"I thought 'critical temperature of water - I must buy that car!'" Oh man I love you, Poliakoff :D
@AAAnjOOO
11 жыл бұрын
I applied for a program for a university that I really wanted to get into and I had to write a supplementary application for admission. One of the questions was to discuss who is my favourite scientist and why he is my role model. I talked about Professor Poliakoff and how he is so passionate in learning about science everyday and I got into my program! Thank you Professor Poliakoff and Brady for being such inspirations in my life!
@bigboam
11 жыл бұрын
This is probably the best explanation of the concept of boiling I've ever seen. Cool story about the car, btw.
@EtzEchad
4 жыл бұрын
Professor: pointing out all the flaws in Brady's experiment was super-critical of you.
@12345JJBB
9 жыл бұрын
this dude is epic
@stealth557
10 жыл бұрын
he got a haircut!
@emberfalcon
11 жыл бұрын
i love watching these videos even if i already understand the topic. You guys just make it interesting.
@pierreder1368
11 жыл бұрын
i SOOOO wanna go to that school, just because of him. the professor is AWESOME! he actually makes chemistry so much more interesting and fun.
@MichaelZola
11 жыл бұрын
amazing footage of Brady at Everest.
@taofledermaus
10 жыл бұрын
Super critical is also called "super heated".
@SEThatered
11 жыл бұрын
The Professor is such a nice and engaging person I swear I could listen and easily learn whatever he would teach.
@ajmann1187
11 жыл бұрын
This guy is awesome! I'm addicted to his videos now and will probably watch them all.
@Kitt797
11 жыл бұрын
Thank you for making your videos, they teach me so much and i really enjoy them. Keep doing what you do!
@boonanaman2739
10 жыл бұрын
omg science is a real man
@error.418
11 жыл бұрын
If you read the video description (still don't understand why people don't do this as a first reaction to having a question, just /before/ commenting), you'll see that it says "From the School of Chemistry at The University of Nottingham" and includes a link to the department.
@tommarshallnikon
11 жыл бұрын
I always took science class in school even when it wasn't compulsory and i failed yr 12 science miserably (i was horrible at math) but i loved learning and knowing the concepts and the physics behind what happens on earth. Great video and keep it up!!!
@Judahmangi
11 жыл бұрын
Thank you for explaining this! My chemistry teacher never explained it very well.
@huyked
11 жыл бұрын
Wow, I learned something awesome today.
@jjhamblett
11 жыл бұрын
The properties of water never cease to amaze me.
@StephenMortimer
11 жыл бұрын
"Brady bashing" by "el proffo" GREAT STUFF!
@GlanderBrondurg
11 жыл бұрын
If you get below the triple point of pressure with some liquids (water in particular), you will find ice sublimating directly to water vapor without going through a liquid phase. Admittedly if the substance is already a liquid it will immediately boil in a vacuum as well, so you are somewhat correct. It is just that such liquids need to form in higher pressure locations in the first place.
@jackster330
9 жыл бұрын
This guy looks like science.
@stevesnowcrash7308
11 жыл бұрын
Yes, the plate is a unique number registered to that car. Not the owner. It is possible to transfer the plate to another car but only if the plate is the same year or older than the car you want to transfer it to.
@AdrenalineVideos1337
11 жыл бұрын
Awesome video! Even on topics that I think I completely understand, these videos always make me see it in a new way, and usually learn something
@boldger13
11 жыл бұрын
I'd LOVE to hear more about your water research as I am an Environmental Engineering student. Thank you.
@DaKineDel
11 жыл бұрын
Isn't anyone else curious about what the correct boiling point is for each of the altitudes in the first video and what it would be a the top of Everest (~8848). I believe it should be possible to calculate it at standard pressure for a given altitude. One of the things that Prof didn't mention is that air pressure varies at any given altitude depending on depth of the air mass above that spot. It varies as a function of air movements and air temperature.
@nickrich56
11 жыл бұрын
... Martyn was as patient as a saint explaining the most basic experiment ... boiling water ... No suprise the signature tie was black and diffused ... 372 C is acceptable Proffesor ... too hot for tea ... well done all ...
@DayaCIDfan
11 жыл бұрын
dear prof. poliakoff, you are awesome.. the best videos on youtube.. I love the way you explain things. Thank you great sir.
@JamageControl
11 жыл бұрын
Chiara's correct for a pure water system. Look up "water phase diagram" and you'll be able to understand better what she has said. As the professor said however, this water is possibly (probably in my opinion) impure.
@oBseSsIoNPC
11 жыл бұрын
ERGO. Just because water is boiling, DOES NOT MEAN it is hot. It only means the water molecules have enough energy to leave the water body into the "atmosphere". So to be scientifically correct, when someone asks you: "Why (when) does water boil?" You would have to answer, see above. Love it
@bingebammer9927
11 жыл бұрын
holy crap i learned something! 374, must remember
@RBuckminsterFuller
11 жыл бұрын
At first I thought your question was crazy, but then I got to thinking and now I'm really curious!
