Paraffin Wax Autoignition
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- Опубліковано 27 лип 2024
- This video is a more detailed breakdown of a demonstration I showed in a previous UA-cam Short, where a boiling sample of wax will burst into a fireball when placed in an ice bath. This demonstration is a good example of how environmental conditions affect a reaction. Even though the boiling hot wax is well above its autoignition temperature of 245 C, it won't autoignite until a vapor cloud is produced with the right amount of thermal energy, wax fuel, and oxygen gas present.
- Наука та технологія
I've got a Ph.D. in chemistry, taught college for 35 years, had never seen such a thing, and think this is a delightful video! Wish I'd had it while I was still teaching. Good job!
Thank you!
35 years is quite a number, sir. Thank you for your service.
To still be as delightful as you are after 35 years of teaching, especially teaching college, you must have a heart of gold. As others have said, thank you for your service to our education system and for teaching our next group of chemists.
It is difficult to get a PhD in anything takes a lot of effort. But then chemistry is superstition at best.
Why can tetracyanoethylene accept an electron but not tertraaldoethylene? Why does anti/aromaticity exist, when all atoms on the ring have a full octet either way?, why is benzene stable, borazine as well, but not hexa aza benzene, n6?
Being unable to answer freethought guestions is the hallmark of nonscience
Well sir what I can tell you I think what he just done here is forcing to cool down the flammable liquid which has reach it's flash point, even in deep fryings once the cooking oil reach its flash point any attempt of trying to cool it either by pouring water it can cause fire explosions, anything that reach it's flash point can be extremely dangerous
We did this in high school in 2003 by accident. My teacher asked to see it again, then told us to never do it again. We didn’t understand what had happened, but we were simply igniting it without the ice. The fireball was impressive. Left a black ring on the ceiling. We all still have and still had our eyebrows…
lol
Cool teacher
That's a good example of why wearing PPE is so important, even if it seems like it isn't necessary. You never know what might happen.
my parents used to seal preserved fruit with wax and i remember them warning me about wax vapors. mom melted the wax bars in a double boiler to keep the temperature at or below boiling water temp, and took it off the stove immediately upon melting to seal the jars of preserve. fascinating to see what they were worried about.
I never knew wax could do that. Sometimes you learn something new.
That is what my mom
Did too
that temp was 700 degrees f. The melting point for canning is probably just over 100 though you would want it beyond its melting point a bit.
Very impressive demo. For a fun and safer demo, light an ordinary paraffin wax candle. Once it has burned for a bit, snuff it out. Wait a few seconds until a nice stream of "smoke" (actually vaporized and condensing wax) forms, rising upward. Light the top of the stream with a lighted match. The stream will ignite, and the fire will run down the stream and re-ignite the candle.
I used to do that as a teen but didn't know that this is the scientific explanation for it. Thanks for that.
That explains why it works with a paraffin wax candle and not a stick of incense or so
I've known this a while, but I could never have explained it like you did. Thank you!
That is not the same concept that is happening here... The reason the candle wick reignites is because the smoke is hot enough and has enough flammable particles in it to be reignited by a flame you introduce. This wax ignites itself, which is already entirely different from your demonstration, for an entirely different reason. One you could have read in the description and realized they are not the same reaction and saved yourself the trouble of this comment.
Two entirely different things.
@@RedTail1-1… wax vapor, oxygen, and heat in the right concentration. Sounds similar enough to me.
Immersive waxing of bike chains (at ~ 200ºF/92ºC) is becoming more popular, because it is better than mineral oil, but some holdouts are citing paraffin's supposedly super-flammable properties to argue against. it. I'm glad that this video exists, so that I can point to it to prove that you have to boil it & then super-cool it to make it auto-ignite, and that doing so in a slow cooker or double-boiler is nigh-on impossible. Thankyou Phil.
Boil it and supercool it in a container that doesn't respond to thermal shock except by shattering.
That still doesn't absolve them of having to deal with the problem of wax vapors. Auto-ignition may not be possible, but thermal ignition still is.
I have been waxing chains for decades.
It melts at just over 100°. No reason at all to take it anywhere near boiling point.
People worry about the damnedest things!
This is an excellent video to show why paraffin oil shouldn't be used as a heating media in a oil bath while setting up a high temperature reaction !
