Argon - Atomic Number 18 Traditional Cache

This cache is the third in a series of 22 hides to be named after chemical elements and placed on Ramsey streets (and sometimes points North) with the same name. The series will speed up the qualification requirements for challenge cache GC2P5TJ, since some already published elements require traveling great distances. The closest cache named Argon is located 70 miles North.

History: Argon was discovered in 1894. However, English scientist Henry Cavendish (1731-1810) had predicted the existence of argon 200 years earlier. When Cavendish removed oxygen and nitrogen from air, he found that a very small amount of gas remained. He guessed that another element was in the air, but he was unable to identify what it was.

When Ramsay repeated Cavendish's experiments in the 1890s, he, too, found a tiny amount of unidentified gas in the air. But Ramsay had an advantage over Cavendish: he could use spectroscopy, which did not exist in Cavendish's time. Spectroscopy is the process of analyzing light produced when an element is heated. The spectrum (plural: spectra) of an element consists of a series of colored lines and is different for every element.

Ramsay studied the spectrum of the unidentified gas. He found a series of lines that did not belong to any other element. He was convinced that he had found a new element. Meanwhile, Rayleigh was doing similar work at almost the same time. He made his discovery at about the same time Ramsay did. The two scientists decided to make their announcement together. The name argon comes from the Greek word argos, "the lazy one." The name is based on argon's inability to react with anything.

Sources: The gas is prepared by fractionation of liquid air because the atmosphere contains 0.94% argon.p>