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dwise1 Member Posts: 5951 Joined: Member Rating: 5.2 |
I feel that I have known and understood most of what I should about the metric system for half a century or so. I'm very comfortable with it, find it far easier to use than the US customary units system, and would like to see the USA finish converting over to metric. I'm even working on a couple web pages on the subject.
However, I've encountered a couple things about liters and how they're used "in the wild" that have confused me. I hope that someone with real world experience (ie, "in the wild", such as in Continental Europe) could help. For example, in Germany in the 70's I found that every cup or glass had a fill-level mark and the volume when filled printed on it -- that included drinking vessels for home use and even paper cups. I saw the same thing a few years ago on a glass in a hotel bar in England. Last night my friend's brother served me some whiskey in a shot glass from a set he had been given. It had a fill line so after I finished my drink (wasn't going to fall for that old Laurel and Hardy trick) I looked on the bottle of the glass and could just barely make out "2.3 L" in which the "L" was in cursive. Knowing from my graduated shot glass at home that a shot glass holds about 30 ml, I deducted that that "L" must stand for centiliters (cl). But whenever I see a cursive capital "L", am I supposed to always interpret that as centiliters? And in which countries would that apply and not apply? (IOW, is it standard?) Then two years ago near Milan was the event that got me wondering in the first place what was going on. The menu at the pizzeria gave the size of its glass of beer as "0,9 cL". To me, that said "0.9 centiliters", which would be a rather small glass, not even a third of a shot (this was before I researched the size of shot glasses). However, it turned out to mean 0.9 liters! So when did "cL" come to mean "liters"? And how prevalent is that? Reference to a page explaining marking conventions would be helpful -- I can handle reading in English, German, French, Spanish, and Italian (even some Swedish in a pinch). BTW FYI and on a side note, one day I was buying a bottle of vitamins at the drug store and the dosage was given as "800 MCG". I hadn't encountered that before so I asked the pharmacist who told me that it meant 800 micrograms. I guess it's a pharmacist convention in the USA since very few of our typewriters have a key for the letter mu (μ) which stands for "micro". Just in case anyone else had encountered that and was wondering.
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dwise1 Member Posts: 5951 Joined: Member Rating: 5.2 |
I can't comment on your liter/centiliter question, but about over-the-counter vitamins, a fair number are sold in mcg units. Folic acid and B12 are two I can think of off the top of my head. Folic acid is the one I had to ask about. The point is that even though I was trained in the metric system in the 60's and have frequently used it, none of my training ever included MCG and I had never before had to pay attention to any dosage involving MCGs. My GP gave me a prescription for 1mg tablets and my cardiologist told me to double that but without a new prescription so I buy half of my folic acid off the shelf. Of course, this time I had to look at the dosage and that was when I first noticed MCGs. So back to the point, MCG is a pharmacist convention which I surmise was invented to work around the lack of a μ on US typewriters. And I only mentioned it for those who also didn't know what that meant.
Wikipedia concurs, though they cite the FDA's fear that confusion over "m" versus "μ" could cause accidental overdosing:
quote:
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dwise1 Member Posts: 5951 Joined: Member Rating: 5.2 |
A cursive l means litre. cL means centilitres. What I had been taught. Actually, in class we normally only dealt with liters and milliliters, but I understand the prefixes of the International Standard (SI) well enough to be able to apply them.
{ABE:
I just checked the Wikipedia page on fill lines. One thing that's included on a German fill line is a mark indicating the manufacturer. I think that might raise the possibility that that ornately cursive "L" was the manufacturer mark and the "cL" units was implied.
