Metric system fading fast

[dogjones]

Check this out. (http://www.guardian.co.uk/science/2007/sep/13/1)

A 118-year-old cylinder that has been the international prototype for the metric mass, and kept under lock and key outside Paris, is mysteriously losing its weight - if ever so slightly.


Hypotheses?

[a_unique_person]

When you measure something, you change it. They have to regularly check it against the standard weights that are used in other countries.

[BlackKat]

http://www.guardian.co.uk/science/2007/sep/13/1
"Physicist Richard Davis of the International Bureau of Weights and Measures in Sévres, south-west of Paris, says the reference kilo appears to have lost 50 micrograms - roughly equivalent to the weight of a fingerprint - compared with the average of dozens of copies."

The low amount of mass lost plus the bolded above seems to make this loss not such a big deal does it not?

Such a small amount could be explained by handling and occassional (however short a time period) exposure.

[dogjones]

Hmmm, your argument has weight.

[madurobob]

Interesting - I never considered that there was a 'thing" out there that defined a Kilogram. But, as I think about it, I guess its necessary.

I don't think this is just a metric system issue though. I believe the pound is defined in terms of grams.. which are defined in terms of a kilogram. So, change the kilo and the change cascades through all of our mass measurements.

Could I hold the world hostage by stealing all the Kilo prototypes and threatening to destroy them, sending the world into measurement chaos? Hmm... sounds like another Austin Powers movie to me.

[Zep]

Is this what is known as (ahem) mass existing since long?

[brodski]

Is this what is known as (ahem) mass existing since long?

Well distributed?

[DouglasL]

[QUOTE=madurobob;2958728] I believe the pound is defined in terms of grams.. which are defined in terms of a kilogram. So, change the kilo and the change cascades through all of our mass measurements.



The pound (as a unit of measure) was around before the gram (or kilogram) so it was not defined in terms of grams originally. English units of measure (foot, yard, pound, etc.) were often defined by the king, using his foot for example, and often varied from place to place. This is before international standardization of course. Maybe someone knows when the English system was standardized? Thanks.

[madurobob]

The pound (as a unit of measure) was around before the gram (or kilogram) so it was not defined in terms of grams originally. English units of measure (foot, yard, pound, etc.) were often defined by the king, using his foot for example, and often varied from place to place. This is before international standardization of course. Maybe someone knows when the English system was standardized? Thanks.

Actually, here in the US we use the Avoirdupois measurements system - its French! http://en.wikipedia.org/wiki/Avoirdupois

In the avoirdupois system, all units are multiples or fractions of the pound, which is now defined as 0.45359237 kg in most of the English-speaking world since 1959

See that - the US pound is really based on the metric system's Kilo!

[Scazon]

50 micrograms in a kilogram is actually quite a lot, 1 part in 20 million, or 24 and a bit bits. Measurements are made to that resolution quite routinely these days, just try buying Parma ham. In fact, a 24 bit ADC costs less than £10 these days. (not saying you can get that ACCURACY quite so cheaply).

I suspect somebody has polished it sometime.

[Rob Lister]

The standard isn't losing mass, the copies are on average gaining mass -- by definition!

lol

[flimflam_machine]

I believe there is someone who, presumably as part of a wider job, has to take care of this standard kilo (which I think is a platinum cylinder?). Despite being kept inside several bell jars, it can gain mass from dust, grease etc. Apparently one of the people who used to hold this sacred position had no compunction in taking it out every now and then and giving it a bit of a clean (with a chamois leather IIRC). It was weighed
afterwards and it appeared that he had done it without causing any loss in mass, although I've no idea how.

ETA: Ahhhh platinum-iridium, pic here

http://www.rsc.org/chemistryworld/restricted/2006/September/MadeToMeasure.asp

[drkitten]

Interesting - I never considered that there was a 'thing" out there that defined a Kilogram. But, as I think about it, I guess its necessary.

It's not necessary, but fixing it is a major bear. There is currently a very expensive multinational project going on to fix the kilogram in terms of a specific number of atoms of specified composition (or equivalently, to define Avogadro's number exactly) which will implicitly define the kilogram exactly without reference to an artifact.

However, you can imagine the technical stuff that needs to go into this. I believe the current plan involves making a perfect and flawless crystal sphere of silicon (http://ieeexplore.ieee.org/Xplore/login.jsp?url=/iel5/6870/18483/00850937.pdf) (because we can make large, flaw-free silicon crystals more easily than we can make other types). Imagine trying to machine a six-inch sphere to be so smooth that there are no scratches on it larger than an atom....

[dogjones]

It's not necessary, but fixing it is a major bear. There is currently a very expensive multinational project going on to fix the kilogram in terms of a specific number of atoms of specified composition (or equivalently, to define Avogadro's number exactly) which will implicitly define the kilogram exactly without reference to an artifact.

However, you can imagine the technical stuff that needs to go into this. I believe the current plan involves making a perfect and flawless crystal sphere of silicon (http://ieeexplore.ieee.org/Xplore/login.jsp?url=/iel5/6870/18483/00850937.pdf) (because we can make large, flaw-free silicon crystals more easily than we can make other types). Imagine trying to machine a six-inch sphere to be so smooth that there are no scratches on it larger than an atom....

