Author Topic: The Kilogram....Huh?  (Read 1622 times)

Offline fartymarty

  • Sr. Member
  • ****
  • Posts: 1492
  • Country: us
  • COG#9712 '10 ABS
The Kilogram....Huh?
« on: November 17, 2018, 11:48:41 am »
https://www.vox.com/science-and-health/2018/11/14/18072368/kilogram-kibble-redefine-weight-science

Huh?  ???

OK, in theory, I sorta-kinda understand it. (definition of what a kilogram is)

In practicality, not so much. (How the accuracy of many machines located around the world can all be the same or at least more accurate than simple blobs of metal made as much as possible to be identical to a kilogram)
It seems that the whole premise of practicality is based on the Kibble balance.
How is the precision of my Kibble balance vs. someone else's Kibble balance different (it's certainly a lot more complicated) than the difference of my 1 Kg. weight vs the one stored and locked up  in France?

Conrad? Brian? Anybody?

Offline MAN OF BLUES

  • Arena
  • Sr. Member
  • ****
  • Posts: 2639
  • Country: 00
  • WHISKEY.Tango.Foxtrot.
Re: The Kilogram....Huh?
« Reply #1 on: November 17, 2018, 02:53:48 pm »
 :rotflmao: :rotflmao: :rotflmao: :rotflmao:

been smokin' the good stuff there Marty? Puffin' the Magic Dragon?

go into McDonald's and order a Royale with Cheese... everything will be fine...



stay away from Burger King....

30 YEARS OF KAW.....

Offline B.D.F.

  • Hero Member
  • *****
  • Posts: 4766
  • Country: 00
  • It's only really cold if you fall down in it.
    • C-14 farkles you almost cannot ride without.
Re: The Kilogram....Huh?
« Reply #2 on: November 17, 2018, 03:05:21 pm »
Technical explanation follows; I have simplified it as much as possible but it cannot be made 'second- grade simple', at least now with my abilities. If one is not really interested in the subject, just skip it- no need to post 'my brane hurts'. :-)


There are very few fundamental units of measure, most things we think of as a base unit is actually not- the simple example is length, area and volume. All <seem> to be direct units but in reality, only length is a basic measurement and the other two are length squared and length cubed. Same thing with velocity or speed, almost all volume measurements, etc., etc.

What we have been using as a 'base measurement' of mass (gram or kilogram) is actually not and worse yet, it is not even linked to any base measurement. It is just a chunk of a material that someone picked out and said 'That is one kilogram'. But how can you define it? How can you make another one? And the idea of using a balance and merely saying that you have another that is the same as the one someone picked (at random) is also really useless. Just like length: it used to be defined by a platinum bar that was exactly one meter long, simply because someone picked that out and so named it "THE meter". But how can that be duplicated anywhere else, by anyone, at any time? It cannot. So the new and much better definition of length is now a certain number of wavelengths of light from the element Krypton 86. Light wavelengths are governed by frequency, which is generated by the exact number of electron orbits that an electron moves- a fundamental thing in our universe that is not changeable: a quanta. This is a bit complex but basically electrons have specific orbits they MUST occupy and while they can change orbits, they MUST go from one very specific one to another very specific one- this is the basis of Plank's constant and 'quanta': energy cannot be created in any amount, it comes only in specific amounts which are ALWAYS increments of quanta (Plank's constant).

So to define mass, they have chosen to use a specific number of atoms of a known and pure material and call that specific amount a gram. Anyone, anywhere, anytime can duplicate EXACTLY that amount of EXACTLY that material and so therefore, it is now a unit 'standardized' by physics, rather than 'some guy' saying 'this magic block is exactly..... whatever'.

Think of it this way: when we say one quart of water, that is not a 'real' definition because it depends on the ambient pressure, the temperature and a couple of other variables. Which is why a milk (almost all water) container left outside breaks when it freezes: because the original liquid quart is smaller than the now frozen quart. So which is the correct one? Neither, and it is not a binary scale either because it varies in volume even when it is in one state (say, liquid). A much better way to define a quart of milk would be to count the number of atoms of all the elements that make up milk and state it: <this> many atoms of water, <this> many atoms of [fat #1], <this> many atoms of [fat #2], <this> many atoms of plutonium oxide dust from Chernobyl, etc., etc. until it is fully defined. But an even better way would be to choose only one element, than count out a specific number of those atoms and viola! we can call that a 'quart' if we want. And it will still be a quart on the moon, still be a quart at 1/2 the speed of light, still be a quart at 1,000,000 PSI and so on although it may or may not fit in your "quart" milk bottle 'cause your milk bottle never was an actual measurement.