That slow-mo close-up was excellent! Quite a video! 😎✌️
This explains the accidents that occur or have occurred in candle factories or accidents at home making decorative candles, which have resulted in children with third degree burns. Thanks for most.
Not really. I very much doubt that anyone making candles is boiling the wax or heating it much beyond its melting point. Accidents are much more likely to be simply because the wax is flammable and close to a flame.
As a kid, I wanted to experiment. Yes, I boiled wax just to see it boil. Why? Because I could. I am totally amazed that I am alive today.
@@oldmech619 you are my fucking hero
No water is necessary. Just tossing molten paraffin into a sink or a pail disperses and oxygenates it enough to autoignite. I did it in high school myself.
This experiment can also be done by heating the paraffin wax and then throwing the hot wax from a height (1.5 metres).
It will ignite when it reacts with air. We called it "Greek fire".
The students just loved it! We still have a black ceiling, it is so cool!
I do enjoy your videos, I love your enthusiasm. It is infectious!😢
That's a good visual representation of stoichometry in action.
Ignition occurs first at the point where the air/fuel mixture is optimum
How do you measure stoicism? It's pretty subjective.
Just kidding I'm just another wise ass with a degree in chemistry AND English. Not a lot of crossover in those two fields but it did help writing papers.
I remember my chemistry teacher in high school loved showing this off. Always been a favourite of mine.
At almost 45 years of age, I might have to take a chemistry course, thanks to your short videos.
I m sixty.i take youtube chemistry .never to old for knowledge
I used to be fascinated by chemistry but realized quickly that I didn't have what it took to master it. Still, I'd be pleased to relearn it.
Depending upon how deep you go into chemistry, it's not that hard until you need math. If you have no problem with math then almost any field in The Sciences can be understood at least at the lower levels.
I used to make candles. Thank you for showing just how dangerous paraffin can be.
This can happen with many other types of waxes and natural waxes. It is not because paraffin is dangerous that this occurs, it's because of the physical properties of wax and how it behaves at various temperatures. This model could easily be replicated with something like soy wax, or coconut wax because they too are made of hydrocarbon chains.
ALL candle waxes are classified as solid fuels.
I have heard of people using paraffin to heat homes, to cook and even power a refrigerator (typically you see them most often in 3rd world countries). I have also seen that the paraffin can cause fires and severe burns to people.
This illustrated why it happens. Thank you!
That's a different substance. In most parts of the world "paraffin" means kerosene.
The modern world uses that paraffin to fuel their flying machines
@@fitzroyfastnet Wow. Those are very different! TY
I still use the old school whale blubber for heating my home
Highly recommend
Paraffin wax is a wax made by a reaction that includes paraffin, the main component of kerosene. The wax isn't kerosene anymore and kerosene isn't the wax. AFAIK, any wax would behave the same way as in this video, but I am not going to test that. I just don't see why it wouldn't.
I've never seen such before. And yes, it raised my awareness of what NOT to mess around doing....
Beautiful, I mean the explanation as well as the process itself.
Dude has a pretty sweet fume hood. I’m jealous, the one I had wasn’t this cool
Excellent demonstration, never herd this trick till now 👍
I use paraffin wax at work. Thankfully, we’re not getting it more than about 100 degrees Celsius, usually no more than 85-90. Past 100, you start to smell it. I guess the boiling water mixing with it at that point starts to do weird things with it. Makes sense now.
"a coil, well insulated by leaving in a pot of hot paraffin until all bubbling has ceased... boiling of the wax shall render it useless and one must start afresh..."
god i have some weird quotes.
@@paradiselost9946 Sounds like some early inductor insulation tutorial, any idea where this is from?
@@mobuildsstuff it will be one of teslas articles i believe. "some experiments with high frequency high potential currents", possibly?
though it might be any of the old induction coil books, actually...
This is the most incredible video I've seen in a while. My eyes went wide as saucers seeing the short, and I had to look up an explanation which led me directly to your main video haha!
I learned so much in such little time, I understood your explanations but was already questioning everything you eventually answered with my background in such fields of science.
tried that several times years ago with a metal can.
heated it to boiling, poured in a small amount of water (using a spoon tied to the end of a stick),
and watched it go FOOM.
