Most of the gases can be prepared in the laboratory but there are some which are found in nature only. Helium is one such gas.
It is an inert gas. It is odourless and tasteless. Helium has some special characteristics due to which it has proved very useful for us. It is second lightest gas next to hydrogen but it has a speciality that, unlike hydrogen, it is non inflammable.
This gas was discovered in 1868 independently by English scientists Sir Joseph Norman Lockyer and French Chemist, Pierre Janssen. While studying the solar spectrum to find the elements present in the sun, they came across some lines which were not observed earlier. These lines suggested the presence of a new element in the sun. The element was named as Helium after the Greek word ‘helios’ meaning ‘the sun’. Thereafter, scientists made efforts to know if helium was present in the earth’s atmosphere. They detected very small quantities of helium in the atmosphere. Atmospheric air contains only one part in 1, 86,000 parts, i.e., 0.0005239 percent.
On account of its lightness and non-inflammability, it is used in weather balloons. Helium is also used to ease the breathing difficulties of asthmatic patients. Deep sea divers are given a mixture of oxygen and helium for breathing so that after coming back, they do not suffer with bends. Helium is also used to weld aluminium. A mixture of helium and neon is used to produce laser beams. Helium can be liquefied at – 268.9 degree centigrade. Liquid helium is used in low temperature work.
There are some places in America like Texas, New Mexico, and Kansas etc. where the amount of helium present in the atmosphere goes upto 8%. It is also present in atmosphere in Canada, Africa and the Sahara desert. America is the world’s richest source of this gas and is therefore the biggest seller of helium to other countries. In earlier times this gas was very costly, but now it has become quite cheaper.