SLE102 Lecture 10: WEEK 10 - Earth's resources through time
9 Aug 2018
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Document Summary
The u e of the earth" re ource through time. 17,000 years ago = metals first extracted from earth. Earliest metals = copper and gold occur in rocks in their native form. 6,000 years ago = copper extracted from minerals by smelting. 5,000 years ago = smelting of lead, tin, zinc, silver and other metals. Smelting: heating up a mineral (or substance that contains the metal e. g. rock) in the presence of carbon chemical reaction occurs pure metal can then be extracted. Formation of alloys the mixing of metals; melting two different metals together. Bronze = copper + tin (bronze is an alloy of copper and tin) 4,500 years ago = babylonians were first people to use oil. Oil was used for fuel; was gathered from natural oil seeps at the ground surface. 3,300 years ago = chinese first people to use coal. Modern industrial age + increasing population = huge demand on non-renewable resources.