@timothypoole5718
11 жыл бұрын
Fascinating. I've been a submarine cook for the last 12 years and I have noticed that water takes longer to boil the deeper we go. We also operate with a slight pressure on the ship. Would that also contribute to water taking longer to boil?
@TheWordofJudas
11 жыл бұрын
They spoke of boiling water and pressure, but never mentioned latent heat of vaporization. With the changes in elevation and air pressure I think this would have been a good experiment to display this concept.
@TazPessle
11 жыл бұрын
1:33. Suddenly, and simply because its Poliakoff, I got excited about a glass of water.
@carbonz1995
11 жыл бұрын
Such a nice bloke. Thanks
@tenyobe
11 жыл бұрын
Great explanation, thanks. I'll use this video for my students for sure :)
@Direkin
11 жыл бұрын
It's very nice of Poliakoff to explain GCSE level physics. And yes, stream water will contain minerals, amongst other things, slightly reducing the freezing point of water.
@ZeZapatiste
11 жыл бұрын
Talking about thermodynamics in a cool way. That is rare ! Would have been super nice if you talked about the Triple point though
@tonberrytoby
11 жыл бұрын
What interests me in this context, is how much the pressure changes the other phase transitions. And how much difference is there from water to other fluids. I always hear that water is pretty unique in many ways.
@jdgrahamo
11 жыл бұрын
I'm not sure what your question is; but a pot 'with a lid on' is a pressure cooker.
@specialk22tt
11 жыл бұрын
Where you can enjoy your tea for 10 seconds before it becomes iced green tea. ;)
@IhabSinno
11 жыл бұрын
Hi, I have got an idea about a new chemistry series for you: can you do a weekly episode where you chronologically mention the highlights of each decade (starting at some arbitrary point, and highlighting one decade per episode). Thus, It will be a series about the history of chemistry, and how things got to where they are today. Thank you!
@Boredclub2ndgen
11 жыл бұрын
Only the professor can make boiling water interesting
@Slithy
11 жыл бұрын
I always thought it will solidify, or freeze, if you want. It's metal after all, and normal state for metals is solid. I mean, the melting poing of mercury is quite close to water (-38 deg. C), but the boiling point is much, much higher (357 deg. C). And it's very dense, so the gas that forms inside can't go out as easily as water vapor. That's why i'm interested in it - both versions are plausible, but only one can be true.
@42x42x42x42
11 жыл бұрын
Thank you! I didn't understood that all the molecules don't have the same energy. But if I understand well, the boiling point is just the temperature when half of the molecules have enough energy to become gazeous? It seems a much more precise way to define the boiling point. (Sorr for my english...i'm french)
@theProcratinator
11 жыл бұрын
it's always relieving to hear someone say "gaseous water" or "water vapor" instead on "steam" when referring to boiling water. steam would burn someone's hand terribly if they put it over steam, but when you boil water you can put your hand over the vapor and be fine. steam is not the same as vapor.
@TommyLau
11 жыл бұрын
You may think that water in the solid and liquid phase doesn't sublimate or evaporate, but have you ever spilled some water and wiped it? Leaving that tiny trace that even though at room temperature: evaporates. The average kinetic energy (definition of temperature) of the solid water (system) in frozen food may by 0 degrees Celsius, but a tiny little fraction of water molecules may have such great kinetic energy that they enter the liquid or even gas phase, and therefore sublimating.
@error.418
11 жыл бұрын
I got super excited to see supercritical fluids when he mentioned the concept in the video. A quick search on KZitem of course landed me right back at the professor showing off a supercritical fluid demo rig he has in his office. You really should link to that video. I can't believe you made it back in 2008 and here we are looping back to the subject. It's here, by the way: /watch?v=yBRdBrnIlTQ
@Der_Arathok
11 жыл бұрын
But you also have to say that the PTC/NTC Sam is using is also not exact to the point, because every measuring instrument has a bit of failures. I also need a little help on the freezing temperature here, Because i also have seen water not frozen at -4 degrees at our place (but i have to say it was no constant cold of many days just 2 hours) and also you can see the water in the lake is rather sludgy than fluid ( i mean about to freeze) soo... please don't be too harsh :) Nice video as always!
@smeagol1414
11 жыл бұрын
at around 2:13 he says that in an enclosed space there is an equilibrium between gaseous and liquid water, and that causes a pressure ( called vapor pressure), but later on the he says that when the vapor pressure is equal to the ambient pressure it boils. How can that be if the space is enclosed? Does he mean that the water is encapsulated by the air?
