Before history began people worked copper. Before humans could write they knew how to make use of its strength and beauty in ornaments, tools, and weapons that can still be seen in museums worldwide. It was easily accessible in its native state, and soft enough to work with early tools. Modern societies continue to make use of copper’s varied qualities.
Copper, symbol Cu, atomic number 39, is from the same group (1b) as gold and silver in the periodic table of elements, and of similar beauty. It has a pinkish luster on a bronze body color in most lights, and weathers to a delicate shade of green. Like gold and silver, copper is rare enough that its ores are highly prized. All three are malleable metals with high conductivity.
Copper is second only to iron in its engineering importance. The price of copper can be a measure of industrial health, because it often fluctuates with the growth of the world economy. Overall, its price trends up, as the world modernizes to the point that the demand for copper is beginning to reach the supply. The industrial world could not function without copper.
Copper has high thermal conductivity that makes it useful in heating and cooling. Gourmets treasure their copper cookware, and moonshiners are famously advised to: “get you a copper kettle.” In industry, it is used for boilers and fireboxes, and it is found in heat sinks for computers.
Its electrical conductivity, though not as great as that of silver, makes it a superior choice for wiring, as well as for the magnetrons that are the heart of microwave ovens. It serves similar purposes in some integrated circuits.
Copper’s corrosion resistance makes it useful for roofing as well as shipbuilding. The green patina that exposed copper eventually forms, copper carbonate, is durable as well as attractive. It’s also found in plumbing, another application where it is valued for its durability.
Copper is biostatic. It interferes with the growth of organisms. For this reason it’s used in medical settings, to prevent the spread of disease. It is also used on the bottoms or ships, to discourage the growth of mussels and barnacles, although in this application it is usually part of the alloy Muntz Metal, which is a brass containing about 60% copper.
Brass and bronze are two copper alloys with wide applications. Brass is copper and zinc, sometimes with small amounts of other metals added. It is stronger and cheaper than pure copper, although somewhat less resistant to corrosion. And without brass we would be missing a part of our orchestras. Bronze is copper and tin. It is stronger than pure copper and more resistant to corrosion. Another copper compound is copper sulfate, a fungicide known as Bordeaux mixture.
Artists have done wonderful things with copper, from the faience of early Egypt, to the copper surrounding the stained glass shards of Gothic rose windows, to the stern and graceful Statue of Liberty. It’s a metal of great beauty and use.