How ice water makes hot water boil

[@SteveMould]

Did you come up with an explanation before listening to mine? Was it the same or different? The sponsor is Skillshare. The first 500 people to go to skl.sh/stevemould6 with get 2 months premium membership for free!

[@SthamerAMVs]

Steve Mould only a minute in but I assume it’s because the cold water causes the pressure inside to reduce meaning the nearly boiling water is then able to boil?

[@patzminihd]

Thanks for the new video

[@chrisdavis3128]

I wondered why there is lots of videos showing super-cooled water forming solid more frequently than super-heated water forming a gas and nucleation sites.

[@MajorLeagueBassboost]

I did but only after you stated ecplicitly to put the bottlecap back on. Nice demonstration i have to say!

[@marcybrook7052]

Yeah, I don't think the pressure drops due to water condensing, there isn't enough vapour in the air to make a difference in pressure. The pressure decreases because the air pressure of the actual air just decreases with temperature. Its like opposite of the old trick where you heat up a dented ping-pong ball to fix it since the air pressure increases inside it when heat is added.

[@BrightBlueJim]

The main thing I was wondering, throughout the video, was how you were managing to pour ice water over hot glass without making BROKEN glass. Good to see it was really just the magic of editing.

[@hardiksinghvi9615]

This is the first video, where I predicted the reason before Steve said it!!

[@RandyJames22]

Me, too. I was like -- I bet you that his daughter punched him.

[@mr2octavio]

You're learning then!

[@leehitashi2621]

same!

[@אורסוויסה-ז5ב]

#metoo

[@lukmly013]

Me too

[@KeppyKep]

"It's hard to boil a cup of tea on top of Mount Everest." Things only a British person would say

[@the_original_Bilb_Ono]

...and Americans from the south... southern usa states drink a lot of tea. Everyone I know drinks tea daily.

[@05r41]

This sounded like a mistake to m- ohhhhhh, it’s because it will boil but still won’t be hot enough for a proper cuppa

[@samuelgunter]

@@05r41 ohhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh

[@CraftQueenJr]

Bilb Ono they aren’t as particular about the brewing temp.

[@castor5580]

Ohh these things were taught in 9th class 😂😂

[@TheLexa000]

It was bugging me, actually. Glad you said something or I was gonna be wondering what happened to your eye for ages.

[@conwaytwt]

@@bracco23 Greetings, time traveler!

[@thec-m]

It was bugging me the whole video, as I noticed it immediately. 6:19 for explanation

[@drewlop]

Steve is so good at anticipating the questions I’m going to have and answering them in priority order, both scientific and otherwise. There’s a certain kind of mind that he caters to perfectly

[@riedsch]

me: seems like a clickbait-title also me: of course, clicks on it video: delivers 100% keep up the good work steve

[@sebastianelytron8450]

This is one of the few non-clickbait channels on KZbin. Unfortunately he pays for that with low sub count. People are dumb.

[@qwertyTRiG]

@@sebastianelytron8450 Adam Neely is not only non-clickbait; he's anti-clickbait.

[@sebastianelytron8450]

@@qwertyTRiG Yeah great channel too

[@FassoliaPlaki]

FINALLY youtube has provided an explanation for that teaspoon/exploding coffee incident that happened to me a few years ago and left me freaked out and constantly wondering what the hell happened. Some people wouldn't even believe me when I told them about this traumatic experience. Thank you Steve!

[@Bisqwit]

“That's why it’s hard to brew a good cup of tea on top of Mt. Everest”. Ahh, what a relatable example that is immediately clear to everyone from daily experience.

[@bucketofinternet2744]

The sarcasm is strong with this one

[@albert_the_cool8092]

@@bucketofinternet2744 the observation skills is strong with this one

[@iaincaillte3356]

My take away: Daughters are more dangerous than steam explosions.

[@TheyCalledMeT]

wise words ^^

[@syafiqnote8668]

Indeed.. hhhh

[@saeedgnu]

Children often develop a few traits opposite of their parents... so if dad is pretty cautious like Steve, she may end up like ElectroBOOM, or vice versa....