} My friend's brother's shot glasses (received as a gift) are about 100 miles away, so it'll be quite a while before I could inspect them again for more clues. Possibilities: You're misremembering or misinterpreting something You saw a menu written by an idiot. To the first, that menu most definitely gave the beer glass size as "0,9 cL". As I recall, we ordered the "0,5 cL" and what was delivered looked like half a liter. Unfortunately for this question (though fortunately for us), that last night in Italy was the only time we ordered beer, preferring instead to drink wine or acqua frizzante. So to the second, yes, the menu possibly could have been written by an ID10T. Though since it was in Italian it wouldn't have been a case of bad translation. But I usually try to consider the third possibility, that the "cL" could have meant something else -- eg, the "L" still liters, but the "c" something else. Or that that "cL" was not strictly SI, but rather some non-SI notation of some kind. Though I just now checked the Italian Wikipedia page, Litro, and it just confirms that even in Italian "cL" means centilitro. IOW, it seemed that there could still be non-SI designations in use in some regions, possible carry-overs from earlier measurement systems that remain in use for special purpose such as drink sizes. For example, in Germany food is still sold by the pound, though the German Pfund is 0.5 kg and not the same as the American pound (0.4536 kg). But it would take somebody who lives or lived there to know.
There are different conventions in different parts of Europe regarding the units used for measuring different drinks (for example, it's common here to order 2 decilitres of wine, while that word is never seen in many countries - they would order 20 cl or 200 ml). I saw more measurements for beer in Germany when I was there in the 70's, but paid less attention during our trip a few years ago. In Baden-Wrttemberg I would order either "'n Viertel" (more like 0.3 l, the volume of a bottle) or "'n Halbe" (half a liter). And I remember the Schnaps being served in a 2 cL glass.
Are you sure the glass was 0.9 litres? That's pretty unusual in and of itself. That was probably "0.6 cL" instead (I am still positive of the "cL").
I've never seen a 900 ml glass of beer anywhere. Then you must not have spent much time in Bavaria. Though instead of shorting you with just 900 ml of beer, they'll serve you a full Ma (one liter). In videos of events like Oktoberfest, I've seen the sturdier waitresses carrying three Makrge or more in each hand (3 Makrge weigh about 7.2 kg (15.9 lb)). In a Spanish-language Deutsche Welle report on Oktoberfest, we see less sturdy waitresses carrying what looks like nine Makrge (21.6 kg) in a kind of embrace -- but that's only for the closer tables. There's even an endurance sport based on the Makrug:
quote: Edited by dwise1, : ABE
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dwise1 Member Posts: 5951 Joined: Member Rating: 5.2 |
In Canada we have been "converting to metric" for more than forty years and, generally, nobody uses it. It's been a mixed bag, hasn't it? For example, in the UK even though they've gone metric they also continue to use miles. The US started to go metric in the late 70's, but then never followed through -- I think we could probably blame that on Reagan. One lasting effect it's had has been with our bottled drinks. Bottled water is in 500 ml or 700 ml bottles. Soft drinks are in 2-liter bottles. Ever since then, you can't buy a fifth of booze (1/5 gallon) anymore, but rather in 750 ml bottles (a fifth would be 757 ml, so they owe us big-time). Transitioning from one system to another can be eventful and must be done with caution and awareness. When I discuss that in my up-coming page I will definitely mention the Gimli Glider (23 July 1983) in which a Canadian airliner ran out of fuel in mid-flight in large part because the ground crew used the wrong calculations. For those not familiar with the story, when the plane ran out of fuel, the pilots flew it like a glider and ended up making a safe landing at the former RCAF Station Gimli.
The first time I ever heard the term "centiliters" was in your post. (I have heard that beer is sold wholesale by the hectoliter, which is about a keg.) Our beer bottles are labelled in ounces and milliliters. I doubt if you could find one Canadian in a thousand who could tell you the metric size of a shot glass. As I recall from 1973, Schnaps was served in 2-centiliter glasses. I also own a graduated shot glass I bought at Bed, Bath, and Beyond which is graduated in teaspoons, tablespoons, fluid ounces, and milliliters. Shot glasses come in slightly different sizes, but this one is the same size as my other shot glasses which I assume to be a standard US size. Those shot glasses hold 45 ml when filled to the brim, but a nominal serving would be about 30 ml.
