Metric Signs

[mgk920]

Well, when a dog or a cat loses a leg (it doesn't matter which one), after the wound heals, the animal won't even miss it.  It will go on with life as though it were still there.

Mike

[Bickendan]

While switching to metric for road uses is overall more useful than US/Imperial, the actual unit of the mile is actually very useful.

At any rate, US and Imperial units have been redefined to metric (the mile and kilometer are effectively a 5/8 ratio, but the actual definition puts the mile to a specific metric length just over 1.6km), and a lot of items are in metric already, most notably 2L soda bottles.

[mgk920]

While switching to metric for road uses is overall more useful than US/Imperial, the actual unit of the mile is actually very useful.

At any rate, US and Imperial units have been redefined to metric (the mile and kilometer are effectively a 5/8 ratio, but the actual definition puts the mile to a specific metric length just over 1.6km), and a lot of items are in metric already, most notably 2L soda bottles.

In fact, in the USA, 'one inch' legally = '25.4 mm'.  Do the arithmetic for the rest.

Mike

[thenetwork]

Depending on the contractor or the sign maker, construction zones pretty much use feet or fractions interchangeably.  Same with local municipalities (Stop Ahead -- 500 Feet).

Never could understand why it is such a cardinal sin to use feet on BGSs along controlled access highways instead of fractions for shorter distances.

[kphoger]

the actual unit of the mile is actually very useful

Yes.

In rural areas in this part of the country, section line roads are based on a mile grid.  One road = one mile.

In urban areas in this part of the country, major city streets are based on a mile grid.  One major thoroughfare = one mile.

So, if I'm still going to benefit from thinking of road distances in miles, then I don't see how changing road signage to kilometers wouldn't hurt rather than help.

Never could understand why it is such a cardinal sin to use feet on BGSs along controlled access highways instead of fractions for shorter distances.

I figure that, on a freeway, if the distance is less than a quarter-mile, then the distance is pretty much irrelevant by that point.  The distance is realistically "NOW!".

[michravera]

Depending on the contractor or the sign maker, construction zones pretty much use feet or fractions interchangeably.  Same with local municipalities (Stop Ahead -- 500 Feet).

Never could understand why it is such a cardinal sin to use feet on BGSs along controlled access highways instead of fractions for shorter distances.

California uses some oddly-specific distances in feet (like 2134 or something like that) on yellow signs when warning of substandard clearances on freeways. I've seen non-binary fractions (such as "1/3") used on blue signs (rest areas come quickly to mind). There are a few one-off exit signs that are in whole hundreds of feet, the CASR-17 "Santa Cruz" sign on "North" (West) bound I-280 in Santa Clara county, for example.

I'm a metric advocate (and, since the FAA went to Celsius for all temperatures, have NO need for Fahrenheit at all), but notice that, if you are willing to go down to inches, a mile can be divided in to whole numbers of inches by 2, 3, 4, 5, 6, 8, 9, 10, 11, and 12. Without inches, you only lose divisibility by 9. Except for the rods and chains used in surveying, I haven't the least idea why you'd need evenly to divide by 11.

I'm not sure what was used when we were part of colonial Spain and independent Mexico, but it sure seems that some of the distances between things, especially along the coast and the Bay, are close to whole kilometers apart.

[Dirt Roads]

the actual unit of the mile is actually very useful

Yes.

In rural areas in this part of the country, section line roads are based on a mile grid.  One road = one mile.

Similar with railroads.  When the Western Union started laying out its telegraph lines, they tried to standardize on 250-foot spacing of telephone poles.  Locomotive engineers on the B&O Railroad quickly found that they could estimate the distance past each milepost simply by counting the telephone poles (anyone care to guess?).  The method was so effective that when the B&O implemented railway signalling* in the early 1890s, they standardized on 20 poles per mile, which staggered just a little bit from the existing Western Union poles.  But this way, train crews could accurately estimate the mileage down to 5/100th of a mile.

*Or should I have said "signaling", since the British word "signalling" was used by the C&O Railway (and perhaps, all of the Van Sweringen Lines, but I can't prove it).

[kphoger]

California uses some oddly-specific distances in feet (like 2134 or something like that) on yellow signs when warning of substandard clearances on freeways.

Or there are the ubiquitous weight limit signs in Texas for exactly 58,420 pounds.

These hark back to 1951, when SB 57 increased the allowable GVW from 48,000 pounds (24 tons) to 58,420 pounds based on AASHO's formula, in order to encourage trucks to be equipped with an additional axle and thereby eliminate overweight axles.  The federal maximum was later increased further in 1956, and Texas followed in 1959 by increasing theirs, but then they had to sign 20% of their highway system for all those bridges that weren't rated for that new higher-higher limit.

[GaryV]

In rural areas in this part of the country, section line roads are based on a mile grid.  One road = one mile.

