JerryQ sends in a story at New Scientist about the criticism NASA is taking for deciding to use Imperial units in the development of the Constellation program, their project to replace the space shuttle. "The sticking point is that Ares is a shuttle-derived design — it uses solid rocket boosters whose dimensions and technology are based on those currently strapped to either side of the shuttle's giant liquid fuel tank. And the shuttle's 30-year-old specifications, design drawings and software are rooted in pounds and feet rather than newtons and meters. ... NASA recently calculated that converting the relevant drawings, software and documentation to the 'International System' of units (SI) would cost a total of $370 million — almost half the cost of a 2009 shuttle launch, which costs a total of $759 million. 'We found the cost of converting to SI would exceed what we can afford,' says [NASA spokesman Grey Hautaluoma]."
Which is the difference between scientists and engineers.... Sometimes the right decision is to listen to the engineers and not the scientists.
The scientists have it easy. They work in theories and numbers. The engineers have to produce usable physical objects. They have to do so in an environment that had significantly established manufacturing infrastructure before the SI standard existed. The countries that have converted to SI are the countries that were late to the industrial revolution party. It is expensive and difficult to overcome a massive established base of equipment. And it's a self perpetuating problem, because you can't just replace individual tools and machines as they wear out. An individual replacement has to be compatible with the rest of your infrastructure.
Sigh all you like. Short of a massive cash investment (Many Trillions of Dollars), or all manufacturing leaving the US and UK for good, Imperial units will stay and be indifferent to the sighs of the "rest" of the world.
(Incidentally, this would have been a *great* thing to spend stimulus money on instead of government employee salaries and other stupid programs.)
Also, SI conversion with stimulus $$ is one of the better ideas I've heard. It creates jobs (and ones that require at least basic education instead of just the ability to pour and smooth asphalt.) Hell, we could have even have offered basic training for people that would be involved in the more trivial but labor intensive efforts.
Mass conversion to SI requires some manual labor (switching road signs, etc), a lot of public awareness stuff, and a lot of Associate-level tech folks (and probably higher-level for review). You know who building a duck pond employs? 4 guys with heavy equipment (or 50 with shovels) and some ducks.
Most of the UK is SI now. Road signs still use miles and you can get two metres of two-by-four but it's liable to be 5cm by 10cm, whatever it's called.
And asking for a kilo of tomatoes got me 'That's two pounds, sir, and f*ck the French'
Lets be clear there are an absolute hat-full of major countries that don't *use* the SI day to day whatever they may have 'adopted'. Forty four years on from UK adoption, my car has a speedometer which is in mph as are the road signs. There are public outrages on central european efforts to prosecute small shop owners for being unwilling to sell fruit and veg in grams yet I have never heard anyone ask for '200 grammes of carrots'. People talk about their weight in stones and pounds and the only time you hear kilos is in international sports. Aircraft power is rate in lbs per square inch....
The fact of what it's based off of is irrelevant, everything comes down to the metric system being consistent in staying in base 10, and the imperial system is not.
Except unit conversions are not the norm. When a grocery store manager orders potatoes, it doesn't really matter if he orders 200 10 pound bags (which is really tough to convert to 2,000 pounds) or if he orders 200 5 kilogram bags (which is really tough to convert to 1,000 kilograms).
Sure, sometimes someone has to get a calculator to figure out how many inches are in 200 feet (but hopefully not most people) before they figure out how many 1.65 inch pieces they can cut that 200 feet into, but the other guy is going to need a calculator (or some scratch paper, whatever) to figure out how many 4.191 cm pieces they can get from 60 meters anyway.
both SI and Imperial units are pegged to arbitrary things. In the case of Imperial units it was some king's foot. In the case of SI it is the distance light travels in some amount of time. whatever.
That's beside the pont. Yes the SI units are pegged to arbitrary things but they are not arbitrarily pegged to *eachother*.
Converting from centimeters to kilometers requires dividing by 100,000. I can do that in my head. Converting from miles to inches requires dividing by 63,360. I can't do that in my head.
Yes the SI units are pegged to arbitrary things but they are not arbitrarily pegged to *eachother*.
Actually "imperial" units [wikipedia.org] are pegged to SI units. Since July 1, 1959, the the inch, foot, yard, and mile have been defined on the basis of 1 yard = 0.9144 meters. The pound is defined as exactly 453.59237 grams.
humans find it much easier to divide into halves than into tenths [...] Give me a gallon of liquid and a set of unmarked jugs and I'll probably have pretty darn close to 1 fl. oz. long before you can cut 1 L down to 1 mL.
a) Wow. Ok. Is that a problem you encounter frequently? This seems a bit artificial.:)
b) Yeah, I'll grant you that dividing something physically in half is easier. But while YOU might be able to pull a fluid ounce from a gallon using unmarked jugs, lets be honest most people would still really struggle with that.
c) Next, people like you and I who could solve this problem are also smart enough to realize that they don't have to physically divide into 10ths, but halves and fifths. So to cut 1L down to 1mL they need to divide by 1000... or 2x2x2x5x5x5. Fifths is harder than halves but not THAT hard.
d) Further its bit of an unfair problem. The SI problem is a 1000th cut, your imperial problem is considerably less. Its only a 128th cut. A closer problem (both in difficulty, and in the actual amounts of liquid involved would be: 4L to 50mL, which 2x2x2x2x5.
e) Further you are cherry picking imperial units. Tablespoon to Teaspoon is 3rds. Feet to inches is 12ths (2x2x3). Yards to feet is 3rds. And from yards to feet is 1760ths... and 1760 factors to 2x2x2x2x2x5x11. Yeah there's an 11 in that one. How many people do you know who are facile at 11ths? I suppose we could dig through rods and chains etc but I'd have to look up what those actually are...
f) decimal is easier for any serious work, where you have paper and calculators and computers instead of sets of unmarked jugs and cherry picked problems.
