The alloy bronze is much stronger than copper and can be used to produce bronze knives and swords that can be sharpened and will hold their edge much longer than those made of copper. This mixture was so useful that an entire age came to be called the Bronze Age (from about 3000 BCE on). They learned that 15% tin and 85% copper produced a very strong alloy-alloy being a mixture of metals-bronze. This was to serve them well because as a result they experimented with adding other metals with a high melting point, such as tin, in various proportions. They found that by mixing and firing Malachite with charcoal in an especially hot fire, after the fire was spent and the result cooled (actually froze!), there resulted a solid puddle of copper, bigger than any nugget. As is usual in these things, this discovery was by accident rather than design. He then goes into the question of how these ancient people might produce many of these nuggets and not be dependent on finding them at random. Throughout, the author’s tone is friendly and encouraging, often giving the reader pats on the back for arriving at correct conclusions. And it must be said that throughout the book the images are well-chosen and extremely apt as illustrations of the very points that Grannis makes in the text. This is followed by a series of images showing the various objects that ancient people made from the originally amorphous nugget. Thus the Mesopotamians considered that this material, called malachite, might be useful for making household objects, tools and weapons. Furthermore, the substance could be pounded almost flat and was malleable enough to take on various shapes. For example, a greenish nugget discovered in Mesopotamia about 10,000 years ago had the property that when cut in half and polished the cut surface took on a shiny brownish tone. He encourages the reader to identify with the protagonists of this journey, experiencing their curiosity and the excitement of finding or deducing answers to the questions raised when results are not as anticipated. In an engaging conversational tone, Eric Grannis invites young readers to ponder the history and unearthing of metal from the ancient civilizations of Mesopotamia and Egypt to the discovery, in the Modern times, of electricity.
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