Tuesday, September 7, 2010

Paradigm Shifts 1

Hi everybody, I'm Sam, and this will be my first contribution to the blog! (cue applause) It will not be a physical modeling exercise; instead I will be writing a little bit about about paradigm shifts in a series of a few posts. I hope it will provoke some interesting discussion.

"But Sam," you ask, "Isn't 'paradigm shift' just a buzzword that people use to sound important?" Well, maybe, but it's also useful phrase used to describe a substantial change in the way something is done. Consider, for example,


(many details from Wikipedia)

In 1791, in the wake of revolution, France became the first country to adopt the recently developed metric system. Since then, every nation in the world has officially adopted the metric system except Liberia, Burma, and the United States. It is the standard measurement system for most physical science, even in the US (as far as I know, no other unit system even has a measurement for quantities like electric field or magnetic field) (also, when I say metric, I of course include cgs and mks and ignore systems that are not meant for measurement, like natural units and Planck units). It has the advantages of easy unit conversion (1 km = 1000 m vs 1 mile = 5280 ft, a value which I had to look up from Yariv's post), and lack of ambiguity in units (mass = kg, force = N vs mass = lbs_mass or stones, force = lbs_force). The strong preference of scientists for the metric system is evident from past experiences:

From CNN, September 1999:
"NASA lost a $125 million Mars orbiter because a Lockheed Martin engineering team used English units of measurement while the agency's team used the more conventional metric system for a key spacecraft operation"

This story also illustrates the equally strong preference of engineers for the English system. Ah, and herein lies the problem. You see, when the metric system was first adopted in Europe, it created a standardized unit system. This proved useful to merchants selling their wares by weight, but more relevant to myself as a scientist, it provided a means for creating scientific recipes, for providing the utterly essential aspect of reproducibility to scientific experiments. However, now the standardization exists even with the English system, given a simple unit conversion. But why not adopt the metric system to avoid situations like the Mars orbiter and make me less confused when I cross the border to Canada and see speed limit signs telling me to do 80? Because it would be too huge of a paradigm shift. Allow me to illustrate my point.

One of the most (if not the most) strongly affected groups by a change in measurement systems is manufacturers, ie people who make stuff. I will use a typical example of a manufacturer, the kind who I interact with in my lab: the noble machinist (keep in mind that machinists are very important, as they are required to make many, many products). If you have ever worked with a machinist in the states, chances are he or she will be totally confused if you try to give them dimensions in millimeters (I have done this, and they weren't very happy with me because it meant they had to convert all the dimensions I gave them into English). It would be extremely difficult to retrain people who have used the English system all their lives. It would be like learning a new language. Inevitably, it would cause a large number of mistakes. More significantly, they would have to get ENTIRELY new equipment. Every machine shop would have to completely replace their tools (drill bits, screwdrivers, wrenches etc) and materials (standardized sizes of bolts, nuts, sheet and bulk material, pipes, connectors, cables, etc etc). You could say, "Come on, it wouldn't be so bad! Listen, we could gradually phase out the old English equipment and just make everything in metric from now on!" However, I would counter that this is not a realistic plan. For starters, there's the problem of having to keep around two sets of equipment (one for the old English stuff and one for the new metric stuff), which would require double the space and double the maintenance. Second, there would be compatibility issues between new and old equipment (e.g. my old 3/4" ipod port wouldn't mate with my new 2 cm connector). Third, the previous two problems would likely be around for a long time, considering the age of some of the equipment that I've seen in labs and elsewhere.

And I haven't even mentioned the economics. If basic parts manufacturers (the people who make the screws, the bolts, and the sheet metal that will later be made into products) began to offer metric parts (now that I think about it, maybe they already do?), I doubt anybody would buy them. It would cost them too much to replace all their machinery infrastructure. There would be no market for them. Maybe you would then ask "Well, what if the government made everybody switch to metric?" Well, other than the backlash this would cause towards whichever administration suggested this, it would likely hurt and maybe even bankrupt companies who were forced to switch. As far as I can tell, it would definitely hurt the US economy in the short term (but it might help other countries who could sell their metric wares here) and not help it at all in the long term. To me, the economic loss (not to mention the difficulty in convincing the US population to swallow the change) outweighs the advantages of switching.

At this point, exhausted from my challenging you at every turn, you may finally say, "Well hey, SPEAKING of Canada, they changed to the metric system only in 1973. How did THEY do it??" The answer is that, well, they didn't. Not entirely anyway. Sure, the country may package food and make road signs in metric (which the US could probably do, if people could somehow be convinced to go along with it), but in fact their engineering materials, which mostly come from the states, are still in English units. Even Canada couldn't justify completely converting to the metric system Which just goes to show how difficult it is to pull off a paradigm shift.

Next time, I'll present an example of a paradigm shift that I think COULD work.