[@JaguarBST]

@@saeedgnu I love how you implied that electroboom is opposite to steve. Makes perfect sense after their past feud and their totally different personalities.

[@nari5161]

@@JaguarBST past feud?

[@allocater2]

I noticed the eye thing 2 seconds before he explained it, like: "Huh, I wonder why he ha...and he just explained it"

[@mrobich321]

This is how my OCD-ish brain works. Started video, saw iced water pored over boiling water in a bottle, thought... "hun? that seems dangerous"... tried to listen to explanation but immediately noticed EYE thing. Paused video at 14 seconds and scrambled to the comment section. Glad to see I was not alone worried and happy to learn that an explanation was coming, but the delay was nail biting. Hardest time concentrating on content ;-) ;-) Then when he displayed the broken bottle, I thought..."ah ha! ..." but I was again wrong.

[@ronwesilen4536]

I was going trough all the knowledge i should have adquired last week when i studied oftalmology for my medical degree trying to guess wich kind of "thingy" this was... Didnt think of punching children

[@sparkythewildcat97]

Man, as soon as I noticed his eye, my eyes started watering.

[@oceannuclear]

I wonder if he did a risk assessment on having a daughter (@Steve?)

[@coryman125]

@@sparkythewildcat97 Same :( which was about 2 seconds into the video so it was a lot of watering

[@casualgamer394]

Me: I think my microwave is broken because my water isn't boiling. Also me: Maybe it just glitched and needs another minute. Microwave: Blow all his water out of his coffee cup for doubting my POWER!

[@BothHands1]

k seriously, get a kettle 😂

[@Tfin]

@@Kelan-pn6em It's not microwaved coffee, it's just microwaved water that will become coffee. Neither tea not coffee cares how the water got hot after the fact.

[@adlockhungry304]

Tfin m, Nuh-uh! Nuh-uh! Fire has magic juju from nature and microwaves have evil man made tech unmagicky bits! True fact!

[@nicobugs]

Put salt or sugar in the liquid, it will help to prevent explosion 😜

[@amberblyledge7859]

Flash boiling. Fun. Always poke a microwaved water container with a stick or something.

[@sebbes333]

4:03 Steam explosions from super heated water is even more common (& more dangerous & more violent) if the water is distilled, so there are no minerals or nothing else than H2O molecules inside. Trying this is REALLY dangerous & you will very likely burn yourself horribly, use at your own risk.

[@victortitov1740]

Well, apart from a chance of burning an eye out if the water decides to explode at the moment you look into the bottleneck, I wouldn't consider it very dangerous. It can cause nasty burns, but the burns aren't really a life threat.

[@sebbes333]

@@victortitov1740 Unless it explodes violently enough to shatter the flask & send "boiling" glass shards into your flesh...

[@victortitov1740]

Well, i doubt it is possible. Unless the bottle is plugged, of course, but that is a different kind of an explosion. The pressure the explosion can produce is limited by vapor pressure of the superheated water, which is a function of temperature. And it would take some serious overheating. But i am meaning to try that, I hope for best destruction if I cover up the surface with a layer of oil, to prevent heat loss to evaporation from surface, and potential disturbances there. I know how much of a mess the water can make in a frying pan, submerged under oil.

[@victortitov1740]

But if it can explode the bottle, yes, I agree it deserves to be called "dangerous" (mainly as an eye hazard).

[@sebbes333]

@@victortitov1740 I hope you film this & upload to KZbin :D I also hope you don't hurt yourself.

[@mikemorr100]

I'm curious how the bottle didn't explode due to thermal shock Oh, nevermind, you mention that in the video. Lol

[@blackoak4978]

I was thinking the same thing, lol. When he showed the broken bottle I laughed

[@Platypus_Warrior]

I want to subscribe twice. One of the best channel for me

[@Tjita1]

It's not hardened glass so it's not THAT sensitive, it's actually surprisingly flexible. Hardened glass, like a pyrex cup, tends to more or less explode from thermal shock.

[@JohnHoggard_aka_DaddyHoggy]

At last - something I remember from my physics degree back in 1994 - actually helped me remember why this would work.