@kurtilein3
11 жыл бұрын
yes, it would be quite explosive. Maybe some liquid water will remain because evaporation cooling cools down a small amount quickly enough, but most of it would blow explosively. So far above boiling point, you can just consider water to be a gas, it would be similar to instant decompression of any pressurized gas container.
@Renaustus1
11 жыл бұрын
Dear Brady, Professor Poliakoff said that the pressure on top of the mountain is less than on sea-level and you proofed that with boiling water. my question is, how does the low-pressure envirnoment affect the solid water on top of the mountains, also shown on your Video footage. is there a simmilar abnormality in melting or something compareable like the boiling water? Thanks
@rituparno100
11 жыл бұрын
gibbs free energy will tell us the value of the equillibrium point at which the two phases can exist or above or below the temparature that one will be stable,it does not come in handy when we want to measure the conversion points at various pressures and temparatures..that is why Dr.Gibbs himself made the Phase rule(F=C-P+2) and perferctly described phase transitions..at normal single temparature cases though you are correct :D
@charlessantosti
11 жыл бұрын
I missed the videos! glad they are back (:
@3metrictensor
11 жыл бұрын
I think I learned something new. At about 3:16 in, is the professor saying that a big component of the heat of vaporization is due to work being done against the atmosphere? I had assumed that it was an entropy thing like the heat of fusion or am I reading too much into it. Thanks
@RockClimberAlex
11 жыл бұрын
Should the professor really give out his license plate like candy? That's a nono in my book.
@ChiaraWatson
11 жыл бұрын
No, the freezing point will go higher to the triple point at 0.01 C and below the pressure for that it would be eventually gas not liquid at -4C since below the triple point liquid is impossible. But the triple point is only 10 millibars are 1% of an atmosphere which would be impossible on that mountain top because as you could clearly see the guys up there didn't die!
@TheNerdReport
11 жыл бұрын
You should make a video about water's Critical Point. That sounds very fascinating!
@sarowie
11 жыл бұрын
Martyn at his best: Exited about a number plate :-) I guess, when this car vanish, he will put the licences plate into his office.
@Timothy656
11 жыл бұрын
Love periodicvideos! Currently studying HND in Chemistry :)
@AngerAndScience
11 жыл бұрын
Air pressure does not change how much we weigh. There is pressure from air pushing down on us, but there is also air pressure pushing up one us, so they cancel each other. We will weigh slightly less, just because we are farther from the centre of the earth, but the effect is negligible because the earth is so large that the change in distance from the centre is also negligible.
@thedarkcreator252
11 жыл бұрын
you should do some a video on other interesting things about supercritical fluids and their properties etc
@ragnkja
11 жыл бұрын
A cheerful kettle? Yes indeed! It's sometimes rather bubbly, even.
@Danielgoerz
11 жыл бұрын
Do a video about the phase change from ice to gas. Most people do not understand the science behind phase change. i.e. It takes twice as much energy to melt a kilo of ice as it does to bring that kilo of water from 0 centigrade to 100 centigrade.
@lopdebif
11 жыл бұрын
The extra footage of this is set to private!
@flyod26
11 жыл бұрын
Funny how a man so scientific is still superstitious. With an apparent life time a critical, logical and analytical thinking, he's still human. I'm not criticizing him, I think the professor is great, just pointing out my observation.
@tehggboss
11 жыл бұрын
Water at -4ºC is less dense than water at 0ºC. That might be the reason why the thermometer read -4ºC, since the frozen layer floated upwards.
@ijunkie
11 жыл бұрын
Oh man Brady. You got ground up. Better get back there and do it again :)
@benmcreynolds8581
Жыл бұрын
It really makes me wonder about all the different variables and states of water you could have when you alter the pressure/ the temperature 🌡️ Then add the situations around other planets or moon's that contain icy worlds but with a liquid ocean layer to them. Same goes for places like titan and places with other liquids. The more I think about it, It's pretty crazy how many variations could be possible with any liquid compared to its pressure and vapor point temp/ freezing temp.
@asergb
11 жыл бұрын
Your TAs are right. But it's not always gonna decrease boiling point, as far as I know. Sometimes, BP would even increase.
@RoyCostasimgeek
11 жыл бұрын
Depends ... if u could boil a spherical blob of water, i assume the the ISS's internal pressure is slightly differnet than at sea level, so it would be slightly different
@Hobypyrocom
11 жыл бұрын
thanks allot your comment really helped me to answer my question. thanks again and best wishes.
@johnchj
11 жыл бұрын
Would very much like to attend his lectures.
@Slithy
11 жыл бұрын
Well, i have no idea. That's why i've asked :D But still, you can't operate just pressure and temperature, it seems to me that other things matter too. Like density, volume and initial temperature of mercury before it was put in space. If you look only at temperature and pressure - any substance should sublimate right away, but it doesn't happen. And i'm not good enough with physics to find the approach to this problem.
