Dec 03 2008
The Magic of Metric
Some time ago I mentioned that (a) I had written a technical paper on the use of SI units and (b) that I should write a blog or two on this topic. Then, I promptly forgot ’cause it’s what I do. I’ve been senile since I was four. Someone asked me today about some comments written back in January. Before the baby? Are you kidding? I do a mindwipe each weekend; I can’t even imagine what I lost when I had a baby. Somehow, though I remember all six wives of Henry VIII and anything else that has absolutely no purpose.
What was I talking about again? Oh right, the metric system.
So here’s the question, why the heck are we still using the English system? What are we, dumb? Now, some of you probably think I’m being harsh or unkind. Yeah, well consider it tough love.
There are a bunch of good reasons to kiss the English system of measurement goodbye, not the least of which is that we’re the last damn country to be using it, including England. Here are a few of them.
*If math makes your eyes roll up into your head, skip to the end.
Units are ambiguous. You know a difference between a pound-force or a pound-mass? Most people don’t. So how much in an ounce? Troy, fluid, standard and, of course, there’s an ounce-force, too. How about a mile? There’s a survey mile, statute mile, Scottish mile, ancient English and Roman miles, Irish mile, international mile and no less that three different nautical miles. Note that the US uses no less than three of these forms of mile. Know how many different kilometers there are? Yep, just the one and they use the same damn one all over the world. The same liters, Newtons, kilograms… One and only one and everyone uses it, even us.
Different units for the same damn parameter. How many units do we have for distance? There’s, of course, all the different flavors of mile, foot and inch. Also furlong, mil, angstrom, parsec, league, yard… In metric there are meters and factors of 1000 of meters. That’s all. In volume, there are cubic inches and cubic feet, also gallons, pints, quarts, barrels, etc. In metric, there are liters and factors of 1000 of liters. The other side of the coin is that, by knowing the unit, you know the parameter. Newtons are force. Kg are mass. Pounds, of course, can be either. Ounces can be a measure of weight or a measure of force or a measure of volume.
Fractions. Whose frickin’ idea was it to use fractions of an inch for measurements? Say you’re fixin’ a car (assuming that even US cars hadn’t gone metric a couple decades ago, which they did). You try your handy dandy 3/8 wrench but it’s too big. So, what’s the next size smaller? 13/32 or 5/16? Or is one of them bigger? You’re sitting there doing conversions in your head. Now which is smaller in metric? 10mm or 9mm? Hmm, tough call.
Side note: One of the arguments still trotted out against metrication is that converting to metric would be prohibitively expensive. A couple of decades ago, the auto industry went metric. One company set up a team to figure out what it was costing them, which they quietly disbanded when they realized that reducing the number of tools required and streamlining spares (# fasteners sizes was reduced drastically) saved them more money than conversion cost them.
Calculations with Fractions. [Math warning for the math squeamish!]: If you think picking a wrench is challenging, try calculating anything, like something simple: area. The room is 12′ 9″ by 15′ 5″ - How big is it? (You go ahead and figure that out. It’s actually faster for me to convert it to metric and do the math: 3.89*4.70=18.283 square meters=196.8 sqf - and no, I’m not converting anything back to fractions). Now, imagine doing calculations on rocket thrust or something complicated with fractions of an inch (I’m trying not to).
Conversion within a unit system. Know how many inches in a foot? Of course you do. How many ounces in a pint? Probably. How about in a gallon? Uh. How many feet in a mile? How about a nautical mile? If you know all those, you have a better memory than I do. Know how many meters in a kilometer? Yep, 1000. How many mm in a meter? Yep, 1000. Know how many grams in a kg? 1000 again. See no memory required. So, how many mm in 5.876 m? 5876. So, how many feet in 756 inches? How many nautical miles in 19, 6758 feet? How easy is it to check to see if your answer is right in metric? And English units? Admit it, you’re going to have to use the calculator twice, assuming you get the same answer both times.
You want to know why European and Asian kids are kicking our children’s butts in math and science? I guarantee this is part of the reason.
Conversion to a different system of units. You know, whenever there’s an issue with metrication, it’s almost always because of conversion. Someone does their calculations in one system of units and then converts it, but makes a mistake along the way. Or someone does calculations in one system of units and doesn’t notice it needs to be converted. We’ve lost spacecraft that way. So, why does that argue for one system over the other. Well everyone but us uses the smart system. If we stop using English units, conversion issues become a thing of the past because, hey, we don’t have to convert any more.
There are, of course, also reasons associated with making us compatible with the rest of the world, improving the appeal of our products overseas. And that it’s the law that we change (which has been there for decades). Tool simplification, drastically reducing long term production costs because of reduced spares and tooling requirements. Lower error rates across the board because it’s so much simpler. There’s the fact that many aspects of life are already effectively 100% metric even in this country, like medicine and real science.
