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Helium
HeliumBackgroundHelium is one of the basic chemical elements. In its natural state, helium is a colorless gas known for its low density and low chemical reactivity. It is probably best known as a non-flammable substitute for hydrogen to provide the lift in blimps and balloons. Because it is chemically inert, it is also used as a gas shield in robotic arc welding and as a non-reactive atmosphere for growing silicon and germanium crystals used to make electronic semiconductor devices. Liquid helium is often used to provide the extremely low temperatures required in certain medical and scientific applications, including superconduction research. Although helium is one of the most abundant elements in the universe, most of it exists outside of Earth's atmosphere. Helium wasn't discovered until 1868, when French astronomer Pierre Janssen and English astronomer Sir Joseph Lockyer were independently studying an eclipse of the Sun. Using spectrometers, which separate light into different bands of color depending on the elements present, they both observed a band of yellow light that could not be identified with any known element. News of their findings reached the scientific world on the same day, and both men are generally credited with the discovery. Lockyer suggested the name helium for the new element, derived from the Greek word helios for the sun. In 1895, English chemist Sir William Ramsay found that cleveite, a uranium mineral, contained helium. Swedish chemists P.T. Cleve and Nils Langlet made a similar discovery at about the same time. This was the first time helium had been identified on Earth. In 1905, natural gas taken from a well near Dexter, Kansas, was found to contain as much as 2% helium. Tests of other natural gas sources around the world yielded widely varying concentrations of helium, with the highest concentrations being found in the United States. During the early 1900s, the development of lighter-than-air blimps and dirigibles relied almost entirely on hydrogen to provide lift, even though it was highly flammable. During World War I, the United States government realized that non-flammable helium was superior to hydrogen and declared it a critical war material. Production was tightly controlled, and exports were curtailed. In 1925, the United States passed the first Helium Conservation Act which prohibited the sale of helium to nongovernmental users. It wasn't until 1937, when the hydrogen-filled dirigible Hindenburg exploded while landing at Lakehurst, New Jersey, that the restrictions were lifted and helium replaced hydrogen for commercial lighter-than-air ships. During World War II, helium became a critical war material again. One of its more unusual uses was to inflate the tires on long-range bomber aircraft. The lighter weight of helium allowed the plane to carry 154 lb (70 kg) of extra fuel for an extended range. After the war, demand for helium grew so rapidly that the government imposed the Helium Act Amendments in 1960 to purchase and store the gas for future use. By 1971, the demand had leveled off and the helium storage program was canceled. A few years later, the government started storing helium again. As of 1993, there were about 35 billion cubic feet (1.0 billion cubic meters) of helium in government storage. Today, the majority of the helium-bearing natural gas sources are within the United States. Canada, Poland, and a few other countries also have significant sources. Raw MaterialsHelium is generated underground by the radioactive decay of heavy elements such as uranium and thorium. Part of the radiation from these elements consists of alpha particles, which form the nuclei of helium atoms. Some of this helium finds its way to the surface and enters the atmosphere, where it quickly rises and escapes into space. The rest becomes trapped under impermeable layers of rock and mixes with the natural gases that form there. The amount of helium found in various natural gas deposits varies from almost zero to as high as 4% by volume. Only about one-tenth of the working natural gas fields have economically viable concentrations of helium greater than 0.4%. Helium can also be produced by liquefying air and separating the component gases. The production costs for this method are high, and the amount of helium contained in air is very low. Although this method is often used to produce other gases, like nitrogen and oxygen, it is rarely used to produce helium. The Manufacturing |
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"Helium." How Products Are Made. 1999. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. "Helium." How Products Are Made. 1999. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1G2-2896800063.html "Helium." How Products Are Made. 1999. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-2896800063.html |
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helium
helium , gaseous chemical element; symbol He; at. no. 2; at. wt. 4.0026; m.p. below -272°C at 26 atmospheres pressure; b.p. -268.934°C at 1 atmosphere pressure; density 0.1785 grams per liter at STP ; valence usually 0.
