BPhO and Other Things

So Friday 13th was the British Physics Olympiad. If you've never sat it, you should maybe be glad, because it's hard as nails. Or maybe you should be upset because it's hard as nails, and it's great practice for becoming better at physics. (It's cousin, the BMO, is as hard as rock by comparison. Maybe that's just because I'm better at Physics than maths, and the maths I know is mainly calculus based rather than geometrical. I digress.)

I don't know whether everyone has sat this paper yet. I know that originally I was due to sit it today due to scheduling difficulties on Friday but it got moved forwards (...yay... I totally didn't want that extra weekend of revision...) so I shan't write anything that's too revealing. I will simply point out that there was an interesting graph question which I'd like to talk about in a future post.

Onto the other things: I'm currently doing the BPhO experimental challenge with a group of four other people as this forms part of Year 13 House Physics. We're doing this under no small amount of time pressure this week as the set-up is quite complicated and fiddly and our lab is not the best outfitted, although it's perfectly serviceable. (Examples of odd things being the curious fact that we're expected to have 1kg spherical masses. What experiment you'd do in sixth form that would require such a mass is beyond me - maybe proving that mass doesn't effect a pendulum's swing?)

And here, lastly, is a letter from Richard Feynman to one of his students: http://genius.cat-v.org/richard-feynman/writtings/letters/problems

This letter reminds me of why I want to study physics: because it always provides an explanation. Sometimes it's an idealised explanation that breaks down under scrutiny. Often that explanation needs to be fixed. But that too is always very interesting. As an off-the-cuff example, consider some simple quantum theory: the first problem students solve is the infinite square well in 1-D. This produces a spectrum of energy levels, unevenly spaced (they're proportional to n^2 I think). It might not be unreasonable to claim that say, a Hydrogen atom is vaguely an infinite square well (obviously it's not: it's a 1/r^2 well, it's curved, it's in 3-D not 1-D and myriad other things probably too) and extrapolate some results. All of a sudden we 'know' why Hydrogen has a a discrete spectrum. We can go deeper into the maths and get it exactly right, but part of the beauty is that we don't always need to - we can solve a toy system which approximates the real problem, and then compare how reasonable our answer is. We can then maybe fix each problem one at a time - solve the 3-D infinite well, or solve a 1-D finite well (or a bunch of them strung together to approximate a 1/r^2 potential). Each time we learn new physics, but it's progressively more niche.

I don't know how Feynman became such a genius. I do sometimes wonder whether I aspire to be a physicist or I aspire to be Richard Feynman, but to my mind they're largely synonymous. But I do suspect that it came from intimately knowing many very simple cases. As his letter says "I would advise you to take even simpler, or as you say, humbler, problems until you find some you can really solve easily". For the details are often not that important.