Copper
Have you used anything copper today?
If you bought something and received change, there was copper in the coins. Did
you use any electrical devices? The electricity was carried to your home by
copper wires. There are even tiny amounts of copper inside you. Your body needs
it for digesting food and keeping your blood healthy.
WHAT IS COPPER?
Copper is a reddish-yellow metal.
When it’s found in pure form in the ground it’s called native copper. Usually,
though, copper is found combined with other elements in rocks. These rocks are
called copper ores.
When combined with other elements,
copper is often greenish in color. The Statue of Liberty is made mostly of
copper. Its greenish color comes from copper combined with the element oxygen
from the air.
Copper was one of the first metals
discovered by human beings. People were making tools and jewelry from native
copper over 10,000 years ago.
HOW COPPER IS USED
Pure copper is a soft metal. Early
humans found that it made poor tools and weapons. They discovered that copper is
much stronger when mixed with other metals. People made bronze by combining the
metals copper and tin. They made brass by combining copper with zinc.
Today, bronze and brass often contain other metals. But copper is still their
main ingredient.
Copper has long been used for
making coins. Copper coins were always less valuable than silver or gold coins,
because silver and gold are rarer metals. Most coins used in the United States
today contain some copper.
Copper sheets were once used to
cover the bottoms of wooden sailing ships. They kept the wood from rotting or
being eaten by sea animals.
Substances that contain copper are
used to make blue-green inks and dyes. Other copper compounds are used as insect
and weed poisons on farms or to purify water.
COPPER AND ELECTRICITY
Copper became more valuable in the
late 1800s. That was when people discovered how to use electricity. Of all
metals, copper is the second-best conductor of electricity. (Silver is better,
but copper is much cheaper.)
Most copper mined today is used in
the electrical industry. The wires in power lines are mostly copper. So is the
wiring in electrical appliances and cords. Copper can be stretched into wires as
thin as 0.001 inch (about 0.025 millimeters).
WHERE DOES COPPER COME FROM?
In ancient times, copper came
mostly from the island of Cyprus in the Mediterranean Sea. (In fact, the name
Cyprus means “copper.”) The ancient Egyptians, Greeks, and Romans made
tools and weapons from Cyprus’s copper.
Native Americans used copper too.
They mined copper in what is now Michigan. Copper ornaments from this region
were traded all over America.
Today, much of the world’s copper
comes from Chile. Arizona, Utah, and New Mexico are leading copper-mining
states.
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