But, the bottom line is that the only reason we’re still doing things the stupid way is because we’re too proud to do otherwise. And our children are paying for it.
*Skipped the math did you?
How’s this for a reason? If you weighed 190 pounds, you’ll mass 86 kg. That’s right, a double digit mass.
I simply HAVE to check out this blog more often. You are brilliant!
I didn’t skip the math, either, but I certainly did enjoy the rant! And even though converting would make gas SEEM cheaper than it really is (Canada was such a shock to me. I’d fill up the tank, and my eyes would bug out at the total), I’d adapt.
I’ve just never been asked to. We learn the stuff in math and science, but then we are never expected to use it. Weird.
These foreign kids you mention may be “kicking our butts” for many reasons, but I assure if any of that is verifiably true, it is not because of the metric system
I always thought it was prohibitively expensive to change tools, and that was the one point I could never rebuke…
Can you quote which company did this research so I can brandish this point when I next have this discussion?
You skipped the main argument against metric: thirds are hard. Ten isn’t divisible by three, but twelve is. Twelve inches to a foot and three feet to a yard means you can cut a board to a 1/3 yard (12 inches) or a 1/2 y (18), or a 1/6 or 3/4. A third of a meter is 33.33… cm. Awkward.
There are many more advantages to metric than standard, but there is still one drawback. The solution is obvious: If we’re going to switch anything, we should switch to base 12 arithmetic.
Nice post, I’m from Canada and we went through this, obviously, in the 1970’s and we survived.
The only exception is people who are used to the old way, it takes time to adjust, certain things like mph and your weight in pounds or height take some getting used to for example if you say a person is 1.8m or 180cm people often say “Hunh?” or a jet can fly 1000km/h will result in “How fast is that?”
After a while you get used to the “feel” of the metric units rather than the actual measurement, a metre is in my brain as a space I can relate to, before it was 3 feet now it’s a metre (yes ‘re’ as we say).
Easier is better, why make something more complicated than it has to be? Even math you break it down to something more simple and proceed from there.
BTW you may want to fix this:
> How many nautical miles in 19, 6758 feet?
You guys *do* realize that it’s essentially a form of trade protectionism, right? It makes it harder to sell stuff here (from a volume perspective), but doesn’t really impact US sales abroad because that market is so huge it’s worth it to support both (and besides most of our manufacturers use metric and convert anyway).
Wrong. They should both be taught. Metric has a gross (technical definition) resolution: humans are all between 1-2 meters, kilograms are useless in human measurements, as is Celsius.
Inch: thumb v. 2.54 cm.
Foot: foot v. 30.4 cm.
Yard: Arm. 91.44cm.
100 degrees: Body temperature v. 30 C.
32: freezing v. 0C.
0: really damned v cold don’t even remember, some bloody negative number.
Pound: 1 pint of water.
People do not have an instinct for metric the same way they do not have an instinct for quantum mechanics: it has nothing to do with the human scale. They should both be taught because 9/5+32 and x1.6 are not hard to learn.
I sympathize, however!
Cheers.
Strictly speaking, litres (liters) are not SI units.
SI units for volume are cubic length measurements:
m3, etc.
I’m from Europe, and all I know about English units is that an inch is about 2.54cm. Oh, and that there are 12 inches in a foot, but 12 feet don’t equals one yard.
I’m.. just read on wikipedia that 1 mile is 5,280 feet! Heck!
I admire your plumbers for being able to work with a cumbersome system like that! I would go crazy for replacing a lamp
When you’ll be done with that, you could start consider the brilliant (ISO) A4 format for paper. There are compelling arguments to use it (the only compelling argument for not using it being protectionism).
http://www.cl.cam.ac.uk/~mgk25/iso-paper.html
I may be wrong (famous last words) but I was under the impression that the Angstrom is a metric unit. If it is not, then I’m pretty sure it obeys all of the rules of the metric system, so six of one a half dozen of the other. 1 to the power of minus ten, meters = 1 A (with a halo).
“But, the bottom line is that the only reason we’re still doing things the stupid way is because we’re too proud to do otherwise.”
Pride/arrogance. Often a very thin and blurred line between the two.
And you are not the only country that has refused to go metric. You are in the fine company of Liberia and Burma (Myanmar).
Yours faithfully
Fully Metric Australia (for over 40 years).
couldn’t agree with you more.
Oh, and P.S. I totally and completely agree with your position on switching to metric, a good argument and well put. I deal every day with small things, so units like nanometers and microns are natural to me. It might take me some time though to spatially grasp what “It’s about 10 kilometers up the road” means. But no such barrier would exist for children who grow up with the system!
I can remember back in school in the 1980’s teachers were saying were going to to metric system but it never happened.
This is by design.
