# Questions re the metric system **URL:** \ **Category:** Factual Questions\ **Created:** [July 12, 2018, 1:39pm UTC](https://boards.straightdope.com/t/questions-re-the-metric-system/817778 "2018-07-12T13:39:42Z")\ **Posts on this page:** 20\ **Page:** 6
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [July 13, 2018, 4:06am UTC](https://boards.straightdope.com/t/questions-re-the-metric-system/817778/101 "2018-07-13T04:06:37Z")
Holy crap, you simply cannot answer a question, can you? I will repeat it, in case you somehow missed it the first time: I would like you to give me one (1) example where a change to a different measurement system was required to cope with the disastrous loss of precision in a computer program caused by the **metric system**. ---
**Author:** ![rat\_avatar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rat_avatar/32/255_2.png) [@rat\_avatar](https://boards.straightdope.com/u/rat_avatar)\ **Post date:** [July 13, 2018, 4:33am UTC](https://boards.straightdope.com/t/questions-re-the-metric-system/817778/102 "2018-07-13T04:33:12Z")
> [@beowulff](#): > > Holy crap, you simply cannot answer a question, can you? > > I will repeat it, in case you somehow missed it the first time: > I would like you to give me one (1) example where a change to a different measurement system was required to cope with the disastrous loss of precision in a computer program caused by the **metric system**. I provided multiple, click the links, but this is bigger then measurement systems. This is freshmen year computer science intro to computers level, and has been for decades, it is not something that is obscure. [http://www.lce.hut.fi/teaching/S-114.1100/lect\_1.pdf](http://www.lce.hut.fi/teaching/S-114.1100/lect_1.pdf) > [@](#): > > Moreover, > most real numbers cannot be represented exactly in a computer. For example, > 1/10 = (0.1)10 = (0.0 0011 0011 0011 0011 0011…)2 > The effective number system for a computer is not a continuum but a discrete set of > numbers called the machine numbers > **[15. Floating Point Arithmetic: Issues and Limitations](https://docs.python.org/3/tutorial/floatingpoint.html)** > > Floating-point numbers are represented in computer hardware as base 2 (binary) fractions. For example, the decimal fraction 0.625 has value 6/10 + 2/100 + 5/1000, and in the same way the binary fra... [https://wiki.sei.cmu.edu/confluence/display/c/FLP02-C.+Avoid+using+floating-point+numbers+when+precise+computation+is+needed](https://wiki.sei.cmu.edu/confluence/display/c/FLP02-C.+Avoid+using+floating-point+numbers+when+precise+computation+is+needed) I repeat, the fact that 1.0 is NOT EQUAL to 10\*0.1 is intro to computers level information and ignoring the math behind it, and multiple examples in a post you just ignored won’t change that fact. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [July 13, 2018, 4:44am UTC](https://boards.straightdope.com/t/questions-re-the-metric-system/817778/103 "2018-07-13T04:44:06Z")
> [@rat\_avatar](#): > > I provided multiple, click the links, but this is bigger then measurement systems. > > This is freshmen year computer science intro to computers level, and has been for decades, it is not something that is obscure. > > [http://www.lce.hut.fi/teaching/S-114.1100/lect\_1.pdf](http://www.lce.hut.fi/teaching/S-114.1100/lect_1.pdf) > > [15. Floating Point Arithmetic: Issues and Limitations — Python 3.12.3 documentation](https://docs.python.org/3/tutorial/floatingpoint.html) > > [FLP02-C. Avoid using floating-point numbers when precise computation is needed - SEI CERT C Coding Standard - Confluence](https://wiki.sei.cmu.edu/confluence/display/c/FLP02-C.+Avoid+using+floating-point+numbers+when+precise+computation+is+needed) > > I repeat, the fact that 1.0 is NOT EQUAL to 10\*0.1 is intro to computers level information and ignoring the math behind it, and multiple examples in a post you just ignored won’t change that fact. So, the answer is “no,” then? This thread is **not about** the imprecision of floating-point math. It’s about the metric system. You made an unsubstantiated claim early on, and have failed to support it in any subsequent post. Sorry, you lose. ---