[@robertfletcher3421]

Steve, you should have followed this up with an experiment I used to love at school. Put water in a glass flask or bottle. Connect this to a vacuum pump. As the pressure lowers the water will boil. At a given point the water will suddenly turn into ice.

[@andymcl92]

I've seen the boiling part of this done by hand using a plastic syringe. The ice part, I hadn't thought of before :)

[@JNCressey]

@@andymcl92, I think if you're able to get it boiling, you can get it to freeze just by repeating the same thing lots of times.

[@jacksonpercy8044]

CodysLab did some videos on that not too long ago, maybe a year or two.

[@Gaehhn]

@@andymcl92 If you make the water evaporate it loses energy and cools down. Once it cools down enough it suddenly turns into ice while boiling. Very interesting to see, especially if you don't yet know the mechanics behind it.

[@andymcl92]

@@Gaehhn Yeah, I get there science (I've actually got a physics degree), is just never seen that part of the demo :)

[@OhhCrapGuy]

I've been making my way through the videos on your channel lately, and it's a credit to your science education success that I immediately understood how this worked when I read the title. My intuitive understanding of physics has advanced that far due to your channel and similar ones.

[@scott_harrison]

I wondered why my tea sometimes boiled after taking it out of the microwave and putting a spoon in, very informative video as always, thank you.

[@scottll]

Shocking behaviour.

[@AlyenaMango]

Steve: Feels bad for making an informative video about an interesting phenomenon based on an older video, giving credit to the other channel. Some other KZbin channels: Reupload stolen content all while somehow staying monetized.

[@besaltman9961]

The steam explosions are actually called "bumping" at least if I remember correctly

[@ParadoxProblems]

I came up with a similar explanation. As temperature and pressure are directly proportional, the decrease of air temp decreases air pressure on its own as well as recondensing the vapor.

[@Zveebo]

That super heated water was kind of scary! 😧 Always thought it was just people being alarmist, but can see how it could do some nasty damage.

[@donolinger6904]

- You've never overheated water in a microwave? I do it all the time. It has gotten my hands with that explosion. Both hands several times and it got me good but it never actually burnt me. No blisters or burn marks of any kind. Yes it hurt like crazy but it did no damage. The pain was gone really fast which frequently happens with bad injuries. It just wasn't an injury, I sure felt injured but only for a few seconds. It was kind of like when my dad spilled boiling hot coffee on my crotch several times. That hurt like crazy too but again it didn't do damage, it just hurt.

[@donolinger6904]

@Nhilistic Komrad I'm disabled and think I'm below a poverty level income. I have a cheap microwave with a rotating plate and I think I could duplicate it every time. Edit - My coffee mug also has plenty of cracks and indentations inside it too. Another reason not to work yet I can still repeat it at will and superheat water anytime. I think there's a flaw in your theory.

[@Zveebo]

Don Olinger I just boil water in a kettle fortunately - never had any real need to use a microwave. But appreciate kettles aren’t a standard kitchen appliance in some countries.

[@donolinger6904]

@@Zveebo - Microwaving food is really bad for you from what I understand and I've heard the same about water. I wouldn't hardly use one for the longest time. I'm going to stop use again. It's just easy and quick. It's really convenient when you're in a hurry.

[@Zveebo]

Don Olinger That’s nonsense. The microwaves just heats up water particles - it’s not harmful for you to eat at all.

[@Cgraseck]

Nice demo! I did this in my classroom with a boiling flask and a rubber stopper. It didn't work particularly well, but the pressure differential eventually forced the stopper into the boiling flask with an almighty pop! The entire class jumped! Maybe it is time to give this one another go. I'll have to find a screw top wine bottle. Cheers, Chris

[@stefanklass6763]

I saw the demo and knew right away what was happening, can I get a star please?

[@SteveMould]

You get a heart and a like

[@cr-yi7ep]

Can I claim the same? Cold water -> cooling the gas -> pressure drop -> boiling the water 8)

[@Theo0x89]

I saw the title and the thumbnail and knew the explanation right away. Then I saw the demo and knew about the dangers of superheated water and broken glass right away. Can someone tell me I'm smart, please?

