I think you did earlier when you said there were 1.6 miles in a km when it’s the other way around.
But that’s my point - it’s so much less likely that you’ll make such mistakes in metric.
There are 1,000 liters in a cubic meter. Calculations of length related to volume are much easier, both with conversion and the math, so mistakes happen much less.
Nope. The mistake was yours. Allow me to walk you through it:
AaronX posted this question:
To which Smapti responded:
To which you responded:
Obviously you misinterpreted Smapti’s response. Read it closely and see if you can figure out YOUR mistake.
I even pointed this out to you:
Smapti also corrected you:
I did not claim there was, I was disputing your assertion that F is superior to C.
I’ve lost track. was he asserting that F is superior to C, or asserting that C is not necessarily superior to F? big difference.
His claim was that F is superior to C because you don’t need to use negative numbers when describing the temperature outside. He apparently has not been to Minnesota.
I was the one who claimed that C is slightly better than F due to the freezing and boiling points marked with 0 and 100 which seem to make more sense than 32 and 212. But I agree that if you want to go truly non-arbitrary, you may want to take a look at Kelvin. The only problem with K is that we would constantly be in the 200-300’s. To avoid this, C is just K-273 so that you avoid the disadvantage of K’s really high values and have the freezing and boiling points marked most sensibly. jz78817 claims that C being less arbitrary is irrelevant, but I disagree because as you see, C is only K-273, and that is so that you avoid really high numbers. And the reason it is 273 is so that the freezing and boiling points come out nicely at 0 and 100. So it is not all that arbitrary and therefore, I claim that C is best for everyday life.
Yeah, I realized that I had it backwards after I posted. I was shuffling around a lot of numbers in my head. The simpler solution which I have always encountered in the US is to buy aquariums by the gallon to begin with.
[Raises hand.] I knew that. Yes, the survey foot is used for surveying. No, the difference between an ordinary foot and a survey foot is not great; it only comes up for precise measurements across, say, half a county.
BTW, surveyors don’t use inches much at all. If the survey is in ‘customary’ units, it will be in feet and decimal feet.
The one instance in my life where metric proved far more useful (as opposed to just arbitrarily picking one system or the other) was when I had to estimate how much a filled aquarium would weigh. Measure height, width and depth in centimeters, multiply to get total number of cubic centimeters, a cc of water weights just about a gram… easy peasy, though I think I converted the resulting weight in kilograms to pounds for the benefit of my mother, whose aquarium it was.
The rest of the time, I use imperial for small distances, kilometers for longer ones, metric for volume, metric for small weights, imperial for larger weights… whatever seems more familiar and useful given the circumstances.
I knew. Actually, this is something I happened to think about while reading through the thread.
Yes. My state is one of those that still uses the US Survey Foot for survey and civil engineering.
The difference between the two definitions can easily lead to non-trivial errors. As I noted above, the US Survey Foot is still commonly used in the US.
Several years ago MicroStation (cad software) switched its coordinate storage system to metric. So internally, everything is actually stored in metric, despite what may be shown on the screen. Any non-metric coordinates, lengths, data input, etc. is actually a conversion based on the values in a configuration text file. Out of the box, the default definitions use the International Foot. To get the software to work correctly for those using US Survey Feet, the text file needs to be modified to use the correct definition.
Where I am, the difference between the two definitions results in an error of about 15 feet for the state coordinate system. That is obviously a significant error when survey and design is generally done to 0.01 ft. And I’ve seen this error crop up numerous times over the years, both within my company and with files from elsewhere. Just recently a new employee’s files weren’t ‘‘lining up’’ with mine and I realized that the IT guy hadn’t set up the new guy’s software correctly.
I don’t have a huge preference for one or the other. Like everyone else, I used the metric system plenty going through school and was perfectly comfortable with it. Switching for me wouldn’t be a big deal at all, but I certainly see the side of the argument that there doesn’t seem to be much true benefit to changing. For the most part, it’s just a different set of numbers to be familiar with.
