Stuff Made of Silver
I'm a bit of a magpie. I like shiny things, and I suspect I'm not alone -- the glint of silver has been hypnotizing people for millennia; more abundant and useful than gold, silver has been hoarded and admired by kings and paupers alike. As coin, silver fulfilled an important function for trade in the history of commerce; but as adornment, it has always been coveted.
On the Periodic Table of Elements, silver (Ag) is 47th. I must admit that even after a moment of reflection this means nothing to me. I wish it did; I'd like to be enchanted by the knowledge that the atomic weight of silver is 107.8682 (107 what ?). What does interest me, though, is that the English word comes from the Anglo-Saxon seolfor (go on, say it out loud; isn't it a great word?). And if you're into the Latin classification, the chemical symbol, Ag, comes from the word argentum -- which leads us to Argentina, and the history of the South American continent explored and exploited for its rich metal deposits.
According to the Silver Institute, the price of silver has quadrupled since 2000 due to investor interest in the market (it reached $20 per troy ounce in the first half of 2008, before settling back to $16, but is holding firm at that price). If this needs a little context, the price in 1950 was 75¢ and the annualized inflation rate in the US between 1950 and 2008 was 3.85%. Sterling silver must have a content of at least 92.5% of the metal, and so any old sterling silver you have lying around has risen in value considerably. Hang on to it.
I just like silver because it's shiny, however. I also like white gold, which is an alloy of gold and silver, but I can't afford it. Silver jewelry is cheap, though (rather than coins or pure silver, the applications of which I'll get to in a minute), so it might be worth your while collecting all your old bits and pieces and melting them down (the melting point is 961.78°C or 1763.20°F, so don't try this at home, folks, and certainly not in any of your wife/mother/BFF's best cookware).
White gold is shiny, too
Applications of silver in science and technology
Since pure silver is the best conductor of electricity and heat that there is (that we know about, yet, at any rate), it is used in some circuit boards, in soldering, and for electrical contacts when all these need to be as efficient as possible (such as any found in NASA projects, for example). So don't throw away your old shuttles or Apollo landing craft, either. (Crews are hired to strip old space craft of all valuable metals and alloys, if you're wondering what they do with them.)
Pure silver is also the best reflector of light known, too, although mirrors made of silver need a protective coating to prevent tarnishing, which I suppose interferes with the reflectivity. For a review of the technical specifications of the reflective silver coating see this great article about the Gemini Observatory. (Astronomical telescopes usually use aluminum mirrors with a coating of silicon dioxide.) If you're wondering, as I was, whether the Hubble Space Telescope used silver -- well, it doesn't. It was manufactured with a "reflective coating of aluminium 65 nm-thick and a protective coating of magnesium fluoride 25 nm-thick" (see this article).
Silver cadmium and silver-zinc (silver oxide) batteries are high capacity options -- nickel cadmium batteries used to be standard on satellites, but Ag-Cd is lighter. Cadmium is a heavy metal, like zinc and mercury, though not as toxic. Silver oxide batteries can be found in missiles and submarines, as can mercury, since toxic waste is the least consideration in a torpedo, after all.
In photography, silver nitrate can be found in some films (remember those?) and photographic papers; again, silver's reflective qualities are key here, and as any older photographer knows, getting the chemistry right when developing prints is the trickiest part for us lesser mortals (sorry; I used to date a photographer who was insufferably smug about all things photographicalistic ).
The most interesting instance of silver in science, though, is using silver iodide to seed rain clouds. As well as inducing rain, though, precipitation can also be suppressed -- silver iodide (AgI), along with dry ice and liquid nitrogen, will be used to seed clouds in China during the 2010 Asian Games in Guangzhou. When smaller quantities of the three agents are used to freeze water in clouds, smaller ice particles are formed which evaporate before they reach the ground (larger particles thaw as they fall and hit us as rain).
Shiny, shiny things
Silver is most accurately described as being a transition element (rather than a metal). I don't really know what that means (I hope there isn't a quiz on all this at the end!) but I like the figurative connotations of transitional states for an element closely aligned with the moon (silver/moon, gold/sun) in literature and lore. Neat.
More by this Author
The two bones of the forearm -- that portion of the arm from elbow to wrist -- are the radius and the ulna. The radius is the inner bone, in line with the thumb, and the ulna is the outer bone. Fractures to these...
Why does the sight of a clean-cut man in a dress uniform look appealing? (I'm sure we can all agree that no one really likes to see a man in combat gear -- unless he's coming home safely, that is.) There is...
I'm always impressed with the impact poetry can have on kids who are sure they won't like it, ever, and any particular poem you ask them to read in class least of all. I always enjoy seeing them dismiss their former...