**Author:** ![rat\_avatar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rat_avatar/32/255_2.png) [@rat\_avatar](https://boards.straightdope.com/u/rat_avatar)\ **Post date:** [July 13, 2018, 5:00am UTC](https://boards.straightdope.com/t/questions-re-the-metric-system/817778/104 "2018-07-13T05:00:03Z")
> [@beowulff](#): > > So, the answer is “no,” then? > > This thread is **not about** the imprecision of floating-point math. It’s about the metric system. You made an unsubstantiated claim early on, and have failed to support it in any subsequent post. > > Sorry, you lose. You may want to look at what forum you are in. But how about showing me examples of doctors losing a patient because they were waiting for a stork. That is how absurd this is. 0.1 = 3602879701896397/36028797018963968 for computers 0.1 ~=0.1000000000000000055511151231257827021181583404541015625 Can you not understand the implications of .1 + .1 + .1 not being equal to .3 Those are all _basic_ examples on the _tutorial_ page for one of the easiest to learn languages in popular use today. And rounding doesn’t fix it. > [@](#): > > \>\>\> round(.1, 1) + round(.1, 1) + round(.1, 1) == round(.3, 1) > False Please provide a cite where I am wrong on this, because your claims that the limitations of dividing by 10 and equality is DIRECTLY related to a **decimal** system of measurement. Thousands of new programmers get bit by this, here is the first hit from a simple google search as an example. > **[Yahoo | Mail, Weather, Search, Politics, News, Finance, Sports & Videos](https://www.yahoo.com/)** > > Latest news coverage, email, free stock quotes, live scores and video are just the beginning. Discover more every day at Yahoo! I think you are trying to win an argument outside of Great Debates because it is not hard to understand the problem when: 1mm + 1mm + 1mm + 1mm + 1mm + 1mm + 1mm + 1mm + 1mm + 1mm != 1 cm. Are you seriously claiming the fact that due to this representation error that 10 millimeters won’t be counted as equal to 1 centimeter is not a problem? ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [July 13, 2018, 5:07am UTC](https://boards.straightdope.com/t/questions-re-the-metric-system/817778/105 "2018-07-13T05:07:30Z")
> [@rat\_avatar](#): > > You may want to look at what forum you are in. > > But how about showing me examples of doctors losing a patient because they were waiting for a stork. That is how absurd this is. > > 0.1 = 3602879701896397/36028797018963968 > > for computers 0.1 ~=0.1000000000000000055511151231257827021181583404541015625 > > Can you not understand the implications of > > .1 + .1 + .1 not being equal to .3 > > Those are all _basic_ examples on the _tutorial_ page for one of the easiest to learn languages in popular use today. > > And rounding doesn’t fix it. > > Please provide a cite where I am wrong on this, because your claims that the limitations of dividing by 10 and equality is DIRECTLY related to a **decimal** system of measurement. > > Thousands of new programmers get bit by this, here is the first hit from a simple google search as an example. > > [Yahoo | Mail, Weather, Search, Politics, News, Finance, Sports & Videos](https://uk.answers.yahoo.com/question/index?qid=20130922043006AASGaBg&guccounter=1) > I think you are trying to win an argument outside of Great Debates because it is not hard to understand the problem when: > > 1mm + 1mm + 1mm + 1mm + 1mm + 1mm + 1mm + 1mm + 1mm + 1mm != 1 cm. > > Are you seriously claiming the fact that due to this representation error that 10 millimeters won’t be counted as equal to 1 centimeter is not a problem? 1mm + 1mm + 1mm + 1mm + 1mm + 1mm + 1mm + 1mm + 1mm + 1mm = 10mm The units you are working in are mm, not cm. And, your example is bad - what you meant to say is .1cm + .1cm +… != 1cm But, of course, this example has nothing to do with the metric system. .1in + .1in +… != 1in either. ---
