section_path: Superfluids and condensates/Superfluid
section_name: Superfluid
paragraph_text: Superfluid
  
  Close to absolute zero, some liquids form a second liquid state described as superfluid because it has zero viscosity (or infinite fluidity; i.e., flowing without friction). This was discovered in 1937 for helium, which forms a superfluid below the lambda temperature of 2.17 K (−270.98 °C; −455.76 °F). In this state it will attempt to "climb" out of its container. It also has infinite thermal conductivity so that no temperature gradient can form in a superfluid. Placing a superfluid in a spinning container will result in quantized vortices.
  
  These properties are explained by the theory that the common isotope helium-4 forms a Bose–Einstein condensate (see next section) in the superfluid state. More recently, fermionic condensate superfluids have been formed at even lower temperatures by the rare isotope helium-3 and by lithium-6.