Brian

https://www.vox.com/science-and-health/2018/11/14/18072368/kilogram-kibble-redefine-weight-science

Huh?  ???

OK, in theory, I sorta-kinda understand it. (definition of what a kilogram is)

In practicality, not so much. (How the accuracy of many machines located around the world can all be the same or at least more accurate than simple blobs of metal made as much as possible to be identical to a kilogram)
It seems that the whole premise of practicality is based on the Kibble balance.
How is the precision of my Kibble balance vs. someone else's Kibble balance different (it's certainly a lot more complicated) than the difference of my 1 Kg. weight vs the one stored and locked up  in France?

Conrad? Brian? Anybody?
Homo Sapiens Sapiens and just a tad of Neanderthal but it usually does not show....  My Private mail is blocked; it is not you, it is me, just like that dating partner said all those years ago. Please send an e-mail if you want to contact me privately.

KiPass keeping you up at night? Fuel gauge warning burning your retinas? Get unlimited peace and harmony here: www.incontrolne.com

Offline MAN OF BLUES

  • Arena
  • Sr. Member
  • ****
  • Posts: 2639
  • Country: 00
  • WHISKEY.Tango.Foxtrot.
Re: The Kilogram....Huh?
« Reply #3 on: November 17, 2018, 03:13:06 pm »
It’s the mass of a hunk of platinum-iridium alloy .... mmmmmm ok......

Platinum 

Atomic Weight       195.084
Density       21.45 g/cm3
Melting Point       1768.3 °C
Boiling Point       3825 °C

Iridium

Atomic Weight       192.217
Density       22.56 g/cm3
Melting Point       2466 °C
Boiling Point       4428 °C

Osmium

Atomic Weight       190.23
Density       22.59 g/cm3
Melting Point       3033 °C
Boiling Point       5012 °C

sooooo... who chose the alloy composition, and why?

why wouldn't an alloy of 2 closer atomic weights and density not have been used? like Osmium/Iridium ?

when electrons are whirling around, does mass change? how does the molecular activity of the alloy come into the equation?








« Last Edit: November 17, 2018, 04:08:03 pm by MAN OF BLUES »

30 YEARS OF KAW.....

Offline fartymarty

  • Sr. Member
  • ****
  • Posts: 1492
  • Country: us
  • COG#9712 '10 ABS
Re: The Kilogram....Huh?
« Reply #4 on: November 17, 2018, 06:56:10 pm »
Technical explanation follows; I have simplified it as much as possible but it cannot be made 'second- grade simple', ........

OUCH! Well OK, maybe I deserved that... ;D

However, and perhaps here is where I reveal my only 1st grade reasoning ability, if I understood your explanation Brian (and I'm not saying I did) isn't your explanation really about the theory part (the part I thought I understood) and not the practicality part? I understand that now it is well defined instead of being only related to a locked up master lump (Big K) of whatever, but is the actual measurement any more "system wide" accurate since it depends on these various devices (Kimble balance) around the world (or universe if preferred) with no doubt at least microscopic differences all coming to the same conclusion? How do I know that the results of my Kimble balance (compared to the master Kimble balance) are any more accurate than my copy of the sequestered and protected lump of whatever?
I guess what I'm asking is, OK we (they) have cleaned up the system from comparison to an arbitrary lump (that may be changing) to something that is measurable and constant, but from a practical standpoint have we made anything more accurate in the real world near term to today?  Let's say that I go into business making Kimble (Watt) balances, will my quality control people be checking for accuracy by weighing a lump of something that was copied from another lump that was weighed by the Master Kimble balance?

Video of interest: https://youtu.be/ewQkE8t0xgQ

been smokin' the good stuff there Marty? Puffin' the Magic Dragon?

 :) No not yet, but I'm thinking of starting just as soon as I can be sure I'm getting a real Kilogram of it for my money.
 

Offline B.D.F.

