Rube-y Goldberg Tuesday: Optics Version

(OK, it’s Thursday, but this was supposed to run on Tuesday but didn’t, owing to operator error)

A Clever Rube Goldberg Machine That Runs on Light

The amplified light fuels a number of different elements like a tub of water and a marble moving down a chute, but it all keeps coming back to optics.

(Nit: it’s not amplified, just focused at various points)

What it is, and What it isn’t

The idea that measurement changes what is being measured is the observer effect, not the Heisenberg Uncertainty Principle. A video explaining the HUP.

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One, Two, Five Sigma!

Five sigma and all that

Another of Lyons’ themes in the article is to address the rather arbitrary “five sigma” (5σ) significance traditionally required by particle physicists to claim a discovery of a new particle or some other new effect.

This is often presented just as physics requiring 5σ, but Butterworth is a physicist and knowns that it’s not true in all sub-disciplines.

Danger, Will Robinson! Links Ahead!

WARNING: wild extrapolation (a classification system for science news)

[H]ere’s a potential classification system for science writing. It’s a bit more complex admittedly, and unlike films, multiple classifications can be applied to a single piece. How like science, to be so uncertain.

I Can See Right Through You

Having some more fun with my thermal camera (after a cold kept me from it for a bit). I had noticed that my lunch did not show up while being microwaved, because long-wave IR generally doesn’t pass through glass — here’s another image confirming this

You can’t see the thermal signature of my hand that’s behind the window. This is, of course, responsible for the greenhouse effect — visible light goes in but thermal IR does not leave, making the greenhouse (or your car, or, with a more wavelength-selective effect, the planet) get hotter.

I wanted to see if I could find anything that was transparent. I checked the transmission of sapphire and discovered it was a possibility — the transmission cutoff is out at 5 microns. Alas, the windows were opaque, meaning either that the windows I looked at were antireflection-coated (a distinct possibility), or that the bolometer sensors aren’t sensitive at the shorter wavelengths. But the plastic bag this window is in transmits just fine!

It’s probably made of polyethylene, which has good transmittance in much of the thermal range — just a few absorption lines (at about 3.5, 6.5 and 13 microns). We happen to have some 1/16″ thick poly sheets, we use for our air sled to allow it to work over porous surfaces, and are opaque to visible light. But not to thermal IR!

You can see a couple of spots where I touched the sheet with my fingertips and warmed it up, but in the picture my hand is behind the sheet and not touching it.

Ian, Freeze!

Through the Cracks Between Stars

Paglen ended his lecture with an amazing anecdote worth repeating here. Expanding on this notion—that humanity’s longest-lasting ruins will not be cities, cathedrals, or even mines, but rather geostationary satellites orbiting the Earth, surviving for literally billions of years beyond anything we might build on the planet’s surface

Neat image of the geostationary dots in a long exposure that shows the background stars’ apparent motion.

Great Bouncing Batteries, Batman!

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In this Corner, Cost. In the Other, Benefit.

Do the benefits of a college education outweigh the cost?

Spoiler alert: yes.

I do have an objection to strictly financial analyses I see; I hope people aren’t choosing careers based solely on how much money they can make rather than something they enjoy. The general benefits of learning how to think and being intellectually challenged are important as well. I wonder if the high cost amplifies a buyer’s remorse feeling, and/or if it pressures students to avoid certain choices which might mean an extra semester or two at school.

Others note that a college degree is no longer required to get a good job, especially since almost four of every ten college graduates are working at jobs that don’t require a college degree. Fruzsina Eordogh is one of those students who dropped out of college to work as a full-time writer for the Daily Dot (Facebook’s Mark Zuckerberg, Microsoft’s Bill Gates, and Apple’s Steve Jobs are three of America’s most famous college dropouts.)

The objection here is that people don’t necessarily know what they want to do at 18 years old, so they have no idea that the job they end up in doesn’t require a degree. Plus there’s nothing here that indicates that these 40% are not aspiring to better jobs that do require a degree. And bringing up Zuckerberg, Gates and Jobs as examples is like encouraging people to play the lottery by saying, “I won it, so that means you can, too!”

I’d much rather focus on efforts to make education affordable and available to anyone who wants it and make personal cost/benefit discussions moot.

Dr. Cookie

I’ve long held that the usual approach to cooking/baking (merely following a recipe) isn’t science. Unless you do some kind of systematic investigation of the result of different approaches. Like this:

The Science Behind Baking Your Ideal Chocolate Chip Cookie

“Even though I can describe what I like,” says Nyberg, “I didn’t know the role of each ingredient in the texture and shape of cookies.” So she looked into it — as only a scientist can.

