David Rubin, age 13, of Baltimore, Md., for his question:
HOW DO WE USE MAGNESIUM?
Magnesium is the lightest metal that man uses to build things. Pure magnesium does not have enough strength for general structure use so special alloys or mixtures of magnesium and other metals have been developed to meet specific needs.
Manufacturers use magnesium alloys in building airplanes, guided missiles, electronic equipment, portable tools, trucks, furniture, ladders and other equipment where light weight is important. Magnesium is also used in baseball cather's masks, snowshoes, skis, boats, horseshoes and the bodies and wheels of some racing cars.
Magnesium alloys are made by adding small amounts of aluminum, lithium, manganese, silver, zinc, thorium, zirconium and the rare earths.
Other uses of magnesium include automobile parts, cameras, hospital equipment and television and motion picture equipment.
Magnesium ranks as the third most abundant structural or building metal in the earths crust. Only aluminum and iron are more plentiful. But seawater is a more important source of magnesium than is the earth.
Because magnesium is so plentiful in seawater, it is available to most of the countries of the world. In the United States, more than 75,000 tons of magnesium are produced each year. Much of this production comes from plants in Texas using the water of the Gulf of Mexico. Two other U.S. plants, one in Alabama and the other in Connecticut, produce magnesium by another process.
Magnesium has a great many non structural uses. It plays an important part in the chemical reactions used to produce such important metals as titanium, beryllium, uranium and zirconium. Magnesium is also used to protect pipelines, underground storage tanks and the hulls of ships from corrosion.
Magnesium is also used in such compounds as milk of magnesia and Epsom salts.
A British chemist named Sir Humphry Davy first produced magnesium metal in 1808. Then in 1833, a British physicist and chemist named Michael Faraday produced magnesium by the electrolysis of magnesium chloride.
Robert Bunsen, a German scientist, developed an electrolytic cell for the production of magnesium in 1852. His cell was the basis for the cell used by German manufacturers in the late 1800s and early 1900s. By 1909, the Germans were producing magnesium on a commercial scale.
American production of magnesium began in 1915 when world War I cut off imports from Germany.
Until the 1930s, manufacturers found few uses for magnesium. Then during World War I, military uses were found. By the start of World War II in 1939, the need for a lightweight metal for airplane construction and other uses resulted in a number of applications.
American magnesium production reached its peak in 1943 when almost 185,000 tons were produced.