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Most precise measuring tool I've used ...

Displaying poll results.
... had an accuracy in picometers
  1546 votes / 11%
... had an accuracy in femtofarads
  469 votes / 3%
... had an accuracy in microvolts
  4899 votes / 36%
... had an accuracy in metric tons
  490 votes / 3%
... had an accuracy in pounds
  1618 votes / 12%
... had an accuracy in attobreadcrumbs
  892 votes / 6%
What is this "accuracy" thing?
  2090 votes / 15%
I'm in marketing, you insensitive clod!
  1263 votes / 9%
13267 total votes.
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  • Don't complain about lack of options. You've got to pick a few when you do multiple choice. Those are the breaks.
  • Feel free to suggest poll ideas if you're feeling creative. I'd strongly suggest reading the past polls first.
  • This whole thing is wildly inaccurate. Rounding errors, ballot stuffers, dynamic IPs, firewalls. If you're using these numbers to do anything important, you're insane.
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Most precise measuring tool I've used ...

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  • by Grisstle (2798631) on Saturday June 01, 2013 @05:50PM (#43885453)
    I'd like to add that I like to measure things in smidgens and shit-tons or shit-tonnes.
  • For me pipetter measuring in nanoletters when taking genetics classes.

  • by techno-vampire (666512) on Saturday June 01, 2013 @07:05PM (#43885835) Homepage
    First, the obvious one: "Who remembers?" Second, back when I was in the Navy, the most precise measurement we ever used was the RCH: Red Cunt Hair.
  • by Anonymous Coward on Saturday June 01, 2013 @07:24PM (#43885941)

    I am studying how quarks and gluons contribute to the proton spin at RHIC. It is an accelerator colliding 255 GeV protons on 255 GeV protons.

  • Politicians seem to consider counting in millions of pounds (sterling) to be fabulously accurate.

    • by lxs (131946)

      Pounds? It's about time you Brits joined the rest of Europe and start paying with kilograms sterling.

  • by chrylis (262281) on Saturday June 01, 2013 @07:37PM (#43886013)

    The most sensitive device I've used was responsible for tracking individual muons/taus [bnl.gov], so the options seems kinda ham-fisted.

    • ...so the options seems kinda ham-fisted.

      Depends. Muons detectors, like most particle track detectors, work by measuring the position where a charge particle crosses a detector plane. The position resolution of this is usually given in microns which is about a million times less accurate than a picometre - so hardly "ham fisted" given the options above.

      On the other hand most detectors I have worked on can measure invariant mass with a resolution of a few MeV/c^2 - which is a resolution of yoctograms which is a little better than a metric ton.

      • by chrylis (262281)

        Our group was focused on muon tracking, and I never got into any detail on the calorimetry. Which detectors did you work on?

  • by devnullkac (223246) on Saturday June 01, 2013 @08:06PM (#43886183) Homepage

    Not to put too fine a point on it, but precision and accuracy are not the same thing [wikipedia.org]. They are complementary ideas, to be sure, but they should not be confused: <pedantic probable-correctness="75%">precision indicates how close the measurement is to other measurements of the same phenomenon by the same instrument, while accuracy indicates how close the measurement is to the actual value</pedantic>.

    • Re: (Score:3, Informative)

      by Anonymous Coward

      The number 3.140000000000000000000 is specified in a much higher precision than 3.14159, but it's a less accurate approximation of PI.

    • by armanox (826486)

      I understood it to mean the highest precision that can be accurately measured with said device (you could say the dial in the scale was halfway between one and two and call it 1.5, but that scale doesn't accurately measure at that precision.

      • by ebyrob (165903)

        Actually, if you've got tick-marks at the integer level, then you should be taking measurements at 10-times that precision. ie: deciding between 1.4, 1.5, and 1.6 for that "half-way" dial by looking at how far the dial is above the top of the previous tick-mark. The scale doesn't precisely measure beyond that resolution. Didn't any of your labs teach this?

        Accuracy is a whole other subject usually involving comparison of a measurement with something "real" (often through other measurements).

