In Illinois, United States
How Geocaching Works
This cache, a peanut butter jar, is located along the Des Plaines River trail south of US 173. The posted coordinates are for the trail/highway intersection. Suggested parking is in the Van Patten Forest Preserve parking lot (N 42 27.959 W 087 56.387).
Metals are as varied as they are important to us. We all know about metals such as steels and bronzes, which are metal alloys (“mixtures” of two or more metals/elements). Many conditions dictate which metal should be used, how it is fabricated and what it is alloyed with. For instance, some applications require a metal be exposed to relatively high temperatures. In this case, a molybdenum alloy might be used. Fabrication techniques such as arc welding may require that a protective gas be used to prevent contamination of the weld. Helium is often used for this purpose. The properties of metals can be improved (or degraded) by many of the less common elements. For instance, ytterbium is added to stainless steels to improve the mechanical properties (strength) and gadolinium is sometimes added to ferrous materials to improve their workability.
As with less common elements, gases can be both beneficial and harmful when in the presence of metals. Oxygen will react with (oxidize) most metals and its presence must always be taken into account when processing them. Nitrogen can be helpful in preventing oxidation. One of the most reactive metals is barium that will oxidize immediately if not covered by oil. Another way to protect metals is with a coating such as zinc on steel (galvanization). We discussed earlier how helium can protect metals during processing.
By now you should have the information needed to determine the cache location. Good luck and enjoy the area while hiking/biking to the cache!
(No hints available.)
Last Updated: on 2/26/2013 6:33:18 PM (UTC-08:00) Pacific Time (US & Canada) (2:33 AM GMT)
Coordinates are in the WGS84 datum