**Author:** ![rat\_avatar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rat_avatar/32/255_2.png) [@rat\_avatar](https://boards.straightdope.com/u/rat_avatar)\ **Post date:** [July 13, 2018, 6:38am UTC](https://boards.straightdope.com/t/questions-re-the-metric-system/817778/106 "2018-07-13T06:38:53Z")
> [@beowulff](#): > > 1mm + 1mm + 1mm + 1mm + 1mm + 1mm + 1mm + 1mm + 1mm + 1mm = 10mm > > The units you are working in are mm, not cm. > > And, your example is bad - what you meant to say is .1cm + .1cm +… != 1cm > But, of course, this example has nothing to do with the metric system. .1in + .1in +… != 1in either. OK, so you are really arguing that 10mm doesn’t equal 1cm??? Or are you saying .1cm isn’t equal to 1mm? But my US tape measures and rulers seem to have 1/2, 1/4, 1/8, 1/16 markings, and I am pretty sure my metric tape measure has 10 markings per centimeter. But I can see how it would be frustrating going to the hardware store looking for a 0.625 nut, only but leaving after they try to sell you one that was 5/8ths. I am also pretty sure that by the 12" my rules and tape measure mark the foot, and not decimal inches. But maybe we use different brands? Or are you using what you think is a debate tactic that I have said division is the problem? ---
**Author:** ![rat\_avatar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rat_avatar/32/255_2.png) [@rat\_avatar](https://boards.straightdope.com/u/rat_avatar)\ **Post date:** [July 13, 2018, 6:45am UTC](https://boards.straightdope.com/t/questions-re-the-metric-system/817778/107 "2018-07-13T06:45:31Z")
s/Or are you using what you think is a debate tactic that ignores I have said division is the problem? ---
**Author:** ![SanVito](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sanvito/32/2805_2.png) [@SanVito](https://boards.straightdope.com/u/SanVito)\ **Post date:** [July 13, 2018, 8:01am UTC](https://boards.straightdope.com/t/questions-re-the-metric-system/817778/108 "2018-07-13T08:01:19Z")
> [@senoy](#): > > Really? They just say in the 20s? That’s a huge range. It goes from comfortable at 20 to hot at nearly 30. If you say in the 20s Celsius, it’s not conveying anything. It’s like saying that the temp is between 68 and 86 Fahrenheit, that’s a huge range that will impact my behavior. If the high is 68, I’m going to pack a jacket. If it’s 86, I’m going to bring a fan. In Fahrenheit, the deciles all roughly correspond to a similar temperature range. If it’s the 70s, I know that it’s a comfortable day. If it’s the 80s, I know it’s going to be very warm. If it’s the 90s, I know it’s sweltering. If it’s the 60s, it’s brisk. If you tell me that it’s in the 10s Celsius, it could be a very chilly day to a quite comfortable one. It doesn’t seem to be precise to say it that way. I would say ‘It’s going to be in the low 20s/mid 20s/high 20s/low teens/high teens etc’. I think you’re over thinking the difficulty of communication. ---
**Author:** ![SanVito](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sanvito/32/2805_2.png) [@SanVito](https://boards.straightdope.com/u/SanVito)\ **Post date:** [July 13, 2018, 8:08am UTC](https://boards.straightdope.com/t/questions-re-the-metric-system/817778/109 "2018-07-13T08:08:29Z")
> [@Orwell](#): > > I disagree completely, and it has little to do with familiarity. Sure, I could get used to C, but it is less useful as a scale for living (as opposed to measuring water freezing and boiling). Most of us live our lives between 0 and 100 F. If it’s below 0F, it’s damn cold. If it’s above 100F, it’s damn hot. In between, each decile has an easily observable and relatable amount of coolness or warmth. That simply doesn’t happen with the C scale. > > I’m probably not going to convince you about F, and you are definitely not going to convince me about C. Well I grew up with F and have been converted to C, through the gradual change that has happened in the UK. There really is NO DIFFERENCE in which system you use. When you know it, you know it. There’s nothing superior about either system, except I know I need to scrape the car windows at 0ºC and be careful on the roads on my bike, which IS genuinely useful to know. ---