The problem with imperial is not what it is based upon (actually, these days the US units are all defined by reference to the SI units anyway - since 1959 an inch is defined as 2.54 cm - see http://en.wikipedia.org/wiki/Inch [wikipedia.org] ) the problem with the imperial system is the arbitrariness and inconsistency of the relationships between the units. The SI system has a consistent relationship between all of the units, and a consistent naming system and a consistent abbreviation system. In the imperial system, the relationships between units are not only arbitrary, but they are also inconsistent, there are multiple uses of the same word (ounces for example) used to describe different measurements (weight as well as volume) or dry vs liquid volumes.
Sure there are a lot of vehicles, but the complexity can be managed by the following easy two-step process: 1. Today switch passenger cars to the right hand side 2. A week from now follow with the trucks too...
You know, a lot of Europeans probably think that U.S. reluctance to embrace the metric system is just another example of our arrogance. But a lot of Americans (like me) are genuinely interested in adopting this system. We even passed a law [wikipedia.org] in 1975 trying to mandate it.
The real problem is that it is surprisingly hard to embrace a new system of measurement when you've spent your entire life thinking in different terms. Try as I might, I still can't picture a kilometer without converting it to a mile first, and still can't picture a centimeter without converting it to inches. The meter is a lot easier because it's pretty analogous to the yard. I think maybe your brain gets locked into a certain measurement pattern pretty early in life and it's very difficult to get out of it, even though many of us would happily embrace it. I'm still trying to think more in metric, but it requires a surprising amount mental effort to do so.
It's not that Americans are really all that arrogant or stubborn about the imperial system. We've actually been trying to embrace the metric system [wikipedia.org] for some time.
I lived in guilders all my life, and the first couple years in Eurotime I could only "imagine" a price by converting back to guilders and thinking whether the price sounded right. Now, I can only "imagine" a guilders price by converting it to euros
I've lived in the UK and US for 1.5 and.5 years, respectively, and I started thinking natively in most units pretty quickly, esp. inches and miles, and of course pints in the UK. Some units are more difficult, either because they have an offset as well as a scale difference (fahrenheit) or because they just don't make any sense (a 22 fluid ounces drink?? gimme a pint, damnit!)
I think the UK is busy converting mostly to metric system, so maybe some UKians can chime in with their experience?
I think the UK is busy converting mostly to metric system, so maybe some UKians can chime in with their experience?
Unfortunately, not really. All street signs still measure distance in miles, and eighths of miles, and the like, and half the population think that the metric system is (like the euro) just another damn frenchie scheme to undermine our sovereignty. We have a long history (this [wikipedia.org], for instance) of coming up with crazy conspiricies to demonstrate why the imperial system is our God-given right, and why the French would like nothing better than to force their evil organised system of measurement upon us.
Meanwhile, for at least a couple of decades now, kids grow up being taught nothing but metric, and wonder why the grown ups still insist on using imperial, and what on earth a fluid ounce actually is. Cos everyone seems to use it, but I don't think anyone under 25 has actually been taught it.
I'm from the UK, and my mental image of measurements is fucked.
I know how much a pint is. I know how much 1kg is, but I don't know how much is 1 pound in weight. I know how tall I am in feet and inches, but not in meters.
All because we use metric for some reasons, and we are still stuck in imperial for others. My milk comes in bottles that are labelled 568ml although *everyone* refers to it as a pint, obviously our alcoholic drinks come in pints and half pints. Our speed limits are measured in miles per hour, yet we used to run the 100 meters at school. My height has always been given to me in feet and inches (while growing up by my parents) and if you speak to pretty much anyone they will also give their height in feet and inches, yet if I go to the doctor, they want me to know how high in meters. If you go under a low bridge, the height is given in feet.
When I go swimming the pool is in meters, when referring to medium distances anyone aged over 40 refers to yards, everyone below that refers to meters, at larger distances it's rare for anyone to use kilometers. Anyone over 40ish only understands Fahrenheit, everyone below uses degrees centigrade.
Generally speaking things are moving to metric (thankfully) but it will take many many years for imperial to die here currently we are in one big measurement mess and we will be for some time, especially as every traffic sign is in imperial.
Which pint? UK or US?
A UK pint is 0.568 liters so you won't like it if you ask for half liter, but if you're American a half liter is a little larger than your pint (0.473 liters). However in most pubs I've been in here in Europe beer is either large or small, whatever that means in that place. Ask for a large beer and you'll be happy:-)
No it's not. I've was born and raised in France, moved in the US at 23, 4 years ago. The only unit I'm still uncomfortable with is F (also one of the stupidest) I have no problem thinking in inches, miles, gallons, ounces without converting.
It would be relevant, but most of the time when people mention a temperature it's inaccurate anyway. Consumer grade thermometers are generally out by a degree or 2 Celsius. Your local weather report is probably more accurate, but only where the temperature is actually taken.
Using Fahrenheit is more precise, it isn't more accurate.