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dwise1 Member Posts: 5951 Joined: Member Rating: 5.2 |
Is it a coincidence that an american quart is 0.94 liters? I would say that, yes, it is a coincidence. The quart is derived from the gallon, such that it is a quarter gallon. But what's a gallon and where did it come from? Well, that's something of a moving target since there have been many different kinds of gallons. For example, in the US we define two different kinds of gallons: wet and dry measure. And the UK's imperial gallon is different from the US' -- in the US booze used to come in "fifths" (1/5 US gallon), but since that's 1/6 imperial gallons then I would guess they were called "sixths" in Canada. Wikipedia lists ten different definitions for English system gallons, which range from 217 in3 to 282 in3. The imperial gallon is given as 277.4194 cubic inches and the US liquid gallon as 231 cubic inches. I have no idea where they get all these apparently arbitrary numbers from, but a slightly older definition of the imperial gallon was that it contained 10 pounds of water under certain standard conditions. The liter and the gram are based on the meter, which itself is based on the size of the earth. 1 cc (cubic centimeter) volume is 1 ml (milliliter) and 1 ml of water masses at 1 gram. A liter is 1000 ml, which would be 1 cubic decimeter (but never described as such to my knowledge). If the two systems had been based on the same phenomena then we could expect to encounter similarities, but I cannot see any such commonality. That would lead me to consider the liter being close to the US liquid quart a coincidence. BTW, I first learned this from Donald Knuth's book series, The Art of Computer Programming: the English system for measuring volume is binary. You go from one unit of measure to the next by either doubling or halving. Here is his list: quote:
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dwise1 Member Posts: 5951 Joined: Member Rating: 5.2 |
I know its not as elegant as the imperial system but still that's how the prefixes work. I was about to reply to that, but then I looked at your grin and realized that you were being sarcastic. And for good reason! In elementary school, our arithmetic textbooks always had a reference page giving the conversion factors between the units in the English system. Well, except for one year (either fourth or fifth grade). That was a really tough year as we were still expected to convert between units (eg, inches or feet or yards to miles). Perhaps that was a more traumatic experience than I had thought and could help to explain my preference for the metric system (for which it is almost trivial to derive your own conversion factors without having to search for any reference pages). One day, somebody passed to me a problem that his farmer friend asked him to figure out. He planned to build a water trough so many feet by so many feet by so many inches, but he wanted to know how many gallons of water that would hold and how much that water would weigh. I converted those dimensions to metric, performed all the calculations with ease, and then converted the results back to English system (US customary units). The only part that required me to look anything up was to get the conversion factors between metric and English. If I had had to do it all in the English system, then I would have been lost without the necessary conversion factors between cubic feet and gallons and weight of water per gallon (it's only been in the past year that I ever even heard that a fluid ounce (volume) of water is about one ounce (weight)) -- remember that this was more than two decades before we had the Internet. A more trivial example was in the early 70's when I wanted to make a pitcher of a powdered drink (Tang) but there wasn't enough powder left for a full batch. Since I couldn't stand watered-down drinks, I needed to know how much water to use. Again, not having the conversion factors required just to work within the English system, I converted to metric, performed the simple calculation, and measured the water with a Messbecher I had brought back from Germany. Again, working within the English system was virtually impossible, however in metric it was trivially simple. And don't get me started on how much harder it is to work in inches than in centimeters! In centimeters, you just simply read the measurement directly and are able to perform calculations with decimal fractions. Simple! In inches, you have to constantly perform fraction arithmetic in your head. That mark is in 32-nds, but how many? It's one more than that 16-ths mark, but which one is that? And if you divide a measurement then you have to convert your mixed fraction to an improper fraction and then convert the result back to a mixed fraction. Or add or subtract measurements, then you've got to find the least common denominator, etc. If you have to do that all day long, day after day, then you might start to be able to read fractions of inches on sight. But reading and working with centimeters is so simple that you do not need to develop special skills in order to perform what should be simple tasks.
"A Guide to Imperial Measurements with ..." Thanks for that video. I think I'll include a link to it whenever I get around to completing my pages on the metric system.