The arson investigation over my gramma's house burning down around her concluded that she did this while making candles in jars to cool them faster and caught the drapes over the sink, then flames went behind the cabinets catching the foam insulation.
Wow. Yikes. Poor grandma.
Guy sets up a fairly dangerous seeming demonstration for us featuring fire and reactions and thanks US! Bravo Mr. Scientist, I know paraffin is a monster to tidy up so: Thank You 🙏🏻!
As kids in 1962 we used paraffin to wax our surfboards. We learned it lasted longer if we would melt it in an old tin can then brush it on our boards. Our parents told us to be careful not to get it near water while we were doing this but never told us why. Now much later, I finally know! (We never got it hot enough to boil - just enough to stay melted while we applied it to our boards). In high school chemistry we learned about state change and a drop in temperature as paraffin is heated to melting but nothing about autoignition - probably a good thing at that age LOL!
Ah you've finally explained it! So many people were speculating so many wild different things in the original video. Most of them made little sense to me. I don't remember exactly how I arrived at the right answer. I think I saw another video of someone explaining that the glass cracks and rushes in. It's also possible that one of the many explanations from people mentioned it.
Very good explanation, I used to always be confused by this!
I remember covering a paper in wax and rolling it and setting it to fire. It sort of exploded and wax spread around it.
I never understood how that happened but after seeing your video i think it was the same phenomenon. Thanks 🙏👍
I love these *to the point* videos, I wish YT was more like this ❤❤❤
Thanks for this video. Many years ago I burned wrist badly by accidentally doing this. I had no idea why it happened until now.
Wax has a very high specific heat capacity of about 2.5 J/gK -- not quite the value of water which is extremally high at nearly twice that of wax but way higher than steel or copper or aluminum. So, when the wax was heated to boiling the heat contained in the wax was enough to instantly vaporize enough water to cause the wax to jet upwards and increase the surface area exposed to oxygen. The energy content of wax is also quite high -- about the same as many fuels we use.
This was soooo imteresting thanks for showimg and explaining in such good way! As soon as you showednthe slow motion i started to figure out whay it is igniting but it is always best to have someone who knows toexplain the extra bit:) Thank you. Subscribing for sure!
Wow! That was awesome! Culver is a nice school. Love going out on lake.
This my favorite thing to do back in the day.. we’d get a whole little metal bucket of wax in a campfire melted to the point it was “on fire” where the surface looked like it was burning.. then we had a bucket of water taped to a rake we would dump onto it and get a fireball 10’ high! We called them “wax bombs”.. really takes me back.
Great video. Here's an idea for a future video: explain why gunpowder needs a little sulfur to work.
I love the “let me show you what I mean” and then just an incendiary goes off
Thanks! Knowledge saves lives!
more of this long-form content please!
Great safety video to demonstrate a form of a BLEVE (boiling liquid expansion vapor explosion). In reality these catastrophic events happen when a superheated tank ruptures. Here the sudden formation of a heterogeneous azeotrope causes a quick vapor expansion.
Bleve
This might be a good place to tell my little story.
It was a cold winter, and the central heating was broken and could not be fixed for a few days. I was feeling cold as hell, and needed to get the room temp up, so I placed seven tea-lights on a small porcelain plate and lit them. It did work fine, giving some very welcome warmth. I had of course ensured that nothing flammable was nearby or above. After some time, all the wax had melted, which isn't unusual with tea lights, however the heat was enough to make the wax boil, and of course the gas ignited immediately with a giant flame, and now the tea lights were continuing to burn as one huge surface of fire, like a pan on a stove with burning oil. I quickly found a metal lid or pot or whatever and placed it over the plate with the tea lights, which killed the fire, but when I removed the lid, it would immediately reignite, until I left it to cool down. No harm done. But it sure was a learning experience. Even tiny tea lights can pose a serious danger! Don't place multiple tea lights close to each other. (I can't recommend repeating this experiment, but if you ignire my advice, at least do it in a safe location, keep the tea candles in a pan for which you have a tight fitting metal lid. The lid will get very hot, so use good insulating oven gloves.)
Use a clay pot over the tea candles.
The clay is a great radiant heater.
The hole in the pot chimneys the gas out.
