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On 23-8-2010 22:33, Jim Henderson wrote:
> On Mon, 23 Aug 2010 15:43:54 -0400, Warp wrote:
>
>> I don't really agree with that. The metric system makes it trivial to
>> switch between units as needed without the need of any calculations
>> whatsoever.
>>
>> For example, a person can be 180 cm tall, or 1.8 meters tall, or 1
>> meter
>> 80 cm tall. All three of these are completely and trivially exchangeable
>> with each other without the need to do any kind of mental calculations
>> whatsoever.
>
> You're making a mental calculation there - you're dividing by 10. It's
> easy, but that doesn't mean there's no calculation at all.
>
Oh come on, you are not dividing, just shifting the decimal point.
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On Mon, 23 Aug 2010 23:04:42 +0200, andrel wrote:
>> You're making a mental calculation there - you're dividing by 10. It's
>> easy, but that doesn't mean there's no calculation at all.
>>
>>
> Oh come on, you are not dividing, just shifting the decimal point.
Which by definition, mathematically, is division (or multiplication if
it's the other direction).
"Shifting the decimal point" isn't a recognised mathematical operation,
well, it wasn't when I took maths. Multiplication and division are.
Just because one takes a shortcut doesn't mean it's a different operation.
Jim
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Jim Henderson <nos### [at] nospam com> wrote:
> On Mon, 23 Aug 2010 23:04:42 +0200, andrel wrote:
>
> >> You're making a mental calculation there - you're dividing by 10. It's
> >> easy, but that doesn't mean there's no calculation at all.
> >>
> >>
> > Oh come on, you are not dividing, just shifting the decimal point.
>
> Which by definition, mathematically, is division (or multiplication if
> it's the other direction).
still, it doesn't demand any calculation at all to correlate 1.80 meters to 1
meter and 80 cm or to 180 cm. They are all equivalent, even in digits...
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On 23/08/2010 7:47 PM, Darren New wrote:
> I think I figured out the real differences there. It's not the "power of
> ten" stuff. After having to decide between 0.2 liters of beer or 0.3
> liters of beer, I realized it's something different.
>
Yes, It is what you are brought with. :-P
>
> Distance: As big as your finger (inch), your foot (foot), your arms
> (yard), how far you can conveniently walk (mile).
>
It's true then. Americans don't walk much. :-P
> Weight: Again, a little bit almost unnoticeable size of a coin (ounce),
> convenient to carry in one hand (pound), convenient for weighing people
> or animals (stone, which nobody seems to actually use any more), about
> as much as you can reasonably ship someplace (a ton).
>
We use stones for weighing people. For instance I am 12 stones but I
would like to be 11 and a half. Or 11-7, that is 11 stones 7 pounds or
73 Kg.
>
> There's nothing lighter than an ounce,
>
What about a dram (not a "wee dram" ;-) ) there are 16 of them in an
ounce and 437.5 grains in an ounce.
>
>
> In practice (for those of you who are used to metric), in every-day
> usage, imperial weird units don't really cause the sort of problem that
> people seem to think it causes. I no more have to frequently convert
> inches to miles than you frequently need to figure out the number of
> minutes in a year. Once you're talking miles, the number of inches is as
> immaterial as asking how many miles are in an inch when you're measuring
> to construct a chair or something. The worst stuff is measuring your
> room to be 12 3/4 feet, and finding out carpet is sold by the inch or
> something.
>
This is true but I would measure the length to be 12' 9" or 12 foot 9
(inches is understood).
--
Best Regards,
Stephen
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> Imperial measurements are generally based on humans, so it's pretty
> convenient for everyday usage.
So long as you don't need to convert between units or do any calculations.
Buying carpet was one example, another is when you tell me you weigh X
pounds and I usually deal with stones, I have no clue whether that's a lot!
Or if you measure someones height with a tape measure marked in inches,
what's that in feet? Or if you are following a recipe that calls for 10 oz
of flour and you want to make 4x the quantity for a party, how much flour do
you weigh out if your scale is in pounds and ounces? These calculations may
seem relatively simple if you're good at mental arithmetic, but people who
aren't struggle (all of the ones above I've witnessed at least once).