        • by femtobyte (710429)

          You should be reading at whatever the design precision of the instrument is --- and if you don't have reliable specs from the manufacturer (or are meticulously cautious), you should be checking this yourself. Tossing in extra digits because you think you can (when the instrument is only precise/repeatable to a lower level) is bad practice; you're basically deceiving the next person reading your data that the final digit is somehow worthwhile.

    • by sFurbo (1361249)
      To be even more pedantic, accuracy is how close the average of repeated measurements is to the true value, but the concept is the same as what you said, and for high precision measurements, the definitions coincide.
    • by Rob the Bold (788862) on Sunday June 02, 2013 @09:10AM (#43888325)

      Not to put too fine a point on it, but precision and accuracy are not the same thing.

      I was thinking the same thing, but then realized that anyone who could understand the explanation would already know that, and anyone who didn't wouldn't understand it anyway even after I tried to explain.

    • I wish that manufacturers would differentiate between the two when putting specifications on the side of a box.
    • by jbengt (874751)
      The definitions you stated would not agree with the normal language understanding.
      Stating that a mile is 5,278 feet 10-11/16" inches is precise but inaccurate.
      Stating that a mile is a little less than 5,300 feet is imprecise, but completely accurate.
      Of course, YMMV, precision instrument users may have a different understanding.
  • by GrahamCox (741991)
    I'm guessing that microvolts is the leader because radio receiver sensitivity is typically down in the 0.1-0.5ÂV region and it's not an uncommon thing to be working on in engineering.

    Or is there some other explanation?
  • by barlevg (2111272) on Saturday June 01, 2013 @09:38PM (#43886543)
    Not too many undergrad institutions (especially of their size) have an atomic force microscope and let their students play with it.
  • micrograms when measuring weights in an analytical chemistry lab.

    • Yeah, I was looking for that too (for the same reason) - but the only available mass/weight options were huge for some reason.

    • by CastrTroy (595695)
      Yeah, I remember in first year chemistry we used some scale to measure some ingredient by weight. Apparently they wanted us to be really precise so they let us use the really sensitive scales. I remember being annoyed because the weight kept changing as the water evaporated from the sample, even though it was at room temperature.
  • For patterning wafers used in the semiconductor industry, we have to maintain absolute positional accuracy during stage motion in X and Y to within fractions of a nanometer. I suppose that counts as picometer measuring... Crazy system... moving an air-bearing stage a couple of feet in X and Y, while maintaining speed and position to those tight tolerances. It was amazing it worked as well as it did!
  • ... beard-seconds.

  • How about picoliters? Each dot in an inkjet printer head is accurately measured in picoliters of ink (well, some print heads, anyway). Does that count?
  • Microhertz and femtoseconds.
    • by rew (6140)

      I planned my vaction 3 months in advance. The plane was supposed to leave at 13:20. That's about 6 microHz accuracy.

      • by Shavano (2541114)
        Not if it didn't repeat, and the clocks I was measuring to microhertz precision were 100 MHz oscillators, so the precision of the measurement was about 1 part in 10^14. They weren't actually that stable, but I could show that they weren't, which takes some precision equipment. It was nothing near precise enough to measure ultra-precision oscillators [colorado.edu] though.
        • by rew (6140)

          Some physical quantities make sense if you do 1/ e.g. 1/resistance or 'conductance' make sense in the electronics world. You know that complicated formula for parallel resistors? Forget it.
          Resistors in series? Just add them!
          conductors (i.e. resistors, but do one over their value) in parallel? Just add them!
          Well, if you have the values of the resistors in ohms, you need to convert to 1 over ohms (Siemens) first. If you need the result in ohms, you have to convert back afterwards.

          Anyway, with the physical qua

  • Accuracy is not an absolute measure. It is always relative to the measurement range and often relative to the value measured.

