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Helium was discovered in 1868 by a French astronomer by observation
of the sun's spectrum. Its name is derived from the Greek helios, meaning
the sun. It was thought at the time to be a metal, hence its name-ending -ium.
It ought to be called helion in order to be consistent with the other noble
gases.
Helium is a light, colourless gas with no smell or taste. It heads the list
of elements commonly called the noble gases.
Helium is inert, lighter than any other gas except hydrogen, and is useful for
its lifting properties. It is the gas of choice for weather and birthday balloons
since it is non-flammable.
Helium is chiefly the product of decay of radioactive elements and is found
associated with ancient deposits of natural gas. It occurs as a minor constituent
of natural gas in some oil fields in North America. It also occurs in the sun
where it is formed by nuclear fusion of hydrogen. The earth's
atmosphere contains about 5 parts per million of helium.
There is plenty of helium in the universe. It is possible to obtain helium
gas directly from the atmosphere but the expense is prohibitive. Commercial
volumes of helium gas are extracted from raw natural gas. Helium is separated
from natural gas either by:
Helium remains in the gaseous state until - 267.9 oC, a few degrees
above absolute zero. Helium's usefulness
goes far beyond toy balloons and making you talk like Donald Duck. Because of
the extremely cold temperature of liquid helium, Fermilab uses it along with
liquid nitrogen to cool the giant superconducting
magnets at the heart of the world's most powerful accelerator, the Tevatron.
The magnets lose their superconductivity if the termperature rises past a few
degrees above absolute zero.
Shown above is the glow discharge
of helium.
