I must say I am dismayed to see that even after days to think it out the SDMB crowd missed the answer. It was a trick question. Anyone who knows anything about Americans ought to know that they don’t care if everyone else in the world has adopted a single fairly sensible standard for physical units. Instead of going metric the US needs to develop the America system. Anyone against converting to American obviously hates the country and Red staters don’t hate America.
In the America system we name the unit of mass after a great modern American named Billy Graham. Noticing that people seem to be having a hard time with weight means it is a perfect time to get away from pounds. By picking the graham carefullly we can change what was once 250 pounds into 113 kilo grahams while still using the graham as a unit of measurement in Apple Pie recipes.
I suspect the SDMB members have enough combined smarts and patriotism to work out the rest of the units.
It’s not completely arbitrary. One half of a full-to-new moon cylce is about 7 days. A quarter moon (I suspect that ancients would have thought of it is 1/2 rather than 1/4) is a pretty distinct sight in the nighttime sky.
What would help the process would be if US schools knew how to teach it. Every one of my kids had to spend the first two weeks of science class each and every year learning about all the prefixes that nobody uses. No matter how metric you are, you just don’t convert millimeters to hectometers. Rather than obsess over the silly prefixes, give the kids hands on experience with how heavy a kilogram is, how long a centimeter is, etc. You don’t think metric unless you experience metric in real terms.
This has nothing to do with the metric system. You can have 1/3 of a meter, just as easy as 1/3 of a yard.
BobLibDem, you’re right. But since you brought up prefixes, maybe we should start a whole new thread: Will people ever use scientific notation in everyday life? Not that they necessarily should, but it would be a bit easier if books written for non-scientists could say things like “The earth is about 6 x 10^9 years old.” Or, what would it be, um… 6 gigayears or something like that?
You missed the point. It doesn’t matter that they’re arbitrary. It only matters that they’re synchronous and periodic. The Mayan calendar worked just as well because there was synchronicity between the long counts and the named weeks.
But the point is that it is vital to have only one standard for time, not two or three, because those standards don’t match. And basing your standard on a variable–like the length of time it takes for the earth to rotate on its axis–is bad bad news.
We’re not going to do away with days and years just because we adopt the metric system, but the length of a day or a year isn’t a matter of definition, it is a matter of measurement.
Or maybe I’m not understanding what your argument is.
It is possible to define a metric day by something invariate, such as the speed of light in a vacuum. Because of variances over time, you’d have to add or subtract leap “microdays” every so often. The meter used to be fixed to one ten-millionth of the length of the earth’s meridian along a quadrant before technology allowed us to measure length more precisely. There’s no reason the metric day couldn’t be fixed to today’s day and adjustments made in the future.
Why must the second resemble 1/86400 of a day when it could easily be approximately 1/100000 of a day? Or it could be set to 1/300,000,000 of the time it takes light to travel a meter instead of 1/299,792,458. It’s an arbitrary standard that happens to be better in some respects than other systems. But it’s far from the most superior possible standard. Why adopt a sub-optimal standard over an existing sub-optimal standard?
Well, a better standard would be 1 second = the length of time it takes light in a vacuum to travel 1 meter, or 10^9 meters if you don’t want to always talk about gigaseconds in the everyday world, since the speed of light is a fundamental physical constant.
But using the rotation of the earth on a particular day as the standard doesn’t make sense, because as you noticed everyday days won’t be in sync with standard days, think of potential errors that could cause. Anyway, sure, they could have defined the standard unit of metric time as a “day”, but they didn’t, they defined the second, which is essentially an arbitrary unit. And now that we have a defined unit, there’s no point in throwing it out for some other arbitrary unit defined as some other multiple of the earth’s rotation, because the whole point of the metric system is that we have standard measurements that don’t need to change.
It makes sense for us to talk about every large periods of time as “days” or “years” rather than megaseconds or gigaseconds, but that’s only because we’re used to those units, and we live on a planet where those units make sense. If we lived on Mars we might conveniently use Martian days and years as well. The Mars rover teams had special clocks made that used the length of the Martian day instead of the Earth day. So defining a second as close to any particular fraction of an Earth day is just as arbitrary as any other fraction. And there’s no way to scale years into it either, unless we alter the orbit of the earth such that we have exactly 1000 days per year.
Anyway, this is moot. We have metric time, it is the second, and there’s no particular reason it should have any decimal relation to any one particular natural cycle.
Yeah, if we were going to do it all over again it would make more sense to tie the second to meters and c, just like it would make more sense to switch to base 12 notation rather than base 10, and eliminate irregular verbs. But we aren’t going to, and there’s no reason to. We switched to the metric system because it was easier than dealing with thousands of incompatible local measuring systems, not make things more difficult.
The big problem with trying to change the measurement of time (and perhaps the reason there’s more uniformity in the way it’s counted throughout the world) is because it’s far more fundamental to our experience of the world than mere distances or volumes. Often, we actually measure distances by using time:
“How far is that from here?”…“A couple of hours’ drive”/“It’s a three-hour flight”/“ten-minute walk”
Actually, after reading your explanations (assuming they’re true), it seems even more stupid than I could have envisionned.
