Chemistry of carbon dating
To see what it takes to get something bigger than that tiny bead, I visit the processing plant where the ore ends up. Here too, extraction begins with crushing, in these huge tumblers. So what the farmers would do is they would say, for example, "David, you loan me some money, okay? I can hardly think of anything that doesn't have either a tiny bit of copper or lots of copper. When placed in a circuit, the negatively charged particles line up and flow as an electric current.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.I wonder, though, if there's a more scientific way to evaluate the metal. First, a polishing wheel gives the bronze a mirror-like finish. We'll have to zoom in a hundred million times to see an atom.To find out, I'm taking a piece of it to David Muller, at Cornell University. Then the sample is inserted into a powerful electron microscope. To understand the scale, imagine if I were floating in space, 2,000 miles above the earth, looking down at the United States. Now what we're actually starting to see is the microstructure of the grains in that bronze. They are meant to absorb and reflect sound, because the microscope itself is so sensitive that if you were to talk, just the pressure wave from your voice is going to, is going to give enough mechanical vibration to shake this thing around.
By bombarding samples with x-rays they were able to create shadowy images of that crystal structure, but the idea that we might one day see actual atoms was beyond imagination. Our bell makers must be true masters of their craft.
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.
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.