What is helium gas?

Most of the gases can be prepared in the laboratory but there are some gases which are found in nature only. Helium is one of them. 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.

Next to hydrogen it is the second lightest gas but it has a speciality that unlike hydrogen it is not inflammable. On account of its lightness and non-inflammability, it is used in weather balloons. It is used by air force, army and navy. 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. This is also used to weld aluminium. A mixture of helium and neon is used to produce laser beams. Helium can be liquefied at -268.4 degree centigrade and hence liquid helium is used in low temperature work.
This gas was discovered in 1868 independently by English scientists Sir Joseph Norman Lockyer and 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. This element was named as Helium after the Greek word '    ' meaning 'the sun'. Thereafter, scientists made efforts to know if helium was present in the earth's atmosphere. They detected helium in the atmosphere, but in very small quantities. Atmospheric air contains only one part in 186,000 parts, i.e., 0.0005239 percent.
There are some places in America like Texas, New Mexico, Kansas etc. where the amount of helium present in the atmosphere goes upto 8%. It is also found in Canada, Africa and the Sahara desert. America is the biggest seller of helium to other countries, since it is the world's richest source of this gas. In earlier times this gas was very costly, but now it has become quite cheap.