I wonder, if the metric system had been adopted back in the Jefferson administration, if the Northwest Ordinance would have called for surveys and land sections based on kilometers?

[michravera]

In rural areas in this part of the country, section line roads are based on a mile grid.  One road = one mile.

I wonder, if the metric system had been adopted back in the Jefferson administration, if the Northwest Ordinance would have called for surveys and land sections based on kilometers?

What else might have made sense? Perhaps doubles or 2.5 km? Perhaps sectioning everything into 100x100 m plots? A chain is quite close to 20 m (about one-half percent high). I'm sure that it would have been adjusted to be EXACTLY 20 m, if it had been required for the survey. I'm not sure what surveyors use in metrics countries that still have to be surveyed. 10 m chains seem short (but usable in difficult terrain) and 100 m seems too long.

[kphoger]

I'm not sure what surveyors use in metrics countries that still have to be surveyed. 10 m chains seem short (but usable in difficult terrain) and 100 m seems too long.

I'm no expert, but I'm happy to pretend I am one after doing a very quick Google search. 

A 10-meter chain, made of fifty 20-centimeter links.  Thus, it's just shy (by a couple of inches) of half the length of a Gunter's chain.

[pderocco]

Similar with railroads.  When the Western Union started laying out its telegraph lines, they tried to standardize on 250-foot spacing of telephone poles.  Locomotive engineers on the B&O Railroad quickly found that they could estimate the distance past each milepost simply by counting the telephone poles (anyone care to guess?).  The method was so effective that when the B&O implemented railway signalling* in the early 1890s, they standardized on 20 poles per mile, which staggered just a little bit from the existing Western Union poles.  But this way, train crews could accurately estimate the mileage down to 5/100th of a mile.

There was a musical number in the 1952 movie "Everything I have Is Yours" called 17000 Telephone Poles, with Monica Lewis counting the poles as they pass in a bus, measuring the distance to home. So that would have been an 850-mile bus ride. But there's also a line about "500 miles of wire". But hey, it's just a dumb song, so I doubt anyone did the math.

[Scott5114]

Similar with railroads.  When the Western Union started laying out its telegraph lines, they tried to standardize on 250-foot spacing of telephone poles.  Locomotive engineers on the B&O Railroad quickly found that they could estimate the distance past each milepost simply by counting the telephone poles (anyone care to guess?).  The method was so effective that when the B&O implemented railway signalling* in the early 1890s, they standardized on 20 poles per mile, which staggered just a little bit from the existing Western Union poles.  But this way, train crews could accurately estimate the mileage down to 5/100th of a mile.

There was a musical number in the 1952 movie "Everything I have Is Yours" called 17000 Telephone Poles, with Monica Lewis counting the poles as they pass in a bus, measuring the distance to home. So that would have been an 850-mile bus ride. But there's also a line about "500 miles of wire". But hey, it's just a dumb song, so I doubt anyone did the math.

Maybe 350 miles of the journey had poles with no wire. Or for part of it they had installed new poles and not yet removed the old ones.

[kphoger]

Or they did the math but decided 'seventeen' sounded better in the lyrics.

[TXtoNJ]

Maybe it's just Rambling Old Man Brain here, but I think may be easier for a child to conceptualize "one-equal-part of four-equivalent-parts" before delving into decimalization, because young children haven't yet been taught one hundred.

The other thought is that fractions are used in elementary classroom settings as a a visual and tangible introduction for abstract thoughts of equality, fairness, sharing, and limitations. Sounds crazy, but classroom environments require boundaries that if Student A gets a single book/block/desk/snack, then Student B [C,D...] also gets the same amount of a limited quantity.

Sure, but you can get the more or less the same point across using division rather than fractions. (Maybe even better—it was embarrassingly late in my school career that I grasped that ⅓ and 1÷3 were the same thing, since the way they taught us in Oklahoma kind of siloed them from each other and never actually explicitly stated that a fraction is just a division problem! And I remember being in fourth grade and getting really frustrated that I tried calculating my own grades and kept getting something like 0.9 when I knew my grade was supposed to be 90%...sigh...)

Teaching physics at OU, I once had a student ask me, in all seriousness, if a millimeter was the same thing as a centimeter. And this was a pre-med student. Makes one wonder about the state of health care in Oklahoma...

The solution is to toss out cm altogether. They're not particularly useful, and mainly taught because they're close to inches.

[pderocco]

Maybe it's just Rambling Old Man Brain here, but I think may be easier for a child to conceptualize "one-equal-part of four-equivalent-parts" before delving into decimalization, because young children haven't yet been taught one hundred.

The other thought is that fractions are used in elementary classroom settings as a a visual and tangible introduction for abstract thoughts of equality, fairness, sharing, and limitations. Sounds crazy, but classroom environments require boundaries that if Student A gets a single book/block/desk/snack, then Student B [C,D...] also gets the same amount of a limited quantity.

