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Ending the Era of the U.S. Survey Foot

nist.gov

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Re: Ending the Era of the U.S. Survey Foot

#151

Post by mark-r »

zokier wrote: post #136
mark-r wrote: post #61

Earlier quoted context omitted.

I once tried to imagine a metric time system, with a deciday of 14.4 minutes. I realized that it would never catch on, because a half-hour TV show would have to be cut to 28.8 minutes losing at least 2 commercials.

14.4 minutes is a centiday btw. For decimal time I think milliday is the most reasonable unit, being very close to conventional minute. In practice Mars might be the best opportunity for enacting decimal time, because Earth based units would be bit awkward on Mars.

Thanks for the correction.

Re: Ending the Era of the U.S. Survey Foot

#152

Post by mark-r »

pjc50 wrote: post #134
d-sc wrote: post #126

Earlier quoted context omitted.

2 * 4 = 8 so the last significant digit should be an ‘8’

Definitely one to cite in the "overreliance on calculators" - the comment you are replying to should have realised that multiplication can't create digits to the right like that! (Most desktop calculators do it in BCD which would give the correct result, too)

I use Python as my desktop calculator. It has a Decimal module that would have gotten it correct, but that would have been way too much trouble.

Re: Ending the Era of the U.S. Survey Foot

#153

Post by mark-r »

zokier wrote: post #139
mark-r wrote: post #112

Earlier quoted context omitted.

In metric, the weight of water in grams is equal to the volume in cubic centimeters, by definition. The volume of a cylinder is the area of the circle times the length. The area of a circle is pi * r^2. So my description above skipped a step or two.

> In metric, the weight of water in grams is equal to the volume in cubic centimeters, by definition. Just to clarify this is not exactly true. It was the original idea, but pretty quickly they realized that it wasn't a practical definition and kilogram ended up being defined by a standard reference object which was carefully stored in a vault in Paris and thus being disconnected from the meter and the density of wat…

I'm sure the updates to the Kilogram definition tried to keep it as close to the original as possible, right? The difference pales in comparison to the other shortcuts I was taking.

Re: Ending the Era of the U.S. Survey Foot

#155

Post by moron4hire »

Taniwha wrote: post #81
moron4hire wrote: post #68

Earlier quoted context omitted.

It's called "US Customary", not "imperial".

Only in the US - except for gallons/fluid ounces - those genuinely are US only

No, that's my point. The system of units that is used in the United States is not "Imperial", it has differences from Imperial. We use "US Customary".

Re: Ending the Era of the U.S. Survey Foot

#156

Post by alamortsubite »

Infernal wrote: post #154
alamortsubite wrote: post #40

If someone had told me this statement was part of a Monty Python script, I'd likely have believed them.

For those of us who came later to the discussion, what was the original title?

I was referring to the content of the post on nist.gov. But I think the title has changed, and may have been simply "U.S. Survey Foot" when I first commented.

Re: Ending the Era of the U.S. Survey Foot

#157

Post by jackfoxy »

function_seven wrote: post #56
jackfoxy wrote: post #33

I knew about the survey foot because both the l00' tape measures I have are in survey feet. Messed me up on a home construction project about 13 years back. It was then I learned there are 2 differing feet definitions.

Are you sure it was the differing length of each version (about 610 nanometers), or was it because your tapes were marked in tenths of a foot instead of inches?

Well this was a false memory I may now remember as false. No, it wasn't tenths. I think more likely it had to do with the claw at the start of the tape for attaching to your starting point, which does not stay at a rigid 90 degrees. My memory is that over several tens of feet I was off by 1/8 inch.

Re: Ending the Era of the U.S. Survey Foot

#158

Post by irrational »

doctor_eval wrote: post #140
irrational wrote: post #98

Earlier quoted context omitted.

It's not the precision. It's the divisibility. 10 can only be divided in half. It can't be divided into thirds, quarters, sixths or twelfths evenly and that ability is invaluable. This is the same reason why, in the old days of grid layouts, grids were 12 columns wide and not 10.

What’s so special about thirds, sixths or twelfths? 10cm = 100mm; 100mm can easily be divided by 2, 4, 5, 8 (=12.5), 10, 20, 25, ... That’s a nice thing about metric. If you don’t like the units you can multiply them

I'm surprised that people are finding the benefits of divisibility to be so hard to understand. Does using the metric system create this blind spot? I've heard of language creating blind spots in what people can easily understand and think about. I hadn't thought about mathematical things, like the metric system, also creating blind spots, but I guess it makes sense.

Re: Ending the Era of the U.S. Survey Foot

#159

Post by nkurz »

Gormo wrote: post #123
mrb wrote: post #120

Earlier quoted context omitted.

The conversion techniques you explained, I use them myself (that's why they always ask for my help, I can do it in my head.) But the fact many Americans are unable to do that is, in itself, evidence the imperial system doesn't work that well for them. > This is definitely the worst example. 0°F is really cold. 100°F is really hot. This might be a sufficient explanation to give to a 5-year-old, but as soon as you need…

American here. I've never once in my 40 years on this earth heard someone say "six pound five". That parlance is often used for feet and inches (almost always in reference to human height), but I've never encountered anyone using it for pounds and ounces.

I'm American, have lived in many parts of the US, and I agree: "six pound five" is not something that we say. As Gormo says, this construction is frequent for feet and inches ("six foot five"), but would not be standard for weight.

And personally, if I were to use this nonstandard construction, I'd probably pluralize "pounds". I don't know why "foot" is usually singular in the parallel construction.

The most charitable interpretation I can come up with is that your relatives are from the American South, and are actually saying "six point five", meaning 6 and half pounds, and you are mishearing them.

Re: Ending the Era of the U.S. Survey Foot

#160

Post by runxel »

jessaustin wrote: post #109
runxel wrote: post #49

Earlier quoted context omitted.

Well, architectural construction is based on the "octameter", so 12.5 cm. That adds pretty well ;)

You've flummoxed me with this. The internet seems sure that "octameter" is a "metrical foot", which in this context is quite a pun. Without a link to confirm an architectural connection, I'll take this as a fairly obscure joke...

Haha, no, it's not a joke as I can tell you as an architect.

Sadly there are no english links, but have a look at Wikipedia [0] and you will see, that I've not dreamed that up :) Of course it has a referenece norm: the DIN 4172, which calls it the "oktametrisches Maßsystem" (_octametric system of measurement_). It is made since a brick would be 11.5 cm and the mortice 1 cm = ∑ 12.5 cm. Eight bricks with mortice are a meter. Pretty easy actually!

[0] https://de.wikipedia.org/wiki/Baurichtma%C3%9F

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