Geoff 🏴󠁧󠁢󠁳󠁣󠁴󠁿Mar 25, 2023

Still wondering how well I did at explaining the #BellsTheorem #Physics experiment I did with 6th years (~18yrs old, meeting this stuff for the first time). It's the polarised sheet experiment where you have two crossed sheets (so "black") and introduce a third a 45deg and it gets lighter.

(1/n)

Show threadGeoff 🏴󠁧󠁢󠁳󠁣󠁴󠁿Mar 25, 2023

My quick explanation:

"We know if a photon passes the ↕️ it can't get through the ↔️ . But ignore the ↔️ for the moment, put a ↗️ there instead. Now it has a 50% chance of getting through, you did that last week, we know it works.

Now imagine a ↗️ followed by a ↔️...again, we know 50% will get through. So a ↕️ followed by ↗️ followed by ↔️ should let 25% through.

Our problem is why this doesn't match with our intuition given that ↕️ followed by ↔️ blocks 100%.

2/n

Show threadGeoff 🏴󠁧󠁢󠁳󠁣󠁴󠁿Mar 25, 2023

The mistake we're making is assuming that a photon "has an actual polarisation". It doesn't, it has a range of likely polarisations, and adding the middle 45deg filter allows it to <WHAT'S THE RIGHT PHRASE?!>"

I don't want to anthropomorphise the photon, they hate it when we do that. It doesn't change its mind, it "allows the wavefunction to skew"? But even then, they've no real idea of what a wavefunction is. Ideas, #quantum #physics people?

3/4

Show threadBrialaMar 25, 2023
@_thegeoff This sounds like probabilities resolving.
Show threadGeoff 🏴󠁧󠁢󠁳󠁣󠁴󠁿Mar 25, 2023
@static Precisely. But which paradigm do we use to resolve them? ;)
Classic high school physics...train them up with X, and then tell them that X is only a limit case and Y is actually true. Except worse.
Show threadBrialaMar 25, 2023
@_thegeoff Ah. That's the "lies to children" model. Aka "you've been taught *this* is true and up to a certain point everything looks that way, but now here's what is *really* going on."
Show threadGeoff 🏴󠁧󠁢󠁳󠁣󠁴󠁿Mar 25, 2023
@static Twas ever thus. My high school physics teacher was good enough to introduce us to the concept at ~14yrs old, and explain why we were going to be taught like that. To be honest, I can't think of a better way. Honest Lies To Children is better than teaching quantum field theory at primary and telling them to derive biology ;)
Show threadmj

@_thegeoff @static

The real problem there is when #QFT (for example) is no better overall at explaining. If the leading edge theories were sufficiently developed, there would be easy to follow modelling.

Also, the notion that #maths are capable of doing this without proper models & explanations leads to false impressions. (shut up & calculate exemplifies this)

I think appeals to authority are part of it, when anyone who is 'supposed to know' can't actually explain without resorting to contradictive analogies, they just fall back to the pressure of 'this is the version that will be given points on the test' for practical consideration, and sprinkling in enough 'mystery & #paradox' to hold the superior emotional center.

This creates a #society educated into false consensus, with little trust in pursuing #reason or truth, and instead places the most value on marching forward without such clarity. The #information trickle down effect places teachers right in the middle of this dilemma.

Note that this is a necessary element we've evolved with; we won't eliminate this. We can however, spend more time #teaching about the shortcomings of the #approximations students are expected to learn, and encourage them to contribute to the next level of understanding rather than to #fear trying & failing.

Mar 27, 2023 at 7:46pmWeb
Show threadGeoff 🏴󠁧󠁢󠁳󠁣󠁴󠁿Mar 27, 2023
@MalthusJohn @static The "shut up and calculate" approach is there for a reason though - we're a century in, and there's still no consensus on interpreting the maths, let alone differentiating the interpretations experimentally. I mean, personally I like Everett's angle, but I freely admit that's just a nice story constructed from the maths. The only near-advance in the last 60 years or so has been Bell's work on refuting hidden variables.
Show threadGeoff 🏴󠁧󠁢󠁳󠁣󠁴󠁿Mar 27, 2023
@MalthusJohn @static But yes, I totally agree that we should be teaching this very issue, interpretations of the maths, lies-to-children etc, so that the students at least know they should take every professor's pet interpretation with a realistic pinch of salt.
After doing the 3-polarised-sheets experiment with the 6th years and our physics teacher I contacted the ex-physics teacher who's now covering maths to give him a heads-up for chatting to them, specifically for this reason.