Heike Kamerlingh Onnes first created this substance, which may be described by the two-fluid model.
The cyclic isomer of the water hexamer clusters was first observed experimentally using this material as a growth medium. Jack Allen observed a thermomechanical "fountain effect" that this substance exhibits when it is heated. This substance is contained in the innermost dewar of an NMR instrument. Heike Kamerlingh Onnes first created this substance, which may be described by the two-fluid model. This substance undergoes Bose-Einstein condensation at 2.17 degrees Kelvin, or the lambda point, where it attains zero viscosity and becomes a superfluid. For 10 points, name this fluid phase of the first noble gas.
The cyclic isomer of the water hexamer clusters was first observed experimentally using this material as a growth medium.
liquid helium [prompt on helium, or helium-3, or helium-4, or superfluid]