  • Hero Member
  • *****
  • Posts: 4766
  • Country: 00
  • It's only really cold if you fall down in it.
    • C-14 farkles you almost cannot ride without.
Re: The Kilogram....Huh?
« Reply #5 on: November 17, 2018, 08:39:49 pm »
Well first of all Marty, that 'second- grade simple' was not an insult or barb to anyone, including you. I was merely stating that I had simplified it as much as my own understanding and education allows; it may be well that someone else (or many others) could explain it in much simpler terms because they understand it on a more fundamental level in the first place. Or, as the old axiom goes 'if you need to use mathematics to explain it, then you do not really understand how it works yourself'. :-)  I believe others can / could explain it better and in simpler terms than I can. So my intent was not to belittle anyone, other than myself of course.

To be honest, I did not pay much (OK, any) attention to the Kimble balance because that is merely a mechanism; I was concentrating on the fundamental idea of calling something, anything, a 'master' and qualifier and then comparing everything else to it vs. having an honest, direct way to measure something that can be duplicated anywhere, anytime and in any condition (such as we know and understand 'conditions'). But I will go back and take a look at that part of your link and see if I can follow along (no guarantees on that one- you can only get what I can give and more than a few times, that just ain't enough.....).

As to the other part, getting your money's worth of Puffin stuff, well that too is a moving target 'cause what defines the value of a dollar, uhm? That is a can 'o worms all in and of itself. :-)

There is a thing out there called 'impedance matching' which I have always found to be pretty complicated and difficult to explain. Then one day, this really sharp fellow I knew (a professor of mine actually) gave the bets explanation I have heard since and it was dirt- simple: he said that land animals need a high impedance mechanism to travel, and our bodies are designed for this high impedance.... we push against the Earth using large muscles to move relatively large mass (our entire bodies). Water is a low impedance medium and sea creatures have evolved to use that medium to travel. But land creatures are really inefficient in water because we are treating water (low impedance) material by using our limbs (high impedance implements) to propel ourselves. And impedance matching device for this problem is..... swimming or diving fins! It allows our big muscles to push against what we now find to be a high impedance material (all the water that the fins are trying to displace, just like fish fins). So you can either get into the water and kick and paddle with your arms like crazy to move relatively slowly or you can put on fins, 'match' the impedance, and make efficient use of 1) our muscles and their abilities in the 2) "wrong" environment but it is a lot less wrong with fins on.

Brian

OUCH! Well OK, maybe I deserved that... ;D

However, and perhaps here is where I reveal my only 1st grade reasoning ability, if I understood your explanation Brian (and I'm not saying I did) isn't your explanation really about the theory part (the part I thought I understood) and not the practicality part? I understand that now it is well defined instead of being only related to a locked up master lump (Big K) of whatever, but is the actual measurement any more "system wide" accurate since it depends on these various devices (Kimble balance) around the world (or universe if preferred) with no doubt at least microscopic differences all coming to the same conclusion? How do I know that the results of my Kimble balance (compared to the master Kimble balance) are any more accurate than my copy of the sequestered and protected lump of whatever?
I guess what I'm asking is, OK we (they) have cleaned up the system from comparison to an arbitrary lump (that may be changing) to something that is measurable and constant, but from a practical standpoint have we made anything more accurate in the real world near term to today?  Let's say that I go into business making Kimble (Watt) balances, will my quality control people be checking for accuracy by weighing a lump of something that was copied from another lump that was weighed by the Master Kimble balance?

Video of interest: https://youtu.be/ewQkE8t0xgQ
 
 :) No not yet, but I'm thinking of starting just as soon as I can be sure I'm getting a real Kilogram of it for my money.
 
Homo Sapiens Sapiens and just a tad of Neanderthal but it usually does not show....  My Private mail is blocked; it is not you, it is me, just like that dating partner said all those years ago. Please send an e-mail if you want to contact me privately.

KiPass keeping you up at night? Fuel gauge warning burning your retinas? Get unlimited peace and harmony here: www.incontrolne.com

Offline maxtog

  • Elite Member
  • ******
  • Posts: 7993
  • Country: us
  • 2011 Silver
Re: The Kilogram....Huh?
« Reply #6 on: November 17, 2018, 09:31:05 pm »
The issue isn't as much with day-to-day measurements.  For that, a lump of metal is probably "good enough" for just about anything.  The problem is when things start getting really small and exact and also theoretical science/physics.  Micrograms, nanograms, picograms, etc.... the error inherent in any "official" lump of mass will start looking larger and larger as you get smaller and smaller.  Exactness starts to really "matter" (pun intended).  :)  Basing mass on something "fixed" in nature/physics means it is universal, never changes, and will have zero error; just that simple.
Shoodaben (was Guhl) Mountain Runner ECU flash, Canyon Cages front/rear, Helibars risers, Phil's wedges, Grip Puppies, Sargent World seat-low & heated & pod, Muzzy lowering links, Soupy's stand, Nautilus air horn, Admore lightbar, Ronnie's highway pegs, front running lights, all LED, helmet locks, RAM Xgrip, Sena SMH10, Throttle Tamer, MRA X-Creen, PR4-GT, Scorpion EXO-T1200,  Tourmaster Flex II

Offline B.D.F.

