The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
(c)1998-2002; (c)2002 by Gale. Gale is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Gale and Design and Thomson Learning are trademarks used herein under license.
The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
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Argon is a noble gas, one of the elements that make up Group 18 of the periodic table. Its atomic number is 18, its atomic mass is 39.948, and its chemical symbol is Ar.
Argon is a colorless, odorless, tasteless gas with a density of 1.784 grams per liter. Its melting point is -302.55°F (- 185.86°C) and its freezing point, -308.7°F (- 189.3°C). Argon is chemically inert.
Argon is the third most abundant gas in the atmosphere, after nitrogen and oxygen. It makes up about 0.93% of the atmosphere. It is also found in very small amounts in the Earth's crust.
Argon was discovered in 1894 by the English chemist John William Strutt (Lord Rayleigh) and the Scottish chemist William Ramsay. The element's existence had been predicted more than a century earlier by the English chemist and physicist Henry Cavendish. Cavendish had removed the two most abundant gases, nitrogen and oxygen, from air, but found that a very small amount of an unidentified gas still remained from the air. Unfortunately, he was not able to identify what that remaining portion was.
The name chosen by Rayleigh and Ramsay for the new element comes from the Greek word argos, meaning "lazy." They thought the name was a good one because the new element seemed too "lazy" to react with any other elements or compounds.
Argon is used to provide an inert atmosphere that will protect materials from reacting with oxygen or other gases. For example, the inside of a light bulb is often filled with argon. No matter how hot the filament inside the bulb gets, it will not react with argon. Argon is also used in welding to prevent the two metals being heated from reacting with oxygen before they join to each other.