The real problem is that it is surprisingly hard to embrace a new system of measurement when you've spent your entire life thinking in different terms.
Yes. Thats why the Canadians haven't been able to do it either. Or the Irish. Not Australia and New Zealand either. Or India.
Oh wait, they *have* all done it. So how come they can, but for the US it's just too hard?
The sticking point is that Ares is a shuttle-derived design â" it uses solid rocket boosters whose dimensions and technology are based on those currently strapped to either side of the shuttle's giant liquid fuel tank. And the shuttle's 30-year-old specifications, design drawings and software are rooted in pounds and feet rather than newtons and meters.
And in 20 years, that'll be the same excuse given for building Ares's replacement with imperial units.
This email goes around archaeological circles every once in a while (I'm sure it goes around other circles, too), and I just got a new copy of it from my uncle yesterday, so it seems as good a time as any to share:
People are always asking why we do things the way we do. Well, here is
the reason: railroad tracks.
The US standard railroad gauge (distance between the rails) is 4 feet,
8.5 inches. That's an exceedingly odd number.
Why was that gauge used? Because that's the way they built them in
England, and English expatriates designed the US railroads.
Why did the English build them like that? Because the first rail lines
were built by the same people who built the pre-railroad tramways, and
that's the gauge they used.
Why did 'they' use that gauge? Because the people who built the
tramways used the same jigs and tools that they had used for building
wagons, which used that wheel spacing.
Why did the wagons have that particular odd wheel spacing? Well, if they
tried to use any other spacing, the wagon wheels would break on some of
the old, long distance roads in England because that's the spacing of
the wheel ruts.
So, who built those old rutted roads? Imperial Rome built the first long
distance roads in Europe (including England) for the legions. Those
roads have been used ever since.
And the ruts in the roads? Roman war chariots formed the initial ruts,
which everyone else had to match for fear of destroying their wagon
wheels. Since the chariots were made for Imperial Rome, they all had the
same wheel spacing. Therefore, the United States' standard railroad
gauge of 4 feet, 8.5 inches is derived from the original specifications
for an Imperial Roman war chariot. Bureaucracies live forever.
So, the next time you are handed a specification/procedure/process and
wonder 'What horse's ass came up with this?' you may be exactly right.
Imperial Roman army chariots were made just wide enough to accommodate
the rear ends of two war horses (two horses' asses). Now, the twist to
the story.
When you see a Space Shuttle sitting on its launch pad, there are two big
booster rockets attached to the sides of the main fuel tank. These are
solid rocket boosters, or SRBs. The SRBs are made by Thiokol at their
factory in Utah. The engineers who designed the SRBs would have preferred
to make them a bit fatter, but the SRBs had to be shipped by train from
the factory to the launch site. The railroad line from the factory
happens to run through a tunnel in the mountains, and the SRBs had to fit
through that tunnel. The tunnel is slightly wider than the railroad
track and the railroad track, as you now know, is about as wide as two
horses' behinds.
So, a major Space Shuttle design feature of what is arguably the world's
most advanced transportation system was determined over two thousand
years ago by the width of a horse's ass. And you thought being a horse's
ass wasn't important? Ancient horse's asses control lots of things...
AND CURRENT HORSES' ASSES NOW ARE ARE CONTROLLING NEARLY EVERYTHING ELSE.
That must be one of the weakest "false" results I've seen on Snopes. As it says itself:
Origins: This is one of those items that although wrong in many of its details isn't exactly false in an overall sense and is perhaps more fairly labeled as "True, but for trivial and unremarkable reasons."
In fact, it collaborates that the English railway was made in the same size as double-horse carriages, that the US share that width because they shared tools and that it's the dominant standard today since the northern US won the civil war. It's a bit of a stretch that double horse carriages were popular only because the romans did it, but they certainly did do it first and built a massive network of them.
Finally, on the space shuttle thing snopes is just being silly. The largest carriage in the table listed by snopes is 9-10 feet. According to wikipedia the shuttle boosters are a little over 12 feet. So while the part about being "slightly wider than the track" is a liberal description, it's certainly possible they couldn't be built bigger because the tunnels aren't bigger.
the issue isn't just one of redoing the drawings along with the various checks and cross checks to make certain the units were converted properly. I'm sure they could that, but the resulting set of new drawings would be extremely prone to encouraging mistakes. As a minor example. Let's assume that on one piece they currently have a dimension of 12 inches +/- 0.01 inches. So they convert this dimension to metric giving a new value of 30.48 cm +/- 0.025 cm. Excuse me?!?!? That's a rather odd and strange dimensional target to hand off to the machinest. And you'll be getting these rather strange dimensions for everything on the original design. Frankly using the metric measurements would make that rocket utterly hell to construct. So the "proper" solution would be to use the original design and then stretch/shrink various dimensions in order to make the dimensions "rounder" and easier to manufacture. But upon doing that, they have effectively come up with a new design that has to be recertified.
We're just talking about units of measure. If it is easier to use imperial units because previous design and drawings were done in imperial, then that's the smart choice. I would be upset if NASA was wasting taxpayer money just so that the design could be done in metric. I actually applaud NASA for making a smart, cost/benefit engineering decision.
It never ceases to amaze me the resistance to going to metric here in the states for measurements but no one bats an eyelash at the fact our money is basically metric (base 10).
