Fun with geekage for August 2020

Technical fields aren't like other fields.

But there's a disturbing trend in education (brought in from non-technical fields) and in the reporting of technical fields (done by people with minimal-to-none interest in the technical matters, and yes, that includes those with putative training in the technical fields whose work is now in the infotainment business) of moving away from technical knowledge even in those technical fields:

The answers to the type 2 questions, real technical questions, from the top:

First question: The combustion equation would be

CH$_4$ + 2 O$_2$ $\rightarrow$ CO$_2$ + 2 H$_2$O

but it's unnecessary; since each methane molecule will yield a CO$_2$ molecule we can simply calculate the ratio of the masses: m(CO$_2$)/m(CH$_4$) = (12+2*16)/(12+4) = 44/16 = 2.75, so a metric ton of methane will yield 2.75 metric tons of carbon dioxide.

Second question: The density of air at one standard atmosphere and 19°C is 1.225 kg/m$^3$, so a 25 m$^3$ room contains 30.625 kg of air. A 1000 W heating element releases 3.6 MJ of energy in one hour. The increase in temperature is therefore (3600 kJ)/(30.625 kg x 0.72 kJ/(kg °K)) = 163 °K, for a final temperature of 182°C.

(Assuming no losses to the outside and using a constant value for the isochoric specific heat for air throughout the temperature range 0-200°C to avoid computing an integral, a reasonable approximation given it varies between 0.70 and 0.74 in that range.)

Third question: At resonance frequency  $wL = 1/(wC)$ so $w^2 = 1/(LC)$, $w = 57,735$ radian/s or f = 9189 Hz. At that frequency the capacitor and inductor cancel each other out (impedance is zero and power factor is 1), so peak power is $5^2/100 = 250$ mW and RMS power is $250/\sqrt{2}$ = 177 mW.

These are not "gotcha" questions: I learned to solve the second in 11th grade; I learned electronics and chemistry by myself as a kid, but the material to solve the first was taught in 9th grade and the third in 11th grade, for students taking a chemical or electronics track in high-school (9th-12th grades). All of this was assumed known for incoming EECS students in the early 80s in Portugal.

Tempora mutantur, nos et mutamur in illis

From a video of an event in 2016. Most of the weight loss happened in the last 12 months as the result of intermittent fasting and a focus on high-protein, low-energy foods.

Another growth industry in San Francisco

When authors want to be science-y, but don't want to do the science…

From a mil-fic book that we'll keep unnamed.

At 18 km altitude, the gravity is 99.4% of the gravity at sea level ($6378^2/(6378+18)^2$), so Colonel Z would need super-human perception to be able to separate that $0.006 g$ from the turbulence and change in aircraft acceleration due to atmospheric changes.

(The story itself makes little sense, it's a remake semi-update of Tom Clancy's "Red Storm Rising," but with several errors of logic and biased by the need to make Russians super-hyper-badissimo-evil idiots.)

Chocolate milk, the high Protein-to-Energy version

Geeky linkage

(Because work has gotten into the way of blogging, social media, and other things. Book is 90-95% complete.)

Claustrophobia-inducing video by Smarter Every Day crawling inside a torpedo tube in a submarine while it's under the Arctic Ice Cap.

Nasa makes Einstein-Bose condensates aboard the ISS.

Scott Manley showcases the ideal villain lair, complete with a rocket to take the villain to a secret space base. Or a smart way to use the oceans to position a launch pad precisely where one wants (on the Equator, for example, to minimize the energy necessary to change the inclination of the orbit for a GEO satellite).

Because a real geek needs some sci- fi in their life.

Fun with numbers for November 9, 2019

Science illustrations made by people without quantitative sensibility

From a tweet I saw retweeted by someone I follow (lost the reference), this is supposed to be a depiction of the Chicxulub impact:

My first impression (soon confirmed by minor geometry) was that that impact was too big; yes, the meteor was big for a meteor (ask the dinosaurs…), but the Earth is really really big compared to meteors. Something that created such a large explosion on impact wouldn't just kill 75% of the species on Earth, it would probably kill everything on the planet down to the last replicating protein structure, boil the oceans, and poison the atmosphere for millions of years.