@SinfulSavant
11 жыл бұрын
Prof. Poliakoff should be a guest star on the tv show Dr. Who, or even better play Dr. Who himself !!!!
@Nerdiator
11 жыл бұрын
You deserve more thumbs up
@CarlosWever
11 жыл бұрын
A question for the professor; This has be hunting me for a while. Why does hot (90*C) water freeze 'faster' than RT temperature water? And if so, does the crystal of the ice difference between them?
@JamageControl
11 жыл бұрын
Hmmm you must be misinterpreting the diagram. Freezing point starts at 0C, 1 Atm yeah? Then take the Freezing point at 0.01C (0.006 Atm). The freezing point is only increasing along that line. At no point can the freezing temp drop below 0C until you get below 0.006 Atm, well below any pressure experienced on a mountain. All good?
@llgla
11 жыл бұрын
Hey Prof, I am not sure how car license plates work in the UK. Is there a way to keep the number, say by buying it? Nonetheless I would suggest that u get a new car. Cars that are too old post a danger to the driver.
@diegonayalazo
4 жыл бұрын
Thanks
@alsifjlasieflooo
11 жыл бұрын
I really enjoy these videos!
@FallenB1ade
11 жыл бұрын
Water is strange. Water expands as it's temperature decreases from ~4 degrees C to ~0 degrees C (at STP). It also expands as it's temperature increases from ~4 degrees C to 374 degrees C.
@VictorVonFox
11 жыл бұрын
deep space has almost zero pressure so there is no way to have liquid water in "deep space". but in a shuttle there's air pressure inside so liquids are capable.
@Der_Arathok
11 жыл бұрын
Sorry for the possible bad english btw let me make sure i don't want to be overly protective or mocking somebody (if it sounds like this) I am doing chemistry projects too at a local shool and the worst part of the protol is always the failure evaluation at the end, where you have to find possible failures in the process of the experiment and you have to be really critical about yourself. Sorry for textboming!
@Mmierks
11 жыл бұрын
That explains a lot about pressurized water reactor temperatures.
@sutematsu
11 жыл бұрын
74C? Perfect for green tea! Apparently if I want a "no muss, no fuss" way to make green tea, I need to hike up Everest. :p
@Bacopa68
11 жыл бұрын
A steam engine works by harvesting energy from the pressure difference between the steam and the atmosphere (or a condenser if it's closed cycle). Trying to boil more water by lowering the pressure would just give you less pressure difference to do work.
@tonyotag
11 жыл бұрын
New experiment, put water inside, then extract some of the water to see how pure the water is. (deionized water in...maybe deionized water out) Would make a great chemistry vid.
@breaneainn
11 жыл бұрын
I work catering in the medical industry. You can kill bacteria a number of ways, not just with heat. They are fragile. You can change the pressure, the temperature, the Ph, the light or the medium and they don't cope. Some bacteria are stubborn and have a waxy shell and are called spore-formers. These ones are not so common but pose a risk because you can dry them, freeze them, hit them with radiation and they just go into hibernation until things improve, then they reanimate and start growing.
@TheScientist40
11 жыл бұрын
Yes. As the pressure of water goes up, its boiling point also increases. And Thanks for your service. That is, if your American.
@teavea10
11 жыл бұрын
Next I'd like to see a discussion on hot water freezing faster than cold water. Does that actually happen under the right conditions?
@ThePharphis
11 жыл бұрын
This guy keeps track.
@LateHarvester
11 жыл бұрын
To deep fry, you use oil heated to around 180 - 200"C. I would hypothesize that you could indeed deep fry a turkey, under high pressure at 374"C it would cook really really fast. The dangerous thing would be removing the lid on the pressure cooker. Would be a cool experiment.
@epicdude000
11 жыл бұрын
Is there any way we can get in touch with the professors? Like a Q and A of sorts?
@majorgoodapollo
11 жыл бұрын
Iv always heard that to make questionable looking water safe to drink you need to boil it to kill of any bacteria or microbes in it and at see level that would be around 100 c. but what about under the vacuum at 14 c. does that render the water "drinkable" or is it less a matter of boiling and more a matter of getting the water hot that kills the crud.
@KarlFFF
11 жыл бұрын
Generally yes. You might get the problem if you put the metal into a vacuum-chamber to lower the boiling point that it starts subliming instead (going directly from solid to gas, like dry ice does)
@MrC0MPUT3R
11 жыл бұрын
The professor has lost his winter coat in preparation for summer.
@Tomatohot
11 жыл бұрын
In industry there is usually a point where the financial balance is the best between lowering pressure and increasing temperature.
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