It is in fact soo damn easy that we can instinctively give somone a $5 and a penny for something that costs $4.01 so we can get back a dollar rather then 3 quarters 2 dimes and 4 pennies....
Boo metric it's too damn easy to use! Forget cutting a board 1.46 meters in half. it's too damn hard to cut it.73 meters! Better yet that 3 5/8th inch board needs to be cut in half so we need umm... err... need some scratch paper here....
I work for an engineering company, and unit conversions are not a trivial operation. All of our drawings are created in autocad, and after several years it becomes difficult if not impossible to find the original file. As such, converting achieved documents requires recreating the document entirely from scratch. We also use a fairly vigorous quality control system that requires 3 engineers to check every document change, verify the calculation, and repeat the calculation using a different method to ensure that no mistakes were made.
We recently acquired an older project where we needed to simply change the title block on each page, and this process took roughly 5000 hours. For something on the scale of the space shuttle, 370 million isn't unheard of.
after several years it becomes difficult if not impossible to find the original file...We also use a fairly vigorous quality control system
How do you keep quality on your products, but not even keep your original documentation files? What happens if there is a change?
our drawings are created in autocad... unit conversions are not a trivial operation
The engineering team where I work uses Solidworks, and there are macros to do the conversions. Of course, those macros only work on the original files, not the printed documents...:-) So that brings us back to having lost the files...
You don't seem to understand, even a little. These numbers are on a piece of paper that no longer exists on a computer. Not even the most advanced computer script in the world can adjust paper. So okay, I understand part of your point, put it into the computer first, and then run the script. These documents are crawling with numbers. Line numbers, electrical classifications, instrument identifiers. Even if I had a script to manage the process, you then have the problem of units. I'm not doing 5000 ft to meter conversions. We have lengths (using both ft, in, ',and "), weights, volumes, temperatures, powers (hp, MMBtu/hr, kW, MW) and so forth. Even if you could have a script smart enough to check for units, how would it tell the difference between a temperature and a temperature change? If I have a heat exchanger with a temperature change of 50ÂF, the correct metric temperature change is 27.8ÂC. If you got 10ÂC, you used the wrong method. The sheer amount of back checking I would have to do to make sure a rogue script didn't destroy my drawings would be insane.
This is not a simple database you're playing with.
You make it sound so simple...when, in fact, this is quite literally rocket science here.
One of the common stories here is people needing to rewrite an entire project because of a new language fad. The old project worked. Rewriting it first means you have to replicate the old project and then deal with new bugs while the old project had all the bugs mostly ironed out.
Why do we insist NASA to reinvent the wheel when we're so against it in our own profession?
by Anonymous Coward
on Wednesday June 24 2009, @10:37AM (#28453171)
It's not like they're building anything new or buying raw materials; they just need someone to re-draw plans with new measurements in a different system.
Frankly, and without trying to be insulting, you're so ignorant of what the issue is that it's laughable that you even have an opinion on it.
This isn't a matter of trivia, where we are worried if plans are marked in inches or mm. Change to metric, now every bolt must be metric pitch thread, every nut must be changed to accomodate. Every calculation of mass and structural integrity has to be reexamined and recalculated for new components. You don't just magically say "ok, our 3/8" bolts are now to be called 9.525mm bolts" and call it a day.
What the hell are they spending this money on? It's not like they're building anything new or buying raw materials; they just need someone to re-draw plans with new measurements in a different system.
And once the drawings are re-drawn, you have to verify the individual drawings. Then you have to verify the interfaces to make sure that vendor 'A' didn't round his tolerances in a direction that means his part will no longer properly mate with a part from vendor 'B'. Then you have to withdraw the old drawings from service and replace them with the new in an orderly fashion. Somewhere along the way you also have to not only update the references between drawings, but also the hundreds of thousands of pages of documentation, specifications, etc... that reference these drawings.
The individual steps are bone simple - but there are a lot of individual steps and they interact in various complicated ways.
An additional problem is that all this has to be done while those drawings, specifications, etc... etc... are in daily use at facilities scattered across the country, which means you have a fairly difficult problem not only in making these changes - but in ensuring everybody is 'on the same page'...
If they paid their engineers $150,000/year, they could hire almost 2500 engineers for a year-long project.
Or, pay 10 engineers to make sure that the adapter between the (imperial) boosters and (metric) Ares is properly sized and be done with it. If you're pulling a boat behind a truck, you don't care if the truck engine's bolts are metric and the boat's are imperial because they don't have anything to do with each other. As long as the hitch pieces are compatible, you're golden.
Please advise us on how you're going to train every machinist, and QC agent, just to name two job categories on how to measure 30.22mm with calipers that are intended to measure in Imperial? If they can't do this, do it reliably, and do it accurately then you're going to have some funny fitting parts on those Ares.
That is just one very simple example in two very limited job categories where changing from SI to Metric would introduce horrible, and potentially disastrous, difficulties.
Yes...stored in electronic form. That's right. Wait, remind me again, what file format did Autocad use in the 1960s? 1970s? 1980s? Was it DWG back then?
Plus we're not building another shuttle. We're going back to the days of Apollo, with a capsule^Wspacecraft on top of a rocket. Apparently, though, they found that they can utilize the SRB design for part of the new project. (The big white rockets that get reused after launches.) The SRBs date from the start of the Shuttle era which...erm, yeah. 1970s.
So here we have a rocket booster already designed that works like a champion. The blueprints are all done. They work. They're reusable. They've been fieldtested over 100 times.
