Helium is an inert noble gas with the chemical symbol He and the atomic number 2. Its boiling and melting points are the lowest of any known element. Helium is both the second lightest and second most abundant element in the universe. Helium exists naturally in a gaseous state and is colorless, odorless and tasteless. It was named after the Greek god of the sun, Helios. It was first detected by French astronomer Jules Janssen and Norman Lockyer in 1868 during a solar eclipse. It was officially discovered in 1895 by two Swedish chemists, Per Teodor Cleve and Nils Abraham Langlet. Helium has a number of applications in the world today. This post will take you through some of the common uses of helium.
- The largest use of helium is in cryogenics. It is used in the field because of its low boiling point and low density. It is mainly used to cool superconducting magnets in MRI scanners.
- Helium is also commonly used to pressurize and purge systems of unwanted gases.
- It is also used in controlled atmospheres when the levels of different gases have to be kept constant. It is used as a protective gas when growing silicon and germanium crystals and when producing titanium and zirconium.
- Helium is used in supersonic wind tunnels because it is inert, thermal and calorically perfect nature, high speed of sound, and high value of the heat capacity ratio.
- For materials easily contaminated by air, helium is used as a shielding gas in the arc welding process particularly when working with aluminum and copper.
- As helium is lighter than air, airships and balloons can be filled with the gas to gain lift. Helium is also non-flammable making it a much safer gas to fill blimps and airships with. (see the article What Caused the Hindenburg Disaster)
- It is this lighter than air property that makes helium the most common gas used to fill party balloons, balloon sculptures and parade balloons. The buoyancy caused by helium can last anywhere from half a day to a week.
- Helium is used to condense hydrogen and oxygen to make rocket fuel. It is also used to purge fuel and oxidizer from support vehicles and to cool hydrogen fuel in space vehicles.
- Helium can be added to oxygen tanks so that divers can breathe more easily. This is especially important for people that go deep diving (over 450 ft below sea level). This helium mix reduces the risk of narcosis and high-pressure nervous syndrome.
- It is used in helium-neon lasers. These lasers can be used to read barcodes. Helium lasers have been mostly replaced by diode lasers.
- Helium is also used as a heat-transfer medium in some gas-cooled nuclear reactors.
- Helium can be used to detect leaks in high-vacuum and high-pressure equipment. Helium can be used to detect leaks (small fractures) in some vessels. This is due to the fact that it diffuses through solid materials three times faster than air.
- The age of rocks which contain uranium and thorium can be estimated using helium dating.
- Helium is often used as a carrier gas in gas chromatography.
- Helium is used in solar telescopes to reduce the distortion caused by temperature fluctuations in between the lenses.