From around 9000 BC, people in different lands began to work with nuggets of soft metals, such as copper. Later, they discovered how to extract metals, such as tin, from rocks by smelting (heating). Finally, they discovered how to melt metals together to make new materials called alloys, such as bronze.
Table 41. SOME OF THE FIRST METALWORKERS
| 9000 BC | Hammered copper, Central Asia |
| 5000 BC | Gold/copper, Europe |
| 4000 BC | Bronze, Middle East |
| 2300 BC | Bronze, Europe |
| 1500 BC | Iron, western Asia |
| 1000 BC | Iron, Europe |
Bronze is a mixture of copper and tin. It is much harder than either metal, and can be sharpened to make a cutting edge. It was used to create more powerful and long-lasting weapons, tools, and farm implements. Craftworkers also used it to make intricate castings—objects made by pouring melted bronze into a mold.
Bronze-workers heated copper and tin in a furnace fueled by charcoal. When the two metals melted, they combined to form liquid-hot bronze, which ran down a clay pipe into containers made of clay or sand. When cold, these ingots (solid blocks of metal) were remelted and poured into different-shaped molds.
The technique of making bronze objects—by pouring molten (melted) metal into molds—was invented in western Asia in around 3000 BC. It was also discovered separately in China in around 2000 BC. The Chinese bronze-makers developed their skills to create much more elaborate patterns and designs.
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