And you want to redesign them essentially from scratch? As many coders here want to say to their bosses when upper eschelon wants to recode an application in the new flavor of the month language: if it is not broken, do not fix it.
Oh the Humanity! (Score:4, Funny)
Re:Oh the Humanity! (Score:5, Insightful)
Which is the difference between scientists and engineers.... Sometimes the right decision is to listen to the engineers and not the scientists.
The scientists have it easy. They work in theories and numbers. The engineers have to produce usable physical objects. They have to do so in an environment that had significantly established manufacturing infrastructure before the SI standard existed. The countries that have converted to SI are the countries that were late to the industrial revolution party. It is expensive and difficult to overcome a massive established base of equipment. And it's a self perpetuating problem, because you can't just replace individual tools and machines as they wear out. An individual replacement has to be compatible with the rest of your infrastructure.
Sigh all you like. Short of a massive cash investment (Many Trillions of Dollars), or all manufacturing leaving the US and UK for good, Imperial units will stay and be indifferent to the sighs of the "rest" of the world.
(Incidentally, this would have been a *great* thing to spend stimulus money on instead of government employee salaries and other stupid programs.)
Parent
Re:Oh the Humanity! (Score:5, Interesting)
Wonderful +1 Welcome to the real world
Also, SI conversion with stimulus $$ is one of the better ideas I've heard. It creates jobs (and ones that require at least basic education instead of just the ability to pour and smooth asphalt.) Hell, we could have even have offered basic training for people that would be involved in the more trivial but labor intensive efforts.
Mass conversion to SI requires some manual labor (switching road signs, etc), a lot of public awareness stuff, and a lot of Associate-level tech folks (and probably higher-level for review). You know who building a duck pond employs? 4 guys with heavy equipment (or 50 with shovels) and some ducks.
Parent
Re:Oh the Humanity! (Score:4, Funny)
Parent
Re:Oh the Humanity! (Score:5, Funny)
Sure, you tried to look smart by using Latin phrases and failed to an epic degree?
Parent
Re:Oh the Humanity! (Score:5, Funny)
Parent
Re:Oh the Humanity! (Score:4, Funny)
The countries that have converted to SI are the countries that were late to the industrial revolution party.
What do you mean? EVERY country in the world uses the SI, except for the USA, Liberia and Burma.
Parent
Re:Oh the Humanity! (Score:5, Informative)
Parent
Re:mod parent +1 realistic (Score:4, Insightful)
Parent
Re:mod parent +1 realistic (Score:4, Insightful)
Except unit conversions are not the norm. When a grocery store manager orders potatoes, it doesn't really matter if he orders 200 10 pound bags (which is really tough to convert to 2,000 pounds) or if he orders 200 5 kilogram bags (which is really tough to convert to 1,000 kilograms).
Sure, sometimes someone has to get a calculator to figure out how many inches are in 200 feet (but hopefully not most people) before they figure out how many 1.65 inch pieces they can cut that 200 feet into, but the other guy is going to need a calculator (or some scratch paper, whatever) to figure out how many 4.191 cm pieces they can get from 60 meters anyway.
Parent
Re:mod parent +1 realistic (Score:4, Insightful)
both SI and Imperial units are pegged to arbitrary things. In the case of Imperial units it was some king's foot. In the case of SI it is the distance light travels in some amount of time. whatever.
That's beside the pont. Yes the SI units are pegged to arbitrary things but they are not arbitrarily pegged to *eachother*.
Converting from centimeters to kilometers requires dividing by 100,000. I can do that in my head.
Converting from miles to inches requires dividing by 63,360. I can't do that in my head.
Parent
Re:mod parent +1 realistic (Score:5, Interesting)
Actually "imperial" units [wikipedia.org] are pegged to SI units. Since July 1, 1959, the the inch, foot, yard, and mile have been defined on the basis of 1 yard = 0.9144 meters. The pound is defined as exactly 453.59237 grams.
Parent
Re:mod parent +1 realistic (Score:5, Informative)
humans find it much easier to divide into halves than into tenths [...] Give me a gallon of liquid and a set of unmarked jugs and I'll probably have pretty darn close to 1 fl. oz. long before you can cut 1 L down to 1 mL.
a) Wow. Ok. Is that a problem you encounter frequently? This seems a bit artificial. :)
b) Yeah, I'll grant you that dividing something physically in half is easier. But while YOU might be able to pull a fluid ounce from a gallon using unmarked jugs, lets be honest most people would still really struggle with that.
c) Next, people like you and I who could solve this problem are also smart enough to realize that they don't have to physically divide into 10ths, but halves and fifths. So to cut 1L down to 1mL they need to divide by 1000... or 2x2x2x5x5x5. Fifths is harder than halves but not THAT hard.
d) Further its bit of an unfair problem. The SI problem is a 1000th cut, your imperial problem is considerably less. Its only a 128th cut. A closer problem (both in difficulty, and in the actual amounts of liquid involved would be: 4L to 50mL, which 2x2x2x2x5.
e) Further you are cherry picking imperial units. Tablespoon to Teaspoon is 3rds. Feet to inches is 12ths (2x2x3). Yards to feet is 3rds. And from yards to feet is 1760ths... and 1760 factors to 2x2x2x2x2x5x11. Yeah there's an 11 in that one. How many people do you know who are facile at 11ths? I suppose we could dig through rods and chains etc but I'd have to look up what those actually are...
f) decimal is easier for any serious work, where you have paper and calculators and computers instead of sets of unmarked jugs and cherry picked problems.
