What Happens When a Liquid Turns Supercritical?

I show you what a supercritical fluid looks like during phase transition.

[TheActionLab]

I want to address a concern that people are mentioning about vapor pressure. When you put a liquid in a container that is bigger than the volume of the liquid, some of the liquid will form a vapor until the container reaches the vapor pressure of that liquid at that temperature. If it is a pure liquid (no air in the container) and all of the liquid doesn't evaporate, then the total pressure will be somewhere along the liquid/vapor line on the phase diagram. But, if there is air in the container, then the liquid will form a vapor and increase the pressure until the partial pressure of the vapor reaches the the point on the liquid/vapor line in the phase diagram. The point is that if you have a *pure* substance and you tell me the temperature and pressure of the container it is in, then I can tell you if it is a liquid, solid, vapor or gas. (Also note that if the temperature and pressure are on the solid/liquid/gas equilibrium lines on the phase diagram, then I can't tell you how much solid/liquid/gas you have unless you tell me how much energy you have input into the system and how much liquid you started with etc.)

[AlexDeGruven]

The supercritical transition is still one of the coolest (heh) things I've ever seen. I've watched a lot of people using supercritical CO2 to make aerogel, and watching the meniscus just gradually disappear still blows my mind.

[adamplace]

This channel has some of the most intuitive explanations (and demonstrations) of scientific concepts anywhere. I've said it before but for almost every video there's an "Oh! THAT'S how that works!" moment for me.

[synthesizer]

This is so cool, as a refrigeration tech I too have been curious of the phase change of supercritical fluids. Our entire industry is largely based supercritical and subcooled fluids to transfer heat and rely on pressure changes to affect said state.

[X-Gen-]

I mean it when I say your videos are very hard to pass on. Every one I see available hooks me and reels me in like a fish lol. Arguably some of the most enlightening and entertaining content on Youtube or anywhere else for that matter. You're a gifted teacher and I've learned a lot without having to try!

[DanPx]

This was a question I had in my mind for a long time but never got to search for an answer. This explanation is much more interesting than I expected!

[mcmaschio]

I learn so much from this channel .. not only in terms of science but content creation as well .. so simple yet so baluable … amazing 🔥💯

[davidannett]

dude, your channel rocks. I;ve been repeatedly impressed with how you can tackle a highly complex topic with seemingly simple demonstrations. I've forwarded many videos to friends with "see, this is why this happens or works this way, etc"!

[ZENMASTERME]

You always bring us the most epic thought-provoking videos I have ever seen on YouTube!

I tip my hat to you Mr. Action Lab 🎩

[krissche]

I super appreciate your work and this channel. It often sorts out concept for me that have been rattling around in the back of my head for ages.

[chaddumas]

Hi, James. This was awesome. I absolutely love studying supercritical fluids, and sublimation of solids to vapor. You have really come a long way with this channel. Good work.

[jeanbonnefoy]

Probably the best (and simplest) way to explain the difference between vapour and gas.👍

[martindelafuente]

I’m guessing it grows a hair and beard, puts on a white tshirt, and gets a deeper voice along with a vernacular full of obscenities.

[christopherdelaney]

Everytime!!! Always so impressive! And thank you for saying the difference between gas and vapor. You ended a very long (friendly) debate between myself and one of my classmates from decades ago! I was so happy to send him this! And always such a pleasure to see your excitement about teaching... Absolutely contagious!
Keep it up friend!
I'll be sure to check out whatever you've got up your sleeve for the next video!
Yeah science!

[yiravarga]

This clarifies so much physics, I had no idea. Your videos always bring something new! I’m 29, and really interested in science, and yet, you never fail to drop new knowledge with every video!

[mikedejesus]

Fun fact: Xenon gas is used in headlight bulbs called "High intensity discharge bulbs" or HID. Electricity is used to ignite the gas and keep it at a stable temperature. The temperature of the gas once ignited determines the color of the light being projected. You can have anything from amber (lower temps), to bright white (slightly higher), to blue (slightly higher), and more.

[Widazer]

Simply explained but still professionally. That’s why I love this dude

[DANGJOS]

The cool thing is that as the supercritical fluid forms, the gas above and liquid below approach having the exact same refractive index, which is why the division between then becomes more and more difficult to discern.

[Christodoulosts]

I find you channel extremely fascinating!!! Even though sometimes I don’t understand anything, I think that makes it even more interesting in some strange way

[nishitmohan]

Great (and simple sounding) explanation for a very complicated process! Also love the visual demonstration with xenon gas! Great video, as always!