Superfluid helium
Why Physics Stack Exchange recommends it
Physics Stack Exchange users link it as a visual reference for superfluid helium behaviour such as film creep, leaking through pores and the boiling that stops at the lambda point.
Recommended by 2 people across 2 different months, 2013 to 2021.
What it is
A short 1m45s film showing liquid helium cooled below the lambda point and turning superfluid. It shows the boiling that stops at the transition and the Rollin film climbing container walls and dripping out the bottom. It is vintage footage uploaded by the ryanhaart channel, with a longer Alfred Leitner lecture video linked in the description.
Cited in 1 Wikipedia article, including Superfluid helium-4.
What people said
Recommends Siva · 2013-03 · Physics Stack Exchange · on “The bizarre behaviour of superfluids! Climbing up walls and geting out of glass beakers”
When the superfluid helium leaks out of the container, that's not tunnelling . A few drops of superfluid helium contain many many atoms and for all of them to tunnel through would be extremely improbably as to pretty much not happen. So what makes the helium flow out? If you notice carefully, the container is not a normal glass mug, but it's bottom is made of some other material (I think it's some kind of ceramic with tiny pores). As the scientist in the video says, the only reason "normal" liquid helium (above the critical temperature) did not flow out through those pores, was that viscous drag kept it from dripping out. After the phase transition to a superfluid, the *super*fluid doesn't h
Recommends user108787 · 2016-11 · Physics Stack Exchange · on “What is the quantum phenomenon called where a very cool liquid glides over a container to a lesser potential energy?”
I hope this is what you mean. I write this summary of the article, just to learn more about the fascinating phenomenon, of which I had baically no knowledge of previously. Thank you to @knzhou for saving me time finding it Read more about it here Helium Superfluid [LINK] Superfluid helium-4 is the superfluid form of helium-4, an isotope of the element helium. A superfluid is a state of matter in which the matter behaves like a fluid with zero viscosity. The substance, which looks like a normal liquid, flows without friction past any surface, which allows it to continue to circulate over obstructions and through pores in containers which hold it, subject only to its own inertia. [LINK] Helium
Cites roblev · 2020-01 · Physics Stack Exchange · on “Can the Superfluid Rollin effect be used as a perpetual motion machine to extract energy from?”
Superfluids such as liquid helium cooled below the lambda point exhibit the Rollin effect where a thin film climbs the walls of the vessel. This still and video from the 1950s shows the effect, where drips of liquid helium form below a cup of liquid helium. [LINK] Superfluid helium video - 1 min 11 seconds for the rollin effect section [this video] If the superfluid climbs the walls of a vessel, then logically it should climb the walls of any structure placed in a pool of superfluid. So if I placed a tower with a shape similar to this (rough) diagram: [LINK] Then the superfluid (shown in orange) should flow up the walls of the tower and collect under the end bowl section of the tower, and form dr
Cites Solidification · 2021-11 · Physics Stack Exchange · on “Why liquid helium boils as its temperature is lowered?”
Water boils when heated. Liquid helium boils [this video] when cooled. Not only that. It boils initially and then stops. Why?