Think Vorlon planet-killer, not Centauri mass driver. 🤓

Using a graphical estimation method (fit a circle over that segment of the Earth to get the radius in pixels, so that we can translate pixels into kilometers), we can see that this is an overestimation of at least 6-fold in linear dimensions (the actual crater diameter is ~150km):

6-fold increase in linear dimensions implies 216-fold increase in volume (and therefore mass); using the estimated energy of the actual impact from the Wikipedia, the energy of the impact above would be between $2.81 \times 10^{26}$ and $1.25 \times 10^{28}$ J or up to around 22 billion times the explosive power of the largest H-bomb ever detonated, the Tsar Bomba.

The area of the Earth is 510.1 million square kilometers, so that's 43 Tsar Bombas per square kilometer --- which is a lot, considering that the one Tsar Bomba that was detonated had a complete destruction radius in excess of 60 km (or an area of 11,310 square kilometers) and partial destruction (of weaker structures) at distances beyond 100 km (or an area of 31,416 square kilometers). And, again, that's 43 of those per square kilometer; so, yeah, that would probably have been the end of all life as we know it on Earth, and I wouldn't be here blogging about it.

A more accurate measurement, using a bit of trigonometry (though still using Eye 1.0 for the tangents):

Because of the eye-based estimation, it's a good idea to do some sensitivity analysis:

(Results are slightly different for the measured case because of full-precision calculation as opposed to dropped digits in the original, hand-calculator and sticky notes-based calculation.)

It gets worse. In some depictions we see the meteor, and it's rendered at the size of a planetoid (using the graphical method here too, because it's quick and accurate enough):

To be clear on the scale, that image is 442 pixels wide, the actual Chicxulub meteor at the same scale as the Earth would be 1-7 pixels wide, which is smaller than the dots in the dotted lines.

For additional context, the diameter of the Moon is 3,474 km, so the meteor in the image above is almost 1/3 the diameter of the Moon (28% to be more accurate) and that impact crater is over 1/2 the diameter of the Moon (60% to be more accurate).

Solar energy density in context

2 square kilometers for 100 MW nameplate capacity… and they're in the shade in that photo, so not producing anything at the moment.

Capacity factor for solar is [for obvious reasons] hard bound at 50%. For California, our solar CF is 26%; let's give Peter Mayle's Provence slightly better CF at 30%, and those 2 square km of non-dispatchable capacity become about 1/20 of a single Siemens SGT-9000H (fits in 1200 square meters with a lot of space to spare for admin offices and break room, works 24/7).

Nano-review of R Programming Compiler for the iPad

Basics: Available on the iOS app store; uses a remote server to run the code, so must have a net connection. Free for the baseline but seven dollars for plots and to use packages, which I paid. The extended keyboard is very helpful considering the limitations of the iPad keyboard. (Also runs on the iPhone and the iPod touch, though I haven't used it on them yet.)

I wouldn't use it to develop code or even to run serious models, but if there's a need to do a quick simulation or analysis (or even as a matrix calculator), it's better than Numbers. Can also be used offline to browse (and edit) code, though not to run it.

The programmer-joke code snippet in the above screen capture run instantly over a free lobby internet in a hotel conference center, so the service is pretty efficient for these small tasks, which are the things I'd be using this for.

Some retailers plan to eat the losses from tariffs

From Bain and Company on Twitter:

My comment (on twitter): Yeah, these are well-behaved cost and demand functions so when a tariff is added to the cost, typically the quantity drops and the price rises, unless there's some specific strategic reason to incur short-term opportunity costs.

