Hi, folks. From October four, two thousand twelve. My Saturday select pick is how fire works. Yeah, you can light a match, Sure, you can use a magnifying glass, and you might be able to rub two sticks together or use a flint in stone. But that is all just starting a fire. How fire actually works is much more complicated and very very cool. So give it a listen. Why don't you welcome to Stuff you Should Know, a production of My Heart Radios How Stuff Works. Hey, and
welcome to the podcast. I'm Josh Clark with me. It's always as Charles w. Chuckle Bryant said, and uh, this is stuff you should know, Josh. We let me stand next to your fire. Sure, okay, come come over here right now? Okay, sorry, Well it's nice and warm over here, isn't it. I'm feverish. It's smoky, and I feel like there's chemical reactions taking place before my very eyes. There are. That's why there's fire. If fire is nothing if not a chemical reaction. Yeah, I got so. Okay. Have you
heard of the Wine Cooff Hotel? Yeah? But born and raised here? Ye? Uh, the Allis Hotel? Was that the hotel fire? Yeah? Yeah, you know that it's now the Ellis Hotel. It's at the corner of Peach Tree and Ellis. Nice referbish hotel. Back in it was called the Wine Coff Hotel and it was the site of the most disastrous casualty wise hotel fire in US history. In December nineteen people died right right here in Atlanta, very said forty 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 of financial shenanigans, right, But isn't that kind of based on Hubris. My point is is that if there's one thing that we shouldn't have hubris towards its fire. Agreed. Do you think we might control fire thanks to Prometheus being given it by the gods? Yep? But fire controls us when it really
comes down to it. That's right. You gotta face off a tete a tete fire. You're gonna lose, buddy, because you're combustible. Yeah. And so also we should say here that this fire as um it should be a prequel to the how wildfires work and how um spontantaneous human combustion works. Those two episodes were great. Agreed, This will seal up our triumvirate, and now we're going to 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 still I was searching for it, and it brought up like a handful of plagiarized versions of this article on the internet. Really. Yeah, those are always fun, especially when it's your own. This one is not mine. This is
a bill Hart, 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. It fluctuates between uh about thirty hundred a year from building fires. Uh. Cooking is far and away the leading cause of a building fire, and arson is 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're right, you know, yes, that's just one or two people falling
into kill awea 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 the sample. He's climbing up the rim and then climbs back down and right when he steps away from it, the magma come 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 imagine what did he say. I don't know, like, holy crap, did you just see 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 wa pony wou 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. We're going to describe how this happens. Alright, 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 the easiest way to describe it. But the wood is the fuel. The wood is the fuel. Oxygen is 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 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, Yeah, But for wood, you have to get it up to um. Uh it's ignition temperature, which is about three d degrees fahrenheit fifty degrees cel, 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 the bottom of the totem pole or instead of top of the
totem pole. Then we can further 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 wills to say would and in the case of would, 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 in turning into what's called char. Yeah, I got a little thing on cell cellulostional Q and then you can just take a home, no man, because that's where I get confused. I'm confused to cellulose about of what 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. I like, supposedly cellophane is biodegradable. It's like, that's impossible. It's plastic, but it's not plastic. There's this old cellophane and from like the fifties maybe, and it's like good things coming twos and it's like these this pair of twins wrapped in cellophane, Oh my god, 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 snapped the picture. For 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 know, I know what the fact of the podcast is. You're gonna save it for when it comes. We gotta save it. 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, yes, Okay, the wood, the
solid matter 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 these it 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 in 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 it'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 cooked with brick ets, charcoal, briqutts, 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. It's 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 a char, then you'll notice you don't get a lot of that stuff. Oh is that right? Yeah? Okay, but the cats aren't as nasty a synthetic Brits. 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 looked into it. It's not super nasty. I mean you probably should cook with siwihere 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 to It's not the hot dogs of cooking materials. That's the corn dog. Okay, um okay, So we've got the components right, yeah. Um. As these volatile um gases continue to heat up um too about five degrees fahrenheit two 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 pace 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. Heat, energy is released, which allows us to cook and be comfortable and feel secure and all the good stuff that comes with fire exactly. And because of the heat that's released as these things are heated up, Um, it is sustainable. That means a fire is sustainable so long as there's fuel and there's
oxygen present. Yeah. That was the kind of creepy part, or 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 if you 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 and erge level will change orbit and when they come back down they emit. They release some of that energy that they have and they release it in the form of photons.
They produce light um and indescence, right, Yeah, it's it's heat producing light. Like we talked about bioluminescence, where basically heat up a filament in a light bulb and it glows. That's the same thing with the fire. It's 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 bunsen 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 Uh, 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. Yeah, you know what I'm saying. I know exactly original bile 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 a mum and I had our 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 one was. 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 um, the reason the 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 there, 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. Yeah, 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 gravity? Sure we have, but I mean they have zero gravity environments? Is do they a 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 a 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 say, huge dummies. Don't you understand that when you start a fire in zero gravity that we all die? That's right? Yeah? 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 in 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 attracted 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 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, okay, 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 temperature, 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, right, 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 piloted 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, and
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 the 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, and your hot water heater. But I'm sure someone knows the answer to 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 going to have way less surface area exposed and combustible then if you had like a toothpick. Yeah, and it 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 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 and my Southern comfort in my comfy chair and the steak is on the grill. I'll do some little survival stuff just kind of for fun. You know. That's cool until I get tired of it and give up. Yeah, but yeah,
it's fun. Um, Well, hats off to you for knowing 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. Yeah, there's the castaway one. Yeah, that's the plow method. Oh that's plow. Yeah, that makes sense. They'd be called that you anything else, I don't think. So do you do you 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. Gets Uh. If you want to know more about fire, you can type fire into the search bar at how stuffworks 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. I'm gonna call this email a bad to the bone so uh. Joscelyn 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 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 Bone. Tim believed, in order to slowly get himself ready for the day, he needed alarms at five am, five thirty and six. I hate that stuff. I, on the other hand, wake up without an alarm at six thirty without fail. What I do? All right? Um? Every morning I was shocked by the full volume darn and or an air, I
would the way to wake up right there. 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 and 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 bleap meeting load star. Huh wow, yeah, look at 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 change 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. We ended up buying an alarm clock radio,
which he also sleeps through. Now, thanks to Tim, every time you hear bad at the Bone in public, I immediately leave the area lest I explode in a muddy, scalding rock going rage like the wamanoo guys or wow, nice reference. Yeah, so, and then she said, ps do a podcast on accordions after all that? Jeez, who's that? Jocelyne, thank you, Joscelyn from Victoria Busi Cannon, thank you, and Tim, Tim, good luck. Tim and Joscelyn helped you guys find a yes song you could both agree on. Agreed, and Tim
just get up, dude? Is it some 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 every ten minute, not that easy to just wake right up, 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. 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 how stuff Works dot com. Stuff you Should Know is
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