Programming for a spaceship outsourced to a college kid who’s so busy partying he doesn’t have time to write the software??? WTF???
Flight instructions delayed from week to week while the the orbiter is approaching Mars, and nobody worried about this ???
Absolutely critical programm uploaded with nobody bothering to check it first??? I mean… They got the software 15 minutes before the orbiter needed it, or what ???
It’s sounds so amateurish that I’ve a hard time believing it actually happened.
If you want to divide a foot into thirds, you get 4 inches. If you want to divide a meter into thirds you get .3333(repeating) meters. Or, you can say 1/3 Meter but that’s still not as simple as the whole number four.
Metric construction in fact has had to work with making things multiples of 300 and 600mm to try and simplify things.
I’m not saying construction in the metric system is any harder, it isn’t. But to someone who has used standard measurements in construction forever dividing a foot into 4 inches or 6 inches or 3 inches when making common divisions is easier than working with units of 600 mm or working with fractions. Thus I see the construction industry being one place standard measurements will survive for quite some time.
And yes, I’m sure there are construction firms in the U.S. that use metric, probably the bigger ones. While I’m equally sure most smaller, local construction firms do not.
Except that in real construction, dividing a foot into thirds is vanishingly rare. What is done frequently is dividing 8’ into sixths. This is also known as framing on 16" centres. Of course, sometimes you want to use fewer studs, so you’ll frame on 24" centres, which also works pretty well. But what if you want to go inbetween and use 5 studs per 8’ instead of 4 or 6? You get 19 and between 1/8 and 3/16 inches. This is actually a defined architectural standard, and decent contstruction tapes will have markings on them at 19.2" intervals. Now what would happen if we went metric, and instead of 4’x8’ sheets of plywood, we used 120cmx240cm (which is really damn close to the same size)? Then we could frame at 6 studs per sheet on 40cm centres, or 5 studs per sheet on 48cm centres, or 4 studs per sheet on 60cm centres. Sounds like a win to me.
That’s an example of a real construction issue being converted to metric. Dividing a foot into thirds? When would you ever do that?
That’s what I mean about it being a dumb argument. Going metric doesn’t mean defining nice round yardages into stupidly over-precise metric equivalents. The UK is metric (largely), and we still have 18-yard boxes and 6-yard boxes on our football pitches, and a cricket pitch is still 22 yards long. OK, in the rules of the game it is stated as “20.12 metres (22 yards) long”, but as I said, that’s a dusty rulebook that nobody reads. In the real, metric, world, it’s 22 yards.
Going metric does not mean banishing imperial measurements from the everyday world!
I have seen this argument a couple times now. Being a carpenter, I must say this is just rediculous. Some points to consider:
The size of intended object being constructed dictates the size of the stock lumber; not the other way around.
I almost never need to divide a piece of lumber in three. If I do I simply divide its length by three. Whether that is in inches or centimeters doesnt matter
We actually build from plans - you know, it just makes things easier. Stuff fits better.
I have never seen a measuring tape with thirds of an inch.
In Canada most carpenters still use imperial, lumber is sold in imperial measurements. Plans are often metric; they are to scale though so once again it doesn matter what units are used.
I dont particularly care which system I use, either works fine and I can switch without thinking. I notice some of the older guys get messed up jumping between cm and mm. Clarity of convention is important when communicating measurements no matter what the units however.
Okay, I’m as big a fan of the metric system as anyone, but… An older house is going to have studs at 16" centers, = 406 mm… right, hardly anyone would measure out stud spacing to the nearest millimeter. Still. Every 4th stud will be 1218 mm apart - call it 1220 mm? If “new” metric plywood is sold in 1200 mm sheets, there’s then a potentially a “drift” of 20 mm (about 3/4") for each sheet of plywood if new plywood is used in older houses. I am not a framer: is this any kind of problem? Or is this just within ordinary framing tolerance?
English fails me sometimes. With three spaces at 16" each, I meant to say that the studs 48" apart are… er… 48" apart. Er. Well, I hope that clears things up. Er.
The only issues would be when doing renos, and when doing renos you’re usually hacking stuff together at odd lengths anyways. A change in stud dimensions would be a bigger deal than the change in sheeting dimensions. But there’s always one way or another to make things fit together. Old houses are framed with 2x4s that are bigger than the 1.5x3.5 studs used today, yet somehow people manage to renovate them.
New construction you’d just build in metric from the get-go, and it’d all be hunky dory.
Another important field that resists conversion is cooking and cuisine. Most measuring cups and spoons now have both systems, though quarts still seem to be the basis for cookware - I haven’t noticed any 1L pans and baking dishes, but I know they are out there. But more importantly, most of the cookbooks and family recipes running around are in imperial.
I no longer work in restaurants, but five years ago everything was imperial measurements also. I think professional baking has made the transistion, any bakers want to weigh in?*
AP
*Did the transistion make a major difference in production? Changing from a measure of weight to a measure of mass is not a major distinction, but was it a factor?