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dwise1 Member Posts: 5951 Joined: Member Rating: 5.2
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As someone who grew up in Canada but now lives in the USA, I was actually accustomed to both systems growing up in the late 70s and 80s. I think that the UK and Canada can serve as models for how the USA's conversion would work. I've been reading a US government document describing the history of our converting to metric. The last big push that I know of was in the late 70's when we'd switch over within 10 years, but then Reagan apparently smothered that plan in the cradle. The main effect of that push was the increased use of liters in drink containers. One of the funnier stories from around 1980 was how the oil crises kept pushing up the cost of gasoline. This created a crisis of its own, because virtually all gas pumps were mechanical, not electronic as they are now, and they simply had never been designed to handle any cost per gallon that wasn't less then $1. As the price of gas kept approaching $1/gal, gas stations were forced to go with the eventual solution which was to install electronic gas pumps. But before that happened, some gas stations went ahead and converted to liters as was the national plan at the time. We saw a news report of a gas station on the interstate in the mid-west that had switched to liters. The drivers were lining up in droves to buy that "cheap gas". They had no concept of how much a liter was; all they saw was gas prices nearly a quarter of everywhere else. The TV reporter interviewing a customer:
Customer: Just look at these great prices! Reporter: But you do realize that that's per liter, not per gallon? Customer: Yeah, yeah. But just look at these great prices! The USA is a little more interesting in that it is still officially using imperial in most areas (miles, feet, inches). But when you work in tech areas including automotive, you will see both. Part of the reason for converting to metric is for purposes of international trade, especially to be able to remain competitive in tech areas. There can also be more resistance to converting in some trades where there are standard measurements that are deeply ingrained (eg, carpentry, plumbing, type setting). In regular life, there would be much less perceived need to convert to metric and hence more resistance. One problem is that we have had a lifetime of estimating sizes and weight by sight and feel, so suddenly having to do the same estimating of metric weights and measurements is seen as nearly impossible and not worth the bother. And of course somebody who has spent years living in a metric world having to suddenly do the same things in any of the English systems would be in the same situation (only in his case he's stuck with having to learn it, because he made the mistake of moving here). But living in both systems at the same time, mixing and matching as we please, can result in problems. By analogy, in social dancing you always keep most of your weight on one foot or the other which informs you of which foot to step on next -- if you go split-weight (equal weight on both feet) then you don't know which foot to step off with next. Using both systems at the same time is analogous to going split-weight. I repeated the story above of the Gimli Glider is a Canadian example. Because of a ground crew confusion over which conversion table to use (to convert dipstick level to quantity of fuel) a Canadian airliner ran out of fuel mid-flight and had to glide to an emergency landing (which was successful). There's also a story that I need to research about the Mars probe we lost because the programmers used the wrong system of units, English instead of metric, for the probe's landing on Mars. To paraphrase Mr. Miyagi: "Either metric yes or metric no. Not metric maybe."
My guess is it will probably take a few decades before things are totally 'converted'. It's already been four decades with virtually no progress. Another few decades with no incentive to change will make no difference.
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dwise1 Member Posts: 5951 Joined: Member Rating: 5.2 |
Does the forum have help on Latex syntax with examples? Basically, where are the resources to learn how to use it?
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dwise1 Member Posts: 5951 Joined: Member Rating: 5.2
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OK, that's not helpful. Though I did have to chuckle at the title for French documentation, "Tout ce que vous avez toujours voulu savoir sur LaTeX", that left out the "mais aviez peur de demander."
Just "how would one use it on this forum?", not "how would I typeset an entire physics book using nroff?"
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dwise1 Member Posts: 5951 Joined: Member Rating: 5.2 |
Downloaded it as a PDF. It'll take a while.
Is this just an nroff and dBCodes thang, or can it be used in HTML?
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dwise1 Member Posts: 5951 Joined: Member Rating: 5.2 |
Google'ing about, I found an example which I did get to work on a local HTML file using Chrome.
In the page quote: Then in the page body, add something like:
quote: And you get: OK, that seems to work. However, I found that on the CodeCogs site. I don't know them and here I am pulling one of their scripts into my site without knowing what all it does. I also don't know which browsers they support or whether their support would continue. So some way to generate an image of the formula would probably be best unless there is some generally available way to support latex in HTML.
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dwise1 Member Posts: 5951 Joined: Member Rating: 5.2 |
I've been working on a couple web pages about switching from the US Customary System of measurements (AKA "Imperial") to the metric system. I'm currently working on the page that offers some short-cut methods to approximate conversion but for the purpose of developing a feel for how much these measurements are. Part of that approach employs a Boy Scout skill we were taught in the 1960's in which we use parts of our body (no, not that part) to estimate lengths.
