Copper

November 24, 2012 1:29 am

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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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