Christopher Stark, age 12, of Brownsville, Texas, for his question:
WHEN DID MAN START TO USE IRON?
As early as the beginning of the Bronze Age, which started about 3000 B.C., some of the people living in the Middle East started to use tools that were made by beating and hammering iron that fell to earth in meteors. But the widespread use of iron didn't begin until about 1100 B.C.
Historians think that the first man made iron was discovered accidentally. A man most likely built a fire on top of a patch of rich iron ore. The iron then probably melted from the ore and combined with sand in the earth to form wrought iron.
Iron was used by ancient civilizations in China, India, Chaldea, Babylon and Assyria. The Egyptians imported iron to make tools and weapons.
In the Bible's Old Testament, iron is mentioned. And ancient Roman author Pliny described the metal as the "most useful and most fatal instrument in the hand of man."
True iron working started in Asia Minor, which is now Turkey, about 1100 B.C. The great advantage of iron was its cheapness, because iron ore was abundant and widespread. In the Iron Age, as the period of time came to be called, workers abandoned the crude tools of the Bronze Age. Craftsmen could then afford metal tools and they quickly made wide use of iron, including iron plows.
People in southern Europe learned the use of iron long before the northern countries did. The Greek poet Homer talked of iron as something precious, like gold. But the people of Scandinavia didn't know anything about iron before the time of Julius Caesar.
During the Iron Age, many inventions came into general use. The alphabet was developed during this period and people also started to use coins. Trade improved and so did transportation and communication.
One of the most important later dates for iron came in 1340 when blast furnaces started to assume their present form in central Europe. The first blast furnace in the United States was built in 1621 in Falling Creek, Virginia.
In the 1700s, a number of new discoveries and inventions made it possible to produce iron in large quantities. The demand for wrought iron to make steam engines, locomotives and railroad rails rapidly built a huge iron industry in Europe and in the U.S. in the 1800s.
In 1740, the "crucible" process of making steel was rediscovered. A crucible is a small pot made of fire clay and graphite. A number of crucibles are placed on the hearth of a furnace, which is heated by gas. Carefully selected scrap is then melted in these crucibles.
During the 1800s, two other steelmaking processes were developed: the open hearth and the electric furnace. These became important methods of making steel because they could reuse large amounts of scrap iron and steel.
Steel is an alloy or mixture of iron and small, definite amounts of carbon and other minerals.