Superfluid Fountain

© Peter Taborek, Low Temperature Materials Laboratory, University of California, Irvine.

Superfluid liquid 4He can flow out of uncapped containers. As this flow is without friction, and as liquid helium is not very dense, it can even appear to defy the law of gravity and flow up and out of a container, sometimes in the spectacular manner illustrated here. Although the liquid flows uphill, energy is not created, as the liquid ends up outside the container (on the floor), with a lower gravitational potential energy.