Fly Casting and “The Barometer Question”

The “Barometer Question” is really a test of the correct positioning of a question when used to measure the understanding of the person answering it. It has seen several variations but the central theme is much the same.

In the barometer question, the query is “describe how you may use a barometer to measure the height of a tall building” the expected, some would suggest required, answer is that if you take the difference in barometric pressure between the base and the top of the building you can estimate the height.

But there are of course a number or correct answers which may not necessarily demonstrate any great understanding of physics.

  • You could tie the barometer to a string, lower it from the building and measure the length of the string.
  • You could measure the length of the shadow of the barometer and the building and a simple ratio given the height of the barometer would tell you the height of the building.
  • You could go to the supervisor’s office and offer him a nice new barometer in exchange for him telling you the height of the building.

There are more possible answers: but the essence is that none are actually incorrect, they just don’t demonstrate any real understanding of the physics of the issue. In effect it is a clear illustration that all too often there is more than one answer and at one level it doesn’t matter that it wasn’t the answer you were expecting. It is, for example, quite possible that using the shadow is going to give you a more accurate answer than using barometric pressure despite the fact that the former is technically not the correct answer.

That brings me to much of the on-line discussion of fly casting, some of it is wildly inaccurate or at least apocryphal, much is well meant and moderately true, at least in a simplistic sense, and to be frank nearly none of it is absolute fact in terms of quantum physics.

The problem is that most of these discussions (read arguments if you wish) relate to teaching fly casting, not in fact the physics of it, and I would suggest that teaching anything requires that one fib, at least just a little bit, if not actually lying, one at least is going to be forced to simplify things beyond what a bone fide geek would accept as factually correct.

This really is the norm when it comes to teaching near anything. We were all taught the same basic structure of the atom in physics in high school. That the electrons whizz around the nucleus (containing protons and neutrons) usually illustrated with something like the diagram below:

Informative perhaps but definitely untrue

Speak to anyone who really knows this stuff and it is wildly inaccurate if not indeed untrue. More “advanced” models have the electrons in an electron cloud with probabilities of their position changing based on wave function.(yes and if that lost you, as it did me, that is the point of the discussion).

Equally and more simplistically I could point out that in reality an electron is about 10,000 times smaller than a proton, but of course how the hell would you draw that on a piece of paper?  Physicists should be screaming from the roof tops that we are teaching our children inaccuracies, and threatening to burn books. We have been teaching lies.

In fact the structure of an atom, as we best understand it, means that a solid isn’t actually very solid at all and is mostly space, and yet with the simple diagrammatic representation above and our concept of what solidity is, none of us worry about sitting on a table for fear that we might fall through and end up with a Higgs Boson up the bum.

It should come as no surprise that I like fly casting, and recognize that it is a functional skill which will no doubt catch you more fish or at the very least make the catching of fewer fish less frustrating. But I like it, I will cast on a lawn with no prospect of catching a fish and still be happy.

I am not sure that I am a card-carrying member of the “casting geek” fraternity, but I could be, I may even aspire to be. My problem comes with much of the on-line discussion related to fly casting, most of which is targeted at learners or the instructors of those very same learners.

It is, I would imagine, imperative, that as an instructor you know more about your subject than your pupil, I would suggest that it is equally important that you don’t necessarily try to convey all that you know during the first class.

I see endless debate about SLP (straight line path) or hard and soft stops at the end of the strokes, I see what are to my mind overly pedantic discussions about the minutia of rod flex or arguments about what is or what isn’t a tailing loop. All good, perhaps if you are an instructor you need to discuss this stuff, I can certainly enjoy the debate, but I don’t believe that you need to baffle your student with it.

The above image supposedly demonstrating SLP (straight line path) and adjustments to casting arc with increased rod bend is in exactly the same class as the atomic diagram. It is wildly inaccurate. There is virtually no translation (stroke) the arm movement is questionable, there is some degree of curvilinear hand movement etc. we can discuss it ad infinitum, but for most novices it is probably “good enough”.

Teaching is, by definition, explaining something to someone who currently doesn’t have knowledge of the subject. To do that, educators require some basic format to work with and it is likely that the format will become more complex and possibly more accurate depending on the level of the education. In fly casting for example, Bill Gammell’s “Five Essentials” have stood the test of time, not perhaps because they are the final word but because they do offer up a workable framework in which to position instruction.

