Supercritical fluids
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- Опубліковано 27 кві 2008
- Is it a liquid? Is it a gas? Professor Martyn Poliakoff demonstrates supercritical fluids in his office at the University of Nottingham. More with Professor Poliakoff at www.test-tube.org.uk/
- Наука та технологія
I would love to see a new upload of this with better quality, or a new periodic video with the prof and his apparatus.
agreed
Better quality 8 years ago is bad quality rn lol.
Little did the Professor know that after this video, he would now be on the path to worldwide fame and a knighthood!
Would really love to see a much more clearer version of this process
I first saw this demonstrated by my physics teacher at the University of Aalborg, Denmark in 1983 and I haven't seen it since - until now. Thank you for sharing. I remember how I was amazed and touched by the beauty of this tiny experiment. We didn't have cameras back, but some lenses and a light source prjected the image on a big screen, It was very fascinating to see these phaseshifts.
There are so many discussions about the toxicity of CO2 that people are forgetting the actual application of CO2 as a solvent. After it is used and the temperature and pressure return to normal the CO2 reverts to a gaseous state and leaves the material. That is why it would be totally non-toxic for use in the production of medicine for example.
It is used extensively in the extraction process involving marijuana b.
And even if traces were left behind, it still wouldn't do anything to you
@@DANGJOS Exactly, there would only be traces. It takes a large amount of CO2 to cause a human being any problems.
CO2 is non-toxic,although it traps heat
Drinks with bubble are full of co2, co2 is in the air too. It's not toxic
Hi Sir Martyn,
Not forgetting you Brady, thank you for your work together, and the upload of this really interesting video, great stuff!
I realise this is just after you started your collaboration, for which I am so grateful, and is history now, but it is the first time I have seen this.
It would be cool to see an updated HD video revisiting this device, I would love to be able to see it clearer!
Science aside, that's the coolest interview/recruitment strategy I've heard in a long time. Why would you want someone who appears to have no real interest or passion for the subject and the job?
THIS IS FREAKING AWESOME.
awesome demonstration. thank you!
I'm just studying this right now and I find this video very educational, besides the teacher (I imagine he's got a PhD or many) explains himself in a very understandable way. Thanks a lot!
I'm fascinated! I wish I was over there to work with Professor Poliakoff. :(
i was never interested in chemestry (more biology) till i watched these videos. i find it so facinating
I suppose I should be working with the Professor - my immediate response was, "Wow! That is truly amazing!" lol More please.
this is absolutly FASCINATING!
I just learned about supercritical fluids today in chem class. But actually seeing how it looked is even more awesome!
i had an interview today at professor Poliakoffs office!
fortunately i allready knew this video ;) i totally freaked out when he showed me the machine
Saw it a week ago and it's beautiful !
Very interesting! I was studying isothermal curves of a real gas, but I didn't understand them very much. I couldn't imagine a supercritical fluid and on my book there was written that it's impossible to see it. Thanks to my favourite chemist!
That video is so cool thanks alot for this educational video.
I find this really fascinating aswell.
Fascinating!
I could probably watch that all day long.
This is an absolutely fascinating effect. It would be even more interesting if we tried this as a plasma in this kind of environment, it's stuff like this that makes me want to be a chemist O_o
This is actually a good representation of the ocean of chaos in the mythic traditions of most world cultures:
There was first the Chaos of the Void and it was later seperated in two, to form the tranquility of the Seas and peace of the Sky
Supercritical fluids are awesome. Nice demonstration!
Very interesting demonstration, i like it
Oh man that blew my mind! 👍🏼👍🏼
I said wow when I saw that... in fact, I wanted to be there and ask some questions about it. I am more of a physicist but this just looks so cool!
thank you so much
@starked1 Oh, and the Apollo Lunar Module stored supercritical helium in its descent stage to pressurize its propellants.
In the Service Module the supercritical O2 and H2 could become non-uniform or "stratified" in zero gravity so fans were added to stir them occasionally for more accurate quantity readings. On one flight, damaged electrical insulation on the fan in one O2 tank caught fire, resulting in the Apollo 13 emergency.
@starked1 Supercritical fluids are already used in some spacecraft. The Apollo Service Module stored hydrogen and oxygen for its fuel cells in supercritical form. The tanks held much more than they could with compressed gases at room temperature but took less heat to vaporize than LH2 or LOX.
It would be neat to see the same thing, only with one of the windows at an angle, so you see the spectrum from refraction.
Can we do an updated video on this using a higher quality camera? :)
Does surface tension play a role in the "storm"? I did see more water stayed up on the sides of the container before "raining" down.