  • Hero Member
  • *****
  • Posts: 4766
  • Country: 00
  • It's only really cold if you fall down in it.
    • C-14 farkles you almost cannot ride without.
Re: The Kilogram....Huh?
« Reply #7 on: November 18, 2018, 01:59:13 pm »
OK, had a few moments and read up on the Kibble balance. It really IS a simple concept, just that it gets cluttered up with all the mechanics around it that cancel each other out leaving only Plank's constant and a portion of mass to compare it to (the mass).

What they are doing is comparing force with mass because the force can be and is defined by nature, again Plank's constant. The actual machine is just there to compensate and remove all the other factors, such as gravity (which is a variable even at different places on Earth), any motion (everything is moving in many directions at one time: the Earth rotates, it revolves around the Sun, the Sun revolves around the center of our galaxy- it really does get complex as to exactly how fast we (everything on the planet) is moving and in what direction.... which is also constantly changing), temperature and all the other variables that we not only do not care about but must be eliminated so that we can actually isolate force and then compare / convert it to mass.

Maybe one way to think of it is like a pendulum used to meter time (think Grandfather clock). There is a long formula to figure out the time period of any pendulum's time cycle but in the end, everything falls out and the only thing left is the length of the pendulum- that is the one single variable that governs how fast a pendulum goes through one cycle. But there are problems in the real world using them, one of which is the expansion and contraction of the material the pendulum is made out of. This defeated humans for decades, centuries until a very clever fellow named Harris came along in the 18th century and figured out a way to make the rod of a pendulum the same length regardless of temperature. When looking at this apparatus, it seems pretty complicated but really it is not. At any rate, concentrating on the temperature compensation is not the important thing to know- understanding that only the length of the pendulum is. So what a Kibble balance is doing is negating all the outside inputs that cause a change in force, and once they are eliminated, the only thing left is force, which is directly compared with mass (and as the force is known, the mass becomes known also).

I did not even try to work through the formulas given, again that is not the real point of the whole thing.

An easier comparison is something else they mentioned, light interferometry. It starts off seeming to be extremely complicated but really it is quite simple: as the frequency (color) of the light is known, the distance between peaks is also known. What the interferometer does is align the peaks as the target is moved closer or further away; it is done with mirrors and the light is split- when the observable light is brightest, you are seeing two peaks aligned so you know it is an exact number of wavelengths away. This is an extremely accurate measurement but it is incremental, meaning you do not know HOW many wavelengths away the target is. The inelegant but effective way around that is to bring the target all the way to the source (less than one wavelength of light away) them move the target away while counting the light and dark bands. Never lose count of those bands and you will always know exactly where you are. This is done all the time on very inexpensive machine tools to determine where the spindle is relative to a 'home' position as designated by the machine's manufacturer.

Brian

OUCH! Well OK, maybe I deserved that... ;D

However, and perhaps here is where I reveal my only 1st grade reasoning ability, if I understood your explanation Brian (and I'm not saying I did) isn't your explanation really about the theory part (the part I thought I understood) and not the practicality part? I understand that now it is well defined instead of being only related to a locked up master lump (Big K) of whatever, but is the actual measurement any more "system wide" accurate since it depends on these various devices (Kimble balance) around the world (or universe if preferred) with no doubt at least microscopic differences all coming to the same conclusion? How do I know that the results of my Kimble balance (compared to the master Kimble balance) are any more accurate than my copy of the sequestered and protected lump of whatever?
I guess what I'm asking is, OK we (they) have cleaned up the system from comparison to an arbitrary lump (that may be changing) to something that is measurable and constant, but from a practical standpoint have we made anything more accurate in the real world near term to today?  Let's say that I go into business making Kimble (Watt) balances, will my quality control people be checking for accuracy by weighing a lump of something that was copied from another lump that was weighed by the Master Kimble balance?

