let a lot more oxygen in, it's

going to be more it's gonna be more hot. And that's why that's when it's gonna be that blue jet the same as when you see like a jet plane, like right next to where the flame comes out, it's gonna be like really blue and then it gets more orange and yellow, you know, like the batmobile. You know what I'm saying, I know exactly the original batmobile. No. Um, we've seen a bunch of batmobiles recently. There's a documentary about the batmobile. That's what all those were there for

a comic con. Okay, we had and I had her picture taken with it with which one the new one, the tumbler, that's what they called the new one, is it? Yeah? The chrystalin one is called the tongue. The chrystal was Yea, it's awesome, it's pretty cool. Uh so yeah. The the reason why the blue one happens to be a different color and hotter is because there's more energy being released, that's right. Uh The lower energy and slightly less hot part of the flame that glows orange yellow is at

the top. And the reason of flame is pointed. This is this is pretty awesome, not the fact of the podcast. The space part is Okay, I think, all right, go ahead. Then, So a flame is pointed and it burns upward because the gases that are burning what you're burning right there are volatile gases. They're being burned off right. Um. As they as they burn, they're they're hotter, but they're also less dance and they're moving upward towards the less dense

air above it, which causes it to be pointed. But if you were to light you take it for granted, but it's kind of cool to know how that works. Yeah, that's why it always burns upward. It tends to burn upward. No, it always does, always burns upward. And that's also why it's pointed too, because the air around it is dense and it's pushing it in right. Pretty awesome, But if you were to light a fire in zero gravity, it would burn as a sphere. I want to see this. I mean, can it be done if we go into

zero Yeah? But I mean they have zero gravity environments, is do they? At Tech? Surely someone has started a fire in one of those just to see this. I think it's a really bad thing if a fire starts in the zero gravity environment, I guess. So that's I just gotta think that someone's tried this. I'm sure. I'm sure there's a video of it on YouTube. Now there's probably a good reason why. And someone's gonna write and some hute dummies. Don't you understand that when you start

a fire in zero gravity that we all die? That's right? Okay? So steam, let's talk about steam, because because we talked about the recombination of atoms, when these gases are released, the same thing happens when you boil water. You know, you get this this gas mixing with oxygen the air, but it's not going to combust, thank thankfully, or cooking would be much more dangerous. Um. It's because some of these atoms aren't as attracted to each other. In the

case of water, for sure, they're tepid towards one another. Yeah. If you're talking fire, though, they have carbon and hydrogen which are really attractive to oxygen, and so they like to get together and uh, combine, recombine more easily. Right, pretty simple. Uh. And then we've been talking mostly about wood as a fuel, but tons of things are fuel. Gasoline is a good fuel. Gasoline doesn't produce char. Basically, heat vaporizes gasoline into nothing but volatile gases which burn. Yeah,

that's so there you go. And I always heard too that gasoline ignites like the vapor ignites, not the liquid. Is that true. Yeah, it's not the it's not the liquid, it's the gas. But heat causes all that liquid to turn into the gas, which. Um, So different fuels are going to catch at different temperatures, and no matter what the fuel, it'll have a piloted ignition temperature and an

unpiloted ignition temperature. Basically, the piloted ignition temperature is that um that point that temperature where the volatile gases are being released and they're heated up to the point where if you introduce a spark it would blow up. That's right. One of the defining characteristics of a volatile gas is

that UM. It basically disperses at room temperature. I believe UM, so at some point, introducing a spark is gonna set that off at some temperature, which I guess means that like if you have gasoline cooled to enough of a temperature, just lighting a match next to it won't set off the gas. I don't know if this is a question we should be raising a general audience. Don't try this.

I'm curious, so we'll have to check that out. But the unpiloted ignition temperature is basically when something gets hit by lightning and the heat is so intense that there's no need for a spark. It just heats it up the point where now it's on fire, where it come bust. Pretty cool, And I try to get to the origin of pilot like a pilot light, which is the same

thing I guess I couldn't find it. I don't know where that came from, because, yeah, I think about it, You've got the gas burning and that it's glowing, yeah, and then you just hit the spark and then bam, you just ignited the gas. So it's at the pilot the piloted ignition temperature in your hot water heater. But I'm sure someone knows the answer that, so if you do send it in. We're raising a lot of questions

in this one and giving some answers. Um the shape, and by shape usually they mean like surface area of a of a fuel effects how efficiently it burns and how easily it burns too. Yeah, I mean this is pretty basic. Like if you have a big thick log obviously you're gonna have way less surface area exposed and combustible then if you had like a toothpick. Yeah, and they can absorb a lot more heat too, big thick

log um. But yeah, if you have a bunch of little pieces of wood, it's gonna burn more quickly catch more easily because there's more exposed surface surface temperature, and more of that fuels is exposed to the heat than a big Like you said, a big log or something. Yeah,

and that's why when you're starting. You know, if you ever watched a bear grills do this thing or or less stroud, they try to get the little like tiny little shavings from the inside of h like you peel away the bark on a tree and then get the shavings off of the tree itself. And that's the stuff that's gonna like really combust easily through friction with like Uh, you know, there's different ways of doing the little I've never been I've never done that. Have you? Have you

started a fire using like friction? Have you? Really? That's impressive. I do that stuff when I go camping now for fun, like in front of the real fire. You know that we started with our big lighters and I'm sitting there with my beer in my Southern comfort and my comfy chair and the steak is on the grill. I'll do some little survival stuff just kind of for fun, you know, until I get tired of it and give up. But yeah, it's fun. Um, Well, hats off to you for no

how to do that? Well, it's pretty easy. I mean there's different ways. There's the plow method or the little bow, uh, where you make the little string to bow. Yeah, and do that little number. Yeah, I've seen that one. There's the castaway one. Yeah, that's the plow method. Oh that's plow. Yeah, that makes sense to be called that. Do you got anything else? I don't think so, do you think Do you feel like we explain this correctly? And well? Yeah,

