At temperatures just below the lambda point, the temperature at which normal fluid helium makes the transition to superfluid helium, the mixture is almost entirely normal. Helium 2 is depicted as a combination of two fluids: normal helium and superfluid helium. In order to explain its strange behaviour, scientists established the two-fluid model. Liquid helium, behaves like water boiling at lower temperatures if pressure is lower.īut there is also the curious case of Helium 2, an extremely unstable – and still very interesting – isotope. Both isotopes can be cooled to below their boiling temperatures by regulating pressure, reaching points below atmospheric pressure. Helium 3 (He3) is in fact the rarer isotope, and boils at 3.2 Kelvin, one degree less than Helium 4. Helium 4 makes up over 99% of the natural Helium, therefore this is the Helium we refer to when we do not specify the isotope. The main distinction is between the two naturally occurring isotopes, Helium 3 and Helium 4. Within the cryogenics scientific community, they distinguish the different kinds of helium. That being said, the unwanted substances that lie within liquid helium, or ‘impurities’, will be in a frozen, solid condition which makes it relatively simple to eliminate and get ‘optically clean’ liquid. Liquid helium is probably the coldest fluid that exists in nature. Liquid helium and nitrogen are usually stored in vacuum insulated flasks (we commonly know these containers as ‘thermos’), officially called ‘Dewars’, named after their inventor, Sir James Dewar.

The way to cool down objects is to submerge them in liquid helium or liquid nitrogen. Liquid helium, due to its extremely low boiling point, can be used in cryogenic systems when temperatures below the boiling point of nitrogen are required. Solid helium will form when pressures above 20 times atmospheric are provided. Liquid helium boils at approximately -268.93 Centigrade (4.2 Kelvin) and will not freeze at atmospheric pressure conditions.

Helium possesses 92% of the lifting power of hydrogen, although it bears double the weight of hydrogen. Being non-combustible, helium is preferred to hydrogen as the lifting gas in lighter-than-air itself. The real difficulty lies with the fact that separation and extraction of helium from other gasses is a bit complicated. It was concluded that it can usually be found in places where deposits of natural gas exist. It was eventually discovered and isolated around 1895 by Sir William Ramsay, a British chemist, who recovered it from a uranium-bearing mineral. Helium has a peculiar and very interesting fact attached to it: it is the only element discovered out of Earth before it was discovered on our planet. Helium is considered one of the noble gases how could it not be? It is the element of the Sun itself! What is Helium? HELIUM, deriving from the Greek word ‘Helios’, Ήλιος’, meaning ‘Sun’, and with the elementary symbol ‘He’ (in the elements periodic table) is a colourless, odourless gaseous element.

Fluid browser vs helium