Technology
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Left we can see how technology developed incrementally: the familiar baking-oven has been enlarged and modified into a high-temperature kiln for firing pottery. Agricultural societies world-wide have discovered that "baking" clay in extremely hot fires for a long period creates hard, durable objects such as the plates, jugs, and pots above. These examples are from 'Ubaid' culture in Mesopotamia, one of the earliest pottery-making societies. Another step in a sequence of technological development was the modification of the pottery kiln into a furnace capable of melting metal ores (below).
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Note that the earliest forms of furnaces for smelting ores at left above even retain the form of the mud oven. Over time, smelting ores became a highly refined technology and furnaces evolved into new forms.