Argon is an inert gas found in the Earth's atmosphere. It is the fourth most common gas in the air, behind oxygen, carbon dioxide and nitrogen. It has an atomic number of 18 and uses the atomic symbol, Ar, according to About.com.
Argon is one of the gases discovered by Lord Rayleigh and Sir William Ramsay as they worked to separate liquefied air into its various components. On Earth, argon accounts for less than 1 percent of the atmosphere. Argon has a boiling point of minus 302.4 degrees Fahrenheit and a freezing point of minus 308.7 degrees Fahrenheit. Electrified argon creates characteristic red lines in a spectrum. The name Argon comes from the Greek word for lazy or inactive, according to Wikipedia.
Welders use argon when their work requires an inert shielding gas to prevent ordinarily inactive materials from becoming reactive at high temperatures. Graphite electric furnaces require the use of argon gas to prevent the graphite from burning as temperatures increase. Storing substances in argon gas prevents them from reacting with the atmosphere. Manufacturers use argon gas in both incandescent and fluorescent lighting as well as other gas discharge tubes. Argon also finds use in lasers, where it produces a distinctive blue-green light.