Video of interest: https://youtu.be/ewQkE8t0xgQ
 
 :) No not yet, but I'm thinking of starting just as soon as I can be sure I'm getting a real Kilogram of it for my money.
 
Homo Sapiens Sapiens and just a tad of Neanderthal but it usually does not show....  My Private mail is blocked; it is not you, it is me, just like that dating partner said all those years ago. Please send an e-mail if you want to contact me privately.

KiPass keeping you up at night? Fuel gauge warning burning your retinas? Get unlimited peace and harmony here: www.incontrolne.com

Offline MAN OF BLUES

  • Arena
  • Sr. Member
  • ****
  • Posts: 2639
  • Country: 00
  • WHISKEY.Tango.Foxtrot.
Re: The Kilogram....Huh?
« Reply #8 on: November 18, 2018, 03:47:55 pm »
 :rotflmao: :goodpost: :doh:

we have jumped from weight, to time, then to distance, when we know by theory, Zeno says it can't be absolute, and an arrow, theoretically can never "reach" it's target...

so, in fact... "there is no spoon"

30 YEARS OF KAW.....

Offline Cholla

  • Arena
  • Full Member
  • ***
  • Posts: 361
Re: The Kilogram....Huh?
« Reply #9 on: November 19, 2018, 11:33:04 am »
I don't know much about weights, but I do know this [  ] is six inches.....
Beware the Black Widows...Feared throughout the land!

Offline fartymarty

  • Sr. Member
  • ****
  • Posts: 1492
  • Country: us
  • COG#9712 '10 ABS
Re: The Kilogram....Huh?
« Reply #10 on: November 19, 2018, 11:36:50 am »
Well first of all Marty, that 'second- grade simple' was not an insult or barb to anyone, including you.

Yeah, sometimes my humor goes un-noticed, or should I say it becomes repurposed into seriousness. Kind of like when your best stuff wasn't having any effect on your Doctor. More personally, a "My name isn't Hanz." type of reaction. The shoe did sort of fit me so I tried to wear it for humor. I tried this once before and it failed (humor) then too, but I'm too lazy to search for it...in a many years ago posting. So to be clear now, I was just kidding and took no offense. Kind of playing with how some can take things one way and they (on the internet mostly) take it one of the ways most likely to cause themselves offense.

Anyway let's move on. So I think my question about practicality is answered. A Kimble balance sounds expensive and if it's man made (same as a pendulum) then it's ability to microscopically cancel opposites out perfectly is suspect. For instance even a pendulum can have more bearing resistance when swinging on one side of straight down that isn't equal to the resistance of the other side. So, no real practical improvement, at least that's the conclusion I have come to until I read or find out otherwise

So getting back to theory. There is something that they didn't mention or perhaps I missed. The gram. The gram was defined as the weight of one cubic centimeter of water held at 4 degrees C, right? And a Kilogram was defined by a mass of something that was 1000X the weight of a gram, or as close as they could get. Now that a kilogram is defined by a constant, (or in practicality, by a master man made machine designed to measure that constant) is a gram now defined as 1/1000th of that result or is it still defined by the weight of a certain volume of water at a specific temperature?

Offline maxtog

  • Elite Member
  • ******
  • Posts: 7993
  • Country: us
  • 2011 Silver
Re: The Kilogram....Huh?
« Reply #11 on: November 19, 2018, 03:26:24 pm »
:)
Shoodaben (was Guhl) Mountain Runner ECU flash, Canyon Cages front/rear, Helibars risers, Phil's wedges, Grip Puppies, Sargent World seat-low & heated & pod, Muzzy lowering links, Soupy's stand, Nautilus air horn, Admore lightbar, Ronnie's highway pegs, front running lights, all LED, helmet locks, RAM Xgrip, Sena SMH10, Throttle Tamer, MRA X-Creen, PR4-GT, Scorpion EXO-T1200,  Tourmaster Flex II

Offline MAN OF BLUES

  • Arena
  • Sr. Member
  • ****
  • Posts: 2639
  • Country: 00
  • WHISKEY.Tango.Foxtrot.
Re: The Kilogram....Huh?
« Reply #12 on: November 19, 2018, 04:51:08 pm »
I'm still awaiting the scholarly answers to post number 3....

so, that still is a conundrum..
I could spend a half hour typing stuff on my nook screen, but  I won't,
basically now we have a "Kilogram" in the ol' K machine, and by precedence, a gram is defined by 1/1000th of that "slug"... whereby all sorts of tolerance can accumulate, as you can't make 1000 identical objects.. and divide said "slug into 1000 pieces without matter loss.. and then total them against the master "kilo" slug... if you did, and took half them away at random, there would be an induced error.. maybe not "measurable" but still it would exist...

that's what I hate about "quantum anything", as far a physics goes..
 and it's all based on some dude spittin' on a scale, centuries ago, and saying "dat's a gram" from here forward...


