Element #11 Traditional Cache
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Difficulty:
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Terrain:
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Size: 
(small)
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Element #11 is Sodium.
Sodium is in the first column of the periodic table, which means it’s classified as an alkali metal. It’s the fourth most abundant element in Earth’s crust, but is never found as the element itself as it’s too reactive (more on this later). One of its most abundant compounds is located right on the other side of the trail from the cache—sodium chloride, NaCl, salt.
Salt is an essential nutrient, being important for all sorts of metabolic functions, not the least of which is supplying electrolyte ions to whiz back and forth across cell membranes to do things like conduct nerve impulses. Too much salt, however, is associated with high blood pressure (hypertension).
Being so important, the production of salt is an important industry. Salt can be mined from underground mines (In fact, 1100 feet below the city of Detroit are vast rock salt mines.). It can also be produced by evaporation of seawater in large ponds. The southern San Francisco Bay has been one of the largest areas of solar salt production. Basically seawater is let into an enclosed pond, and allowed to evaporate leaving behind a residue of salt. The process is repeated over and over until a thick crust of salt remains which is scraped off and hauled away.
In the year 2002, the Cargill Salt Co. sold many of its salt ponds to various public agencies, to be restored to the original salt marshes they were before salt production began in the Gold Rush times. The salt pond near by the cache is designated pond R (Ravenswood)-3. Its salt production has stopped and limited tidal action will be allowed, while the agencies determine the best eventual fate of the pond. Thus, the salt features in this pond are slowly eroding over time.
Sodium as an element was first isolated in 1807 by Sir Humphrey Davy by passing an electric current through a solution of sodium hydroxide (lye). Sodium metal is extremely reactive, and must be stored under oil to prevent it from reacting with air or water. Throwing a small piece of sodium into water was always great fun in high school chemistry class. It skitters across the surface of the water and fizzes as it produces hydrogen gas. It also gets hot. If you have a big enough piece, you can get the sodium hot enough to catch fire, melt, or even boil. Of course, if that happens an even bigger explosion follows because of all the hydrogen being generated!
Sodium has another interesting use. If you heat it up to glowing, it gives off a very particular almost monochromatic orange light. (This particular spectral feature was first seen in the spectrum of the SUN—there’s a hint for you.) Because of their efficiency, sodium vapor lamps are popular as lights on streets and parking lots. Because of their monochromatic orange color, it is difficult or impossible to distinguish colors under these lights, making everything seem a muted orangy-gray color. These lights are particularly popular in Silicon Valley as the light pollution from these lamps is easily filtered out by the telescopes up on Mt. Hamilton.
The cache is a small water-tight swim container, and is located outside the fence of the nearby office park. When replacing, please make sure it’s not visible from the trail. Co-ordinates should be pretty good, although I’m always willing to accept better ones should they seem off! The trail is likely to be crowded on weekday lunchtimes, and deserted at other times. The nearest legal parking is by this cache, and the cache is kid-friendly if you follow the trail.
Additional Hints
(Decrypt)
Onfr bs cbyr oruvaq Gerr # 1206