I’m more impressed by that fancy yard stick with the claw on the end affixed with painters tape!😂😂😂
Ahhhh… science!🧪
I used to take scrap wax and fill a coffee can.
The coffee can would sit in the middle of a bonfire.
Eventually the vapor would ignite above the fire itself.
If you were to spit in it, it would eject a ginormous column of Fire!
You remind me of my own highschool chemistry teacher, Mr. Topping. He would do really cool demonstrations for the class.
I did this on small scale when i was 13, i was very cool, and it never left my mind
Holy crap that's awesome!!
A two sided fume hood!
Funnily enough I have done this, My dad worked in wax for a big oil company so there was always blocks of wax about at home.
Did you ever wax some curbs to skate?
Going to school in the 60s and 70s as much as I loved science having a learning disability I always sucked at understanding it. Watching videos on the subject I always wish we had the technology back then we have nowadays.
I've worked in oil and gas industry. Raw parrifin is clear black. Really flammble.
Youve been most helpful.
😊
Very unintuitive behaviour, but the video is straight to the point and explains it well!
The heavy thick oil type compounds seem to have a lower auto ignition temperature, wax is probably close to diesel, gasoline has a higher auto ignition temp, and methane is probably even higher.
Want to hear a Potassium joke?
K!
Na, I prefer sodium jokes.
NaBrO - Sodium hypobromite jokes are the best.
Same occurs with sugar dust in refineries
Not exactly the same, those types of events still require some sort of ignition source, usually from an electrical system, but sometimes just static discharge.
Not at all the same phenomenon. Sugar and wheat flour factory explosion are simply the ignition of ultrafine dust suspended in the air. There's no critical temperature like the flashpoint of the paraffin, it is merely the result of fine dust in the air, surrounded by plenty of oxygen plus an ignition source. One of the horrifying things about some of those Factory explosions is that the first explosion might be in a side room but the Shockwave dislodges dust from the rafters and beams Etc in other rooms and eventually ignite from the first blast which usually starts a fire, so there can be a chain reaction throughout many rooms and areas of the factory all starting from one spot where the proper mixture met an ignition source, be it static electricity or something like a pilot light.
I'm going to try this!
Good info. Thanks.
This is very familiar to people who home-can foods. A layer of wax on top of a jar of homemade jam or relish will keep air from touching the food. But melting and pouring all that wax can sometimes lead to ignition of the wax vapors. Instead of wax, the patented canning jars keep food fresh without the risk of fire. Since I used to make homemade treats and give them as CHristmas gifts, I was much happier using the commercial canning products, so my wrapped gifts didn't leak.
There's a very wide temperature gap between the melting point and the boiling point, though... It seems to me that it shouldn't be difficult to stay at a safe temperature.
ahhh, the old vacola.
never thought of wax lids, but it makes sense. you are boiling them with the lids on, thats enough to melt but not ignite wax. throw a chunk in any old time and it naturally will float to the surface... and ensures theres absolutely no air in there.
lol, theres still mulberries, beetroot, and peaches from about 79 that my mother jarred back then hiding in the back of a cupboard...
seems to be the rubber seals that perish. wax wont do that... especially proper flexible sealing wax like used on cheese.
as a child, home pickled beetroot was the norm, highly acidic. store stuff just hasnt got anything close, with its "sweetened purple dirt" taste....
I came to watch this because I still have a package of paraffin wax.
Forget the water, let's go out where no one is around and use something more explosive....lol
This used to be "a game" back in my day, we called them "dragoncitos" (little dragons), we made them because they gave out candles, like the ones on a birthday cake, it was fun, but looking back, probably we are lucky no one got a major burn outside of a missing eyebrow perhaps.
I'm not going into detail of how we made it, but most of the stuff we found in the trash or laying on the street.
Reminds me of my ex's cooking!
Not kidding
the smoke detector was the dinner bell.
Funny story, set my shirt on fire like that.
My son said "daddy do it again! I wasn't ready with the camera!"
He had a UA-cam channel at the time too.
We did a similar trick, but dropped hot wax drip-wise into a pan of cold water.
It didn't always flare up, but when it did it was dramatic!
The paraffin doesn't vaporize upon hitting the ice water. It is the the water that enters the tube and is heated by the paraffin to steam.
