Balloon bursts for Noble gases as they come of age
10 December 2004
From light bulbs to scanners at supermarket checkouts, Noble gases have become an intrinsic part of modern living, thanks to Sir William Ramsay who won the Nobel Prize for Chemistry for their discovery at University College London.
Running out of helium will spell the end of high pitched voices and floating balloons, but more critically helium is an essential component of the non-invasive diagnostic tool, MRI scanners.
Dr Andrea Sella of UCL's Department of Chemistry explains:
"Helium is the second most abundant element in the universe but it is so light and fast-moving that it's able to escape from the Earth's pull of gravity and leaks away. Instead, the chief source of helium is from natural gas where the element is trapped by the rock surrounding the deposit.
"The US holds 80 per cent of the world's supplies and demand for helium has grown by five per cent over the past 10 years - a trend that is likely to continue. Yet there is no substitute for helium in cryogenic applications.
"Liquid helium, at a temperature of -269 degrees Celsius, is required to cool the magnets in MRI scanners to produce an intense magnetic field. Helium is the only possible refrigerant for these low temperatures, since almost anything else will freeze. Were it unavailable magnets such as those used for MRI would not be possible.
"Look around any room - there's no getting away from how dependent we've become on Noble gases. Argon is used in electric lighting, fluorescent lamps and even double glazing. Neon is, of course, infamous for its use in bright lighting the element lends its name to and helium-neon gas lasers are used to scan bar codes in shops everywhere.
"Thankfully, supplies of other Noble gases are more plentiful than helium, but if we don't find new sources of helium, floating balloons at kids' parties could soon be a thing of the past."
Sir Willam Ramsay discovered helium, argon, neon, krypton, xenon and radon in the late 1800s and was awarded the 1904 Nobel Prize in Chemistry. It was comments made by British physicist Lord Rayleigh that led Ramsay to predict there may be a hitherto undiscovered heavy gas in the air.
Lord Rayleigh, who won the 1904 Nobel Prize in Physics for the same discovery, asked chemists to explain the difference between the atomic weight of nitrogen prepared by chemical synthesis and that of nitrogen isolated from the atmosphere. By devising methods that assured the total removal of nitrogen, oxygen, carbon dioxide and moisture from the air, Ramsay found (1894) a chemically inert gaseous element, later called argon, that makes up nearly one per cent of the atmosphere. The following year Ramsay liberated helium from the mineral cleveite and thus became the first person to isolate that element. He later (1903) demonstrated that helium, the lightest of the inert gases, is continually produced during the radioactive decay of radium, a discovery of crucial importance to a modern understanding of nuclear reactions.
Dr Sella adds: "It's astounding to think just over 100 years ago the periodic table found on the wall of every chemistry classroom looked so different. It was the skill of Ramsay as a chemist that led to the discovery of the group 18 elements as the gases' unreactive nature meant no one suspected they were there."
Dr David Giachardi, chief executive of the Royal Society of Chemistry, comments:
"Ramsey and Raleigh were the first Britons to be awarded Nobel Prizes in the physical sciences and over the past 100 years the UK has had an excellent record in winning the Prizes. If we intend to be a world leader in science and keep on winning then the government needs to ensure thriving physical science departments by giving them the support they need."
A symposium , 'UCL Chemistry before Ramsay' , including a lecture on 'Sir William Ramsay - The Man, The Myth (and the Bicycle)' will be held at UCL on Friday 10 December and a Royal Society of Chemistry Chemical Heritage Plaque will be unveiled at the Slade School of Art, the site of Ramsay's original lab was.
Notes to editors
For further information please contact:
Judith H Moore, UCL Media Relations office, Tel: 07917 271 364, e-mail: Judith.email@example.com
Facts about Noble gases
1. They are colourless, odourless, tasteless gases and were once believed not to form any chemical compounds
2. The low chemical activity of the gases is due to the fact that their outermost electron shell is complete.
3. They are all gaseous, which is unusual for the elements further down the group: xenon's atomic size is larger than gold, which is solid.
4. Only hydrogen is more abundant in the universe than helium
5. Other planets in our solar system that have atmospheres have much higher levels of inert gases than we have here on Earth.
6. Breathing helium dramatically raises the pitch of the voice because sound travels three times faster in helium than in air
7. The first neon sign was made by George Claude in 1910, and were soon adopted by the advertising industry
8. Xenon and krypton's ability to deliver an intense burst of light when pulsed with electricity makes them an essential component in every compact camera
9. Blue argon lasers are used in surgery to correct defects of the eye, to weld arteries and destroy tumours
10. Argon is used in used in the tyres of luxury cars to protect the rubber from attack by oxygen and makes the tyres less noisy when the car is moving at speed.