[@dreggory82]

@@Theo0x89 you're smart.

[@zenvir1680]

If somebody knows at lower pressure water boils at lower temperature, it is not that difficult

[@AnimilesYT]

I'm at 0:18, but my guess is: The water is exactly at boiling temperature, but the pressure inside is a bit too high. When the cold water is poured over the bottle the air inside shrinks which reduces the pressure and makes the water boil.

[@rutvikpanchal466]

Exactly the same guess

[@AnimilesYT]

(at 3:13 now) Interesting. I got it mostly right, but I missed the crucial part of water evaporating which builds up the pressure. Then again, I didn't know that the water was boiling and that the cap was put on right after it which would increase the pressure. If I knew the whole setup without any explanation I might've guessed it. But I'm already a bit proud of myself that I got so much of the answer right :D

[@JustinKoenigSilica]

Almost but not quite :)

[@Bebeu4300]

6:20 Thank you for the explanation. It was bugging me somewhat.

[@nazrulislam-ol8wt]

Oohhh man I cannt explain the quality level of this channel. The videos are beyond amazing. He has this weired quality of making science interesting. And I am seeing as if I am watching comics . Great job Steve. You are the best.

[@gheorghyu]

Q: Does superheated water phenomenon occur in an egg? Story: My wife is boiling an egg in boiling water and after it starts peeling it, she discovers it's to soft, so she puts it in an empty glass, in the microwave... After 1 minute she took it out an starts probing it and then, the damned egg exploded while she was watching closely. Result: a visit to E.R. and damaged vision for 2 months. The explosion was so powerful that the eyeball was covered completely with hot hardened egg. She is lucky to be completely recovered.

[@pigeonlove]

No, that was the chick's revenge for taking its life🐣🐤🐥🐔

[@doug6531]

@@pigeonlove No, commercially farmed eggs are not fertilized, and can never result in a chick.

[@JayVal90]

A single egg 1 minute in the microwave???? Yeahhhhhh that’s a LOT of energy for such a tiny object. My guess is that such a thing could happen with superheated egg yolk.

[@SteamShinobi]

Yes, it does. Good question, it is very much a similar situation as what's present here.

[@ambulocetusnatans]

I blew the door off of a microwave once by trying to cook an egg.

[@adlockhungry304]

This is a great way to demonstrate how simple, rather intuitive principles can lead to unexpected, rather, at least superficially, counterintuitive phenomena.

[@NetAndyCz]

4:08 it is scary, but it is way scarier if you super-heat an acid:)

[@GRBtutorials]

Especially sulphuric acid!

[@adlockhungry304]

Ugh! I used to have to clean porta-potties that way! Sulfuric acid drizzled inside, then sprayed out with hot water from a high pressure hose! (Gross out emoji) Just one more reason not to be born working class, people! Take it from me. :-P

[@NetAndyCz]

@@adlockhungry304 yikes, I had been heating acid only in test tubes and the important rule is to wear protection and never point it at anyone. But the superheating is super scary as there is no way to stop it once it goes off. And it goes off rather quickly. PS: and yeah, I may have got my degree at university but taking samples from canalisation is gross still:)

[@adlockhungry304]

NetAndyCz, Ew! Yeah that’s grody! Well, to be fair, it wasn’t super heated water I was spraying. More like scalding hot water from the tap type hot. Still, it steamed up a bit, got all sulfuric vapor-like. I had rain gear and goggles but no respirator. Too young and ignorant to know I should be insisting on such a thing. 😆

[@adlockhungry304]

Also, I’m guessing I wasn’t dealing with the type of concentrations of acid that one might see in a lab. ✌🏻🧑🏼‍🔬

[@xMaverickFPS]

@4:08 - this man just knows how to find every glitch in the matrix.

[@cezarcatalin1406]

Tickleshits Minecraft developer logic: It might be a bug but if it’s useful it’s just an unintended feature !!!