Parent
Re:mod parent +1 realistic (Score:5, Insightful)
The problem with imperial is not what it is based upon (actually, these days the US units are all defined by reference to the SI units anyway - since 1959 an inch is defined as 2.54 cm - see http://en.wikipedia.org/wiki/Inch [wikipedia.org] ) the problem with the imperial system is the arbitrariness and inconsistency of the relationships between the units. The SI system has a consistent relationship between all of the units, and a consistent naming system and a consistent abbreviation system. In the imperial system, the relationships between units are not only arbitrary, but they are also inconsistent, there are multiple uses of the same word (ounces for example) used to describe different measurements (weight as well as volume) or dry vs liquid volumes.
Parent
Re:Oh the Humanity! (Score:5, Funny)
Next task for UK: driving on the right hand side.
Sure there are a lot of vehicles, but the complexity can be managed by the following easy two-step process:
1. Today switch passenger cars to the right hand side
2. A week from now follow with the trucks too...
Parent
Re:Oh the Humanity! (Score:5, Funny)
Parent
If you give up the inch, they'll take the mile (Score:5, Insightful)
You know, a lot of Europeans probably think that U.S. reluctance to embrace the metric system is just another example of our arrogance. But a lot of Americans (like me) are genuinely interested in adopting this system. We even passed a law [wikipedia.org] in 1975 trying to mandate it.
The real problem is that it is surprisingly hard to embrace a new system of measurement when you've spent your entire life thinking in different terms. Try as I might, I still can't picture a kilometer without converting it to a mile first, and still can't picture a centimeter without converting it to inches. The meter is a lot easier because it's pretty analogous to the yard. I think maybe your brain gets locked into a certain measurement pattern pretty early in life and it's very difficult to get out of it, even though many of us would happily embrace it. I'm still trying to think more in metric, but it requires a surprising amount mental effort to do so.
It's not that Americans are really all that arrogant or stubborn about the imperial system. We've actually been trying to embrace the metric system [wikipedia.org] for some time.
Re:If you give up the inch, they'll take the mile (Score:5, Informative)
I don't buy it
I lived in guilders all my life, and the first couple years in Eurotime I could only "imagine" a price by converting back to guilders and thinking whether the price sounded right. Now, I can only "imagine" a guilders price by converting it to euros
I've lived in the UK and US for 1.5 and .5 years, respectively, and I started thinking natively in most units pretty quickly, esp. inches and miles, and of course pints in the UK. Some units are more difficult, either because they have an offset as well as a scale difference (fahrenheit) or because they just don't make any sense (a 22 fluid ounces drink?? gimme a pint, damnit!)
I think the UK is busy converting mostly to metric system, so maybe some UKians can chime in with their experience?
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Re:If you give up the inch, they'll take the mile (Score:5, Informative)
I think the UK is busy converting mostly to metric system, so maybe some UKians can chime in with their experience?
Unfortunately, not really. All street signs still measure distance in miles, and eighths of miles, and the like, and half the population think that the metric system is (like the euro) just another damn frenchie scheme to undermine our sovereignty. We have a long history (this [wikipedia.org], for instance) of coming up with crazy conspiricies to demonstrate why the imperial system is our God-given right, and why the French would like nothing better than to force their evil organised system of measurement upon us.
Meanwhile, for at least a couple of decades now, kids grow up being taught nothing but metric, and wonder why the grown ups still insist on using imperial, and what on earth a fluid ounce actually is. Cos everyone seems to use it, but I don't think anyone under 25 has actually been taught it.
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Re:If you give up the inch, they'll take the mile (Score:5, Informative)
I'm from the UK, and my mental image of measurements is fucked.
I know how much a pint is. I know how much 1kg is, but I don't know how much is 1 pound in weight. I know how tall I am in feet and inches, but not in meters.
All because we use metric for some reasons, and we are still stuck in imperial for others. My milk comes in bottles that are labelled 568ml although *everyone* refers to it as a pint, obviously our alcoholic drinks come in pints and half pints. Our speed limits are measured in miles per hour, yet we used to run the 100 meters at school. My height has always been given to me in feet and inches (while growing up by my parents) and if you speak to pretty much anyone they will also give their height in feet and inches, yet if I go to the doctor, they want me to know how high in meters. If you go under a low bridge, the height is given in feet.
When I go swimming the pool is in meters, when referring to medium distances anyone aged over 40 refers to yards, everyone below that refers to meters, at larger distances it's rare for anyone to use kilometers. Anyone over 40ish only understands Fahrenheit, everyone below uses degrees centigrade.
Generally speaking things are moving to metric (thankfully) but it will take many many years for imperial to die here currently we are in one big measurement mess and we will be for some time, especially as every traffic sign is in imperial.
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Re:If you give up the inch, they'll take the mile (Score:4, Insightful)
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Re:If you give up the inch, they'll take the mile (Score:4, Interesting)
No it's not. I've was born and raised in France, moved in the US at 23, 4 years ago. The only unit I'm still uncomfortable with is F (also one of the stupidest) I have no problem thinking in inches, miles, gallons, ounces without converting.
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Re:If you give up the inch, they'll take the mile (Score:5, Insightful)
Fahrenheit is a wonderfully human temperature scale. Over 100 is Way Too Damn Hot, and under 0 is Way Too Damn Cold. I like that.
