Permeameters for Dummies

permeable concrete

When there are two different meanings for a term, it's only natural for perfectly ordinary people to find themselves confused about its use. When that happens, we – of course – use the opportunity to look to an authority for clarity. That only works, however, if the authority is actually authoritative. The precise opposite occurred at wiseGEEK.com when they allowed someone calling itself Alexis W. to write a post entitled, "What Is a Permeameter?" (now at AboutMechanics.com, but still stupid).

Our staffer was a little surprised to learn that Alexis' opening sentence is based in truth. It's utter crap, of course; but based in truth, if you believe Wikipedia to be the final answer:

"A permeameter is a measuring device used in instances where the amount of electromagnetic permeability of natural substances such as iron may be identified to determine whether or not they are suitable for commercial use."

The entry actually says that a permeameter is "an instrument for rapidly measuring the electromagnetic permeability of samples of iron or steel." The staffer's surprise was because our staffer was quite well-acquainted with the permeameters used to evaluate the permeability of soil and rock samples instead of iron and steel. Weird. Perhaps the fact that W.¹ couldn't find any more information about the permeameter described in the Wikipedia article is why she conflated that usage with the permeameter used by soil scientists and other materials investigators. That's (probably) where the "natural substances..." came from.
Alexis attempted to pivot to soil permeability pretty quickly:

"Permeameters may also be used to determine whether or not the soil content of a specific area of land may be suitable for a wastewater treatment system, by testing the permeability of the ground around where the system would be placed."

She remained confused about just what a soil permeameter measures, however, as shown by the following:

..."the two main functions are to measure the amount of electromagnetic permeability in different soil components and to determine soil compaction for suitability for construction"

Oh, she sort of got to the point a little later when she blathered a bit about the permeability of concrete and asphalt, but when it came time to explain a compaction permeameter, W. was a little... confused:

"...it acts as a pressure tank, applying water pressure to a soil sample to determine the amount of water needed to permeate the soil sufficiently to make it shift or wash away..."

...which, frankly, we could not make heads or tails of.

It's pretty obvious that Alexis never quite understood that a permeameter measures the transmissivity – to water or other fluids – of soil, rock, or other material; also known as permeability. Because Alexis was baffled by the Wikipedia entry for "permeameter," she spent the rest of her article confused... a Dumbass of the Day, in other words.

¹ We suspect that Alexis W. at wiseGEEK is the same person as Alexis Writing at eHow, and somehow came to the conclusion that this is in reality a consortium of freelancers instead of one person.

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