supercritical fluids

liquid CO2 is heated in a pressure cell until it reaches the critical point were it changes into a supercritical fluid

[werrkowalski]

And its only 30 degrees, if my hand could somehow resist the high pressure i could dip it in this supercritical fluid, i wonder what would it feel like.

[joshuatidwell]

Just to think supercritical fluids are deep within Jupiter's atmosphere. Super interesting world.

[ChristmasEve]

This is so cool!! You actually see the point at which liquid CO2 can no longer be a liquid and see it happen before your eyes. But not like a liquid in a chamber whose pressure is decreased until it boils; then you just see it boiling away and maybe freezing. In this case, the critical temperature is reached and the temperature and pressure are still increasing. The liquid stops boiling because of the pressure and you kind of see it just reach the same density as the gas and it takes on an intermediate form right before your eyes!! I want a small chamber like that...one that's not going to explode and kill me.

[Troglodude]

Ah thank you. I’ve been trying to imagine what the in between layers of gas giants
could act like.
Because with all of the pressure from the gas above, and giant hydrogen oceans below i thought there couldn’t be a clear line between the two.
Though this probably isn’t exactly what it would look like without the same temperatures and density’s it gives me a vague sense of what it could be like.

[_Tzer]

I want to become an alien just so i could feel supercritical fluids

[kaityginter]

Great examples of Critical Opalescence as it goes supercritical! I wish I had found this video last fall.

[lorenwilson]

To actually pass through the critical point, the vapor-liquid mensicus needs to stay in the middle of the vessel (equal volumes of the liquid and gas) at the moment that the two phases merge. If the meniscus drops, you are evaporating all the liquid before you hit the critical point, and your density is a bit low. Conversely, if you start with too much material in the vessel, then the liquid level rises and you pass by the critical point in the compressed liquid side of the phase diagram. Agitating the fluid in the vessel by rocking it works very well to show that the densities of the two phases approach each other as the fluid approaches the critical point.

[cascadia]

Some of the best footage out there of this

[Flachzange]

Hi,
yes you can fill a container completely with liquid CO2, if the container is cooled during the filling process. If not the temperature will rise due to the Joules Thomsen effect.
The pressure would be (at 70F = 21°C) about 60 Bar.

[andrewferguson]

The turbidity is caused by small temperature differentials around the critical point where liquid is boiling then recondensing quickly. At equilibrium there would be no turbidity.

[guitartommo]

Hi Flachzange. I've been reading about producing methane directly from reaction of hydrogen with supercritical CO2. If the gas in your container were hydrogen and the hydrogen and CO2 were in the correct proportions could you create that reaction safely in your container? I think the temperature has to be raised above 300degrees centigrade and some form of catalyst may be needed. The aim behind that idea on a large/world scale is: if you can create methane (natural gas we use in the home) synthetically from hydrogen (electolysis of water) and CO2 (captured from industrial processes) additional carbon is not added to the atmosphere by the ongoing continuous burning of the fossil fuel for energy. The electricity for the electrolysis is coming from a renewable energy source, solar, wind or hydro.

[zoran]

this is what rocky core of uranus consists of! It has stone and ice, and its surrounded by layer of supercritical fluid. Who knows what swimming in those would feel like (if you have some special suit that would prevent you from getting crushed, that is :) )?

[DCUPtoejuice]

awesome.  i love seeing that transition with the raining CO2.

[Sara-L]

@mrjazzycharon2 Earth's atmospheric pressure is too low to support supercritical fluids at room temperature. For example, the supercritical point of water can be found in the deepest ocean trenches from undersea vents called 'smokers', at pressures that would crush any human being, at around 330C in temperature.

[CoolMusicsChannel]

That happens because with the temperature, the pressure rises. The liquid water lowers its density, the density of the gaseous water rises til the critical point where the density of both is the same.

[danz]

nice video of something I could not figure out!

[Shirolicious]

It looks alot like 'clouds' in the sky, very cool

[Pepsimaniaco]

the pressure it's kept constant at about 73 atm for CO2, the temperature in this case is increased to reach that supercritical point, google 'phase diagram for CO2' it will make more sense to look at the graph.

[pcorf]

2:30 looks amazing and rather scary. Imagine swimming in it!

[TheSequestrator]

one of techniques that I can propose - you my use high pressure pVT cell (or any container that can persist high pressures) - (1) - if you fill the cell with CO2 and have a second vent, air should go out of the cell (if the vent is at the top) because higher CO2 density. After that you have only CO2 in the cell.
if you can keep constant temperature, by increasing the pressure in the cell you can reach "vapor curve", i.e. dew point of CO2 (which at 70F is 58 bar).