Wrong, Wrong, Wrong

Aside

[You’ll have to take my word that this post was planned before Megan left a comment to much the same effect on Facebook. I still wrote it, because I love sharing space trivia, but because it took several more days to finish, my summer schlamperei cannot be questioned.]

Last week I discussed a mistaken explanation in one of my engineering textbooks. The specific explanation was wrong, but there’s two other issues with that innocuous caption in chapter one.

Hibbeler attributes a NASA image to a PhotoShop artist on Shutterstock. Now there’s nothing wrong with getting images from there. I find them a bit overthetop personally, but when has that ever been an impediment to the authors of textbooks on serious topics? Never, that’s when.

But why would you go through a stock image company when NASA images are public domain? It seems unnecessary, strongly suggests that author or graphic artist did a quick Google search, rather than having a clear image in mind. That brings us to the other problem.

This is a very specific, very recognizable image of Bruce McCandless operating the Manned Maneuvering Unit during STS-41B. You even see the same cloud patterns on the NASA website. And the last I heard, Bruce McCandless is a man.

Misgendering McCandless was obviously done for inclusion, but would it have been so hard to get a picture of a woman astronaut? It certainly would go further toward fixing the image of female spacetravelers in the reader’s mind.

Unfortunately for Hibbeler, there aren’t any pictures of women EVAing without a tether because no woman has ever operated the MMU. If that seems problematic, consider that the MMU was an experimental piece of technology that was really too dangerous to use regularly. Only six astronauts ever wore them, the last in November of 19841. After the Challenger disaster, NASA cancelled all the potential flights which might use the MMU and unofficially retired them from use.

But, we don’t really need a picture of a female astronaut operating untethered, because Hibbeler got it wrong. Astronauts aren’t weightless in orbit because they’re far removed from Earth’s gravity; they’re weightless because they’re falling around Earth at the same rate as their spacecraft and everything in it2. We can use an interior photo, this classic picture of Mae Jemison aboard Endeavour being a logical choice:

mae_jemison_in_space

Now was that really so hard?


1To be explicit about it: including that final mission, only four American women had reached orbit, and only one had performed an EVA. The Soviet Union, meanwhile, only ever sent up two female cosmonauts. Tereshkova, in 1963, was basically a publicity stunt: she never returned to space and the Soviets resumed all-male crews until Svetlana Savitskaya launched in 1982, by which point it was clear that American women were going to space to stay. Nevertheless, Savitskaya beat Kathryn Sullivan to the first female spacewalk by 78 days.

2If we wanted pictures where the inverse squared law has kicked in, our selection is limited to the deep space EVAs during Apollo 15, 16, and 17. Performed during the coast back to Earth, terrestrial gravity had lessened, though their weightlessness was still attributable to free fall. However, our selection is all-male: Al Worden, Ken Mattingly, and Ron Evans.

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Beware Scientific Metaphors

I’m about a quarter finished with Isabel Paterson’s The God of the Machine, which I’m finally reading after several years of intending to. So far, it’s been both pleasurable and interesting. My main reservation, however, has been an extended metaphor which both illustrates the central idea and potentially undermines it.

Paterson develops a notion of energy to describe the synthesis of material resources, cultural virtue, and human capital which results in creativity and production. As metaphors go, this is not a bad one. That said, my engineering background gives me cause for concern. It isn’t clear that Paterson has a clear understanding of energy as a scientific concept, and her analogy may suffer for it. Complicating matters, she sometimes also phrases “energy” as if it were electricity, which is another can of worms in and of itself.

Mechanical energy behaves oddly enough for human purposes, being generally conserved between gravitational potential and kinetic energy, and dissipated through friction and heating. It emphatically does not spring ex-nihilo into cars and trains. Coal and oil have chemical potential energy, which is released as thermal energy, then converted into kinetic energy and thus motion to drive an internal combustion engine.

Electrical energy is even weirder. It’s been enough years since I finished my physics that I won’t attempt to explain the workings in detail. (My electronics class this spring bypassed scientific basis almost entirely.) Suffice to say that the analogy of water moving through a pipe is not adequate beyond the basics.

Atomic energy, the most potent source yet harnessed, does create energy, but at a cost. A nuclear generating station physically destroys a small part of a uranium atom, converting it via Einstein’s famous relation to useful energy. But more on that in later posts.