In that section, I'm including some methods from a German constellation atlas which estimate degrees of separation of sky objects with your hand held out at arm's length; from my page's draft:
quote:I should also include what I had been taught in my youth, that you can estimate how long before the sun sets with the same method, but each finger of your hand represents 15 minutes. My question is regarding an instrument I've seen in medieval woodcut prints which was used to measure angles of separation in the sky. Here is the description in my current draft:
quote: Is anybody familiar with that instrument and knows what it was called as well as just how it did actually work?
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dwise1 Member Posts: 5951 Joined: Member Rating: 5.2 |
Just lost all my work.
According to drilling down through Wikipedia, the Davis quadrant was a refinement of the back-staff, AKA "Jacob's staff". The illustrations I see (https://en.wikipedia.org/wiki/Jacob%27s_staff) show the main stick being graduated. Thank you.
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dwise1 Member Posts: 5951 Joined: Member Rating: 5.2 |
US Customary System and Imperial System are two different systems. That "AKA" is wrong. True, true, true. We split from the British Empire (was it an empire by that time?) around 1776. Perhaps in response to French attempts at standardization, around 1824 the UK standardized their measurements, especially the ones regarding volume. We Yanks wanted nothing to do with any of that. So now there are still different standards regarding volume. Gee! Wouldn't everything just be so much better if everybody just switched to metric?
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dwise1 Member Posts: 5951 Joined: Member Rating: 5.2 |
And yes, we should all move to metric. I fully agree. However ... My other metric web page -- and the original one -- will look into the failed history of the US going metric and examine the false reasons people give for rejecting the metric system. But at the same time, there are also a few valid reasons (following list is not complete):
Still, metric is so much easier to use. I use a quote of Christoph Waltz from "Comedians in Cars Getting Coffee" (he's in a hardware store when Jerry Seinfeld calls him):
quote:There are also several videos on this question. The problem is that inches are divided into halves, quarters, eighths, sixteenths, 32nds, 64ths. Every single time you see a mark on a measuring tape, you have to perform fraction arithmetic to figure out what that measurement is -- yes, if you do that day after day then eventually you'll know that on sight, but I never worked at it regularly enough to ever get there. And if you have to add or subtract measurements or even divide a measurement then you're trapped into doing the most complicated form of fraction arithmetic in your head -- actually, we'd use a simpler method to find and mark a mid-point. Every time I had to do that, I'd have to relearn it. First day on the construction job in Germany, I was given a Meterstock and told to get a board of a given measurement and I could do it first time no problem. After that (since we were supposed to metric) I got a tape in both systems: inches for my father and metric for me. Much earlier, right after going to Germany in 1973 I wanted to prepare a pitcher of Tang, but there wasn't enough for a full pitcher. Not knowing the necessary customary units conversion factors to figure out how much water to add, I converted it to metric and figured it out with no problem -- plus I had shipped back a Messbecher in metric, since we didn't have any metric measuring cups at that time. A bit later, somebody's friend who was a farmer needed to figure out how much water a trough of given dimensions would contain and how much it would weigh. Having no idea what those special conversion factors would be, I converted the dimensions to metric and immediately figured it all out (1 cubic centimeter is one milliliter and one ml of water weighs one gram). Just that simple, just that quick. Even earlier in elementary school, every math textbook had a page that listed all the conversion factors within the customary units system. I had to use that page constantly. Then in either 4th or 5th grade that page wasn't there. I was completely lost that entire year. Which brings us to a quotation from John Quincy Adams' assessment of converting to the metric system, "Report Upon Weights and Measures" (22 February 1821):
quote: Le plus a change, le plus la mme chose. (The more things change, the more they remain the same.) Edited by dwise1, : Added translation of the French in the final line. For our unwashed. Edited by dwise1, : Setting the scene of the Christoph Waltz quotation in a hardware store Edited by dwise1, : The death of the fifth of booze, sacrificed on the altar of metrification
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