Category: Tools and Technology

Under pressure

Callan Bentley turns the screws on a diamond anvil cell. Pressures inside the cell, a little gizmo smaller than a snow dome, are on the order of 60 GPa. He writes:

  • 60 gigapascals is therefore a pressure equivalent to about 2100 kilometers of depth in the planet – most of the way through the mantle, though not quite to the outer core (which is at ~2900 km depth).
  • A pressure cooker cooks at 0.0001 GPa.
  • Your car’s tires are inflated to a pressure of 0.0002 GPa (2 bars, or ~30 psi).
  • 60 GPa is a lot more than 0.0002 Gpa.

(Sorry, but I had to go to that song.)

I’m with you on the illegible part

In a quite useful five-part series, Steve N.G. Howell explains how field notes work and how and what you might want to record, either in the field or in the motel at the end of the day. He saves the best advice for the last installment:

In conclusion, your notes are your notes. Write what you want, but in later years you’ll only have yourself to blame if your old notes don’t contain the information you find you want. If you have time, write it all down. If you don’t, pick and choose. But whatever you do, or don’t do, the main thing is to enjoy birding.

Halfway down the block before realizing that you’re headed the wrong way

A simple, analog solution to SOSED (Sudden-Onset Subway Exit Disorientation): low-profile wayfinding signs on the stairway risers, designed by Ryan Murphy and documented by Vicky Gan. Much more useful than smartphone beacons, also discussed in the post: who wants to be staring at a screen when you and 1,000 of your new best friends are trying to get off the platform and into the light?

I am relieved

The states of North and South Carolina are completing the resurvey of their common boundary, using high- and low-tech means, as Stephen R. Kelly notes in a recent op-ed and Kim Severson reported some time back. The colonial-era border was intended to consist of two straight lines, the 35th parallel and a diagonal crossing up from the coast. But 18th- and 19th-century surveyors made a hash of it, resulting in today’s rumpled compromise.

The rework was not intended to smooth out any of the coarse wrinkles, like the wobble around the city of Charlotte, but rather to replace the notched trees, now dead, and wandering survey monuments (including one moved by a golf course in order to impress golfers [?!]) that had originally marked the boundary.

But rest assured! South of the Border is still where it “Otto B.”

Two distinct problems

Charles Severance reflects on his experiences teaching MOOCs. In much the same way that John Markoff analyzes the situation (as I summarized earlier), Severance draws an important distinction between the objectives of conventional university training and those of massively open online courses. From the full article (behind a paywall):

My goal in a MOOC is to teach as many volunteer learners as I can and keep them engaged and learning as long as I can. In an on-campus course, my goal is to teach captive students as much as I can over a set 15 weeks. [Emphasis in original.]

Yuck

The supply of recycled CRTs and televisions, laden with hazardous lead, is booming. Unfortunately, the demand for this e-waste has crashed. As a result, recycling firms are going out of business and abandoning the waste, leaving toxic dumps for the states and federal government to clean up. The market is upside down.

In 2004, recyclers were paid more than $200 a ton to provide glass from these monitors for use in new cathode ray tubes. The same companies now have to pay more than $200 a ton to get anyone to take the glass off their hands.

Even worse, there seems to be no recycling market at all for LCD screens.

Ian Urbina does the grim reporting.

Some links: 65

Snow days are good for cleaning up the inbox of bookmarks.

  • Jeff Kelly shows how to build your own RFID data logger for $40 or less. It’s suitable for tracking birds at feeders, nest boxes, anywhere they hang out. The system works with any animal species large enough to carry an RFID tag; a battery at the logging station provides the power.
  • A new paper by G. Bohrer et al. describes an “exclusion zone” approach to siting wind turbines in an urban environment, as Roberta Kwok explains. The approach manages the tradeoff between maximizing the power produced by an array of turbines and minimizing its adverse effects on wildlife.

Working for scale

John Markoff posts an interesting item about evaluating the success of MOOCs. (Aside: tell me again what the difference is bewteen an MOOC and distance learning?) There’s been a lot of chatter about the fraction of students registered for a course that actually complete all of ites requirements—numbers like 10% are being kicked around.

Markoff emphasizes the point that 10% of a class of 100,000 is nevertheless more than 100% of a class of 500 in a conventional freshman lecture course. And, as one of the panelists at the Frontiers in Education conference in October pointed out, there’s a lot of uncertainty about how many of that hypothetical 100,000 are serious registrants. When the course is free and there’s no cost to dropping out, a lot of students will sign up on a whim. Some registrants are even other instructors, checking out how their colleague handles this new environment.

Leta has participated in two classes offered by Coursera in the past year and has been very pleased with the results. Meanwhile, I’ve been fairly busy with traditionally structured classes:

  • Short-term training in proprietary software technology. Three days of slideware and coding exercises — what Andy Hunt calls sheep-dip training. Moderate value for the money: I did refer to the class workbook a couple of weeks ago for some code samples. Having the instructor on hard was useful when I got stuck.
  • Foreign language instruction from Fairfax County Public Schools. Classroom time with a native speaker, a workbook for writing exercises, and a DVD with lots of listening drills. Good value for the money.
  • The Natural History Field Studies program from Audubon Naturalist Society and Graduate School USA. Each course is different, but it’s usually a blend of reading, lecture, writing, giving presentations to the class—and field trips. Moderate to excellent value for the money, depending on a couple of factors, but every field trip has been worth it. Some of the courses are reviewed by an accrediting agency: these have been the most challenging and the most valuable.

Markoff considers Duolingo, a web site for language instruction that doesn’t precisely fit the MOOC model, but it is operating at that scale, with roughly a million users. I could see myself giving it a try.

I need seven credits to finish my NHFS certificate. I think MOOCs have a ways to go before they can capture the five-senses experience of a cordgrass salt marsh.

MOOCs are scaling up the evaluation of students by problem sets and short writing assignments. I wonder how they can deal with evaluating spoken contributions: speaking a foreign language, giving book reports and oral presentations.