One useful model of these substances posited that they contain two components, one of which carries
 all the entropy; that model was posited by Tisza. One hallmark of these substances is the fact that a
 pressure gradient has no effect on their motion, and it is also impossible to maintain a thermal gradient
 across one of these substances. Substances with this property can produce Rollin films, and when
 temperature is applied on one side of a porus plug, these substances will product jets. Landau won the
 Nobel Prize for his work on these substances, which only exist below the lambda point. Common
 substances of this type include very cold helium-3 and helium-4, and they creep out of the sides of their
 containers. For 10 points, name the
One useful model of these substances posited that they contain two components, one of which carries
 all the entropy; that model was posited by Tisza. One hallmark of these substances is the fact that a
 pressure gradient has no effect on their motion, and it is also impossible to maintain a thermal gradient
 across one of these substances. Substances with this property can produce Rollin films, and when
 temperature is applied on one side of a porus plug, these substances will product jets. Landau won the
 Nobel Prize for his work on these substances, which only exist below the lambda point. Common
 substances of this type include very cold helium-3 and helium-4, and they creep out of the sides of their
 containers. For 10 points, name these substances with zero viscosity.
One useful model of these substances posited that they contain two components, one of which carries
 all the entropy; that model was posited by Tisza.
{superfluidity}