The steam projectiles the paraffin into fine droplets, which ignite due to a large contact area with oxygen.
Futher, the micron sized droplets have a lower energy for ignition, a similar phenomenon happens in dust explosions.
This means that the collision energy of tiny droplets releases enough energy to ignite with oxygen the paraffin.
One of the experiments I like to show too. There is another experiment where you can show that heating paraffin-oil at boiling point for some time generates gaseous and liquid cracking products (alkens). So I guess this and the intermediate formation of radicals might play a role in this self inflammation(?)
Very nice!
And this is why spilling water into a overheated casserole of melted paraffin wax causes a fireball?
When we were kids we would melt the wax (not boil) and throw into a tub of cold water. It made cool sculptures.
1:24 "It cracks". Watching the initial video made me think of the MythBusters episode where they dropped a frozen turkey in hot oil. Hilarity Ensued when the ice melted and then pushed up the oil, overflowing the pot and igniting it.
Just tested this. Awesome.
finally, a use for that old bag of Ikea tea lights !
You should definitely invite the Slow Mo Guys to your lab, I'm sure you can make awesome videos together!
The reaction is impressive and scary at the same time !
Also, I was wondering, why are there what seems to be two gaseous phases (a more cloudy one on the upper part of the tube and a coloress one between the cloudy one and the melting paraffin) at 1:04? Are they the different substances from the paraffin with a different melting point and density ?
If I had to guess, the clear lower part is hot enough that the wax stays as a vapour, but higher up the glass is cooler and so the wax can condense on it? Kinda like how there's usually a gap between boiling water and the visible steam
@@coryman125 Sounds right yeah, it could be it but the fact that the two layers are separate makes me think of a other byproduct formed or something like that
I believe that this is more of a physics question than a chemistry question but yeah I guess the explanation above is correct.
The "cloud" is vaporized wax that hasn't reached oxygen yet to react. You can see this happening in a normal candle flame as well.
Edit: Oops, misread the question, but the above is still true as well.
Yes the clear zone is similar to what water does at higher temps or lower concentrations, it is clear. The cloud forms as wax starts to condense as it cools a little leaving the bulk material. Then when it leaves the tube, it spontaneously reacts with the oxygen in the air.
Subbed because you’re awesome
My grandma used paraffin wax when plucking poultry to remove the fine hairs on the skin. Melted over the bird, cooled, then peeled. I remember those packaging boxes too. If I had known this back then, I think I might have advised against using it, lol.
I instantly wanted to try this at home
thank you for your ideas
i speculate
A CLEANER TEST? a more clearcut visuals, might be not using a flame ignition source to heat test tube, use an electric heating of test tube, this would rule out any flame ignition source, show even more clearly,
also please show,
the flame ignition of boiling vapors in slow motion too please to see if one can see anything of interest here too, i speculate
thank you
i support you
love love love
always did wonder about rags soaked in linseed oil needing to be discarded in a self sealing container.
I once directed a stream of O2 over a lit candle. It was from an oxygen concentrator (medical). It was a 2" dia candle. The wick was no longer necessary! Entire top of the candle turned into a while hot roaring inferno. Scared the crap out of me. Luckly, removing the oxygen returned it to a more easily controllable flame! Ever since then, I had a heightened sense of danger with paraffin wax!
Oh man. I have to try that!!!
Great video. I've seen this reaction before where the boiling tube stays intact and you get the same effect. To be honest, I didn't realise that the boiling point was above it's auto ignition temperature and I had assumed that the ignition must be something to do with latent heat as the liquid wax droplets start to solidify but that didn't seem particularly realistic. Your explanation here certainly makes more sense but what causes the wax to eject itself so vigorously from the tube on initial contact with the iced water in the case where the tube stays intact (I just checked and the video I mentioned was actually your UA-cam short from back in October last year)?
> something to do with latent heat as the liquid wax droplets start to solidify but that didn't seem particularly realistic. Your explanation here certainly makes more sense but what causes the wax to eject itself so vigorously from the tube on initial contact with the iced water
The tube BREAKS. That lets water contact the 370C paraffin, which turns some of the water almost instantly into steam, which expands in volume 100s of times in basically an explosion, which ejects the paraffin and blows it apart into in effect an aerosol or similar, with massive surface area with which to react with oxygen.
