Tuesday, August 27, 2013

A Pretty Metal Story Part One

by akshiv, This post originally appeared at Neurons and Quarks.

I have been trying to find a way to mould my block of aluminium that Mr. Milne graciously provided; the main issue has been to find a mould not the process of actually melting the aluminium. Anyway this whole business got me thinking about the history of metals and where all of this metallurgy comes from. After all Benjamin Franklin did say: “There never was a good knife made of bad steel.”
So the story really begins about 6,000 BCE when for the first time people were trying to obtain metals simply by heating up ores. This is a process known as smelting and this point it was possible to obtain silver, copper, tin, and lead in this way. It was not very efficient and most of the time surface ores were needed to obtain the metals. There is also the curious case of iron which was the “metal from heaven” often being sold for six times its weight in gold. This is because the only way to get iron at this point was to extract it from meteorite that had fell to the earth. Also a quick note on gold, it was sort of found freely and since it was malleable worked its way into culture. This period of time ends with the beginning of the Bronze Age where it was discovered that combining and tin produced a superior metal (namely Bronze), this was either found in ores or combined during smelting.
The next sort of revolution came with iron. Different places in the world discovered this at different times but the first sort people that seem to hold iron in high regard are the Hittites. Essentially, using the experience they had gotten after years of smelting bronze, humans began to try to smelt iron ores. The technical challenge is in the hot working required to manipulate it.  Not only does the temperature have to be high but the sample cannot be cooled during the process either. This is most likely the reason it took so long to shift from being able to make bronze to making iron.
The Chinese then take this process and improve it ten fold, and once the Industrial revolution hits there is no stopping the growth of metallurgy and the increase availability of new metals and alloys. Stay tuned for part two of the history of metal on Saturday it will be available here.
An example of the kind of meteorite that would have given early civilizations access to iron.
Image is in the public domain, obtained from: http://upload.wikimedia.org/wikipedia/commons/8/8d/TamentitMeteorite.JPG

About this Contributor: I just finished my final year of high school. I love playing ultimate frisbee, skiing and playing the clarinet/guitar. I am happiest when learning random trivia or stargazing. Learning for me is its own reward, whether it is about the quantumly tiny or the cosmologically large.

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