[@malikaikinn1153]

5:10 So mesmerizing! Thanks you have cleared up so many different concepts that I didn't quite understand up until today. Beautifully and simply explained in a way it made sense. Much appreciated for all you've passed on over the years. Still waiting for the great punchline :)

[@DirtyPoul]

5:52 Fellow edutainment KZbinr CGP Grey has this happen to him and he ended up in the hospital with quite severe burns. He mentioned this incident in one of the early episodes of his Hello Internet podcast with Brady Haran. Incidentally, Brady has made videos with Steve in the past, so the circle has been completed with this video. Good job completing the circle Steve!

[@Martcapt]

Was thinking about this!!! He threw his mug against the wall and everything, there is a great hello internet animated about it! I would believe they know each other though

[@DirtyPoul]

@@Martcapt I was not aware of the animation depicting the incident. I'll have to check that out. I would be very surprised CGP Grey and Steve Mould don't know each other, at least as acquaintances.

[@NuisanceMan]

3:04 That's exactly the same noise that my head makes when I remove the seal bit on top.

[@MrMaselko]

0:36 Focusing on the cap gave it away with cartoon like light bulb moment.

[@alipuk]

Being an engineer helps in stuff like this, have you tried anything about how jet engine intakes control pressure by using Bernoullis Principle? And yes, yes your eye was bothering me hope it gets better soon :)

[@genau14zeichen]

Being an engineer helps in a lot of situations 😁

[@sailaab]

Ano Nym.. does it help in **not** getting punched in the eye by a daughter though¿ :D

[@alipuk]

sailaab tbf only if we are aware of the danger first

[@genau14zeichen]

@@sailaab Well, I think after a period of extensive testing regarding the propability of punches in certain situations we could figure out a solution that would keep that propability reasonably low. It's a compromise, but in engineering, what isn't?

[@sailaab]

_ /|\ _ 🙇 right¡👌👍

[@Chrisallengallery]

The bottle is sealed, which keeps the pressure high. The cold water lowers the pressure and the boiling point lowers. Water will boil at a much lower atmospheric pressure while hiking up a mountain, for example. As a mechanic, engine cooling systems are pressurised to keep the coolant from boiling at temps way above 100*c.

[@zirize]

I worry about your right eye.(Never mind)

[@anarcho.pacifist]

This video nicely illustrates the fact that heat is nothing else but the vibration of molecules. The higher the molecules move, the greater the pressure (due to repulsion between electrons). Cooling down the vapors, means slowing down the atomic movements, which lowers the pressure, allowing new bubbles to form, eventually reaching an equilibrium. Very nice experiment!

[@OpreanMircea]

0:48 oh, you are reducing the pressure in the container by cooling the hot air inside, that's why you are pouring water over the empty area

[@nineball039]

That is where the water vapor is which is what he is cooling. It's not empty!

[@sparkythewildcat97]

@@nineball039 water vapor and air.

[@LiooRyuuguu]

In 10 years, another KZbinr be like: I think that video deserves a remake, as that old video is only 4K@60fps so basically ancient.

[@JustinKoenigSilica]

Before I watch: cold water makes the water vapour condense, lowering the pressure, making it boil.

[@treeinafield5022]

you want a medal for that?

[@holydiver233]

Way to go, champ.

[@brycering5989]

well done.

[@brycering5989]

@@treeinafield5022 there are about 100 more people making the same sort of comment, Feild day for you eh ;)

[@benshakespeare268]

Guessed the basic theory, but interesting to know about the heat carrying ability of water in a vapour vs a liquid. PS: As father, I always use eye & ear protection when handling toddlers 👍

[@kenycharles8600]

I had coffee jump out of a cup onto my fingers when I dunked a cookie one time. One time only. Now I know why.

[@blackoak4978]

Odd that it would happen with coffee... There should be plenty of impurities in the water to provide nucleation sites

[@phxgen]

@@blackoak4978 agreed, I'd have figured the same thing, but unfortunately as I was caring for my senile old grandfather over his last year he developed a taste for pre-brewing coffee and later microwaving it to like solar-corona-status hot every morning. We witnessed this disastrous phenomenon with coffee a handful of times. I always wondered if the broken turntable motor in my ultra-powerful ultra-overpriced ripoff GE Advantium microwave contributed to the "coffee exploding violently when disturbed" effect.