Rationale (from any Econ 101 course, but I felt like drawing my own, just for fun):

Note that Bain's breakpoint at 50% of the tariff is the solution to the problem under linear demand with constant marginal cost, but other shapes of demand can make that number much bigger, for example, this exponential leads to 74% (numbers rounded in the diagram but not in the computation):

The demand function is nothing awkward or surprising, just a nice decreasing exponential:

On the other hand, if the marginal cost decreases with quantity, particularly if marginal cost is strongly convex, there's a chance the actual price increase from a tariff is higher than the tariff, even with linear demand:

Note that this is different from lazy markup pricing. Lazy markup pricing always raises the price by more than the tariff, so in places where such outdated pricing practices [cough Portugal /cough] are common, tariffs have a disproportionate negative impact on the economy and general welfare.

Late non-numerical entry: Another news item based on not understanding the life cycle of technologies

From Bloomberg (among many others) we learn that there's a new solar energy accumulator technology, and as usual the news write it up as if product deployment at scale is right around the corner, whereas what we have here is a lab testing rig… that's a lot of steps before there's a product at scale. And many of those steps are covered with oubliettes.

Schrödinger's Cat Litter

"Quantum mechanics means that affirmations change the reality of the universe."

Really, there are people who believe in that nonsense. I don't know whether affirmations work as a psychological tool (ex: to deal with depression or addiction), though I've been told that they might have a placebo effect. But I do know that quantum mechanics has nothing to do with this New Age nonsense.


The most misunderstood example: Schrödinger's cat

A common thread of the nonsense uses Schrödinger's cat example and goes something like this:

"There's a cat in a box and it might be alive or dead due to a machine that depends on a radioactive decay. Because of quantum mechanics, the cat is really alive and dead at the same time; it's the observer looking at the cat that makes the cat become dead or alive. The observer creates the reality."

No, really, this is a pretty good summary of how the argument goes in most discussions. It's also complete nonsense. The real Schrödinger's cat example is quite the opposite (note the highlighted parts):

(Source: translation of Schrödinger's "Die gegenwärtige Situation in der Quantenmechanik," or "The current situation in quantum mechanics.")

As the excerpt shows, Schrödinger himself described applying quantum uncertainty to macroscopic objects as "ridiculous." In fact, in the original paper, Schrödinger calls it burlesque:

In other words, this New Age nonsense takes Schrödinger's example of misuse of a quantum concept and uses it as the foundation for some complete nonsense, doing precisely the opposite of the point of that example.

Sometimes "nonsense" isn't strong enough a descriptor, and references to bovine effluvium would be more appropriate. In honor of the hypothetical cat, I'll refer to this as Schrödinger's cat litter.


Say his name: Heisenberg (physics, not crystal meth)

Schrödinger isn't the only victim of these cat litter purveyors: the Heisenberg Uncertainty Principle also gets distorted into nonsense like:

"You can't observe the position and the momentum of an object at the same time. If you're observing momentum, you're in the flow. If you're observing position, you're no longer in the flow."

As I've mentioned before, when over-analyzing a Heisenberg joke, the uncertainty created by Heisenberg's inequality ($\Delta p \times \Delta x \ge h$) for macroscopic objects is many orders of magnitude smaller than the instruments available to measure it. TL;DR:

Police officer: "Sir, do you realize you were going 67.58 MPH?
Werner Heisenberg: "Oh great. Now I'm lost." 

Heisenberg's uncertainty re: his position is of the order of $10^{-38}$ meters, or about 1,000,000,000,000,000,000,000,000,000,000,000,000 times smaller than an inch.

And yet, these New Age cat litter purveyors use the Heisenberg uncertainty principle to talk about human actions and decisions, as if it was applicable to that domain.


What are the "defenders of science" doing while this goes on?

Ignorance, masquerading as erudition, sold to rubes who believe they're enlightened. Hey, I'm sure many of the rubes "love science" (as long as they don't have to learn any).

Meanwhile, "science popularizers" spend their time arguing politics. Because that's what science is now, apparently...