I don’t buy that the ease of converting cubic meters to liters, etc. as any real incentive for the reason others have repeatedly pointed out. I also don’t consider either system to be all that more intuitive than the other. Like others have noted, it’s just whatever you get used to.
Realistically, I think that without meaningful advantage, inertia will tend to win out. And that’s what we see: where it makes economic sense to switch it’s already been done and where it doesn’t, switching probably will not happen.
Then is the NIST wrong?
Units of measurement are standards. Standards come from authorities. The NIST is an authority. You are not. Therefore, in some contexts, the ounce and the kilogram do indeed measure the same thing.
But you see, no one uses the “International Foot”. In the US we always use the Survey Foot.
They can’t usually measure close enuf that 2 parts per million makes a difference is a house or a street.
And the difference is NOT significant:
National Geodetic Survey also states, “these two conversion factors produce results that differ by 2 parts per million; hence for most practical work it does not make any difference to the average surveyor which one is used since [surveyors rarely] encounter distances [large enough for this to be a factor]. Converting a distance of 304,800 meters to feet using the two conversion factors, these are the results: 304,800 meters = 999,998 U.S. Survey Feet and 304,800 meters = 1,000,000 International Feet. A difference of 2 feet in one million feet.” [Editor’s Note: A million feet is approximately 189 miles.]
And if you’re measuring from a reference benchmark at the corner of a state, that could indeed make a difference of several feet at the other end of the state. Which, yes, can be quite significant.
So, yes, you really are unclear on what a Sig-Fig is. It doesnt matter if they are identical or not- if the difference is not significant or will be less than the fuzziness brought in when measuring on that scale. When you’re surveying a road, a difference of 2 feet in one million feet doesn’t mean much. Even for the longest road in the world, the difference is less than an inch.
We can agree to disagree on whether I know what a Sig-Fig is.
Apparently we also disagree on whether the longest road in the world exceeds 8 miles or not.
I know what a significant figure is, I just can’t puzzle out the math in this “longest road” dispute.
Yonge Street was once cited as the longest road, at 1178 miles, or 6.220 million feet, or 7.464 x 10[sup]7[/sup] inches.
But I can’t tell if that’s relevant.
Well, someone sure doesn’t know what significant figures means. The international inch and the surveyor’s inch are both defined precisely in terms of metric units, and those definitions are different. There are precisely 2.54000508 centimeters in one surveyor’s inch. There is no chance that a surveyor’s inch might actually be 2.54000507 or 2.54000509 cm. It’s always 2.54000508 precisely. Therefore, all of those digits really are significant.
Even if the official definition of the surveyor’s inch went out to 20 decimal places, or 50, or 100, those digits would still be significant digits, because that would then be the definition. It matters not that the Universe is not large enough to tell the difference: In any actual calculation, the precision would be much less than that, but that’s a limitation of the measurements, not of the definition of the unit itself.
I’m almost 3 times as old as the OP and I wasn’t even born yet when this went on…
From wiki:
In various technical fields, “accuracy” refers to the closeness of a given measurement to its true value; “precision” refers to the stability of that measurement when repeated many times. The number of significant figures roughly corresponds to precision, not accuracy. The smaller digits are not significant because they effectively random noise generated by the measurement process having little to do with the true value; they, they can be omitted for some reporting purposes. (This approach ignores techniques such as averaging to produce a higher-precision result.)
In other words, if the tools being used or the work that is being done can do or use that level of accuracy, it is not SigFig.
And yes, I made a math error about the road.
Here is a story that illustrates the concept. A guard is giving a tour of the natural History Museum. He comes to a skeleton of a dinosaur and says “This dinosaur lived 250 million and 14 years ago”. Someone in the tour group asks “How can you possibly know it’s exact age?.” The guard replies “All I know is that when I started here they told me it was 250 million years old; and that was 14 years ago”.