I mean it's it's pretty basic chemistry. We're basically heat breaks down a fuel so that it can combine with oxygen and ignite. Yeah, and then burned. That's right. And it's self sustaining so long as there's fuel and oxygen. And then all you need is a bear skin rug and some cinemax and you're all set for Friday night. Awesome. If you want to know more about fire, you can type fire into the search bar at how stuff works dot com and that will bring up this article and

plenty of other stuff too. Um, maybe even some survival stuff by one Charles W. Bryant. Uh, And I said search bar. So it's time for a listener mail, Chuck. Yes, we should tell everybody about something very special and due to our hearts New York City. That's right. We are going to Comic Con and we will be doing a live podcast on Friday, October twelve at Comic Con at the jab At Center. It's like our new thing. We did San Diego, now we do in New York. That's

right next up Albuquerque. So if you are going to Comic Con, you should come back and see that. But after Comic Con, we have one of our famous that's famous to us, All Star Trivia Nights. Um, where is it gonna be the Cutting Room. It is at the grand reopening of the Cutting Room in the flat Iron District, which is what's the address? It is forty four East thirty second Street in New York. And uh, it's in the flat Iron you said. And doors open at seven thirty.

Trivia goes down to eight thirty. And what is first come, first serve? Right? Free free, free, first come, first serve. We will have a bar there that you can buy a drinks. Yeah, you can buy us drinks. That's right. We're gonna basically be having a really good time if you if you're not familiar with our trivia nights, like, just come out and check it out. It'll be worth your while, absolutely, and stay tuned for info on Facebook and Twitter about the makeup of the All Star team.

We're filling that out as we speak, but we will have some special guests that you will want to meet. Yeah, and at the very least you can come take on me and chuck right, yeah, okay, it's just fun. So what is that? That's Friday, October twelfth, right, yep, the panels that went. The panel is at at beleave okay, and then we're gonna be at the cutting room starting at thirty. Trivite starts at eight thirty doors at seven thirty. Be there, be square. You're good at this, Thank you?

All right? The time for listener mail. I'm gonna call this email bad to the Bone, so Jocelyn Stone here in Victoria, BC, Canada apparently hates bad to the Bone just as much as I do. So we are we're friends in that way, uh, she says. A few years ago, my partner, or Tim, discovered that he could set anything on his heart desired on his alarm clock for his cell phone. He searched for the perfect song and decided

on bad to the Punt. Uh. Tim believed, in order to slowly get himself ready for the day, he needed alarms at five am, five thirty and six. I on the other hand, wake up without an alarm at six thirty without fail, which is what I do all right. Um. Every morning I was shocked by the full volume darronn or an airn Air. I would there's the way to wake up right. I would blast up to a sitting position in bed, my heart exploding out of my chest, and look next to me at Tim, who was sleeping

through the whole event. I would punch him, get up, turn off the alarm myself, and then repeat this two more times. What kind of business partners are these? I don't think their business partners. That was like an American beauty remember that? Oh yeah, It's like I'd like you to meet my partner. He's like, oh, what line of work you guys? That was a quantum bleat meeting lone star? Huh wow? Yeah, what could you um? For some reason, no matter how much I begged him, he wouldn't change

the song or let me turn down the volume. If I secretly changed it before bed, he would change it back. But I tried to turn it off and hide his phone, he would find it and turn it back again. If I turned the volume down while he was sleeping, his spidy sense would start tingling and he'd wake up and turn it back on. It turned into a game that lasted a full year, finally ending when I told him the slipper of amusement I found in the game was gone and I would throw his phone into the ocean

if he didn't change it. So eventually she just had enough. It's like, this isn't fun anymore. I ended up buying an alarm clock radio, which he also sleeps through. Now thanks to Tim, every coming here bad at the bone in public, I immediately leave the area lest I explode in a muddy, scalding rock going rage like the Wamano guys er, Well nice, yeah so, And then she said, ps do a podcast on accordions after all that? Who's that? Jocelyn from Victoria? Duci can thank you and Tim? Tim,

good luck, Tom and Jocelyn. I help you guys find a yes song you can both agree on. Agreed? And Tim? Just get up, dude? Is it time? For some people? It's hard. I never understood the snooze because wouldn't you rather to sleep that time? No, I'm with you, but I'm saying like, instead of being woken up everything, that's not that easy to just wake right up and right eyed and bushy tail and to accept others as they are. Uh, let's see what do we what do we want? Um? Geez,

I don't know. I don't know either. We'll have to figure it out. Yeah, um yeah, send us anything. I guess this is the it's a generic call out. You can send us anything via Twitter at s Y s K podcast. You can join us on Facebook dot com slash stuff you should know and send us an email containing anything. And if you send us an email it just says anything like, you'll be one of five thousand

people that do that, so just stop. Um. You can send that email that doesn't just say anything to Stuff podcast at discovery dot com for more on this and thousands of other topics. Is it how stuff works dot com mhm