> Metric has the advantage that you don't get into weird problems with units
> when you do science.
Yes, it's very odd looking through an imperial science text book where every
formula has some bizarre constant like 537.4 in it!
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scott a écrit :
>> Imperial measurements are generally based on humans, so it's pretty
>> convenient for everyday usage.
>
> So long as you don't need to convert between units or do any
> calculations. Buying carpet was one example, another is when you tell me
> you weigh X pounds and I usually deal with stones, I have no clue
> whether that's a lot! Or if you measure someones height with a tape
> measure marked in inches, what's that in feet? Or if you are following a
> recipe that calls for 10 oz of flour and you want to make 4x the
> quantity for a party, how much flour do you weigh out if your scale is
> in pounds and ounces? These calculations may seem relatively simple if
> you're good at mental arithmetic, but people who aren't struggle (all of
> the ones above I've witnessed at least once).
>
>> Metric has the advantage that you don't get into weird problems with
>> units when you do science.
>
> Yes, it's very odd looking through an imperial science text book where
> every formula has some bizarre constant like 537.4 in it!
>
>
Is it really any weirder than 273.15?
Likewise, I don't think 9.81 is a more convenient constant than 32.2!
My biggest beef with the imperial units is that I usually screw up the
16th and 32nds marks on my measuring tape and end up cutting my planks
just a little too short. It is much harder to mix up the cm and mm lines.
--
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> Is it really any weirder than 273.15?
>
> Likewise, I don't think 9.81 is a more convenient constant than 32.2!
Sorry I meant the unnamed numerical constants in equations, rather than the
official named constants like 'g'. I was just used to seeing simple
equations in text books with no numbers in them (just symbols) yet in one of
my books they use imperial units and almost every equation has some
numerical constant in it. On top of that they find it necessary to write
the units needed for every quantity, which I guess have to tie up with the
constant. It just looks messy (and presumably quite hard to remember),
that's all.
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On 8/23/2010 10:53 PM, Jim Henderson wrote:
> "Shifting the decimal point" isn't a recognised mathematical operation,
> well, it wasn't when I took maths. Multiplication and division are.
> Just because one takes a shortcut doesn't mean it's a different operation.
Shifts are perfectly legitimate mathematical operations. Many of the
things computers do couldn't be done easily without a shift operation :P
--
~Mike
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Stephen wrote:
> It's true then. Americans don't walk much. :-P
Well, I mean, there's a small multiple right? It's not like you can only
drink one pint of beer, either. :-) Walking somewhere between 0.1 and 10
miles is convenient. Outside that, you're going to measure in yards or
you're going to take a horse.
> We use stones for weighing people. For instance I am 12 stones but I
> would like to be 11 and a half. Or 11-7, that is 11 stones 7 pounds or
> 73 Kg.
Cool. Where is this?
>> There's nothing lighter than an ounce,
>
> What about a dram (not a "wee dram" ;-) ) there are 16 of them in an
> ounce and 437.5 grains in an ounce.
I wasn't sure if a dram was imperial or not.
> This is true but I would measure the length to be 12' 9" or 12 foot 9
> (inches is understood).
Yes, exactly. The construction rulers here measure in both inches and feet,
so it's trivial to get either measurement in situations where people use
both scales.
--
Darren New, San Diego CA, USA (PST)
Quoth the raven:
Need S'Mores!
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On Tue, 24 Aug 2010 08:41:13 -0500, Mike Raiford wrote:
> On 8/23/2010 10:53 PM, Jim Henderson wrote:
>> "Shifting the decimal point" isn't a recognised mathematical operation,
>> well, it wasn't when I took maths. Multiplication and division are.
>> Just because one takes a shortcut doesn't mean it's a different
>> operation.
>
> Shifts are perfectly legitimate mathematical operations. Many of the
> things computers do couldn't be done easily without a shift operation :P
Binary shifts are multiplication and division as well. :P
Jim
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