Dr. Oluseyi first explained them to my Electronic Measurement Techniques class this past Spring in the following manner:
Imagine you have a bathtub full of water and you take a glass, open side up, and push it halfway into the tub. The water level will rise around the class displacing an amount equal to the volume of the glass inserted into the tub. Now imagine you have a bathtub full of a superfluid. You do the same thing and push a glass into it. The superfluid will crawl up the sides of the glass and fill it until the level of the liquid is the same inside and outside of the glass.
What?
Oh, but you're too blasé to be impressed by this. So second example also courtesy of Dr. O. Now imagine you still have your bathtub full of a superfluid. You take a glass full of the same superfluid and hold it suspended a foot above the bathtub. It will crawl up the edges of the cup and down the outside before dripping into the bathtub so that all of the super fluid is once again at the same level.
WHAT?!
This could have kept going all class but Dr. O decided to get back to the "lesson" and us curious scholars were left broiling with curiosity. A little wikipedia research and I came upon the following.
"Superfluidity is a phase of matter or description of heat capacity in which unusual effects are observed when liquids (typically of heliuMonetizem-4 or helium-3) overcome friction by surface interaction when at a stage (known as the "lambda point", which is temperature and pressure, for helium-4) at which the liquid's viscosity becomes zero."
Major Point to take away:
viscocity = zero
Viscosity is the measure of the resistance of a fluid which is being deformed by shear stress or tensile stress which I will leave Rafi to explain because he just loves correcting me when I try (your public awaits, Wonderful). In simplest terms water has a low viscocity and honey has a higher one. So since a superfluid has zero viscocity it has absolutely no resistance to flowing and can just go.
Feynman worked on it!
Specifically he helped develop some theories on the roton, which was posited as an elementary excitation or quasiparticle in superfluid Helium-4. I know that that probably doesn't help clarify things but in my defense this wiki article was preceded by a warning:
"This article may be too technical for most readers"
and a request:
"Please improve this article by making it accessible to non-experts"
So of course I decided as a third year physics major I was up to the challenge but may have entered the fray overconfident.
Regardless what I find fascinating about this is that we are all taught from elementary school or something that there are three phases of matter: solid, liquid, and gas. Then along the way someone throws out plasma as the fourth but never really explains it all that well except as what the core of the sun is At least that was the explanation I initially received. Then 90 percent or more go on to careers where they never even reconsider these bald statements but some go on to become chemists, physicists, engineers even and learn that this is just the beginning. There are Superfluids, supersolids,
Its as if you can pick absolutely anything you feel certain about in the sciences and with enough research you'll find you were staring at only one leaf of a tree. (the iceberg metaphor is really overdone). This is immensely satisfying and equivalently daunting.