**Author:** ![Colophon](https://avatars.discourse-cdn.com/v4/letter/c/f05b48/32.png) [@Colophon](https://boards.straightdope.com/u/Colophon)\ **Post date:** [July 13, 2018, 9:25am UTC](https://boards.straightdope.com/t/questions-re-the-metric-system/817778/110 "2018-07-13T09:25:12Z")
Exactly. I grew up with Fahrenheit but now use Celsius. Back then I knew that 70F was the threshold for a pleasant (for England) day. Now I know that is 21C. Likewise 25C+ is warm, and 30C+ is hot. The mistake is in thinking that you have to convert everything back into another measurement system. You don’t. You just come to get a feel for the new system. I don’t know anybody who still converts prices into shillings and pence either. ---
**Author:** ![bob\_2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bob_2/32/3341_2.png) [@bob\_2](https://boards.straightdope.com/u/bob_2)\ **Post date:** [July 13, 2018, 10:44am UTC](https://boards.straightdope.com/t/questions-re-the-metric-system/817778/111 "2018-07-13T10:44:05Z")
> [@Colophon](#): > > I don’t know anybody who still converts prices into shillings and pence either. I do sometimes… Just as a mental exercise and to shock myself with how much prices for small things have gone up since decimalisation 47 years ago. 12/6 for a loaf of bread??? ---
**Author:** ![clairobscur](https://avatars.discourse-cdn.com/v4/letter/c/839c29/32.png) [@clairobscur](https://boards.straightdope.com/u/clairobscur)\ **Post date:** [July 13, 2018, 10:45am UTC](https://boards.straightdope.com/t/questions-re-the-metric-system/817778/112 "2018-07-13T10:45:18Z")
> [@senoy](#): > > Do you say the low 20s? What if you’re trying to differentiate between the low and the high decile? Does that just not happen? I’m actually interested. Over here, people don’t really say “in the 20s”, “in the 30s”, let alone “lower 20s”. If they wanted to express the same idea on TV, I guess they would say something like “temperatures will be between 20 and 25 degrees” ---
**Author:** ![SanVito](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sanvito/32/2805_2.png) [@SanVito](https://boards.straightdope.com/u/SanVito)\ **Post date:** [July 13, 2018, 10:57am UTC](https://boards.straightdope.com/t/questions-re-the-metric-system/817778/113 "2018-07-13T10:57:20Z")
> [@clairobscur](#): > > Over here, people don’t really say “in the 20s”, “in the 30s”, let alone “lower 20s”. If they wanted to express the same idea on TV, I guess they would say something like “temperatures will be between 20 and 25 degrees” Watch out, someone will be along in a minute to tell us metric is inefficient with language. FTR, we’d say ‘low 20s’ in the UK. ---
**Author:** ![clairobscur](https://avatars.discourse-cdn.com/v4/letter/c/839c29/32.png) [@clairobscur](https://boards.straightdope.com/u/clairobscur)\ **Post date:** [July 13, 2018, 11:05am UTC](https://boards.straightdope.com/t/questions-re-the-metric-system/817778/114 "2018-07-13T11:05:53Z")
> [@SanVito](#): > > Watch out, someone will be along in a minute to tell us metric is inefficient with language. > > FTR, we’d say ‘low 20s’ in the UK. Well, maybe. I guess it’s cultural. In fact, I can’t even think of a proper way to translate “low 20s” in French. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [July 13, 2018, 1:01pm UTC](https://boards.straightdope.com/t/questions-re-the-metric-system/817778/115 "2018-07-13T13:01:38Z")
> [@senoy](#): > > 100 doesn’t matter for cooking. The 100 is only at sea level and most of us don’t live there. “Most of us” live close enough. 80% of the world, that is. > [@Kiwi\_Fruit](#): > > The baby’s weight thing repeats here though. Official weight might be 3800 gm but all parents seem to say the lbs and ozs thing. Here we don’t even have that holdout. Baby’s weight are given in kilos and that’s what everyone uses when talking about it too. ---
**Author:** ![senoy](https://avatars.discourse-cdn.com/v4/letter/s/dbc845/32.png) [@senoy](https://boards.straightdope.com/u/senoy)\ **Post date:** [July 13, 2018, 1:35pm UTC](https://boards.straightdope.com/t/questions-re-the-metric-system/817778/116 "2018-07-13T13:35:06Z")
> [@MrDibble](#): > > “Most of us” live close enough. 80% of the world, that is. I don’t know the numbers. In the US, only 9 states have an average elevation below 500 feet which is roughly a 1 degree Celsius difference in boiling point. There are certainly states though with high average elevation that still cluster along the coasts, so I really don’t have an answer. I can’t imagine that 80 percent of the US population is hugging the coasts, but I suppose it’s possible. At least 1/4 of our states have no land below 500 feet. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [July 13, 2018, 1:47pm UTC](https://boards.straightdope.com/t/questions-re-the-metric-system/817778/117 "2018-07-13T13:47:18Z")