Remember, Dr. Cookie is the scientist, and Dr. Cookie’s Monster is the creation.

What Do You Do With a Red-Hot Nickel Ball?

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A red hot ball of nickel dropped into liquid nitrogen.

What We’ve Got Here is Failure to Communicate

That’s why they play the game

That claim of “statistical” predestination is confused.* We know the odds of a coin-toss or of the roll of a die before we ever pick them up. Those things are set, predetermined. But it was not preordained by the universe that Shaquille O’Neal would be a .527 free-throw shooter for his career. It’s weirdly mystical to speak of statistics that measure the outcome of an athlete’s performance over time as though they were that athlete’s “scientific” destiny.

And it’s ironic that such mysticism comes from those desperate to dismiss talk of being “in the zone” because they see that as uncomfortably mystical-sounding.

This is the second commentary of this sort I’ve seen over the weekend; unfortunately I can’t recall the first one or the article that precipitated it, but this one will suffice.

The sentiment is correct as far as it goes: anyone who is saying that statistics pre-ordain performance is wrong. But that’s a straw-man for the scientific discussion — it’s not the actual argument. I think that it’s obvious that there are parameters that affect one’s performance when one goes out sportsing. The analysis going into the phenomenon of “the streak” or being “in the zone” is not claiming otherwise, and there’s a fundamental misunderstanding of what the analysis is claiming that is in play here.

As an aside, I think it’s a similar misunderstanding that has developed with the so-called 10,000 hour rule: that you’ll become an expert when and only if you put 10,000 hours of work into your craft. Which is not to say that you’ll become world-class if you do so, but I’ve seen articles where it’s implied that the only thing standing between you and the pro sportsing circuit is the required investment of time. Bollocks. There’s innate talent for the craft as well, and the quality of your preparation, and perhaps more to it. A similar straw man has been constructed over this statistical analysis, via the retelling in a version of the “whisper game”. Purple monkey dishwasher.

The basic premise is that athletes get into “the zone” where the ball seems bigger and/or slower or perhaps the opposite, depending on what sport is being played, and the athlete does really well. Great. But we’re scientists, and we want a model of this, and the model here (for basketball, where the original study was done, by Gilo, Vallone and Tversky) is that when a player hits several shots in a row — they are “hot” — their odds of hitting shots is higher. That is, a player who hits e.g. eight shots in a row, does so because s/he is on a streak, and thus a higher shooting percentage is expected. In other words, the streaks should be deviations from a normal distribution.

The statistics, however, say otherwise. The streaks are completely consistent with a normal distribution — hitting those eight in a row is an expected consequence of some underlying probability of success and a large number of attempts. The model, which predicted a deviation, is wrong. There is no evidence of streaks.

The model isn’t rejected because of mysticism. It’s rejected because the prediction it makes is not observed, and if a model disagrees with the experiment, it’s wrong. Here’s where the subtlety comes in. What the results don’t say is that there is no such thing as “being hot”. It says that this model of streaks is wrong.

One also has to look at what wasn’t measured. The study was only an analysis of hitting shots based on making the previous shot (which is very much like the Gambler’s fallacy) but no analysis of a player that goes e.g. 16-for-20, or any other effects that might make the results end up being random. Far from being mysticism, these results just tell is where we might look next and where not to look next. However, we also know that any working model will have to give results that are consistent with the randomness we observe. We have a tendency to see patterns in randomness. This might have the same result as a lucky pair of socks — no real effect, but plenty of confirmation bias and apophenia.

The issue isn’t whether Shaq was somehow “predestined” by his 52.7% free-throw accuracy. But that number isn’t the real issue — the reality is that Shaq was a mediocre free-throw shooter, and the number reflects that. The question is whether Shaq performed differently from a player whose talent and preparation made him a free-throw shooter with ~50% chance of hitting each shot, and that answer (thus far) is no.

Physics — It’s Practical!

Helmhurts

A few posts back I was concerned with optimising the WiFi reception in my flat, and I chose a simple method for calculating the distribution of electromagnetic intensity. I casually mentioned that I really should be doing things more rigorously by solving the Helmholtz equation, but then didn’t. Well, spurred on by a shocking amount of spare time, I’ve given it a go here.

It turns out that the Helmholtz equation can also be applied to the modelling of the forced vibrations of the square plate, where the choice of conditions above equates to applying a force at the centre of the plate and clamping the edges. The rice/sand/etc settles at the nodes of the plate, i.e. the positions which stay stationary in the oscillation.

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