30 YEARS OF KAW.....

Offline B.D.F.

  • Hero Member
  • *****
  • Posts: 4766
  • Country: 00
  • It's only really cold if you fall down in it.
    • C-14 farkles you almost cannot ride without.
Re: The Kilogram....Huh?
« Reply #13 on: November 19, 2018, 06:10:47 pm »
Yep, I missed the humor. ?? Hey, it happens..... Yes, there is a relationship between volume (of water) and mass but that is just a happy (but planned) coincidence. It does not define the unit of mass, it merely 'links' it with volume in a clever, and sometimes useful way. And hey, it is certainly a better link thank, say, "furlongs per fortnight" is for measuring speed.

I <think> you are missing the point of what NIST has done here regarding mass. Mass is a fundamental unit of measurement that cannot depend on being compared with anything else that is not fundamental..... and that lump of stuff in France is NOT a fundamental unit in physics :-) The point of the balance is that it allows a way to define a basic unit, in this case mass, with another fundamental unit, in this case force. This is the key: no matter where (or perhaps even when) you are in the universe, you can always grab a handful of quantifiable force. So the objective becomes to define ALL fundamental units based on at least one of the other, defined and quantifiable units.

So how about a practical example: suppose you find yourself visiting the city of Hemorrhoid on the planet Uranus and you want to weight a rock (or at least what you truly and deeply is a 'rock' that you just found in Uranus). But you do not have that pesky piece of French 'stuff' that you know weighs a kilogram (well, it <masses> a kilogram, weighs a Newton but let's not make this problem we have in Hemorrhoid any worse than it already is). What to do, what to do? You can measure the lump of 'stuff' you have but then you would have to know its density and that is most certainly NOT a fundamental unit of any kind. In fact that is multiple <not> fundamental units. What to do. I know- what if there was a standard fundamental force that you could compare, using some kind of machine or formula or other duplicate method, which ALWAYS works because it is a CONSTANT, and then derive your unit(s) of mass? Hey, that would work. But comparing differing units is often impossible, for example, how many gallons in a foot? See? What we need is some key that we can use to 'jump categories' and directly compare fundamental units of.... well, stuff. Why just a few weeks or months ago this would have been impossible but in today's mail, we find a flyer for how to build your very own Kibble balance, which will allow YOU (read: anyone, anywhere, anytime) to compare Force to Mass directly. Now as force is a fundamental unit, you can grab yourself a "pound" of force, or better yet a 'metric pound, or Newton (the SI unit of force..... in the English system it is really 'Slugs' (really) but we cheat and use the world Pound and just put a little 'f' to indicate we mean pound, force, not pound, weight), and compare it with your 'thing' from Uranus and you will know EXACTLY how much mass it has! You may not be sure what it is but at least you know how much of it you have (kinda' like being in the chit or in deep chit- big difference!). And even better yet, you can show all of the local Hemorrhoids just how to measure their own 'stuff' regarding mass with nothing other than force, which they too will have in abundance (though I understand some Hemorrhoids are more forceful then others but again, I digress).

So like when the Ancient Greeks (who may or may not have known about Hemorrhoidians) discovered Pi, the point was not how accurately they could calculate it nor how fast, and it did not matter what units they expressed it in (degrees, radians, quadrants). The point is that they discovered a fundamental relationship between a circle's circumference and its radius: there are always, exactly, two Pi radians in the circumference of each circle, and Pi is the 'tool' we have to convert one to the other. Same thing with measuring length with light- light is the constant of the universe and so can be directly linked to length, meaning length then becomes a fundamental unit in and of itself.

As far as friction of the pendulum used to measure time, I would not worry too much about that.... time is NOT a constant anyway so it becomes a trivial measurement. Unless, of course, you happen to be waiting for a public stall to open up on Uranus.... then it could become critical. But still not a constant.

Brian (for homework, see if you can determine how many ergs of energy it took me to type all of that foolishness......)