I won’t say that the “energy” metaphor is strictly-speaking wrong, because I haven’t done the work of dissecting it in detail. Paterson was a journalist and writer, but she was also self-educated, and therefore we cannot easily assess the scope and accuracy of her knowledge of such phenomena. But I don’t think it matters: even if the metaphor is faulty, the concept which it tries to communicate seems, on the face, quite plausible without grounding in the physical sciences.

I bring this up now, well before I’ve finished the book, because I’ve seen much worse analogies from writers with much less excuse to make them. The God of the Machine was published in 1943. Authors today have a cornucopia of factual knowledge at their fingertips and still screw it up. For instance, take this caption from my statics textbook:

HibbelerAstronaut

Hibbeler, R. C., Engineering Mechanics: Statics & Dynamics, 14th ed., Pearson Prentice Hall, Hoboken, 2016.

There is no excuse for a tenured professor (or, more plausibly, his graduate students) to screw this up. The correct equation is on that very page and they couldn’t even be bothered to run the numbers and see that, no, you’re not significantly lighter in low Earth orbit. From my perspective, such a blatant error is unconscionable in the opening pages of a professional text.

Now that isn’t exactly a metaphor, but it illustrates the risks of discussing fields nominally close to your own which nevertheless you know very little about. Imagine the danger of using metaphors from totally different fields you’ve never formally studied.

So, I would advise writers to be sparing with scientific metaphors. If you can learn the science correctly, that’s great: you’ll construct metaphors that are both interesting and accurate. But as we’ve seen above, even PhDs make stupid mistakes. Err on the side of caution.

Do You Hate Math or Just Counting?

Last weekend KU held their annual Engineering Expo, a fairly typical sort of event for trying to get little kids interested in science and engineering. If you’re unsure what that might entail, come drop by next year.

Presumably this is fun for the little kids—most of them seemed pretty enthusiastic, and I never went to such events myself. And it’s fun for most of the students putting it on. We get to hang out with our friends, tell people about our majors, and get a day off class (though could you maybe have not scheduled it during midterms this year?). Half the fun is getting set up beforehand.

Because we’re nerds, we covered most of the leftover whiteboard space in the SEDS room with various engineering equations: thermo, flight dynamics, orbital mechanics, even the definition of a derivative. This predictably elicited a number of comments, mostly from parents but also from the kids themselves, about how much they hate(d) math.

This was particularly striking to me because when I was that age, I hated math. Or rather, hated what I thought was math. In elementary school, I didn’t know very much math. Pretty much all I knew how to do was glorified counting.

Addition? Counting. Subtraction? Backwards counting. Multiplication? Fast counting. Division? Backwards fast counting. Medians and means? Counting!

This pattern holds when we move onto the secondary school subjects. Algebra is almost entirely about counting graphically. Not all of geometry is counting, but a good fraction of it—vectors, for example—is. The same goes for a lot of trigonometry.

Only when you get to calculus, a senior year subject if it’s on the table at all, do you really start focusing on relationships versus the raw numbers. Calculus was the first math class which I enjoyed. That was the first time math became a tool rather than an obstacle. (Consistently, at least.)

A lot of students abandon mathematics long before they get to the stage where it becomes useful and meaningful. This concerns me. While there are plenty of people whose brains just aren’t made for math, there’s also a lot of great minds being lost because they aren’t made for endless dull arithmetic.

Spend years struggling away with contrived problems, truth held outside of grasp, and well, yes, giving up is certainly a reasonable response. You spent the last fifty years making science and math inaccessible and now, dear politicians and school administrators, you lament that more kids aren’t studying engineering. Behold the completely predictable consequences of your actions.

But this is not just an intellectual problem, or even an economic one. It’s a political nightmare.

Learning integral calculus completely rebuilt my perception of government finance. Just gaining an appreciation for statistics made me rethink dozens of policy positions. And yet I’d bet half our sitting Senators don’t even know what “differentiation” means. This should scare us shitless when they’re trying to plan for the next year, yet alone the next ten or twenty.

I hope that we changed a few minds last weekend, or at least planted a seed of doubt.  If technological civilization is going to survive the next 100 years, we need to rethink the way our culture approaches math and science. I’m severely tempted to do pro bono math education out of fear, but a few college kids can’t do it alone.

So, for your children’s sake: Do you hate math, or just counting?