Scientific Terminology for Dummies

wind transport and saltation

Every day, tens of millions of students, from elementary school to college, ask their favorite search engine for help with homework questions. A couple of decades ago, someone got the bright idea to leverage those questions by "scraping" the search queries, assigning them to freelancers to answer, and wallpaper the resulting text with ads to generate cash. Sounds like a plan... except that the weak link was the freelancers, who too often had no idea what the answer actually was and were reduced to performing a half-assed copy-reword-paste job on something they found on the 'net. Today's DotD, Susan Sherwood, may have had an PhD in education, but she definitely did not know "What Is the Difference Between Deflation & Saltation?" for Sciencing.com.

That's a bizarre question, to be honest, since the two are closely related phenomena; so closely related that saltation is one of the processes by which deflation occurs. It's not dissimilar to asking, "What is the difference between baking and kneading?"

Deflation, in the geomorphology sense (as opposed to economics) is the removal of soil and fine sediment from a flat surface by wind action. It is more common in arid environments where there is insufficient plant material to hold down surface material. Saltation, on the other hand, is one of the methods by which deflation occurs: it is the movement of particles by eddy currents in fluids (either air or water), and proceeds by bouncing loose material along a substrate. This is as opposed to suspension of grains in a fluid.

Sherwood managed to cough up a partial description of deflation, telling her readers that,

"During deflation, small particles of sediment or soil are moved by the wind. Clay, silt and fine sand are often moved by this process."

In fact, she's merely described wind erosion here, not to mention that we wonder what else is moved by the process: cars? trees? iPads? She followed up on her halfway explanation by babbling about desert pavements, confusing aeolian transportation with deflation. After hemming and hawing for a couple hundred words, Susan finally got around to actual examples of deflation, saying that,

"Sometimes, in areas without moisture or vegetation, the wind scoops out matter, leaving dips in the landscape."

'Nuff said... Sherwood also attempted to define saltation, telling her readers that,

"In contrast to deflation, saltation moves medium-size particles about 0.1 to 0.5 mm in diameter. The wind carries these bits just above the surface. The particles travel for a short distance and then fall to the ground. There they dislodge other grains, causing them to bounce."

desert pavement

While Sherwood accurately (as far as we can tell) reworded her source, that source was entirely about aeolian transport. What Susie didn't know (lack of background rears its ugly head) is that saltation is common to all fluid transport, including water, and that boulder-sized particles routinely undergo saltation in steep mountain streams. She also blew the concept of a desert pavement, saying that the phenomenon is a result of moist substrate when it's actually a surface stripped of fines by wind erosion. Idjit.

Here's what happens when self-declared "science experts" like Sherwood venture into science they don't understand: we give them the Dumbass of the Day award. For Susan, it's her third award... in three different scientific disciplines. Yeah: science expert.

SI - GEOMORPHOLOGY