  1. I like the idea that metric/imperial would need a paradigm shift a lot, only in the lab where I used to study we already did that. If we had to buy parts from the States, they came in Imperial, and we'd have to find a way to fit them into our metric setups. And yes, two sets of nuts, bolts, and everything. Must be a bit like keeping Kosher: a cabinet with metric nuts and bolts, and a cabinet with imperial nuts and bolts, and never the two shall mix. It must be like a 90/10 mix, but still, it does occur regularly enough. And then you fiddle until it works, just like regular physics. ;)

  2. My guess is, any largish parts manufacturer already does metric as well. They couldn't compete in the export market - or supply manufacturers that do - otherwise.

    Similarly, most shops of any size and professionalism probably have a fairly complete set of metric tools. Their heavy machinery such as lathes are easily settable between metric, US imperial and perhaps British imperial too. Reason being, they may regularly be asked to make parts for, or repair equipment originating from a country using metric. Only small or specialized shops could hope to stay with US measurements only without turning down significant business.

  3. So just call it 2.54 cm instead of an inch. How hard can it be? I have no problem talking about (metric) pounds and fathoms when I want to.

  4. "Unit conversion" does not work for the precision machining. there are such things as bolt sizes and wire thicknesses that are always in integer fractions of one or the other unit. Our machine shop just has a stock of metric stuff for that. The adoption of metric system might just happen gradually by itself as less and less actual stuff is being manufactured in the US or by US-only corporations.
    Occasional Reader

  5. Hi. Please don't read too much into Canadians using both systems. We do that a lot - spelling, ways to write dates, proper etiquette. It can be confusing :)

  6. I was planning on writing a witty comment with backed up assertions, but in the end, all I can think of is that you've posted two problems:

    You think it's not worth the time and money.
    You think Americans are too set in their ways (lazy?).

    I could accept those as opinions, though I think they're both wrong. Consequently, calling it paradigm shift is really nothing more than attaching a label to your unwillingness to shift to what is clearly a more efficient system. I'm not convinced.

    Tell me, how many hogsheads of wine would you order for your wedding? And how many chains per gallon can your car get? If you don't know those measures, perhaps you'll admit that the Imperial System is already degrading, and it's survival is not necessarily guaranteed.

  7. First of all, I wanted to thank you guys for commenting. I was hoping to inspire a bit of debate.

    Anna brought up that in her lab, parts come in both metric and imperial with a 90/10 mix or so. I'd definitely believe that it's possible for a laboratory to deal with both. The problem is a complete shift to all metric in manufacturing, suppliers, and everyday use.

    Janne thinks that manufacturers would have to supply in metric as well to be competitive. I disagree, based on experience. I've tried to get quotes for materials in my lab by giving them metric requirements. They would always quote to me the closest thing they had in imperial. As Anonymous was saying, when suppliers make materials, they go through production runs where they create a lot of pieces at set sizes. So they'll make 1", 1.5", and 2" diameter rods, but if your metric part calls for 3 cm, you're stuck buying a larger rod and cutting it down. Which means wasted material, and extra machining. So Sili, you're right that conversion is possible, but at a significant cost.

    Anthony, you sound personally offended. You say that I, myself, am unwilling to switch to metric, but I am not. In fact, I already use metric. I actually come from Canada, and I couldn't even tell you what room temperature is in Fahrenheit because I'm not used to those units. Neither am I used to hogsheads or chains, but I don't think anyone in the states is. I'm certainly not claiming that people should use all weird imperial units, but I am saying the common ones would be very hard to phase out. And I don't think Americans are lazy--I hope you didn't pick up that opinion from my post--I don't think laziness has anything to do with it. A politician trying to engineer a significant shift can bring about a lot of frustration towards them (look at the flak that Obama is taking for health care--I use this as an example apolitically, by the way, I don't want to start a political discussion on this board). And significant shifts are expensive. There has to be some payoff to justify them. In Canada's and in Europe's case, there was no standard unit of measurement at all, and something had to be set (Canada was using some non-imperial and non-metric unit at the time when it switched). But the US already has a standard that is working fine and really not causing too much confusion.

    For everyone who objects to staying with imperial: nobody so far has brought up a good reason to switch to metric. Anthony, you say my opinion that "switching is not worth the time or the money" is wrong. Why do you think that it is worth it? I personally like metric, but that doesn't mean it is worth it to switch. What are some concrete reasons that it is better to switch?

  8. In terms of road signs, I think it's possible to shift to the metric system. After all, what these signs mainly do is just notify the passersby how far their destination is from that point, so I guess it wouldn't really hurt if they're changed.

    But metric or not, I think the important thing here is that they're there. The galvanized steel strapping and stainless steel banding used to affix the signs should be strong enough to withstand storms and the like.