Very cool stuff!
the pressure and temperature go below the Tc and Pc. This causes the liquid droplets to condense because there energy is low and the gas to bubble out because the molecules making the gas have a higher energy. This make a phase boundary quite rapidly and produces the storm ( the separation of the supercritical fluid into liquid and gas phases)
Wow 🤩… it’s so amazing to watch this
its kind of cool how you can have the liquid and gaseous co2 under the same pressure... If I could ask, what is the pressure in the containing vessel professor..?
That was cool!
The significance is from 3:43 to the end. Since you can use the supercritical fluid as a solvent instead of an inorganic solvent, it would be useful in medicine where an inorganic solvent introduced into an organism might be harmful, for example.
awesome! i love him!
That's the same monitor I use :) Interesting effect too.
So awesome!
"just ignore the blurriness"
Kinda hard to do in a cropped 240p video.
What has amazed me ever since I first saw it is the water droplets that fall out of the air when an airplane breaks the sound barrier. It goes from air to water INSTANTLY. Its like alchemy or something.
Martyn is my scientific idol.
Nice to meet you, Timmy McMouthfull.
@DubIDubblix Thank you so much for your explanation!
Can you please now explain what surface tension is?
Why when surface tension present a liquid behaves the way it does and why when it is not present the liquid behaves differently?
"Seeing something happen" is a whole order of magnitude in difference to understanding and being able to explain why it happens!
Since you have mentioned solid-liquid phase equilibrium of water (you talked about ice), we
have to say that in this case we also observe
an interesting behavior. This interesting behavior is that the P-T solid-liquid coexistence curve has a negative slope (whereas in other fluids is positive) and this has to do with the fact that the density of ice is lower than this of liquid water. Due to this fact, increasing the pressure drives the water into the higher density phase, which causes melting.
would it be possible to colour the liquid to make the change visually clearer.?
@danx033 Supercritical fluids are basically one state f matter that doesn't know what to be because it's under alot of pressure so the molecules can spread out
Has this been done at the ISS/weightless environment?
I working on solubility of salts right now learning about Ks. So how would the Ks value change in supercritical solvents than in conventional solvents? If you could ask the professor.
i am interested how many chemicals have this been dun with and have u ever tried mixing chemicals this way
what is the maximum p.s.i. in this demonstration? as well as the temperature in of the vessel Celsius?
Can lower temperature supercritical fluids be used as lubricants, or as a suspension matrix for industries ? It would appear that they have a greater measure of "slipperiness"
has this experiment been done in Space (in a 0 gravity environment) already? or are there any predictions on how the condensation process will occur?
i mean in the video you can see how the supercritical fluid liquidizes again at the bottom of the container, which one could expect in a gravitational environment. i would be interested, whether it will form one big sphere or many tiny ones, or just randomly/chaotically condensate in a 0g environment...I am not quite sure if you understand what i mean..
I think when cooling, water should form a big drop (after some time) with gas around it.
Well, supposedly, the process of separation would instead show the liquid material not actually falling, but rather gathering from individual particles, into droplets, into tiny balls, and then, in a perfect environment, a single unified sphere of the liquid surrounded by the gas.
In freefall I bet the water would stick to the wall of the container cuzza adhesion, and the vapor would be the the ball in the center.
@threejchapman
The maximum pressure in this experiment is not higher than 75bar.
I have build such an apparatus and it gets supercritical at 31°C.
Can I use liquid butane or methane?
Does this apply to the weather? The reason why there are storms.
@DubIDubblix You said - "The surface tension disappears. I have no degree and was able to grasp it." - I just skimmed through the wiki on surface tension and am most impressed that you understand this area given the molecular and mathematical complexity of surface tension. It does not answer how when surface tension disappears that a liquid will flow up vertically though.I don't think you understand the slightest thing about this area which is why you have fobbed me off with visiting the wiki
There are so many discussions about the toxicity of CO2 that people are forgetting the actual application of CO2 as a solvent. After it is used and the temperature and pressure return to normal the CO2 reverts to a gaseous state and leaves the material. That is why it would be totally non-toxic for use in the production of medicine for example.
copy pasted for reference
@Defonthana Yes, providing it is stable and does not decompose at the critical temperature and pressure, every substance can be made supercritical. For instance, some of the very efficient power generation plants use supercritical steam.
Professor Poliakoff - I think this would be an amazing apparatus to put on the ISS! What would be your thoughts of what might happen when the material is alternately heated and cooled without the effects of gravity?
Wow, very neat.
Any followup to this? Applications of this effect, such as CO2 as a solvent?
@jagara1 The surface tension disappears. I have no degree and was able to grasp it. You can see it happen.
