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Metric versus US versus Imperial Units

Discussion in 'Off Topic' started by Brian H, Aug 8, 2012.

  1. Brian H

    Brian H Banned

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    Confusingly, those are called British or Imperial Units. That was from before the UK committed cultural s-EU-icide.
     
  2. AndyM

    AndyM Member

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    Interesting reading tonight.. http://en.wikipedia.org/wiki/United_States_customary_units
    For practical purposes, US or Imperial are both considered acceptable. I bet in Myanmar they call them something even more different.

    ( our moderators must be sleeping tonight... surely this would have been called off-topic by now )
     
  3. brianman

    brianman Burrito Founder

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    It's more on topic for this thread than any other existing thread on the forums that I'm aware of.
     
  4. Brian H

    Brian H Banned

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    Unit-y

    For those needing a verbal or mental defense against SI:
    A forearm length = foot length = 1 foot.
    Width of a male thumb knuckle = 1 inch (one "pouce" in French, means inch or thumb!)
    One ounce of pure water at room temp weighs one ounce.
    The Fahrenheit thermometer range from freezing to boiling is 180°, which can be factored by 2, 3, 5. 100°C only by 2 & 5.
    One pound of water is one pint. 10 lbs is 1 Imperial gallon (160 oz.)
    2 yards tall is a tall man. 2 meters tall is a freak.

    SI units have no (zero, none) connections with normal human scaling, while Imperial units are natural, intuitive, and derived from human physiology. The only advantage SI has arithmetically is order-of-magnitude steps. But a factor of 10 is just beyond the normal range of human memory/attention/imagination (factors of 6 or 7 are comfortable).

    When the French did their copy-cat Revolution, they got that wrong. They then compounded the error by developing and imposing (by Napoleonic decree) the totally abstract and impractical SI system. And now the EU is collapsing. Coincidence? I don't think so!!
    :tongue::rolleyes::tongue::crying:
     
  5. brianman

    brianman Burrito Founder

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    And then the computer generation came along and some would say everything should be related by powers of 2...
     
  6. mknox

    mknox Well-Known Member

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    I think car makers went to "US Units" since the US gallon is about 5/6 of an Imperial gallon. This makes US MPG different than Imperial MPG. I grew up in Canada where we used "Imperial" units and Canadian cars always appeared to get better mileage than US counterparts because of this one difference. It stems from a US pint having 16 oz. rather than the Imperial pint having 20 oz. From there on it's the same (2 pints in a quart, 4 quarts in a gallon etc.).

    ...and now back to our regularly scheduled forum topic :)
     
  7. Doug_G

    Doug_G Lead Moderator

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    Which, thanks to the miracle of moderation, is now units of measurement...
     
  8. doug

    doug Administrator / Head Moderator

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    #8 doug, Aug 9, 2012
    Last edited: Aug 9, 2012
    Your opinion does not appear to be based on fact. Counting things by 12 (e.g., 12 hours on the clock, 12 inches in a foot, etc.), is historically common since 12 is integer divisible by 1, 2, 3, 4, and 6, where as 10 is only divisible by 1, 2, and 5. So it's easy if you want to sell eggs by the dozen, or the half dozen, or even the quarter dozen. However, dividing a set of 10 eggs by four would be a challenge.

    But our Arabic numeral system, which was a great advance since it made arithmetic easy, is base 10 (probably because we have 10 digits on our hands). If we count things by 10 and use a base 10 number system, then it's also easy to convert to different orders of magnitude by simply moving the decimal point.

    Now in terms of what the actual units are based on... Basing units of measure on human physiology is obviously of limited usefulness since everyone's body is different. Clearly things need to be based on a standard. The units in the metric system are based on actual physical constants, in many cases fundamental constants of the universe.

    I suppose ideally when SI was proposed, we should have also converted to a base 12 number system. But that would have never caught on, just like the decimal clock never did.
     
  9. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    The Arabic numeral system added a zero, which the older systems didn't have. In other words a base 12 system 12 would be 10 and you could still move the decimal place just like in base 10, although I suppose it wouldn't be called a decimal place :) However math would be easier to do because there are fewer repeating numbers and larger amounts can be expressed by fewer digits.
     
  10. NigelM

    NigelM Recovering Member

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    ...and 2.
     
  11. doug

    doug Administrator / Head Moderator

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    ^^ it was there when i typed it in my head. :confused:
     
  12. Johan

    Johan Took a TSLA bear test. Came back negative.

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    In the history of the imperial system, one purpose was to convey to the commoners how "great" the regent/king was - the inch was his quite large thumb, the "foot" was larger than most people's foot etc. etc. People in the middle ages were smaller than today, and so were the kings, but the exaggerated quite a bit. Of course 99.99% of the population never got to see the actual king, but by the definition of for example a "foot" they would get a sense of what a big and great man he was. Of course, the "foot" would change as new (supposedly bigger) kings came along.

