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If David's microscope is powerful enough, we should see regular rows of copper atoms with tin atoms packed in between. Well, thanks for my tour into the, to the unseen and to what used to be the pure, purely theoretical.I can't believe I can now put on my resume that I've seen atoms. This amazing ability to see atoms has opened up new worlds for scientists. Every day she receives hundreds of samples of earth taken from the mine. …then pulverized to the consistency of baby powder. But two rows above gold is another metal of antiquity that looms large in our lives: copper; symbol Cu; atomic number 29—29 protons, 29 electrons. Bronze helped to spur global trade, and, once forged into tools and weapons, it played a defining role in the empires of antiquity. I'm here because they're about to cast several bells. This rock face is about a quarter mile below the surface, and, according to John Taule, it's loaded with gold, somewhere. That's where Gayle Fitzwater and the assay team come in. I think I've seen one of these machines at Starbucks. It is, perhaps, the most emotional of the elements. Tin added in small amounts to copper makes bronze, the first manmade metal alloy. This is The Verdin Company, a 170-year-old family-run business in Cincinnati, Ohio. Gold has been sought since ancient times, yet all the gold ever mined would fit into a single cube about 60 feet on a side. It was a sacred material to ancient people, and it's never lost its luster. Only a few natural elements have greater density than gold: rhenium, platinum, iridium and osmium. Like all elements, gold is an atom that gets its identity from tiny particles: positively charged protons in the nucleus, balanced by negatively charged electrons all around, plus neutrons, which have no charge at all. It's virtually indestructible, yet also soft and malleable.The crack could have been caused by the way the atoms were arranged within the metal. If the metal is allowed to cool, flaws could develop, ruining the bell.Too much tin, and the copper atoms can't move at all. When the bronze has reached the proper temperature, 2,200 degrees Fahrenheit, it's time to pour. Even though the foundry has the technology to precisely control the temperature, and Ralph and his team have decades of experience, bronze remains unpredictable. The bells have to cool for 24 hours, so it's the next day before we can find out if they'll be making music or ending up as scrap. A gleaming chrome, silver magnificent church bell ready for hanging? And now, for the moment of truth: will this bell be good enough to sing? Time to celebrate the millennia-old tradition of bronze.
And that sets the stage for the trickiest step, coaxing the microscopic gold out of the rocky ore. And then, in the future, I will sell you that crop that I planted for this amount of dollar." So what I'm doing is I'm selling you the right to buy or sell my future crops. The sea of electrons also creates flexible, metallic bonds among the atoms.Out of every hundred bells they pour, 20 or 30 will fail. Our bell resonates with a beautiful tone, and it takes many seconds for the note to die out, thanks to the interplay between copper and tin.Even the best bell makers can't know whether their bronze will be too stiff or too soft, until they pour a bell and strike it.This is what can happen if the amount of tin isn't right.No one is certain why the Liberty Bell cracked, but a chemical analysis indicated there was too much tin and perhaps other impurities in the bronze.
Here, at the Cortez Mine, in Nevada, high-tech prospectors are moving mountains, closing in from above and below. Which raises a question: if the gold is invisible to the naked eye, how do they even know if they're digging in the right place? Eight bars, $12 million, sitting on this unassuming little table. Of all the elements that touch our lives, nothing drives humankind to acts of love or destruction like gold. Copper alone is impressive stuff, but when ancient metallurgists combined it with another element, they invented a much tougher material that went on to conquer the world. Tin; symbol Sn; atomic number 50—50 protons and 50 electrons.