B -the strange discovery of helium

The strange discovery of helium

Helium was first discovered spectroscopically in the sun by Sir Joseph Lockyer of England in 20 October 1868. Pierre Janssen of France in March 1869 also made a similar discovery .

Helium was first isolated on earth by Sir William Ramsay of England in 1895.

Helium is

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  tasteless.
  
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  odourless. If breathed in it makes your voice sound like "Donald Duck".
  
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  colourless
  
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  normally nontoxic,
  
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  lighter-than-air
  
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  the second most abundant element in existence (after hydrogen)..
  

In 1995 was the 100th anniversary of the discovery of helium by Ramsay. Having a 100th birthday may not seem particularly remarkable--until you realize that helium is the second most common element in creation, accounting for one in every ten atoms in the Universe - which prompts the obvious question: how in the world did we manage to miss it until 1885?

The simple answer is that helium is both chemically inert and extremely light.
Its inertness ensures that it rarely gets trapped in compounds, while its lightness means that as soon as it is released into the air it floats off into space. Space, on the sun, is where the gas was first found.

Helium is unique in being the only element to be discovered on the Sun before it was discovered on Earth.

Norman Lockyer - the discoverer of helium

The man who spotted it there was Norman Lockyer, a civil servant from Wimbledon who, among other things,

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  wrote the first book on the St. Andrew's rules of golf,
  
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  founded London's Science Museum in South Kensington and
  
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  launched the international science journal Nature,which he edited for 50 years.
  

On 20 October 1868, Lockyer pointed his 6-inch telescope at the sun and examined the light with a spectroscope.In the spectrum of a solar flare he was surprised to see a yellow line.The line was observed a little later by the French astronomer Pierre Jules Cesar Janssen from India . Both men failed to reproduce this spectra in the laboratory and, in 1870, Lockyer make the bold suggestion that the line was the "fingerprint" of an unknown element which he called helium from the Greek word for the sun "helios"

Ridicule follows

Lockyer was ridiculed for proposing the existence of "helium" and had to wait 25 years to see his critics silenced. The man who proved him right and found helium on earth was the Scottish chemist William Ramsay, the only person to discover an entire group of the periodic table of elements--the noble gases. In March 1895, while examining the spectrum of gases given off by a uranium mineral called cleveite, Ramsay spotted a mysterious yellow line. Lacking a good spectroscope, he sent gas samples to both Lockyer and to William Crookes, a physicist famous for experimenting on cathode rays.

Within a week Crookes had confirmed that the gas was the same as the one Lockyer had observed. Lockyer was beside himself with joy as he squinted through the spectroscope at the "glorious yellow effulgence" he had first seen on the Sun a quarter of a century before.

Today, helium is used in

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  arc-welding equipment,
  
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  lasers
  
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  gas-cooled nuclear reactors.
  

Deep-sea divers avoid the bends by breathing a mixture of helium and oxygen.