[@ayhamsaffar8407]

Really liked this video. Just published a report for my company talking about if oil can evaporate or bump once superheated in the high pressure compressor of a jet engine so it cool seeing all that here.

[@JohnLeePettimoreIII]

When a daughter hurts her father, it's NEVER an accident.

[@sailaab]

is this a hypothesis or a proven 'theory'¿

[@Paul-sj5db]

You can show the pressure change by trying it in a plastic bottle. As the ice cold water is poured the pressure will go down and the bottle will start to crumple instead of the water boiling.

[@GoranNewsum]

My initial solution was magic. It's almost always magic.

[@zshakoblahROBLOX]

I'm a vacuum technology engineer, and this video explained my whole job in less than 5 minutes. Brb gonna go find a new career.

[@tofolcano9639]

4:48 Is that why every moist thing I put in the microwave makes loud popping noises like it's popcorn? What's the deal man? Even chicken does that

[@raykent3211]

Reduce the power, extend the time and you're okay. Just gotta give the heat more time to distribute.

[@kostaschousianiths6076]

Well, not exactly. You see, most foods (like chicken) are full of water molecules that are trapped inside. When the water is heated enough, it turns into steam, but it is still trapped. So, when it surpasses a certain pressure point, it will rapture and make its way out of the food, thus creating the familiar popping sounds...

[@13mudit]

Well i guess a live chicken experiencing sudden change in temperature may want to express its pain

[@guythat779]

It's trapped steam in the food as most food has some water

[@mbrusyda9437]

@@guythat779 food that goes inside a microwave needs to contain water anyway, since microwave (mainly) only heats the water

[@Kenionatus]

A related and even more impressive experiment is the crushed barrel one. You boil water in a steel barrel and put the cap on. Proceed to cool it down with cold water. As the steam condenses, a vacuum is formed and the ambient pressure causes the barrel to crumble.

[@CoffeeMug444]

Is your eye okay?

[@Akideoni]

Yea it looks like bloodshot eye!

[@Assault_Butter_Knife]

I hope you reported your daughters to the authorities. Domestic abuse is a criminal offence

[@aidanclarke6106]

Today I learned that blue water makes pink water boil! That's magic! 😂🤣

[@WanderTheNomad]

Water vapor takes up more volume than water, so when it's boiling, the pressure increases. When you seal it, the pressure keeps increasing. It's harder for the hot water to boil at higher pressures because the pressure is "pushing down on the water preventing bubbles from forming (aka boiling)". Since no more water vapor is being produced, the pressure reaches an equilibrium. When cold water is added, some of the water vapor condenses back into water, decreasing the pressure of the sealed bottle and allowing the hot water to continue boiling again. I didn't pause the video btw, but I just wanted to write the explanation in my own words.

[@nostalgia1036]

dosent the glass crack ??

[@cr-yi7ep]

As Steve pointed out at 5:58, yes it sometimes does.

[@nostalgia1036]

@@cr-yi7ep ive had the same happen when making tea.

[@JAmes-BoNDOO7]

It condenses the vapour, thus it decreases the vapour pressure in the bottle, and the boiling point of water decreases in low pressure so the water boils. Hope I am right. Writing this before watching the video

[@d4mdcykey]

Fascinating as always, Steve. Seems I'd heard of this phenomena in the past but was unclear on the specifics. And yes, over-heating water in a microwave is quite dangerous, had a friend that made the mistake of the spoon immersion and it caused fairly serious burns to his cheek and hand.

[@deezynar]

The key that makes all the difference is putting the cap on it. No cap, no boil.

[@Eidolon2003]

This reminds me of a later Mythbusters episode. They filled a tank car with hot steam, then showered it with cold water to see if it would collapse under the pressure. God I miss that show sometimes

[@Yotanido]

I didn't pause the video to come up with an explanation, I actually thought about it before clicking on it. It was the same.

[@robertoricardoruben]

The secretary at the office where I used to work burned her hand BADLY after heating a mug of water for making tea because of an steam explosion. It was an older microwave, those without a spinning platter.

