Supercritical Fluid and subzero

[rohanprabhu]

I saw a video on youtube or somewhere which showed that Helium somewhere around 4-5 degrees near Subzero, becomes a supercritical fluid i.e. it has 0 viscosity. And the video showed that the liquid was coming out of the glass by climbing up the walls.

I'm pretty surprised by this.. and some people said that this could be used to make perpetual motion machines, which, however I am totally against [I'd rather believe in a Flying Spaghetti Monster].

so, if the fluid is to climb by itself, it needs a force that counteracts gravity. And that force purely will act, as the glass or the container walls cease to apply any force on the fluid. As such, I think that the force is caused by inter-molecular repulsions.

However, if we build something like a perpetual motion machine [not exactly perpetual], and the fluid continuously flows up and down. Then owing to work done by inner charges, the energy of the fluid must decrease after successive flows.

In that case, the temperature of the fluid must decrease. If we continue to do it, maybe at a point, the temperature may near sub zero. We might be able to reach the lowest temperatures ever.

What are your views on this?

 

[olgranpappy]

I saw a video on youtube or somewhere which showed that Helium somewhere around 4-5 degrees near Subzero, becomes a supercritical fluid i.e. it has 0 viscosity. And the video showed that the liquid was coming out of the glass by climbing up the walls.

I'm pretty surprised by this.. and some people said that this could be used to make perpetual motion machines, which, however I am totally against

I am *for* them. Unfortunately, they can not exist.

[I'd rather believe in a Flying Spaghetti Monster].

so, if the fluid is to climb by itself, it needs a force that counteracts gravity.

No. A gas will also "climb out" of a container. There is no "extra" force causing this to happen. etc.

And that force purely will act, as the glass or the container walls cease to apply any force on the fluid. As such, I think that the force is caused by inter-molecular repulsions.

However, if we build something like a perpetual motion machine [not exactly perpetual], and the fluid continuously flows up and down. Then owing to work done by inner charges, the energy of the fluid must decrease after successive flows.

In that case, the temperature of the fluid must decrease. If we continue to do it, maybe at a point, the temperature may near sub zero. We might be able to reach the lowest temperatures ever.

What are your views on this?

 

[sir-pinski]

Thank you for sharing your thoughts on supercritical fluid and subzero temperatures. It is indeed fascinating to see how different substances behave under extreme conditions.

As you mentioned, supercritical fluids have unique properties such as zero viscosity, which makes them flow more easily than regular liquids. This can be advantageous in certain applications, but it is important to note that it is not a perpetual motion machine. The force that allows the fluid to climb up the walls is due to intermolecular repulsions, as you mentioned, and it requires energy to maintain this flow.

While it is possible to reach very low temperatures by continuously flowing the fluid, this would require a constant input of energy. And as you pointed out, the fluid's temperature would decrease with each cycle, eventually reaching subzero temperatures. However, it is unlikely that this method could be used to reach the lowest temperatures ever, as there are other more efficient and reliable methods for achieving extremely low temperatures.

Overall, the behavior of supercritical fluids and their potential applications are still being studied and researched. It is important to approach claims of perpetual motion machines with a critical and scientific mindset, as they often defy the laws of thermodynamics. Thank you for bringing up this interesting topic for discussion.