The University of Waikato - Te Whare Wānanga o Waikato
Faculty of Science and Engineering - Te Mātauranga Pūtaiao me te Pūkaha
Waikato Home Waikato Home > Science & Engineering > Physics Stop
Staff + Student Login

June 2014 Archives

Long story cut short: I'm currently writing a paper on a piece of work I presented at the (fairly) recent conference on Threshold Concepts, that was hosted here at Waikato. In order to do this, I'm needing to learn a new language, namely that of qualitative research. 

Qualitative Research is not something that comes naturally to a physicist. The most obvious problem is that it requires a paradigm shift - from the positivist approach that underlies most of science, and particularly physics, to the (ahem) social constructivism that is common-place in the qualitative literature. I need help. 

So, yesterday, under cover of darkness*, with heavy coat and thick scarf wrapped around my face, I sneaked into the library, passed by the familiar  'Q' section and headed across the corridor** to raid the 'H' section***. I knew my target - I'd already searched the on-line library catalogue in the safety of my office - so it was a quick mission. Get in there, grab the books, get them issued (on the self-service kiosk, certainly not the front desk lest I be recognized for what I was - a scientist carrying subversive literature) and get out of there before any of my colleagues, or worse still, any of my students, spotted me. Catching a positivist (or p******ist, as they're refered to in the social science literature) raiding the 'H' section would be sure to inflame cross-disciplinary tensions so discretion was absolutely paramount.  Mission safely accomplished, I returned to the safety of EF-link block.  

However, my mission has hardly begun. The next step is to decode the language. The words might be English, but they're written in some kind of secret code known only to practioners of social constructivism. Fortunately, my wife Karen has come across such writing before and is familiar with teasing out some of the hidden meanings in the language. With some tuition, and hard work, I've begun to make a little sense of this writing. It is a hard and frightening task - there is so much that is just utterly alien to me. I feel that there must be some underpinning concept behind it that I just haven't grasped, that makes it so troublesome - if I get it - if I discover what that secret code really is - it will all fall into place and at last I'll be able to see what qualitative research really is about. 

But one thing I do know, is that I'm dealing with a threshold concept here. And there's the deep irony. In order for me to support my paper on threshold concepts, I need to get into the qualitative research literature, and this in itself is a threshold concept to me. The introductory chapter of one of the books, which explicitly states that it is for people with no familiarity with qualitative research, is still intractable to me. Why? The words are English, the sentences aren't long, but somehow it appears to draw from hidden knowledge that I am not familiar with.  I just don't get it - the sense isn't there - the concepts are so troubling. I'm sure then the very notion of 'qualtiative research' is, to someone trained as a scientist, a threshold concept in itself. And I'm not yet over that threshold. Not completely, anyway. . 

So, to close, I'm still grappling with this stuff. But perhaps the greatest impact is that I now have some idea of what my students are going through when they complain "I just don't get it" when dealing with what I feel is the blatantly obvious

 

*OK, so it was actually about 9.30 in the morning, but that doesn't sound as dramatic. 

**One might actually say 'crawled under the barbed wire laid long the border': This metaphor has echos of Glen S. Aikenhead (1996) Science Education: Border Crossing into the Subculture of Science, Studies in Science Education, 27:1, 1-52.

***The Q and H refer to US Library of Congress coding of books - Q is (broadly) where physics lives, H is where the qualitative research methods books hang out, looking menacing.

| | Comments (0)

I've just been at a great lecture by Peter Leijen as part of our schools-focused Osborne Physics and Engineering Day.   He's an ex-student of ours, who did electronic engineering here at Waikato - and graduated just a couple of years ago.  He now works in the automotive electronics industry. That's an incredibly quickly growing industry. So much of a car's systems are now driven by electronics, not mechanics. Being a car 'mechanic' now means being a car 'electronic engineer' just as much as it does being a mechanic. 

One interesting piece of electronics is the ignition timing system. The mechanism that produces the spark in the cylinders from a 12 volt battery is really old and standard technology - one uses a step-up transformer and kills the current to the primary coil by opening a switch - the sudden drop in current creates a  sudden reduction in magnetic flux in the transformer, and these collapsing flux lines cutting the secondary coil create a huge voltage, enough for the spark plug to spark. That really is easy to do. The tricky thing is getting it to spark at the right time. 

One needs the fuel/air mix in the cylinder to be ignited at the optimum time, so that the resulting explosion drives the piston downwards. Ignite too early, while the compression is going on, and you'll simply stop the piston rather than increasing the speed of its motion. Apply too late, and you won't get the full benefit of the explosion. It's rather like pushing a child on a swing - to get the amplitude of the motion to build, you need to push at the optimum time - this is just after they've started swinging away from you. 

All this is complicated by the fact that the explosion isn't instantaneous. It takes a small amount of time to happen. That means, at very high revolution rates, one has to be careful as to exactly when you make the ignition. It has to be earlier than at lower rates, particularly if the throttle setting is low, because the explosion takes a significant proportion of the period of the oscillation.  This is called 'ignition advance'.  

On newer cars, this is done electronically. A computer simply 'looks up' the correct angle of advance for the rpm and the throttle setting of the car, and applies the outcome. The result: a well running, efficient engine, using all the power available to it. Or so you might think.

But here's the revelation from Peter: car manufacturer's can deliberately stuff up the timing. Why do they want to do that? Well, there's a market for selling different versions of the otherwise same car. The high-end models have performance and features (and price tag) that the low-end models don't have. There's status in buying the high-end model (if you're the kind of person who cares about that - and the fact that these things sell says, yes, there are such people), but, alternatively, if that extra couple of horsepower doesn't bother you, you can get the lower-spec model for a lower price. Now, the manufacturers have worked out that making lots of different versions of the otherwise same car is inefficient. It's far easier to have a production line that fires out identical cars. So how do you achieve the low-end to high-end specification spectrum? Easy. You build everything high-end, and then to produce  low-end cars deliberately disable or tinker with the features so they don't work or don't perform so well. That is, make the car worse. 