[@rick57hart]

I think it would be more interesting, to really harvest energy from the cold, and than use it to really boil water: To run a sterling engine you need to different temperatures. For example - 20°C in the winter outside, and +11 °C 2 meters deep in the ground. With this temperature difference we can run the sterling engine, produce electricity, and boil water. So we turn the negative energy cold into the positive energy heat.

[@arduous222]

1:38 I live in Korea, and when we explain this concept in school we usually say "it's difficult to cook rice atop Mt. Everest". I'm not sure if this 'tea' example is commonly provided in western cultures or it's purely because you're a British being a stereotypical British, but this difference is very amusing.

[@tusharjamwal]

I'm going to make an attempt at explaining this at 0:49. Since the waste is not being poured over the water but rather the empty party of the bottle, it's cooling the air inside and reducing the pressure. Reduced pressure causes the booking point to reduce. This wouldn't work with the cap open, with a lot more hot water inside, or with a plastic bag instead of the glass bottle which would just change it's shape to keep pressure equilibrium.

[@DavidGuild]

ONI taught me that water has the same specific heat at all phases. That contradicts what you said at 2:30. My guess is that it's not heat capacity at all, it's thermal conductivity and temperature. The water vapor is diffused in hot air and the air has a much lower specific heat than water. So the cold water pulls heat from the glass, which pulls heat from the air, which quickly equalizes with the steam because it's all a gaseous mixture.

[@90benj]

In thermodynamics we learn to think in terms of gas surface pressure. Every face, liquid water and such, has a pressure, with which the molecules are pressing out of the phase. For liquid water, the pressure is usually lower than the ambient pressure, so it doesn't boil. Now you two ways of boiling it: either you increase the gas pressure of the water, by heating it, so it is higher than the ambient pressure, or you decrease the ambient pressure enough, with a vacuum pump, so that the gas pressure again is lower than the ambient pressure

[@tundeadesanya8935]

Felt very smart knowing what's going on before the explanation

[@chriscollins6488]

You can use thermal shock on a bottle to make a clean straight lip. Tie a piece of string around bottle and soke with meths, set fire to it and when string falls off it cracks where the string was tied. Not done it myself but was on a video years ago.

[@Vinni-2K]

you are the first yter that admitted to have taken another channels video idea in a video i have watched. just for that you are great!

[@stevewalston7089]

Cool experiment. To further show that the pressure is decreased in a sealed vessel containing boiling water and then pouring cold water on it, look up the classic demonstration of boiling water in a metal can. For those not aware, do not attempt to boil water in a can in the microwave ...

[@georgebartholemew8444]

Although you are correct in saying that the reduced pressure causes the water to boil at a lower temperature the recondensing vapor is a minor element while the lower temperature of the air is a much larger factor.

[@OrenKaplan83]

Nice demo and explanationof super heating. The first part is also very neatly done but I figured the concept the moment you said that you capped it, like you said some of us might.

[@Seegalgalguntijak]

The superheating of the water is also the reason why there was at least one larger stone put into the boiler of steam engines, like on locomotives, after they had quite the number of accidents from water suddenly starting to boil and tearing apart the boiler in the process.

[@raykent3211]

No need to apologise for passing on information, but nice that you credit your source. I understood the phenomenon already, but hadn't seen it demonstrated without lab vacuum pumps. Nice!

[@johannes7935]

thank god i found this channel. Imo one of the best science youtubers. keep up the good work !

[@dragon67849]

I cannot believe how spot on I was with my explanation actually. I love scishow, Vsauce, smarter everyday, minutephysics, NileRed, Cody's lab etc etc for making me able to come to that conclusion on my own. And lastly, but definitely not least, you.

[@samuelolteanu]

I'm glad to say I figured out the answer before he explained. Not immediately, but still.

[@EnthalpyAndEntropy]

Heat is a process. It's not an entity to be added nor removed. It's the energy that's added or allowed to leave.

[@bloogaming8827]

It’s because there’s a cap on the bottle and so the pressure went up and raised the boiling point. The cold water lowers the temperature and, therefore, pressure of the air in the bottle which, in turn, lowers the boiling point enough for it to start boiling

[@w.t.h.2040]

Good info about how everything that gets further from the center of the earth needs less energy to do something.

