Data: 26 February 2013
Place: Bar la Plaça, Celra, Spain
Helium is a colourless, odourless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table. Helium is named after the Greek God of the Sun, Helios. It was first detected as an unknown yellow spectral line signature in sunlight during a solar eclipse in 1868 by French astronomer Jules Janssen. When helium is cooled to absolute zero (- 273ºC) it becomes Helium II, a superfluid, a quantum mechanical state of matter with very strange properties. One of these properties is the creeping effect. When a surface extends past the level of helium II in any container, it can creep up along that surface, against the force of gravity. As a result of this ability to leak through any tiny openings, however small, it is very difficult to confine Helium II. Unless a container is carefully constructed, the helium II will creep along the surfaces and through valves until it reaches somewhere warmer, where it will evaporate.