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Re:If you give up the inch, they'll take the mile (Score:4, Funny)
What's so special about 100? Oh, a decimal number... The irony is delicious.
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Re:If you give up the inch, they'll take the mile (Score:5, Insightful)
It would be relevant, but most of the time when people mention a temperature it's inaccurate anyway.
Consumer grade thermometers are generally out by a degree or 2 Celsius. Your local weather report is probably more accurate, but only where the temperature is actually taken.
Using Fahrenheit is more precise, it isn't more accurate.
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Re:If you give up the inch, they'll take the mile (Score:5, Insightful)
The real problem is that it is surprisingly hard to embrace a new system of measurement when you've spent your entire life thinking in different terms.
Yes. Thats why the Canadians haven't been able to do it either. Or the Irish. Not Australia and New Zealand either. Or India.
Oh wait, they *have* all done it. So how come they can, but for the US it's just too hard?
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Re:If you give up the inch, they'll take the mile (Score:4, Insightful)
Oh wait, they *have* all done it. So how come they can, but for the US it's just too hard?
No, I think it's because too few people care, so politicians don't care...and it never gets done. Simple as that.
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Let's all help the guys over at NASA (Score:4, Funny)
1 foot = 0.3048 meters
There you go, NASA. That one's for free.
Conversion is Exact (Score:5, Informative)
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Just get it over with already (Score:4, Funny)
The sticking point is that Ares is a shuttle-derived design â" it uses solid rocket boosters whose dimensions and technology are based on those currently strapped to either side of the shuttle's giant liquid fuel tank. And the shuttle's 30-year-old specifications, design drawings and software are rooted in pounds and feet rather than newtons and meters.
And in 20 years, that'll be the same excuse given for building Ares's replacement with imperial units.
Horses Asses (Score:5, Interesting)
Re:Horses Asses (Score:5, Funny)
Why is my mailbox full of unfunny spam?
Because a bunch of horses' asses keep hitting the Forward button.
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Re:Horses Asses (Score:5, Informative)
Claim: The United States standard railroad gauge derives from the original specification for an Imperial Roman war chariot.
Status: False
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Re:Horses Asses (Score:5, Interesting)
That must be one of the weakest "false" results I've seen on Snopes. As it says itself:
Origins: This is one of those items that although wrong in many of its details isn't exactly false in an overall sense and is perhaps more fairly labeled as "True, but for trivial and unremarkable reasons."
In fact, it collaborates that the English railway was made in the same size as double-horse carriages, that the US share that width because they shared tools and that it's the dominant standard today since the northern US won the civil war. It's a bit of a stretch that double horse carriages were popular only because the romans did it, but they certainly did do it first and built a massive network of them.
Finally, on the space shuttle thing snopes is just being silly. The largest carriage in the table listed by snopes is 9-10 feet. According to wikipedia the shuttle boosters are a little over 12 feet. So while the part about being "slightly wider than the track" is a liberal description, it's certainly possible they couldn't be built bigger because the tunnels aren't bigger.
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obligatory simpsons quote (Score:4, Funny)
Abe Simpson: The metric system is the tool of the devil! My car gets forty rods to the hogshead and that's the way I likes it.
I can definitely see their point, because (Score:5, Insightful)
the issue isn't just one of redoing the drawings along with the various checks and cross checks to make certain the units were converted properly. I'm sure they could that, but the resulting set of new drawings would be extremely prone to encouraging mistakes. As a minor example. Let's assume that on one piece they currently have a dimension of 12 inches +/- 0.01 inches. So they convert this dimension to metric giving a new value of 30.48 cm +/- 0.025 cm. Excuse me?!?!? That's a rather odd and strange dimensional target to hand off to the machinest. And you'll be getting these rather strange dimensions for everything on the original design. Frankly using the metric measurements would make that rocket utterly hell to construct. So the "proper" solution would be to use the original design and then stretch/shrink various dimensions in order to make the dimensions "rounder" and easier to manufacture. But upon doing that, they have effectively come up with a new design that has to be recertified.
Find something better to complain about (Score:5, Insightful)
Metric (Score:4, Insightful)
It never ceases to amaze me the resistance to going to metric here in the states for measurements but no one bats an eyelash at the fact our money is basically metric (base 10).
It is in fact soo damn easy that we can instinctively give somone a $5 and a penny for something that costs $4.01 so we can get back a dollar rather then 3 quarters 2 dimes and 4 pennies....
Boo metric it's too damn easy to use! Forget cutting a board 1.46 meters in half. it's too damn hard to cut it .73 meters! Better yet that 3 5/8th inch board needs to be cut in half so we need umm... err... need some scratch paper here....
Re:really? (Score:5, Informative)
I work for an engineering company, and unit conversions are not a trivial operation. All of our drawings are created in autocad, and after several years it becomes difficult if not impossible to find the original file. As such, converting achieved documents requires recreating the document entirely from scratch. We also use a fairly vigorous quality control system that requires 3 engineers to check every document change, verify the calculation, and repeat the calculation using a different method to ensure that no mistakes were made.
We recently acquired an older project where we needed to simply change the title block on each page, and this process took roughly 5000 hours. For something on the scale of the space shuttle, 370 million isn't unheard of.
