7 ms·

Kinda off topic: How is this good news for dieters? New kilo is lighter than old one, thus making all new measurements bigger in absolute numbers. Besides, ca

Kinda off topic: How is this good news for dieters? New kilo is lighter than old one, thus making all new measurements bigger in absolute numbers. Besides, can't they recreate a "canonical kilo" with the required measurements?

martin-adams 13y ago
It's because dieters measure their progress in kilos lost. So if it's lighter, they can lose more kilos for the same effort.
- ewzimm 13y ago
  Those dieters who measure fifty millionths of a gram in weight loss have bigger problems.
  - solistice 13y ago
    For example the incredibly devastating fluctuations due to shedding of skin and subsequent gains due to snowflakes.
    - ewzimm 13y ago
      I refuse to go outside because I'll get fat.
- vesinisa 13y ago
  Valid point, but your starting mass also increases. Then there's also that if the measurement changes, the results can become pretty bizarre. Say, you are on a diet for one month. At the start of the month, the kilo prototype weights 1 skg and at the end 1 ekg = 0.9 skg. You measure yourself at the start of the diet, and get that you weight 100 skg. You use some very precise diet-fu to draft a program that should see you losing 5 skg during the month. And lo and behold, you manage to stick to the program and loose exactly 5 skg. But at the end of the month, when you measure yourself against the now-lighter prototype, you get that you now weight 106 ekg. So, you actually achieved your target and lost 5 kilos, but meanwhile ended up with 6 kilos more body mass than before the diet! (Disclaimer: real changes in the prototype mass are of course way, way smaller.)
  - martin-adams 13y ago
    Ha, love it. I wonder if that's like receiving dividends on shares in a foreign currency. Your share value (weight in kg) changes over time due to currency fluctuations (lowering value of 1kg), but the dividends paid out (variable weight loss for a given time period) are also affected by the same currency fluctuations (lowering value of 1kg).
hughes 13y ago
If the kilo is getting lighter, it means that your mass in kilograms is going up! Better hit that treadmill before the meter starts shrinking and you need to run farther.
- Hellenion 13y ago
  "I'm not getting heavier, the kilo is getting lighter!"
thejosh 13y ago
it's a joke.
- wpietri 13y ago
  Jokes are funnier when they reveal truth rather than cause confusion. See Halpern & Close's Truth in Comedy.
  - meepmorp 13y ago
    Have you ever been diagnosed with an autism spectrum disorder? Serious question, not intended to offend.
    - jholman 13y ago
      Have you? Semi-serious question, genuinely not intended to offend. It's perfectly reasonable to have the opinion that wpietri advanced, and it's perfectly reasonable to raise it in this context. One could believe that for aesthetic reasons, or for political reasons, or other reasons, or a combination thereof. And I suggest that it's a higher caliber of comment than the mean HN comment, given that it suggests a source for deeper study of the commenter's opinion. On the other hand, attempting to (tentatively) diagnose psychiatric disorders based on a single sentence on HN is completely implausible, totally insensitive (to actually ASD sufferers, I mean.. I'm sure wpietri can take it), totally oblivious to social context, and suggests that you might have a "stereotyped pattern of behaviour or interest". Unless, of course, you have professional qualifications for such a (tentative) diagnosis, in which case I take it back.
    - wpietri 13y ago
      You're some random anonymous guy on the internet asking a public and very personal question about somebody's mental health with no obvious context, no sense that some people might consider that a sensitive topic, and apparently no awareness that doing so looks like you're calling them clueless. You do all this while claiming to be asking a serious question. (Rather than, say, emailing me.) And you're wondering if I have have problems functioning in society? The headline writer for the original article put in a joke. Xentronium, correctly, pointed out he appeared to get the joke backwards. Somebody else said, "it's just a joke", which is a thoughtless thing to say when you're trying to analyze why a joke does or doesn't work. If there's anywhere it's reasonable to nerd out on a nerdy joke, it's here. So I pointed out a great source, written by experts in funny, explaining why getting to truth really matters in comedy. I am unable to fathom why you think that's a sign of a social disorder, let alone sufficient license to act like a dick.
ISL 13y ago
For dieters, you're entirely correct. A lighter kilo makes the dieter have a greater mass when measured in kilograms. > Besides, can't they recreate a "canonical kilo" with the required measurements? This is the main point of the drive to redefine the kilogram. Right now, the IPK (the French kilogram) is the SI standard for the kilogram. Groups are working hard to redefine the kilo in terms of either Planck's constant or the Avogadro number. In order to do so, the experiments that measure one of those fundamental constants must be more reliable than the IPK. They're very close, but absolute mass measurements of the required precision at the kilogram scale have never been done before.
- tedks 13y ago
  Why not do it for a gram and just multiply?
  - emhs 13y ago
    Because that maintains the imprecision. Multiplying won't somehow scale the precision up as you go. It will in fact magnify the imprecision.
    - tedks 13y ago
      I was under the impression that precise measurements could be made at a smaller scale, but apparently that isn't the case.
  - ilyanep 13y ago
    I don't think the problem is that we can't get anything that big to be precise, but rather that we just don't have any mass experiments that are precise enough period. If you look at the definition of a second, you can see that scientists aren't squeamish at all about multiplying things.
  - ISL 13y ago
    Because the SI specifies the kilogram as the base unit of mass. If you want to generate a kilogram to a certain precision (say, a part in 10^8) as a sum of a thousand well-measured grams, the grams need to be measured sqrt(1000) better (about a factor of 30). If you could multiply, you're fine, but since you're required to make (or measure) an actual kilo, you have to sum. If we were to accept the multiplication method, it would be equivalent to restandardizing the SI upon the gram. That would be an okay thing to do, but to maintain continuity with past measurements (referenced to the IPK), we'd still have to make or measure an actual kilo, requiring precision sufficient to do the sum.

