We read a while ago about how long, long ago people began to make tools using stone, and so the time when those people lived was called the Stone Age. Every so often, however, people would find lumps of a material which was not stone, lumps of pure metal: gold, iron or copper.
Gold was the most frequently used metal during the Stone Age. It does not rust or tarnish, but is always bright and shiny. In areas where gold is found in the rocks, flakes and nuggets of gold can sometimes be found in streams or rivers. The first Neolithic people to use gold probably found it in these pure forms.
Gold is very soft. People could form it into shapes even without heating it. Often Neolithic people hammered gold out into thin sheets and made ornaments in the shape of animals or symbols. Gold could also be softened at a fairly low temperature over a campfire, so people could soften or melt it in order to make beautiful jewelry or sculptures out of it. But since gold is so soft and so rare, it was never used for tools, only for jewelry and other beautiful things.
Copper is only rarely found in exposed lumps of pure metal, so when people first began to use it to make tools about 5,000 to 4,000 B.C. this meant that they had to mine copper ore (rock with copper in it), crush it into small pieces, and heat it in order to melt the copper and skim out the bits of rock and other impurities. This processes is called smelting, and it required a fire hotter than a normal wood camp fire. In order to smelt copper, early metal workers had to use a bellows or blow pipe to force more air into the fire to make it burn hotter.
If you have ever blown on the coals of a campfire or barbecue, you have seen how blowing air on a fire can make it burn hotter. That is because oxygen, one of the gases in the air we breath, is needed for fire to burn. Blowing air on a fire gives it more oxygen and allows it to burn faster and hotter.
All this sounds like a great deal to figure out, yet by 5,000 B.C. people who lived in Anatolia [an-uh-toh-lee-uh] (what is now Turkey) and Mesopotamia had learned all this and were mining copper ore, smelting it, and pouring the molten copper into molds to make tools, artwork and jewelry.
Copper tools did not chip or break like stone tools, and they could be made into shapes which would have been difficult to make from stone. However, copper is a fairly soft metal, so copper knives and axes got dull quickly, and copper tools dented from hard use. By 3,500 B.C. people had learned that mixing certain other metals with copper produced a harder, stronger metal called bronze which had the added advantage of melting at a lower temperature than pure copper.
Ancient smiths made bronze by mixing copper ore with either arsenic or tin ore. Arsenic was easier to find, but arsenic is also a poison. The fumes could make bronze-smiths sick causing partial paralysis. Perhaps this is why the ancient gods of metalworking such as Hephaestus and Vulcan are portrayed as being lame. After about 2,000 B.C. only tin was used for making bronze.
Bronze was much, much better for making strong tools than copper or stone, and so bronze tools and weapons became highly prized throughout Europe, Mesopotamia and Egypt. The knowledge of how to smelt both copper and bronze spread across Europe and the Middle East, and even the people who did not know how to make bronze themselves traded for it. By 2,500 B.C. metalworking was being done as far away as Britain.
Making tools and weapons for the thriving city states of Mesopotamia and for the Pharaoh's armies in Egypt required huge amounts of bronze. In areas where copper and tin could be found, miners dug deep holes into the mountains to get out all the ore they could find. Smelting furnaces roared as the ores were refined and poured out into molds, forming bars of solid bronze called ingots. [ing-guhts]. These ingots could then be traded with other people who did not live where copper and tin could be easily found. Archeologists have found ancient shipwrecks in the Mediterranian Sea of trading ships loaded with bronze ingots.
Often miners could not find tin and copper near each other. So people developed long trade routes to get the materials they needed. Miners in Britain found large deposits of tin which they smelted into ingots and traded for other things that they wanted. By 2,000 B.C. there were trade routes stretching more than two thousand miles from Britain to Mesopotamia and Egypt.
Bronze weapons and tools (and the trade routes that people built up in order to make and get them) changed the world so much that historians call the time when people used bronze tools the Bronze Age. The Bronze Age stretched from around 3,500 B.C. (just as the first big cities like Uruk were being founded) to about 1,200 B.C.
By 1,200 B.C. people had learned how to use a new metal which could be made even stronger than bronze: iron.
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