Americans are purposely not educated or mis-educated in the hopes of maintaining the need for immigrants to fill jobs, to justify the business practices of men that should have been deported from this country along with their entire lineage centuries ago.
Yes, “a pint’s a pound the world around” but a liter is a kilogram, and is 10cm^3 as well, which relates volume, length and mass (of water at STP).
Two small mistakes:
“There are a bunch of good reasons to kiss the English system of measurement goodbye, not the least of which is that we’re the last damn country to be using it, including England.”
You forgot Myanmar and Liberia!
“Know how many different kilometers there are? Yep, just the one and they use the same damn one all over the world.”
And yet, all over the world they still use funny units like knots (technically a “non-SI unit accepted for use with the SI”). Switching to metric doesn’t necessarily imply ceasing all use of non-SI units.
But you forgot the most important (to me!) reason to go metric: it’s what all my teachers taught me back in the 1980’s when they said we’d be using metric in 5 years. I have no clue how many ounces in a pint because nobody ever taught me.
Schools are already metric. Industry is already metric. Science is already metric. Only a few consumer products (foodstuffs, gasoline/distances, paper, houses, weather, people) still use imperial units.
While I agree the US should switch to the metric system, it’s stupid to say that Asian kids are kicking the USA’s butt at math because they use a simpler system. That’s like saying that weight lifter is so massive because he uses lighter weights that are easier to life.
The fact is, the real reason people don’t know how to convert a slug, furlong, or even a nautical mile is that average people don’t use these measurements on a daily basis. Average people will live their entire life and never encounter these measurements. People that *do* use them know how to convert them very easily.
For the record, us high-schoolers use the metric system in science and math 99% of the time. God help us if they decide this is a bad idea.
It’s ironic that imperial units are actually defined in terms of SI units. Thus for example 1 inch = 2.54 cm exactly, by definition. So if you think in inches and feet, you’re really using some very weird multiples of SI units.
As an european, I have been surrounded by decimal system all my life, so for me its so easy (NOW).
Remember how much it took to learn the letters of the alphabet?
I’m sure you don’t, if you want to recall, try with a new simple alphabet like katakana and hiragana. They are as simple(as many symbols) to learn as uppercase and lowercase.
But we find them particularly difficult, why?, because we have to make the effort to learn them so it becomes easy.
The same way for me it’s a pain in the ass to think in inches, miles, pounds, stones, apples or kingdom feets. There is people here that had made the effort so they don’t want to change.
I’m two meters high, is that simple. A centimeter, decimeter, and meter are easy to visualize for me. Today is 0 grades celsius and that means my plants are going to freeze, and I have to be careful when driving.I’m 80 kilos(grams)weight. I can visualize 1, 10 and 100kilos and grams easy too. So no problem for me.
I really find it comical how so many people think that metric units cannot be visualized the same way imperial units can.
I grew up in Canada, learning to measure people in feet and inches and pounds.
At age 25, I went to Japan, and lived there for 5 years. In about a year I got used to the measurements and was able to visualize them quite well. I am 190cm tall and weigh 82kg. If someone told me they were 170cm tall, I could picture it in my mind. And not only me; ALL Japanese can visualize it perfectly. As can all other Asians, and Europeans, and EVERYONE BUT North Americans.
In the end, the primary reason for keeping the imperial system is fear of change.
Jim,
Measuring time in a base 10 system using the rotational period of our planet as the primary unit would work. Indeed, many such systems have been proposed, and then rejected for the same reason that Americans refuse to give up on the imperial measurement system: fear of change.
It’s the same argument made against improving ANY process: It kind of works now, and it would be more work to fix the system as a whole than to just do this one project under the existing, but cumbersome, system.
Nobody looks to the future, and so nobody cares that the total time wasted fiddling around in the current system FAR exceeds the time it would take to overhaul the system in the long run.
I think it’s more a generational thing in Canada, anyone younger than 35 or so has no problem with metric and uses it; people around my age (40) are in the middle, pretty comfortable with both since we were in the transition era; people over 45 still stick with Imperial.
It’s actually funny, when I think about a person’s height and mass, I immediately think of ft/in and lbs; when I think of volume, speed, distance, or mass of an object or food, it’s in metric. Odd how the brain works.
Speaking of odd, can anyone tell me why the UK (if it’s only England, please excuse me) still uses stone as a unit of a person’s mass in everyday measurement? For the life of me, I cannot see the logic or practicality in using a unit of measurement that is 14 lbs. Guess you have to grow up with it.
Actually there is a pressing need for America to go metric: Metric-Imperial conversion errors are not only costing money, they are costing lives when critical parts fail due to a conversion error.
When you are the ONLY country using an archaic measuring system that is different from the rest of the world’s, you should notice a problem.
