Archive for April, 2021

Experiment airs dirty laundry

This headline by BBC Science Focus Magazine caught my eye the other day: “Scientists are burying 2,000 pairs of underpants in Switzerland.” What in the world?

Further research revealed that this is a ‘thing’ for those who love their mother earth: Bury your briefs (provided they be 100 percent cotton). Then dig them up later and inspect their holiness, that is, degradation due to desirable microorganisms in your earth.

“The more active microorganisms live in the soil, the faster and the more holistically the underpants will be eaten up.”

  – Swiss research institute Agroscope

The BBC reports that volunteers will each receive two pairs of pants, along with tea bags as a control. One will be dug up after a month, the other after two months and both analyzed for holes. My observations:

  • It is good that the scientists leave nothing to chance by not allowing helpers to bury their personal underwear. (Yuk!)
  • This is a great example of a paired tea test (inside statistical joke).

Some farmers in southern Minnesota buried their undies a few years ago and discovered them to be completely disintegrated after only a couple of months—nothing left but the elastic bands. That is not surprising given the incredible fertility of land down there. As you can see in this report by MPR News, the remnants serve well for scaring off crows. However, I question the organizers’ judgement for naming this experiment “Soil Your Undies.” That is just gross.

For a more scientific approach to this methodology for assessing the quality of your soil, see this 2015 report from a research technician at the Ontario Ministry of Agriculture. However, though attention getting, using actual underwear versus cotton swatches may not be the best idea for quantitative measurements and decency—though the elastic bands can be very handy as I learned the hard way as a child with mischievous friends who liked to inflict wedgies.

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Illuminating results from sparkler experiment

This video, concluding with the obligatory lighting up of multiple sparklers, lays out the results of another fun and educational experiment by Chemical and Biological Engineering (CBE) students at South Dakota School of Mines and Technology (SDSMT) for their Applied Design of Experiments for the Chemical Industry class.

The testers: Anthony Best, Henry Brouwer, and Jordyn Tygesen, uncovered significant interactions of wind, water and lighting position on the burn time as illustrated by the Pareto chart of effects from Design-Expert software.

I expect these three experimenters will be enjoying extremely sparkly celebrations this summer!

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Mentos volcano rocks Rapid City

It was my pleasure to oversee another outstanding collection of fun experiments by the Chemical and Biological Engineering (CBE) students at South Dakota School of Mines and Technology (SDSMT) for this Spring semester’s Applied Design of Experiments for the Chemical Industry class presented by Stat-Ease. They continued on the excellent tradition established by the class of 2020 which I reported in my blog on “DOE It Yourself” hits the spot for distance-learning projects.

As promised, I am highlighting a few of the many A+ projects in StatsMadeEasy, particularly those with engaging videos. My first selection goes to Dakin Nolan, Erick Hoon and Jared Wilson for their “DOE Soda and Mentos Experiment”. They studied the “heterogenous nucleation of gases on a surface” caused by type of soda, its temperature and volume versus the quantity of Mentos. See the results in the video (“the moment you’ve all been waiting for”). Do not miss the grand finale (“The Masterpiece”) that shows what happens if you mix 15 Mentos in a 2-liter bottle of hot Diet Coke.

It’s hard to say how high the cola spouted in the blow out at the end, but it must have made a big sticky mess of the surrounding area. At similar conditions but at a more prudent maximum of 3 Mentos (the highest level actually tested in the DOE), Design-Expert predicts a peak of 310 inches—an impressive 25 feet of magma.

Further work will be needed to optimize the dosage of Mentos. Perhaps 15 of the sugary oblate spheroids may be overkill. There’s always room for improvement, as well as more fun, making volcanoes.

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