> [@senoy](#): > > I can’t imagine that 80 percent of the US population is hugging the coasts, but I suppose it’s possible. [Half of the US population](https://www.livescience.com/18997-population-coastal-areas-infographic.html) lives in counties _directly_ abutting the shoreline. This includes the Great Lakes, though, so factor that in. Then all the counties that are at lower elevation but not _directly_ on the coast…people really like living on coasts and the bigger (hence lower) rivers. ---
**Author:** ![bob\_2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bob_2/32/3341_2.png) [@bob\_2](https://boards.straightdope.com/u/bob_2)\ **Post date:** [July 13, 2018, 1:56pm UTC](https://boards.straightdope.com/t/questions-re-the-metric-system/817778/118 "2018-07-13T13:56:21Z")
Hopefully beowulff and rat avatar have gone out into the playground to fight it out. Yes, of course 12, 16, 60 etc have more whole number sub-multiples, but the metric system is a darn sight easier for kids to learn, especially since we count in tens. Maybe it would be different if we all had six fingers on each hand…? ---
**Author:** ![penultima\_thule](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/penultima_thule/32/3833_2.png) [@penultima\_thule](https://boards.straightdope.com/u/penultima_thule)\ **Post date:** [July 13, 2018, 11:52pm UTC](https://boards.straightdope.com/t/questions-re-the-metric-system/817778/119 "2018-07-13T23:52:19Z")
> [@SanVito](#): > > There really is NO DIFFERENCE in which system you use. Conceptually, yes. But do you know any country that has switched \*\*from \*\* metric to imperial? If all the traffic is one way except for that budding third world country in the north Atlantic about 75W, what does that tell you? Am an Aussie born at a time when the country was exclusively imperial. Was in primary school when the currency went metric and nobody thinks that guineas, pounds, crowns, half crowns, shillings, sixpences, thripennies, tupennies, pennies, hapennies and farthings was superior. I now think in metric with one exception, human height. And that’s only to crosscheck how much of a beanpole 196cm and how much of a munchkin 150cm is. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [July 14, 2018, 2:29am UTC](https://boards.straightdope.com/t/questions-re-the-metric-system/817778/120 "2018-07-14T02:29:49Z")
The metric system has four key advantages over the “customary” system. The least significant of these, but for some reason the most often cited, is that it’s based on powers of ten. The next advantage is that it’s used by the vast majority of the world. This isn’t an inherent advantage, since after all there was a time before all of them switched, but it’s still a real one. Much more important is that the metric system is what’s called a coherent system of units. What this means is that, for instance, the metric unit of power is equal to the metric unit of mass times the square of the metric unit for length divided by the cube of the metric unit of time. By contrast, the customary unit for power is not one foot-pound per second, but 550 foot-pounds per second. And finally, the customary system isn’t even standardized, which defeats the whole point of a system of units. That image someone linked of all of the different international inches is an excellent illustration of this. Not only do people all over the world use units called “kilogram” and “meter” and so on, but everyone who uses those units means the same thing by them. You never have to stop to ask “Which inch?”, or “What kind of gallon?”, or the like. [Previous page](https://boards.straightdope.com/t/questions-re-the-metric-system/817778.md?page=5) [Next page](https://boards.straightdope.com/t/questions-re-the-metric-system/817778.md?page=7)