From floating air balloons to making people talk like chipmunks, we are all aware of the interesting properties helium exhibit. But the lesser known properties that makes it even more interesting in the eyes of scientists and explorers like us, is its ability to exists in two states distinct liquid phases. Thats right!
When Helium is cooled below its boiling temperature of -452 degrees, it's viscosity becomes zero. As a result, it is able to escape through cracks, above surfaces of its containers. It also remains in the same position when the container is spun, like water in zero-gravity space. In essence, the interactive forces between particles become negligible. According to John Beamish, an experimental physicist at the University of Alberta in Edmonton, it never settles down and keeps , not even after millions of years.
But what's the reason behind this?
When normal liquids are cooled below their freezing point, the mutual attraction between particles become greater than the heat vibrations which are then reduced significantly. As a result, particles become closely packed solids. However, when it comes to helium, the situation is different. It's particles are so light, that despite a sufficient reduction in vibrational energy due to cooling, the mutual attraction isn't still enough to hold them together, making them what is termed as a "super-fluid".