    • by sFurbo (1361249)
      As devnullkac said further up, accuracy is how close the average of repeated measurements is to the true value, so it is an absolute measure. You can talk about relative accuracy (accuracy divided by the value measured), or accuracy relative to the measurement range, but that is not the same as to say that accuracy itself is relative.
      • by gweihir (88907)

        Untrue, but it may seem like it of you do not look to closely.

        There are two possibilities to express it: You can express it "natively" as a relative measure, giving absolute range or value measured and absolute error (no, accuracy does not have to be in relation to value measured, relative to measurement range is perfectly permissible as well), or you can express the relation, in unit-free from. Then you still need to state whether the relation is for absolute range or for value measured and the relation st

        • by sFurbo (1361249)
          That isn't the definition of accuracy, at least not in analytical chemistry, nor according to Wikipedia. From WP:

          In the fields of science, engineering, industry, and statistics, the accuracy[1] of a measurement system is the degree of closeness of measurements of a quantity to that quantity's actual (true) value.

          I can see the utility of precision relative to measurement range, but not accuracy. What is the utility for accuracy relative to measurement range?

  • But I once did the Kessel run in under 11.986 parsecs!

  • by theedgeofoblivious (2474916) on Sunday June 02, 2013 @02:09AM (#43887281)

    I think it's accurate to say that upon reading this poll, dozens of college science professors will be looking at their respective screens in their respective locations in the world and collectively shaking their heads from side to side.

  • Let's be honest - measuring money is the most fun, especially if it's yours.

    • by dkleinsc (563838)

      To be more precise: Measuring money is most fun when it was somebody else's and is now yours.

  • I used superconducting quantum interference devices [wikipedia.org] in university to measure single flux quantums (5E-18T=5aT).
    The electronics was off the shelf scientific equipment, but the cryogenics [wikipedia.org] were of some sophistication (to reach 300mK) and the manufacturing of the SQUIDs required high purity aluminum and a controlled level of oxidation (the hardest part). It took about a day to manufacture a simple sample.

  • The magnetometer at NIH has a noise floor around 5-10 fT, depending on the channel. It uses SQuIDs at 4.2 K to measure the magnetic field of the human brain. The LSB of the digitizer is around .2 fT, IIRC. Typical brain fields are on the order of a picoTesla.

  • Accuracy and Precision are not the same!

  • That's the problem with polls like this. I want to assume the attobreadcrumb is the joke option, but I can't help but think someone's going to come along and explain how it's used as a real-life but horribly obscure discrete unit of measurement.

  • No mass option ... (lbs is a weight)
  • I was one of the developers of a diagnostic method based on proton induced nuclear reactions. Our "device" could detect as low as 10 fg (femtogram) of fluorine on a thin sample. It was the most amazing thing I ever did as a physicist. Too bad it was more than twenty years ago...
  • I used to measure the weekly time offset between two cesium clocks then I compared the two cesium clocks against a master cesium clock over a satellite link (taking into account distance to satellite, Doppler, etc.). We'd get a report back telling us to advance or retard one or both cesiums by a nanosecond or two each month to keep everything in sync
  • With no "less than"-options, I'm forced to choose the "metric tons", although the correct answer for me is probably .000001, .0000001 or .00000001 metric tons. I can't remember which.

    BTW, which is more accurate? An apple or an orange?

  • I use Royal Cubits. Way simpler than Imperial units.

    1 royal cubits = 7 palms = 28 fingers. Simple as that.

  • ...had an accuracy in microvolt. It turns out that it is really small...
  • The most precise tool I've used is a Vernier graded micrometer. It measures down to 0.001mm.

  • Pretty much everything in this list was metric, why not use metric pounds too ?
  • by iapetus (24050) on Monday June 03, 2013 @08:48AM (#43894997) Homepage

    Measure with a micrometer. Mark with chalk. Cut with an axe.

  • While yelling these words, a friend of mine connected my DMM to an electronic circuit to measure the supply current. Unfortunately he had previously switched my DMM into ohmmeter mode. After that measurement, my DMM wasn't anymore what it used to be, and the friendship started to wear out...

"In matrimony, to hesitate is sometimes to be saved." -- Butler

 



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