Paraffin Wax Autoignition
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- Опубликовано: 22 июл 2023
- This video is a more detailed breakdown of a demonstration I showed in a previous RUclips 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.
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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.
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.
@@RedFail1-1… wax vapor, oxygen, and heat in the right concentration. Sounds similar enough to me.
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.
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 !
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 slow-mo close-up was excellent! Quite a video! 😎✌️
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.
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 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 remember my chemistry teacher in high school loved showing this off. Always been a favourite of mine.
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 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...
Thanks for this video. Many years ago I burned wrist badly by accidentally doing this. I had no idea why it happened until now.
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.
Excellent demonstration, never herd this trick till now 👍
Dude has a pretty sweet fume hood. I’m jealous, the one I had wasn’t this cool
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.
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.
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!
I love these *to the point* videos, I wish YT was more like 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 🙏👍
Very good explanation, I used to always be confused by this!
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.
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!
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.
I've worked in oil and gas industry. Raw parrifin is clear black. Really flammble.
I’m more impressed by that fancy yard stick with the claw on the end affixed with painters tape!😂😂😂
Ahhhh… science!🧪
I did this on small scale when i was 13, i was very cool, and it never left my mind
Great video. Here's an idea for a future video: explain why gunpowder needs a little sulfur to work.
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.
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 🙏🏻!
Thanks! Knowledge saves lives!
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.
Wow! That was awesome! Culver is a nice school. Love going out on lake.
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
I love the “let me show you what I mean” and then just an incendiary goes off
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?
Is the Bunsen Burner....which is *RIGHT THERE* igniting vapors?
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.
Youve been most helpful.
😊
The flame of a candle is burning the volitals accumulated at the top of the wick. Did you do a flash point with the Cleveland Open or Closed cup?
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.
Holy crap that's awesome!!
A two sided fume hood!
Very unintuitive behaviour, but the video is straight to the point and explains it well!
Why does the test tube crack when dropped into water, but not when heated by the Bunsen Burner?
more of this long-form content please!
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.
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?
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.
If be interested in a video on the chemistry behind self ignition of oily or solvent soaked rags when piled up
When we were kids we would melt the wax (not boil) and throw into a tub of cold water. It made cool sculptures.
You remind me of my own highschool chemistry teacher, Mr. Topping. He would do really cool demonstrations for the class.
I feel bad for the first guy to figure this out
In one of the clips, it looked like the test tube didn’t break, but the fireball still happened?
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.
Is paraffin wax safe on car paint/ clear coat .
Does it have the clingyness of wax to paint.
Also, does it haze up like wax on car paint ?
Thanks
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
I never knew that wax could so easily combust due to temperature changes.
Does the ignition occur because the vapourised wax used the vapourised water molecules, or would this occur had there not been a rapid change in temperature due to the ice bath? Would it work similarly if for instance the water bath was filled with hot water instead?
Why did the vapors coming out of the test tube when you were boiling the paraffin not ignite when you were heating it?
Remember that it is the vapor that ignites, not the liquid, and at the surface of that boiling liquid, there just isn't enough oxygen to support the reaction. Especially so in the restricted space of a tall test tube. It's much the same reason you can throw a lit match into liquid gasoline and (sometimes) it will not ignite.
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.
how does the explosion in flour ou corn starch silos happen? what kinds of substances become that volatile when very fine particles are accumulated floating in a given space?
Dust explosions happen simply because you have many fine particles of fuel (the dust), and enough oxygen for them to burn. Because the dust has a lot of surface area, the reaction happens extremely quickly. Almost anything that can burn is at risk of dust explosions, including powdered metals from machining.
Good info. Thanks.
Is this at all similar to pouring water on on a foaming pan or putting ice in a hot fryer?
So how come we don't see the wax vapors igniting while you're heating the test tube? I'd think as soon as they leave the top of the test tube there should be sufficient oxygen to burn.
I instantly wanted to try this at home
What happens if you pour the boiling paraffin straight into the ice water ? Would it do the same, but maybe on a smaller scale.?
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.
Subbed because you’re awesome
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 RUclips channel at the time too.
Very nice!
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!
After the melted paraffin, what can I use to keep it melted inside a closed bottle?
I wonder if this is causing some of those candles in jars deflagrating?
I'm going to try this!
Could someone please clarify.
The glass cracks because of the difference in temperature, the water then boils creating steam which in turn pushes the boiling wax out of the tube?
I'm also curious to know why the ice is needed, wouldn't it suffice with water?
Want to hear a Potassium joke?
K!
Na, I prefer sodium jokes.
NaBrO - Sodium hypobromite jokes are the best.
What type of wax is used in lava lamps? Most if not all waxes I've tried to use float in water but lava lamp wax sinks in water. How is lava lamp wax modified to sink? The Internet says they used to mix the wax with carbon tetracloride. Is that true?
Can wax be considered compressed (à la Diesel) to ignite.
Just tested this. Awesome.
Basically the frozen thanksgiving turkey in hot oil thing
Would it self ignite if you just poured the contents without any ice?
What if the test tube was made of borosilicate PYREX glass? (The temperature differential is really high, though, so the glass might break anyway.)
Phil, just wondering on history of your lab coat with Culver Military Academy logo. ken class or '59
Would this also take place with liquid paraffin, the lantern fuel I have says paraffin can it act the same way?😮
Whoa!!! Is why some skin cream (cetraben comes to mind) have warnings on to keep away from naked flames??
The explanation is that the autoignition temperature is lower than the boiling temperature in case of paraffin wax.
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.
Any chemical reactions resulting in fire or explosions are welcome! Thanks.
always did wonder about rags soaked in linseed oil needing to be discarded in a self sealing container.
Quick question: What is paraffin made out of?
Thats cool, but the sound it makes up close at the very end just sounds so funny to me
Why does boiling wax erupt when it is rapidly cooled?
A1: It solidifies and contracts from the outer periphery, so it ejects from the open top.
A2: While the inside is boiling, the outer periphery near the surface solidifies, which narrows the path of the steam and increases the flow velocity, causing it to eject.
Which understanding is correct?
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!
I have one question. Who intentionally boils paraffin wax?
Never thought that overheated molten paraffin can be so dangerous.
If the testtube did not crack, meaning the wax is not sent into the air, would we still see a smaller reaction as just the vapor inside the testtube mixed with the cooling wax or would the liquid wax just solidify as the testtube cools?
It would just cool and solidify.
The large expulsion of vapour which was above the auto-ignition temperature of paraffin was the reason it ignited.
Where did the spark or ignition come from?