Can Supercritical Helium Create Perpetual Motion at Subzero Temperatures?

  • Context: Graduate 
  • Thread starter Thread starter rohanprabhu
  • Start date Start date
  • Tags Tags
    Fluid
Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
1 reply · 3K views
rohanprabhu
Messages
410
Reaction score
2
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?
 
Physics news on Phys.org
rohanprabhu said:
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?