Ignition timing is one example, says Peter. There are in fact companies who will take your low-end car and un-stuff-up your electronics for you - in effect reprogramme it to do what it should be doing. In other words, turn your low-end car back into a high-end one (which is how it started out life) without you having to pay the premium that the manufacturer would place on it for not stuffing it up in the first place. 

Who said free market economics resulted in the best outcome for consumers?

 

| | Comments (0)

A couple of weeks ago saw the University of Waikato Open Day. (Acually, two days). There were some fantastic displays set up across the whole univerisity, with some exciting lectures and activities. With a dual-audience of would-be students and members of the public, our displays were meant to be eye-catching and fun, and I thought they were. There were some good whizz-bang displays, and some really great whizz-whizz bang-bang displays and activities. I think nearly everyone had a good time there. (Naturally the Van de Graaff generator was its usual hit...)

However, when the feedback on the day(s) began to roll it, it became apparant that some displays were not as fun as I thought. At least, the audience didn't think so. Too boring. I wonder whether this is because people have come to expect that whizz-bang-interactive-touch-it-yourself-excitement is the normal, basic thing to expect in science displays now.   Whizz-bang just doesn't cut it - you need to be double whizz - double bang or you don't get a look-in now. 

Is this down to 'interactivity inflation'?  When I was very young,  the most exciting place in the world to visit was the Natural History Museum in London. Back in the late seventies it wasn't really interactive - that came in slowly - there was lots of stuff in cabinets just to look at. But what it did have was a fossil skeleton of a diplodocus in the main entrance hall (yes, some entrance hall). It didn't move, it didn't grunt (or whatever diplodoci did), it just stood there looking, well, wow! - dinosaur-ish.  What more could you want. Further into the museum one found the whale skeleton suspended from the ceiling - again - wow! with the pickled contents of its stomach in a large glass jar.  At that time, a large jar of krill in formaldehyde was indeed exciting stuff. I loved it. 

Nowadays a jar of long-dead krill is simply silly. Yuck. Have we come to expect too much from our scientific displays? Or is it an example of the current generation's requirement for things that can be instantly double-clicked, shared, downloaded, posted or liked.  Whatever, it certainly takes a lot of time and thought to put together something double-whizz double-bang.

And, finally, is WWBB what recruits future students anyway? Sure, it gets their attention. But does it maintain it over several years? I suspect not.   

P.S. I've just looked at the Natural History Museum Website.  (Obviously a thing that didn't exist when I was 8.) The first thing on it: "Download the UK Tree Identification App." What happened to taking the time to carefully learn different leaf and fruit shapes, bark texture, canopy shape etc? Who cares about that - just let the app do the work...

| | Comments (0)

A few days ago I was updating one of the lectures I do for my Experimental Physics course. I was putting in a bit more about safety and managing hazards, which are things that are associated with doing experiments for real. When I was a student, we didn't learn anything about this - my first introduction to the ideas behind hazard management came only when I joined an employer. Before then, I simply hadn't thought about the issues involved. 

One of the things that gets banded around Health and Safety discussions is Heinrich's pyramid, dating back to 1931. The basic idea of this is that accidents don't just happen out of the blue. For every fatal accident there are several non-fatal but major accidents, for every major accident there's several minor accidents, and for every minor accident there's a whole heap of incidents (things that could have been accidents if circumstances had been different). The implication is then that by addressing the minor things that crop up frequently, we make the workplace a safer place.  I've seen various versions of the pyramid on-line, but here's one:

enerpipe_img-SafetyPyramid.jpg

Diagram taken from http://www.enerpipeinc.com/HowWeDoIt/Pages/safety.aspx 

That all seems to make some sense. However, searching around for a good picture to include in my lecture notes, I came across this article by Fred Manuele:

http://www.asse.org/professionalsafety/pastissues/056/10/052_061_f2manuele_1011z.pdf

It calls into question the whole basis of this pyramid and its implications for health and safety in the workplace. Specifically, Manuele reports that:

1. No-one can trace Heinrich's original data

2. If it exists, then the extent to which 1920's and 30's data applies in today's workplace is dubious. 

3. That the pyramid idea is counter-productive to ensuring a safe working environment since it over-emphasizes the importance of minor non-compliance issus (not wearing one's lab coat) and focuses attention away from major, systemic failings in senior managment and even government regulators and legislators whence the really big events tend to come. [Think Pike River, where MBIE's own investigation points the finger at itself (in the form of its predecessor, the Ministry of Economic Development) for carrying out its regulatory function in a 'light-handed and perfunctory way'.]

There's some lovely statistics included on what a focus on reducing small incidents actually does. Here's some US figures on the reduction in accdient-related insurance claims between 1997 and 2003 (F. Manuele,  “State of the Line,” by National Council on Compensation Insurance, 2005, Boca Raton, FL):

Less than $2000: Down 37%

$2000 - $10000: Down 23%

$10k - $50k: Down 11%

above $50k: Down 7%

See the issue here? Focusing attention on small incidents and small accidents does wonders for reducing small incidents and small accidents, but very little on reducing the big accidents. That's because, as Manuele describes, they have different underlying causes. 

The paper's worth a read, and cuts at what I've been taught over several years about health and safety. One notable feature is that it actually draws from hard data, rather than myth, which is how Manuele labels Heinrich's work. 

And the consequence for my experimental physics students? I shan't be including that pyramid in their lectures.

 

 

 

| | Comments (2)