martin-adams 13y ago

It's because dieters measure their progress in kilos lost. So if it's lighter, they can lose more kilos for the same effort.

ewzimm 13y ago
Those dieters who measure fifty millionths of a gram in weight loss have bigger problems.
- solistice 13y ago
  For example the incredibly devastating fluctuations due to shedding of skin and subsequent gains due to snowflakes.
  - ewzimm 13y ago
    I refuse to go outside because I'll get fat.
vesinisa 13y ago
Valid point, but your starting mass also increases. Then there's also that if the measurement changes, the results can become pretty bizarre. Say, you are on a diet for one month. At the start of the month, the kilo prototype weights 1 skg and at the end 1 ekg = 0.9 skg. You measure yourself at the start of the diet, and get that you weight 100 skg. You use some very precise diet-fu to draft a program that should see you losing 5 skg during the month. And lo and behold, you manage to stick to the program and loose exactly 5 skg. But at the end of the month, when you measure yourself against the now-lighter prototype, you get that you now weight 106 ekg. So, you actually achieved your target and lost 5 kilos, but meanwhile ended up with 6 kilos more body mass than before the diet! (Disclaimer: real changes in the prototype mass are of course way, way smaller.)
- martin-adams 13y ago
  Ha, love it. I wonder if that's like receiving dividends on shares in a foreign currency. Your share value (weight in kg) changes over time due to currency fluctuations (lowering value of 1kg), but the dividends paid out (variable weight loss for a given time period) are also affected by the same currency fluctuations (lowering value of 1kg).

hughes 13y ago

If the kilo is getting lighter, it means that your mass in kilograms is going up! Better hit that treadmill before the meter starts shrinking and you need to run farther.

Hellenion 13y ago
"I'm not getting heavier, the kilo is getting lighter!"

thejosh 13y ago

it's a joke.

wpietri 13y ago
Jokes are funnier when they reveal truth rather than cause confusion. See Halpern & Close's Truth in Comedy.
- meepmorp 13y ago
  Have you ever been diagnosed with an autism spectrum disorder? Serious question, not intended to offend.
  - jholman 13y ago
    Have you? Semi-serious question, genuinely not intended to offend. It's perfectly reasonable to have the opinion that wpietri advanced, and it's perfectly reasonable to raise it in this context. One could believe that for aesthetic reasons, or for political reasons, or other reasons, or a combination thereof. And I suggest that it's a higher caliber of comment than the mean HN comment, given that it suggests a source for deeper study of the commenter's opinion. On the other hand, attempting to (tentatively) diagnose psychiatric disorders based on a single sentence on HN is completely implausible, totally insensitive (to actually ASD sufferers, I mean.. I'm sure wpietri can take it), totally oblivious to social context, and suggests that you might have a "stereotyped pattern of behaviour or interest". Unless, of course, you have professional qualifications for such a (tentative) diagnosis, in which case I take it back.
  - wpietri 13y ago
    You're some random anonymous guy on the internet asking a public and very personal question about somebody's mental health with no obvious context, no sense that some people might consider that a sensitive topic, and apparently no awareness that doing so looks like you're calling them clueless. You do all this while claiming to be asking a serious question. (Rather than, say, emailing me.) And you're wondering if I have have problems functioning in society? The headline writer for the original article put in a joke. Xentronium, correctly, pointed out he appeared to get the joke backwards. Somebody else said, "it's just a joke", which is a thoughtless thing to say when you're trying to analyze why a joke does or doesn't work. If there's anywhere it's reasonable to nerd out on a nerdy joke, it's here. So I pointed out a great source, written by experts in funny, explaining why getting to truth really matters in comedy. I am unable to fathom why you think that's a sign of a social disorder, let alone sufficient license to act like a dick.

ISL 13y ago

For dieters, you're entirely correct. A lighter kilo makes the dieter have a greater mass when measured in kilograms. > Besides, can't they recreate a "canonical kilo" with the required measurements? This is the main point of the drive to redefine the kilogram. Right now, the IPK (the French kilogram) is the SI standard for the kilogram. Groups are working hard to redefine the kilo in terms of either Planck's constant or the Avogadro number. In order to do so, the experiments that measure one of those fundamental constants must be more reliable than the IPK. They're very close, but absolute mass measurements of the required precision at the kilogram scale have never been done before.

tedks 13y ago
Why not do it for a gram and just multiply?
- emhs 13y ago
  Because that maintains the imprecision. Multiplying won't somehow scale the precision up as you go. It will in fact magnify the imprecision.
  - tedks 13y ago
    I was under the impression that precise measurements could be made at a smaller scale, but apparently that isn't the case.
- ilyanep 13y ago
  I don't think the problem is that we can't get anything that big to be precise, but rather that we just don't have any mass experiments that are precise enough period. If you look at the definition of a second, you can see that scientists aren't squeamish at all about multiplying things.
- ISL 13y ago
  Because the SI specifies the kilogram as the base unit of mass. If you want to generate a kilogram to a certain precision (say, a part in 10^8) as a sum of a thousand well-measured grams, the grams need to be measured sqrt(1000) better (about a factor of 30). If you could multiply, you're fine, but since you're required to make (or measure) an actual kilo, you have to sum. If we were to accept the multiplication method, it would be equivalent to restandardizing the SI upon the gram. That would be an okay thing to do, but to maintain continuity with past measurements (referenced to the IPK), we'd still have to make or measure an actual kilo, requiring precision sufficient to do the sum.