P.S. Thermal expansion is measured in units of length (of expansion) per units of length per units of temperature change (inches per inch per degree change in temp. or Delta T). This one time, at banned camp, I gave an answer to a thermal expansion question in these units: inches, inches, degrees Centigrade. It was marked wrong but it was not wrong; it was merely me amusing myself and hopefully, those who read it. Not so much to the Professor who marked it wrong and then corrected my grade..... although begrudgingly. We agreed that 1) it was a correct answer. 2) it was in 'bad taste' to state it that way (mixing English and SI units in one expression, technically correct but NOT NORMALLY DONE or, in this case, well received). 3) One of us found it amusing......

Yeah, sometimes my humor goes un-noticed, or should I say it becomes repurposed into seriousness. Kind of like when your best stuff wasn't having any effect on your Doctor. More personally, a "My name isn't Hanz." type of reaction. The shoe did sort of fit me so I tried to wear it for humor. I tried this once before and it failed (humor) then too, but I'm too lazy to search for it...in a many years ago posting. So to be clear now, I was just kidding and took no offense. Kind of playing with how some can take things one way and they (on the internet mostly) take it one of the ways most likely to cause themselves offense.

Anyway let's move on. So I think my question about practicality is answered. A Kimble balance sounds expensive and if it's man made (same as a pendulum) then it's ability to microscopically cancel opposites out perfectly is suspect. For instance even a pendulum can have more bearing resistance when swinging on one side of straight down that isn't equal to the resistance of the other side. So, no real practical improvement, at least that's the conclusion I have come to until I read or find out otherwise

So getting back to theory. There is something that they didn't mention or perhaps I missed. The gram. The gram was defined as the weight of one cubic centimeter of water held at 4 degrees C, right? And a Kilogram was defined by a mass of something that was 1000X the weight of a gram, or as close as they could get. Now that a kilogram is defined by a constant, (or in practicality, by a master man made machine designed to measure that constant) is a gram now defined as 1/1000th of that result or is it still defined by the weight of a certain volume of water at a specific temperature?
Homo Sapiens Sapiens and just a tad of Neanderthal but it usually does not show....  My Private mail is blocked; it is not you, it is me, just like that dating partner said all those years ago. Please send an e-mail if you want to contact me privately.

KiPass keeping you up at night? Fuel gauge warning burning your retinas? Get unlimited peace and harmony here: www.incontrolne.com

Offline B.D.F.

  • Hero Member
  • *****
  • Posts: 4766
  • Country: 00
  • It's only really cold if you fall down in it.
    • C-14 farkles you almost cannot ride without.
Re: The Kilogram....Huh?
« Reply #14 on: November 19, 2018, 06:18:55 pm »
I am exhausted from typing a long answer, all the way from Hemmeroid, to Marty.

But I believe you are incorrect in that a 'gram' is a variable unit. It is a made- up unit to be sure, but it is fundamental and constant anywhere in what we perceive as the universe. One o' dem- dare natural laws that govern the place. Mass. Force. Speed of light. Stuff that cannot be changed. Well, kinda', mostly and within certain parameters at least.  :rotflmao:  Remember, the faster you go, the more you mass (often incorrectly stated as 'weigh') and the shorter you are until you hit the speed limit, where you have infinite mass and no length. But force, lots and lots of force.... if only you could get there. But hey, maybe we can get there- think African- American void (I want to be politically correct here so as not to have the forces of FaceTwit align against me).

Brian

I'm still awaiting the scholarly answers to post number 3....

so, that still is a conundrum..
I could spend a half hour typing stuff on my nook screen, but  I won't,
basically now we have a "Kilogram" in the ol' K machine, and by precedence, a gram is defined by 1/1000th of that "slug"... whereby all sorts of tolerance can accumulate, as you can't make 1000 identical objects.. and divide said "slug into 1000 pieces without matter loss.. and then total them against the master "kilo" slug... if you did, and took half them away at random, there would be an induced error.. maybe not "measurable" but still it would exist...

that's what I hate about "quantum anything", as far a physics goes..
 and it's all based on some dude spittin' on a scale, centuries ago, and saying "dat's a gram" from here forward...
Homo Sapiens Sapiens and just a tad of Neanderthal but it usually does not show....  My Private mail is blocked; it is not you, it is me, just like that dating partner said all those years ago. Please send an e-mail if you want to contact me privately.

KiPass keeping you up at night? Fuel gauge warning burning your retinas? Get unlimited peace and harmony here: www.incontrolne.com