@wannabeers oh right i think he mentioned its SF6 at some point so yah the pressure would be decently low
If you put a tiny sealed drum inside and was spun like a car tire and it had
a small hole one side and a axle on the other to spin it. Would a phase bounder form
from hole to the spinning inside tangent edge be formed?
A gas to super critical from the centrifugal force.
The inside would have fin to help the gas get moving.
what if you have a supercritical fluid container, but force more water/steam into it? until it reach a denity above that of the original water. can it be considerd a fluid again?
thats so awesome :D
what are the pressures this is happening at?
Whats the difference between a super critical fluid and plasma. My chem teacher never taught me?
There are a ton of other applications as well. Like I just mentioned in my mast post, you can run wastewater through a supercritical fluid to destroy the bad things and get clean water. Supercritical water forms an extremely, extremely harsh environment.
can you please upload a high quality version
so, I don't think that a video from 13 years ago would be any better than this
could you re-make this video in better quality? :)
my text says boiling cannot occur in a closed vessel. wouldn't this be considered a closed vessel since it is a closed cell? if so, then how is it boiling.. .?
Wow!
What's that 'storm' at 2:33? What is happening on a molecular scale?
@Ducky1138 You appear to be unclear on the definition of fluid. In common speach they are often used interchangably but there is technically a difference.
Simply put, a fluid can be any material which can flow, which includes gasses as well as liquids. The critical point is the point on a pressure/temperature graph at which the transition from two distinct phases (liquid and gas) to a single phase (as shown in the video) occurs. As this exists above that point it is called super-critical.
I wonder which demonstration he saw 20 years ago. I saw it done with CO2 in the British Science Museum in London about 10 years ago, and I was also fascinated. I think he uses SF6 here because CO2's critical temp is only 31.1C and can be reached on a warm day. SF6 has a critical temp of 45.5C, well above room temperature, so his demo is guaranteed to work even on a warm day.
I'd definitely go "Wow!"
Hahaha!
You're hired!
That was interesting.
Do they use this method in industrial processing of material at all?
Decaffeinated coffee, for one. All foodstuffs must use "food-grade" solvents, such as CO2, not toluene or chloroform.
These patent applications:
P.403320 - The method of disposal of mixtures and suspensions of the hydrated 27.03.2013
P.403322 - Disposal of mixtures, suspensions and solutions in the states of: sub-, and supercritical 27.03.2013
I would have expected this as part of a physics demonstration, we're seeing physical properties of phase-changes that are done and undone by physical means.. Was this experiment initially discovered performed by a physicist?
Why is it called a Super-critical Fluid, rather than a Super-dense Gas? Does the Super-critical Fluid have more properties related to fluids than gases? Is CO2 condensed to make this since at room temperature it's a gas already?
Carbon dioxide is totally non-poisonous. I love that line. I think he's one of the 16 Concerned Scientists.
Now, this is cool.
For a better look at exactly what happens in the cell, check out: DjkG7Pt5mgE
Marty, we gotta get back to the future!
i learned more from this video then a whole hour in school
c) treatment of a supercritical reactor tube without flow - to work periodical - the disposal of the body (cremation supercritical water), disposal of medical waste.
d) a dosing and bleed into the reactors.
Is this what led to the Periodic Table of Videos?
am i confusing super critical with super heated."a pressurized liquid will stay liquid past its point of boiling"?i herd of it in steam engine design on a wiki site or sumthin about injecting super critical water into an unpressurized cylinder it expands quickly becoming gas.you know the rest it was supposedly a better than conventional steam type engine power/weight ratio wise. kinda make sense but yours didnt stay water it deffinitly didnt look like i imagined it if it is even the same thing??
What was the previous comment?
I'm not interested in a degree, or a change of occupation, but I would seriously pay admission to come hang out with you guys while you work =).
P.403323 - The way of the pyrolysis 27.03.2013
P.403744 - Disposal Mobile mixtures, suspensions and solutions in the states of: sub-, and supercritical 29/04/2013
P.403784 - Mobile as periodic disposal of mixtures, suspensions and solutions, especially in the states of: sub-, sub-and supercritical 05/06/2013
P.403785 - Dosage and bleed flow, the pressure reactors 06/05/2013
I expect to have two numbers of applications.
In liquids you can have two immiscible phases. Can supercritical fluids do that? i.e. can you have a vessel with two supercritical fluids that separate out like oil and water, or do they always mix like gasses?
Absolutely. I am measuring VLE of ethers and CO2 and once supercritical conditions for CO2 are reached in the "gas phase", and equilibrium of liquid phase (Ether+CO2 dissolved) and a gas phase (supercritical CO2+Ether) is observed.
AGREE!
Which model of toaster was this recorded on?