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"helium." The Columbia Encyclopedia, 6th ed.. 2011. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. "helium." The Columbia Encyclopedia, 6th ed.. 2011. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1E1-helium.html "helium." The Columbia Encyclopedia, 6th ed.. 2011. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1E1-helium.html |
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Helium
Heliummelting point: −272.2°C—does not solidify under its own vapor Helium, a colorless gas at room temperature, is the first element in the noble gas group, and forms few compounds. It is rare in the atmosphere (1 part in 200,000) and recovered on Earth principally by its separation from natural gas obtained in underground wells. Named for the Sun (in Greek, helios ), helium is a component of the production of energy as well as the basis of the science and technology of cryogenics. Its presence at the surface of the Sun was first confirmed by amateur British astronomer Joseph Norman Lockyer (1868), who observed characteristic lines in the optical spectrum of the Sun, at whose surface helium is produced via the energy-releasing fusion of hydrogen and deuterium nuclei. Because it is such a light, nonreactive element, helium condenses (at atmospheric pressure) only at 4.2 kelvins. Furthermore, because of quantum mechanical effects, helium solidifies (under the application of 25.3 bars of external pressure) only at the lowest temperatures. Liquefied in large compression refrigerators, helium is used to cool cryogenic equipment, in particular the superconducting magnets used in medical magnetic resonance imaging (MRI). At 2.17 kelvins liquid helium transforms into an unusual quantum phase , called a superfluid, which has no viscosity and exhibits bizarre flow properties, such as its creeping out of containers. The gas is also used to fill balloons, in gas discharge lamps, and as an additive in the breathing gases of astronauts and scuba divers. The rarer stable isotope of helium (3He) is produced by the decay of radioactive tritium, and is used in resonance imaging and in the attainment of very low temperatures, about 0.010 kelvin, via a process known as dilution refrigeration. see also Noble Gases; Nuclear Fusion. David G. Haase BibliographySeibel, Clifford W. (1968). Helium, Child of the Sun. Lawrence: The University Press of Kansas. |
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Haase, David G.. "Helium." Chemistry: Foundations and Applications. 2004. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. Haase, David G.. "Helium." Chemistry: Foundations and Applications. 2004. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1G2-3400900235.html Haase, David G.. "Helium." Chemistry: Foundations and Applications. 2004. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3400900235.html |
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helium
helium (symbol He) Nonmetallic element, a noble gas, discovered in 1868 by Jules Janssen. First obtained in 1895 from the mineral clevite, the chief source today is from natural gas. It is also found in some radioactive minerals and in the Earth's atmosphere (0.0005% by volume). It has the lowest melting and boiling points of any element. It is colourless, odourless and nonflammable, and is used in light-air balloons, to make artificial ‘air’ (with oxygen) for deep-sea divers and in welding, semiconductors and lasers. Liquid helium is used in cryogenics (physics dealing with low temperatures). Properties: at.no. 2; r.a.m. 4.0026; r.d. 0.178; m.p. −272.2°C (−458°F); b.p. −268.9°C (−452.02°F); single isotope He4.
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"helium." World Encyclopedia. 2005. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. "helium." World Encyclopedia. 2005. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1O142-helium.html "helium." World Encyclopedia. 2005. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O142-helium.html |
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helium
he·li·um / ˈhēlēəm/ • n. the chemical element of atomic number 2, an inert gas that is the lightest member of the noble gas series. (Symbol: He) |
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"helium." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. "helium." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1O999-helium.html "helium." The Oxford Pocket Dictionary of Current English. 2009. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O999-helium.html |
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helium
helium (hee-li-ŭm) n. a colourless inert gas that is used in combination with oxygen in respiratory tests and therapy and to prevent decompression sickness in deep-sea divers. Symbol: He.
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"helium." A Dictionary of Nursing. 2008. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. "helium." A Dictionary of Nursing. 2008. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1O62-helium.html "helium." A Dictionary of Nursing. 2008. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O62-helium.html |
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helium
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T. F. HOAD. "helium." The Concise Oxford Dictionary of English Etymology. 1996. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. T. F. HOAD. "helium." The Concise Oxford Dictionary of English Etymology. 1996. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1O27-helium.html T. F. HOAD. "helium." The Concise Oxford Dictionary of English Etymology. 1996. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O27-helium.html |
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helium
helium
•columbium
•erbium, terbium, ytterbium
•scandium • compendium
•palladium, radium, stadium, vanadium
•medium, tedium
•cryptosporidium, cymbidium, idiom, iridium, rubidium
•indium
•exordium, Gordium, rutherfordium
•odeum, odium, plasmodium, podium, sodium
•allium, gallium, pallium, thallium, valium
•berkelium, epithelium, helium, nobelium, Sealyham
•beryllium, cilium, psyllium, trillium
•linoleum, petroleum
•thulium • cadmium
•epithalamium, prothalamium
•gelsemium, premium
•chromium, encomium
•holmium • fermium
•biennium, millennium
•cranium, geranium, germanium, Herculaneum, titanium, uranium
•helenium, proscenium, rhenium, ruthenium, selenium
•actinium, aluminium, condominium, delphinium
•ammonium, euphonium, harmonium, pandemonium, pelargonium, plutonium, polonium, zirconium
•neptunium
•europium, opium
•aquarium, armamentarium, barium, caldarium, cinerarium, columbarium, dolphinarium, frigidarium, herbarium, honorarium, planetarium, rosarium, sanitarium, solarium, sudarium, tepidarium, terrarium, vivarium
•atrium
•delirium, Miriam
•equilibrium, Librium
•yttrium
•auditorium, ciborium, conservatorium, crematorium, emporium, moratorium, sanatorium, scriptorium, sudatorium, vomitorium
•opprobrium
•cerium, imperium, magisterium
•curium, tellurium
•potassium • axiom • calcium
•francium • lawrencium • americium
•Latium, solatium
•lutetium, technetium
•Byzantium • strontium • consortium
•protium • promethium • lithium
•alluvium, effluvium
•requiem • colloquium • gymnasium
•caesium (US cesium), magnesium, trapezium
•Elysium • symposium
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"helium." Oxford Dictionary of Rhymes. 2007. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. "helium." Oxford Dictionary of Rhymes. 2007. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1O233-helium.html "helium." Oxford Dictionary of Rhymes. 2007. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O233-helium.html |
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