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>> THERE WERE MORE SURPRISES AHEAD.
IN THE 1930'S ANOTHER STRANGE PHENOMENON WAS OBSERVED
AT EVEN LOWER TEMPERATURES.
THIS RAPIDLY EVAPORATING LIQUID HELIUM COOLS UNTIL
AT TWO DEGREES ABOVE ABSOLUTE ZERO THE DRAMATIC
TRANSFORMATION TAKES PLACE.
>> SUDDENLY YOU SEE THAT THE BUBBLING STOPS AND AT
THE SURFACE OF THE LIQUID HELIUM IS COMPLETELY STILL.
THE TEMPERATURE IS ACTUALLY BEING LOWERED EVEN FURTHER NOW
BUT NOTHING IN PARTICULAR IS HAPPENING.
WELL THIS IS REALLY ONE OF THE GREAT PHENOMENON IN
20TH CENTURY PHYSICS.
>> THE LIQUID HELIUM HAD TURNED INTO A SUPER FLUID
WHICH DISPLAYS SOME REALLY ODD PROPERTIES.
>> HERE I HAVE A BEAKER WITH AN UNGLAZED CERAMIC BOTTOM OF
ULTRA FINE VERACITY.
>> ORDINARILY THIS CONTAINER, WITH TINY PORES COULD HOLD
LIQUID HELIUM, BUT THE MOMENT THE HELIUM TURNS SUPER FLUID
IT LEAKS THROUGH.
>> WE CALL THIS KIND OF FLOW A SUPER FLOW.
>> SUPER FLUID HELIUM CAN DO THINGS WE MIGHT HAVE BELIEVED
IMPOSSIBLE.
IT APPEARS TO DEFY GRAVITY.
A THIN FILM CAN CLIMB WALLS AND ESCAPE ITS CONTAINER.
THIS IS BECAUSE A SUPER FLUID HAS ZERO VISCOSITY.
IT CAN EVEN PRODUCE A FRICTIONLESS FOUNTAIN,
ONE THAT NEVER STOPS FLOWING.
SUPER FLUIDITY AND SUPER CONDUCTIVITY WERE
BAFFLING CONCEPTS FOR SCIENTISTS.
NEW RADICAL THEORIES WERE NEEDED TO EXPLAIN THEM.