For the average, or even relatively advanced student, the casting equivalent of the above atomic diagram is more than sufficient to convey what needs to be conveyed.

Certainly, our understanding of some things has evolved, as indeed should be the case, by all means question everything, but the reality is that students often need to understand things in a more practical than scientific sense.

So, the old “casting clock” system of moving the rod between 10 o’clock and 2 o’clock has been debunked, it is pretty easy to prove that that isn’t a reliable manner of casting a fly line and I wouldn’t accept anyone using that as a reasonable method of tuition. Even for a complete novice such instruction, although simple is perhaps “too wrong” to be reasonable.

Other things however, if still not entirely true on a quantum level, are to my mind “good enough”. Suggesting that a student try to move the rod tip in a straight line is probably a fair explanation of what we are aiming for. That some of us recognize that a true SLP isn’t possible and quite likely not even desirable doesn’t matter a jot. The student is trying to improve their casting and “SLP” is a reasonable approximation of the truth, at least until they reach considerably more advanced levels.

So, a recent on-line discussion as to whether the rod tip in a video by Carl McNeil actually moved in a straight line as he suggested, is on the one hand a fair and reasonable discussion, on the other hand what Carl is attempting to demonstrate in a video aimed at relative novice casters is to my mind “good enough”. Actually, more than good enough, he produces in his “Casts that Catch Fish” series some excellent tuition, all clearly filmed and in glorious surroundings. I would recommend those videos to any aspiring fly caster.

Virtually all of my academic education was focused in the sciences, it is essential that from that perspective we continually update our knowledge, question the status quo and explore better explanations, it is equally important that we don’t become overly dogmatic and accept new evidence as it is presented. The demise of the “clock system” is evidence of the benefits of doing exactly that. But the vilification of a teaching method because it isn’t “entirely true” probably over steps the mark.

Most five-year old’s have a fairly limited understanding of physics and most fly anglers cast poorly, neither group requires the quantum mechanics explanation of cosmological string theory to help them better function in the world. What they need are clear and simple explanations which whilst perhaps not entirely accurate are “good enough” for them to progress.

It is probably important to be as accurate as one can when teaching something, but absolutes rarely exist and if they did may still not be entirely desirable.

For all of that, if you are a novice caster I would highly recommend to you that you get proper instruction from a certified instructor at your earliest convenience. Most of us (instructors) spend far more of our time undoing ingrained faults in anglers who have been taught poorly than we ever do with beginners who with a few simple instructions can improve greatly.

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2 Responses to “Fly Casting and “The Barometer Question””

  1. Bernd Ziesche Says:

    Nice article, lots of proper points being well said. I always strive for as correct as possible teaching concepts. Obviously they still need to be easy understandable and best helping the student to achieve his/her goals. It’s here only where teaching success can be measured!

  2. Paul Kenyon Says:

    Thanks for another thought-provoking article Tim.
    I haven’t seen the criticisms of Carl McNeil’s failure to maintain a straight line path in his instruction videos (which incidentally I found very impressive for reasons I won’t go into to avoid more controversy) so I’ll keep clear of that straw-man issue.

    I agree with your comment about Bill Gammell’s “Five Essentials”. I regard them as items to feed to a beginner “one-spoonful-at-a-time” to avoid overwhelming their ‘memory span’. They are very useful for guiding instruction, but I wouldn’t mention them to a beginner, especially if they aren’t displaying any of the symptoms.

    It’s interesting to look at the Five Essentials from an absolute beginner’s perspective. They spell out desirable end-points. They don’t spell out exactly what to do to achieve the desired result. That’s left up to the instructor.

    I’ve seen slow-motion videos of a range of casting styles, and there may be mathematical formula that describe different casting strokes. But for sure excellent casters do not describe their performance in mathematical terms, and they certainly aren’t doing the maths during the cast !

    I’m reminded of research on professional baseball fielders who manage to catch a ball using simple heuristics ( ‘rules of thumb’ ) rather than calculus.

    I wonder if conversations with experienced fly-fishers might reveal similar ‘rules of thumb’ that could be taught to beginners.

    Some people I see are hampered by transferring prior experience gained throwing balls etc. to throw a fly. This is understandable in terms of how we all learn “practical physics” (i.e. heuristics) to deal with our environment.

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