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Re:really? (Score:4, Insightful)
after several years it becomes difficult if not impossible to find the original file...We also use a fairly vigorous quality control system
How do you keep quality on your products, but not even keep your original documentation files? What happens if there is a change?
our drawings are created in autocad... unit conversions are not a trivial operation
The engineering team where I work uses Solidworks, and there are macros to do the conversions. Of course, those macros only work on the original files, not the printed documents... :-) So that brings us back to having lost the files...
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Re:really? (Score:5, Insightful)
Next time you should replace 4999 of those hours with a simple BASH script.
The original files were not available. What shell do you use that compiles to paper?
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Re:really? (Score:5, Informative)
You don't seem to understand, even a little. These numbers are on a piece of paper that no longer exists on a computer. Not even the most advanced computer script in the world can adjust paper. So okay, I understand part of your point, put it into the computer first, and then run the script. These documents are crawling with numbers. Line numbers, electrical classifications, instrument identifiers. Even if I had a script to manage the process, you then have the problem of units. I'm not doing 5000 ft to meter conversions. We have lengths (using both ft, in, ',and "), weights, volumes, temperatures, powers (hp, MMBtu/hr, kW, MW) and so forth. Even if you could have a script smart enough to check for units, how would it tell the difference between a temperature and a temperature change? If I have a heat exchanger with a temperature change of 50ÂF, the correct metric temperature change is 27.8ÂC. If you got 10ÂC, you used the wrong method. The sheer amount of back checking I would have to do to make sure a rogue script didn't destroy my drawings would be insane.
This is not a simple database you're playing with.
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Re:really? (Score:4, Insightful)
There's a VERY good reason to re-use the SRB's, they are a well tested design with the flaws worked out and the real operating parameters known.
We would be remiss if we did not note that the engineering kinks of the SRBs have been ironed out, by that they killed seven people in the process.
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Re:$370 million? (Score:4, Insightful)
You make it sound so simple...when, in fact, this is quite literally rocket science here.
One of the common stories here is people needing to rewrite an entire project because of a new language fad. The old project worked. Rewriting it first means you have to replicate the old project and then deal with new bugs while the old project had all the bugs mostly ironed out.
Why do we insist NASA to reinvent the wheel when we're so against it in our own profession?
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Re:$370 million? (Score:5, Insightful)
It's not like they're building anything new or buying raw materials; they just need someone to re-draw plans with new measurements in a different system.
Frankly, and without trying to be insulting, you're so ignorant of what the issue is that it's laughable that you even have an opinion on it.
This isn't a matter of trivia, where we are worried if plans are marked in inches or mm. Change to metric, now every bolt must be metric pitch thread, every nut must be changed to accomodate. Every calculation of mass and structural integrity has to be reexamined and recalculated for new components. You don't just magically say "ok, our 3/8" bolts are now to be called 9.525mm bolts" and call it a day.
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Re:$370 million? (Score:4, Insightful)
And once the drawings are re-drawn, you have to verify the individual drawings. Then you have to verify the interfaces to make sure that vendor 'A' didn't round his tolerances in a direction that means his part will no longer properly mate with a part from vendor 'B'. Then you have to withdraw the old drawings from service and replace them with the new in an orderly fashion. Somewhere along the way you also have to not only update the references between drawings, but also the hundreds of thousands of pages of documentation, specifications, etc... that reference these drawings.
The individual steps are bone simple - but there are a lot of individual steps and they interact in various complicated ways.
An additional problem is that all this has to be done while those drawings, specifications, etc... etc... are in daily use at facilities scattered across the country, which means you have a fairly difficult problem not only in making these changes - but in ensuring everybody is 'on the same page'...
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Re:$370 million? (Score:5, Insightful)
If they paid their engineers $150,000/year, they could hire almost 2500 engineers for a year-long project.
Or, pay 10 engineers to make sure that the adapter between the (imperial) boosters and (metric) Ares is properly sized and be done with it. If you're pulling a boat behind a truck, you don't care if the truck engine's bolts are metric and the boat's are imperial because they don't have anything to do with each other. As long as the hitch pieces are compatible, you're golden.
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Re:$370 million? (Score:5, Insightful)
Please advise us on how you're going to train every machinist, and QC agent, just to name two job categories on how to measure 30.22mm with calipers that are intended to measure in Imperial? If they can't do this, do it reliably, and do it accurately then you're going to have some funny fitting parts on those Ares.
That is just one very simple example in two very limited job categories where changing from SI to Metric would introduce horrible, and potentially disastrous, difficulties.
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Re:Now I know what NASA stands for... (Score:4, Insightful)
Yes...stored in electronic form. That's right. Wait, remind me again, what file format did Autocad use in the 1960s? 1970s? 1980s? Was it DWG back then?
Plus we're not building another shuttle. We're going back to the days of Apollo, with a capsule^Wspacecraft on top of a rocket. Apparently, though, they found that they can utilize the SRB design for part of the new project. (The big white rockets that get reused after launches.) The SRBs date from the start of the Shuttle era which...erm, yeah. 1970s.
So here we have a rocket booster already designed that works like a champion. The blueprints are all done. They work. They're reusable. They've been fieldtested over 100 times.
And you want to redesign them essentially from scratch? As many coders here want to say to their bosses when upper eschelon wants to recode an application in the new flavor of the month language: if it is not broken, do not fix it.
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Re:Do we really need metric? (Score:4, Insightful)
And a liter of water weight exactly a kg. There are exactly 1,000 meters in a kilometer. And there's exactly a year in a light year.
Wait ... one of those is wrong.
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