[@craighousesounddesign5944]

Steam Explosions. I guess that explains why sometimes when I'm heating tomato soup, without stirring, there will be a sudden burst of energy kicking the lid up.

[@markweikle5645]

We could say the water is Boyle-ing. I.e following Boyle's law

[@candykanefpv]

Something to do with pressure. Okay so the water vapor since it’s hot the molecules are spaced apart. When you cap it, the pressure is lower than atmospheric. When the cold water is poured over it causes some of the water vapor to condense which lowers the pressure even more and causes the warm water to boil to keep equilibrium.

[@powertomato]

I spent 6 minutes asking myself if your bloody eye is the result of a failed previous attempt. I'm glad it wasn't

[@dylanbeddoes24]

0.45 in and I'm guessing it's because the cold water condences the air creating a slight vacuum that lowers the boiling point of the water which is already just below boiling, this is my theory or educated guess.

[@sscswimmer1]

I figured it had to do with pressure, but I couldn't work it out before clicking and finding out. Cool demo though, definitely made me think about it in a new way

[@PMX]

For this experiment you are going to need: water, a microwave, a bottle, health insurance

[@fj4695]

In a video practical engineering made a similar experiment with a water bottle full of steam and a bowl of cold water, when he put the bottle open upside down in the bowl the vapor condensed and sucked most of the water inside the bottle

[@kasrabtw]

Instructions weren’t clear ended up getting drunk trying to empty the bottle

[@kevinmartin7760]

It isn't necessary for the cold water to cause condensation. It is enough to cool the vapour causing its pressure to drop, although that can only generate a finite amount of boiling before condensation starts.

[@formbi]

Bosch actually advises users to put a metal spoon in when heating water in a microwave oven

[@mark.fedorov]

I forced myself to stop the video and think for a minute, and came up with the right conclusion. Thank you)

[@JohnnyX50]

I experienced the super heating by accident when I was just trying to heat up a small amount of water in my microwave in a glass cup. I took my attention away from it for a few seconds and I heard an almighty whoosh and bang and thought I'd broken my microwave. When I opened the door the water was gone from the glass and the inside of the microwave was covered in water. It gave me an excuse to wipe the inside clean but at the same time I realised this wasn't a good idea in the future as something terrible could have happened. Thank you for helping me understand what happened :)

[@jayyyzeee6409]

I burned my hands pretty badly because of a steam explosion once. Instead of separately heating a container of water to make coffee in a french press, I boiled the water it in a microwave directly inside the french press container and it had no nucleation sites to the point where it was super-heated. Then I poured in the ground coffee. Big mistake! All those coffee particles provided many nucleation sites simultaneously and it erupted showering my hands with super-heated water. Make sure to pour the water onto the coffee that's already in the container and don't be holding it so the effect is more gradual and so you can move away if it overflows.

[@Observ45er]

The cooling of the vapour is fast because the ice water also contacts a larger area where the vapour is than the water is.

[@TheSdzfr]

My explanation initially was regarding the Latent Heat. The cold water loses heat to turn into Ice, while hot water gains heat to boil. But the loophole with my explanation is that it should technically cool the liquid rather than boiling it, in fact ice cold H20 didn't turn to ice.

[@mohamadadnaneljeiroudi9206]

Actually, this technic is traditionally used in Italy when making coffee using the caffetiera (Italian coffee pot). so when water doesn't boil you just resin the caffetiera in cold water and put back on fire and it boils right away. I always wondered how does it work. thank you for explaining the physics behind it !!!

[@CamiloSantana]

As soon as you said, "cap it" vacuum was obvious solution.

[@Holobrine]

I think the ice water cools the air in the bottle, thereby condensing it and decreasing the air pressure, so the hot water boils until the air pressure is back at some equilibrium point.

[@DraRed73]

Apart from the heap capacity of water, the heat lost from the water boiling is going to be reversed by the water vapour condensing. The only extra loss of heat is going to come from the larger surface area losing heat due to the extra convection induced by the boiling water.