When all of the smart people in your country are using metric while you continue to use ridiculously cumbersome measures, you should notice a problem.
The world is not going to adapt to your system. You have to adapt to the world’s.
stephanieebarr, I was quite surprised too. I’ve spent the last 8 years working overseas and have worked with quite a few Brits. The first time one of them said they weighed ‘15 stone 3 pounds’, I had to do a head shake. Wasn’t only one guy, either, they all did it (although they were all fluent in kgs). I couldn’t get an explanation from any of them as to why they still used it. Tradition, I guess.
Bah! My car gets 14 rods to the hogshead and that’s the way I likes it!
For all the “Pint is a Pound” crowd (it has been said before me, but I will reiterate):
1ml is 1cc, which is a cube of water 1cm on each side and weighs 1 gram. 1 litre weighs a kilogram, 1 ton of water is 1 cubic metre.
What calculations do you have to do to work out what a container of water weighs if you measure the dimensions in inches?
Will your decking support a spa pool that holds 1500 litres?
If a river is 10m across and 3m deep in the middle and a stick thrown in moves downstream at 2m a second, can you guesstimate what volume of water moves through every minute? Again, much harder in imperial.
Metric is easier and more elegant by far.
“Now, imagine doing calculations on rocket thrust or something complicated with fractions of an inch (I’m trying not to).”
Real life calculations do not use integers, so complaining about fractions is useless when you are doing decimal math in a calculator anyway.
Its interesting to consider why the US uses United States Customary System and not metric and it is interesting to consider what the cost would be to switch to all metric.
In the end, we use whatever works. For some people that means both systems. Like when you converted from USCS to metric back to USCS when computing the square footage of a room.
Americans, get over yourselves and get with the program. Metrics is the way to the future.
I think what you’ll find is both sets appearing on products, e.g. soda bottles, produce scales.
This gradual approach sidesteps the ‘massive infrastructure’ problem, and helps the general population get a handle on what the Metric measurements actually are.
There’s another problem with converting between systems.
In engineering fields, you need to round off your results to a certain number of significant digits at various intervals. If one team works with one unit of measurement, and another team uses a different measure, converting at the end, you end up with two very slightly different answers. That can often mean the difference between it working and it not working.
Imperial units are a dinosaur. Even the British abandoned it for a system devised by the French, whom they dislike.
And today it makes for yet another reason everyone makes fun of America.
To stephanieebarr:
You assume that computationally expensive operations will have many conversions. I think you are looking at this on a different level than me. But like I said, if using two systems works better than one, then use them. If not, then stick to only one.
From your posted article: ” It would have been easy for us to adjust the parameter that controlled how long the delta-V monitor waited before testing the engine — but nobody told us.”
I see an issue of miscommunication here, where a design change in one part of the system (” the propellant had further to travel to reach the engine” necessitated a design change in the software that never happened?
And also for Apollo 11 again: ” The performance of the descent engine had been improved, but the ICD was not modified accordingly. The actual time lag for the descent engine was about 0.075 seconds. It turned out we had overcompensated. As a result the throttle was barely stable.”
Same problems with miscommunication (I believe that ICD stands for Interface Control Document. However, maybe a single units system will improve communications. Possible, but not guaranteed.
I submit that metric is superior for everything except air temperature.
In the laboratory, degrees Celsius make great sense. 100 degrees between freezing and boiling of water, etc.
When talking about the weather, though, not so much. In Fahrenheit, 0 degrees is really cold and 100 degrees is really hot. Plus, there’s just something cool about having the difference between freezing and boiling be 180 degrees, like it’s on a protractor.
Try teaching your non-military educated citizens the 24-hour clock!
Why stop there, you have me because I don’t have a military background myself. I am learning to adapt because my husband came from a military family so everything at my house is in military 2400 format (which I can see the logic behind) - but I struggle. Even after more than five years, it’s not natural to me. My daughter refuses to learn it, but that may just be a teenage thing.
> Try teaching your non-military educated citizens the 24-hour clock!
The Japanese use a 24-hour clock and have no trouble with it.
Many “imperials” talk about how they don’t feel “natural” with the metric measures. It’s obvious that it would be the case, since (unlike people in the rest of the world) you have been taught to think with imperial units since you were born.
Well, that’s sad, but it’s part of living in a highly integrated world: many things have to be learned again, some changes seem awkward, but they may be (and in this case, ARE) needed. The imperial system is expensive to maintain and error-prone, and there’s NO real argument supporting it (10 not being divisible by 3? Come on! Grow up.).
Ok now I may not be a genius but if that went over your head than you probably cannot use the imperial system you use now. Also i guess known as the English system??
Now maybe people in the US think it would be a big deal to switch but hear in Canada most big name tool makers and companies also make metric products as well.
And I went for a 10km run sounds way better than a 6.2137119 mile long run.