    The Metric system has most logic, even though the actual meter has no good connection to anything real, except when it was defined the first time it was supposed to be 1/10.000.000 of the distance from the north pole to the equator (through Paris, France). One kilo is one liter of water at maxium density (About 4 degrees Celsius) and at normal air pressure, where one liter is derived from the meter (one cubic decimeter). Then for temperature you have Kelvin (which starts a the absolute 0) or for daily use Celcius (which is the same only displaced upwards 273,15 degrees so that 0 Celsius is the freezing point of water at normal air pressure).

    Since all of the world now uses to 10-10 numeral system we should all use units that are in line with that. "6 feet 11 inces" for example is illogical IMO, it uses a base of 12, which we normaly only use for time-keeping.
     
  13. widodh

    widodh Model S R231 EU

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    Still, metric is much, much, much easier :)

    Metrication - Wikipedia, the free encyclopedia

    Multiple with 10, divide by 10.

    That's one thing I don't like about the Roadster, internally it does everything in miles and when you set it to 'Metric' it does a lazy conversion and your odometer will increment with 200 meters each time instead of 100 meters.


    Offtopic: I'm in the EU and nothing is wrong here :)
     
  14. ggr

    ggr Roadster R80 537, SigS P85 29

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    Funny, that... an ounce of anything weighs one ounce. ITYM a "fluid ounce", which is a measure of volume, not weight.

    But of course the 32 degree offset can only be factored by 2, whereas zero can arguably be factored by anything non-zero.

    You seem to have missed the fact that US gallons and Imperial gallons (and pints) are different!

    US: one pint is 16 fluid ounces. "A pint is a pound, the world around!" [Sic... it's only true in the US.] A US gallon of pure water weighs eight pounds.

    Imperial: one pint is 20 fluid ounces. "A pint of pure water weighs a pound and a quarter." An imperial gallon of pure water weighs 10 pounds.

    When yards were defined as a unit of measure, a two yard tall man was a freak.
     
  15. raymond

    raymond Member

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    a) There are seven SI units. Your observations only pertain to length.
    b) There have been many definitions of "one foot". In 1959 the foot was standardized to 0.3048 meter. It took SI to standardize the foot. :wink:
    c) Conversions suck when working with units like lb.ft and psi. Rockets have been lost due to that.
     
  16. doug

    doug Administrator / Head Moderator

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    When I shop for groceries I often compare the unit price of food items. It is sooo annoying when one brand does its unit price per ounce and another brand does it price per pound. This wouldn't be an issue with metric (or if I could quickly divide by 16 to two decimal places).
     
  17. Doug_G

    Doug_G Lead Moderator

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    Yeah, but your zero is really 273.16 degrees.
     
  18. brianman

    brianman Burrito Founder

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    Evidence that doug is a cyborg.
     
  19. raymond

    raymond Member

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    When buying Loctite glue the other day the label read: "Loctite glue - €3.79 / 3 gr; €1263.33 per KG"

    Unit pricing gone overboard?
     
  20. Brian H

    Brian H Banned

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    #20 Brian H, Aug 13, 2012
    Last edited: Aug 13, 2012
    Degrees (angles) come from Babylonian numbering with base 60! But really they only had 2 symbols, 1 & 10 (sideways 1), attached in rows. (Simple 'cuneiform' symbol: triangle indent with stroke tail, a bit like our letter Y.) 9 was rows of 3 1s, stacked 3 high, then sideways 1 for 10. So that was implicitly decimal. 2 10s immediately to the left of 5 1s for 25, etc., etc. But when you reach 5 10s plus 9 1s you jump left to another group, leaving a gap, which is then counting in units of 60[sup]2[/sup]. Etc. So 360° was written "60°" in Babylonian. When zero units in a position happened, a space was left. So that 60° (our 360°) effectively looked like 6 ° (versus 6° for 6x1°). Later versions had a symbol for "space", which was de facto thus a zero. We now use a comma (or period in SI) for the gap between groups, in a sense.

    None of this stuff was decided by committees; it just happened, so to speak. Merging civilizations made accommodations. There's some thought that 12 and 60 were the maximum hand-countable numbers: 3x4 finger segments on one hand, tapped by that hand's thumb counts to 12, or pointed to by the 5 alternate digits of the other = 60. (Maybe the 2 "counted hand" thumb segments used for powers of 60?) Which happens to be divisible by every number up to 6 -- very "handy"! :wink:

    Decent discussion here: Babylonian numerals
     

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