@@lqr824 in the video, the first time he plunged the tube, it seemed to be unscathed after taking it out? (liquid wasn't leaking profusely out of tube). Or was the crack too small to have any effect?
Every time I’ve done this demo, the test tube has cracked. In some attempts, the cracks were smaller such that residual solidified wax held the tube together.
@@Chemteacherphil Ah, right. I did post a reply to @lqr824's comment with a link to your original short where the tube does appear to be intact - but I guess UA-cam deleted it because of the link. So this is really a self-igniting variation on the old 'chip pan fire' demo. Great video and love the channel!
@@Chemteacherphil Maybe a kind of Venturi effect ?
Paraffin is used in home canning jam/jelly which I now realize is very dangerous. I once created a fireball by just tossing the molten wax into a sink in the chem lab. Saves some steps
We have a day known as Mid-Autumn festival back in Hong Kong, people would sometimes light many candles in a mooncake case, our parent always warn us not to do that, this is the reason why.
We used a bottle cap & a candle to do this all childhood. Calling it GhantiLa (Meaning scary avra cadavra)
Kept the cap between two bricks with candle burning & heating it from underneath
Some pieces of wax put in the cap which melted & a drop of water gave this effect on a smaller scale
Fantastic
gonna mess with the people at the skate park when i ask to borrow their wax next time hehe
That is a bleve. Boiling liquid expanding vapor explosion. You don't even need an ice bath. Quickly toss/drop some boiling paraffin from a height on a cold day and you can create the same fireball. That boiling liquid is already well passed ignition temperature, so all you need is proper dispersion of the vapor in air. Best to do this over ground that is either non flammable or covered in snow.
Very interesting.
Very good
Let grade school boys watch this, and in 10 years we will have the best chemists in the world.😊
Awsome thank you
at halloween when i was a kid the stores sold tasty orange colored wax harmonicas that you could chew like chewing gum , when you grew tired of trying to make music with them . years later tried chewing candles to prove to someone that indeed you can chew wax . years later still , deduced that those harmonicas must've been made of bee's wax . so OF COURSE i'm smart enough not to try to duplicate the vid at home . lol .
I had a candle explode in a cabin a few years back. I thought the tin can i was using as a candle holder somehow turned into a spring via some kind of bi-metal reaction but now i wonder if the wax wasnt slowly boiling away until it got some cold snow through the window.
I was sleeping and only saw the immediate aftermath but it was clear that wax had sprayed.
I feel bad for the first guy to figure this out
As someone famous once said, "Fascinating." 😉
Basically the frozen thanksgiving turkey in hot oil thing
Before I watch the rest of the video, this is my hypothesis: By melting it than plunging it into ice cold water, you force the wax to condense into fine particles. That sudden condesation causes a vacuum which forces air to rush in and stir and throw up the fine particulate. With the high suface area and oxygen rich atmosphere outside the tube, it ignites. Will edit if I'm right or wrong.
Edit: Partially wrong. Rather than an inrush of air, it was the tube breaking and an inrush of water that caused the wax to vaporize and ignite.
Never thought that overheated molten paraffin can be so dangerous.
Interesting, as a kid I used to play around with tea lights and burn gummy bears and chips etc in them. Suddenly there was a ~2m jet flame that was even really loud. Now I know what must have happened. Has really sprayed the flame at that time.
You can also take a burning splint and touch the tip of the test tube once it starts fogging over with fumes and it'll ignite the fumes inside the tube and cause a fairly loud explosion within the tube. Don't ask me how I know this...
Love the Channel.
Psssst.
Fbi are on their way
If you take paraffin wax and pack the hollow in an airgun pellet then shoot it a diesel l effect ignites it and the pellet comes out of the barrel with a whole bunch of velocity added. 3in1 oil also works.
I will try this at home.
Great illustration of flash point, too? It appears that the part that initially ignites is a darker gray than than the bulk of the vapor cloud. Does ignition always occur within the dark areas? Could that be sayinig something about droplet size?
We had a good time doing this in grade school. A metal barrel with a bunch of wax and throwing water balloons into it!
“But the glass will crack!”
“Yes, that makes it all happen!”