Sure, but you can get the more or less the same point across using division rather than fractions. (Maybe even better—it was embarrassingly late in my school career that I grasped that ⅓ and 1÷3 were the same thing, since the way they taught us in Oklahoma kind of siloed them from each other and never actually explicitly stated that a fraction is just a division problem! And I remember being in fourth grade and getting really frustrated that I tried calculating my own grades and kept getting something like 0.9 when I knew my grade was supposed to be 90%...sigh...)

Teaching physics at OU, I once had a student ask me, in all seriousness, if a millimeter was the same thing as a centimeter. And this was a pre-med student. Makes one wonder about the state of health care in Oklahoma...

The solution is to toss out cm altogether. They're not particularly useful, and mainly taught because they're close to inches.

I don't like centi either. Fortunately, no one bothers with deci, deka, or hecto.

It's always annoyed me that one of the two standard unit systems is CGS, or centimeter-gram-second, while the other is MKS, or meter-kilogram-second. So why not MGS, or meter-gram-second? I always think of the prefix on the unit as part of the number, so 33km is 33k meters, not 33 kilometers. As soon as you multiply it by something else, the prefix changes, while the real unit doesn't.

[freebrickproductions]

IIRC, in the "trades", metric sizing uses magnitudes of 1,000 (i.e. mm, m, km, etc.) when going up and down the scale, which honestly makes a lot of sense. For example, in electrical applications, you won't see "centivolts" as 10 millivolts honestly just makes a lot more sense.

[kphoger]

The hectometer seems like it would be a halfway-useful measurement.  But it really isn't ever used, except of course that a hectare is one square-hectometer.

[michravera]

The hectometer seems like it would be a halfway-useful measurement.  But it really isn't ever used, except of course that a hectare is one square-hectometer.

A hectare is basically two football fields. An "are" is a 10 m x 10 m square. That, conveniently, is a square the size of one of those metric surveying chains which were mentioned earlier in the thread.

The two prefixes that I *NEVER* see used are those for 10000 and 100000. 10000 would be hand in Japan (which has a number separately named for 10000, which, unfortunately, sounds similar to the Latinesque  word for 100). Multiples of 10000 would be handy one the way to 1000000, if we did more things in multiples of 100. I can't think of a single case where I have naturally found it convenient to work in multiples of 100000. Besides, we hardly ever get 5 digits of precision on anything. 4 digits sometimes. 3 digits more commonly. 2 is often not enough. That's the reason for using multiples of 1000.

[Scott5114]

The solution is to toss out cm altogether. They're not particularly useful, and mainly taught because they're close to inches.

If you ask someone from a metric country how tall they are, they usually answer in cm. So clearly they are perceived as having some utility that is not derived from burger units.

The two prefixes that I *NEVER* see used are those for 10000 and 100000.

That's because there aren't any. Kilo is 1000, and is followed by mega for 1,000,000.

[pderocco]

Don't forget kibi, mebi, and gibi, which are powers of 1024.

[CtrlAltDel]

The two prefixes that I *NEVER* see used are those for 10000 and 100000.

That's because there aren't any. Kilo is 1000, and is followed by mega for 1,000,000.

Well, myria- used to be the prefix for 10,000, but it was eliminated in the 1960s, apparently for the mundane reason that there were too many other prefixes that started with m- (mega-, milli-, and micro-).

[kphoger]

Decimega- should mean 100,000 of something.
Decakilo- should mean 10,000 of something.
And/or we should bring back the myriad.

[hotdogPi]

I'm wondering what a system based on purely powers of 2 would be.

The closest power of 2 Planck lengths to a human height (arguably the most natural starting point) is 2^116, which is 1.34 meters or 4'5". This unit of 2^116 would have a name.

The unit of volume would be that cubed, where a Length™ cubed would be 2.42 m^3, and smaller units closer to liters would be 1/4096 that (2^112 on a side), equivalent to 0.591 liters or almost exactly 20 US fluid ounces.

If we use density of water as a baseline like we do for metric units, the "0.591 liters" would become 591 grams, or 1.3 pounds as the base unit of mass.

Time would be a bit more tricky, since the year:day ratio isn't a power of 2.
If the Planck time is used, 2^144 ≈ 1.20 seconds, of which there are 71863 in a day.
If a day is divided into 2^16 (65536) seconds, ignoring Planck units, one Time™ is about 1.32 seconds.
The calendar would be similar to ours, since there's no way to force powers of two onto a 365.25:1 ratio.

(Side note: Google Calculator doesn't recognize "Planck time", but "Planck length/c" works perfectly fine.)

[kphoger]

Time would be a bit more tricky, since the year:day ratio isn't a power of 2.

Just ignore measurements of time.  It's not like there are US Customary hours and Metric hours—let alone months and weeks.  Some wackos tried that in the past, and it didn't work out.