Cool, but wouldn't it be easier to define a gram, or even a microgram, in this manner and then extrapolate upwards to a kilogram?

[Old man]

Is this what is known as (ahem) mass existing since long?
Sounds more like a 'mass extinction', to me. :eek:

Really though, this -
compared with the average...
implies that some of the copies have 'gained' a little mass, while others have lost a little, with the average net change in the copies being positive.

Move on, folks. Nothing to see here.

[Spindrift]

So all of a sudden I now weigh more?

That's all I need, to be even more overweight.

[Yllanes]

Cool, but wouldn't it be easier to define a gram, or even a microgram, in this manner and then extrapolate upwards to a kilogram?

Probably what they are going to do. Anyway, the Gravity Probe B already ahs gyorscopes that are perfect spheres save for a few tens of atomic diameters. If the Earth were so perfect, Mount Everest would be 3 m high.

[Psi Baba]

http://www.guardian.co.uk/science/2007/sep/13/1
"Physicist Richard Davis of the International Bureau of Weights and Measures in Sévres, south-west of Paris, says the reference kilo appears to have lost 50 micrograms - roughly equivalent to the weight of a fingerprint
Perhaps there was a fingerprint on it and it evaporated.

[Lucifuge Rofocale]

BTW, when you, Americans, will get rid of the obsolete system you have?:D

[Garrette]

BTW, when you, Americans, will get rid of the obsolete system you have?:DWhen you pry it from our cold, dead fingers, of course.

[dogjones]

Probably what they are going to do.

Not according to Dr K's linked article:

Summary: Density measurements with relative uncertainty of 1×10-7 have been made on a highly polished 1 kg single crystal silicon sphere. The molar mass, crystal quality and lattice parameter have been measured elsewhere, enabling a determination of the Avogadro constant to be made. The purpose is to obtain a definition of the kilogram in terms of a specific number of 12C atoms

[drkitten]

Probably what they are going to do. Anyway, the Gravity Probe B already ahs gyorscopes that are perfect spheres save for a few tens of atomic diameters. If the Earth were so perfect, Mount Everest would be 3 m high.

I think it makes more sense to try to define the kilogram directly, simply because the errors of measurement will be less.

Think about it. A 1kg sphere is about six inches across (fifteen cm for you civilized types). A 1g sphere is about six-tenths of an inch across. A 1mg sphere is about six hundredths of an inch across, and a 1ug sphere is about six thousandths of an inch across. The "few tens of atomic diameters" of imperfection is a thousand times more significant an error on the 1ug sphere. What they would really like to do, I suspect, would be to make a 60-inch sphere that weighed a metric tonne, but they don't have the fabrication or machining capacity....

[dogjones]

I see what you mean. Balls.

[JoeTheJuggler]

Hmmm, your argument has weight.

Don't make light of it. It's a matter of some gravity.

[neutrino_cannon]

Alright math people, what if it's undergoing radioactive decay? The thing is platinum/iridium right? Surely those have some radioactive isotopes.

Not sure if that's good enough to account for the observed loss, however.

[l0rca]

The way it's worded, the media would have us think that as a human race, we were stupid enough to have only one reference.

We're not that dumb, right?

[Zep]

When you pry it from our cold, dead fingers, of course....minus a few atoms of iridium??

[rustytunes]

It's not necessary, but fixing it is a major bear. There is currently a very expensive multinational project going on to fix the kilogram in terms of a specific number of atoms of specified composition (or equivalently, to define Avogadro's number exactly) which will implicitly define the kilogram exactly without reference to an artifact.

However, you can imagine the technical stuff that needs to go into this. I believe the current plan involves making a perfect and flawless crystal sphere of silicon (http://ieeexplore.ieee.org/Xplore/login.jsp?url=/iel5/6870/18483/00850937.pdf) (because we can make large, flaw-free silicon crystals more easily than we can make other types). Imagine trying to machine a six-inch sphere to be so smooth that there are no scratches on it larger than an atom....
See previous thread Avogadro Project (http://forums.randi.org/showthread.php?t=90329)

[dogjones]

Don't make light of it. It's a matter of some gravity.

Stop ad-lbing, or I'll pound some sense into you.

[Jimbo07]

The way it's worded, the media would have us think that as a human race, we were stupid enough to have only one reference.

We're not that dumb, right?

If it wasn't a fundamental physical property... how could you possibly have more than one?

Each national standard kg in the world is a copy, IIRC.


Really though, this -

Quote:
compared with the average...
implies that some of the copies have 'gained' a little mass, while others have lost a little, with the average net change in the copies being positive.

Move on, folks. Nothing to see here.

Not at all. What if the net change in the reference mass falls outside a couple of standard deviations of the average?

[NobbyNobbs]

BTW, when you, Americans, will get rid of the obsolete system you have?:D

Well, our measurement system, along with our monetary system, have been around so long that we may as well keep them at this point.

As they say.....




....in for a penny, in for a pound. :D

[This Guy]

BTW, when you, Americans, will get rid of the obsolete system you have?:D

Well, with all this hotter weather and stuff going on, I hope never!

See, I done figured it out! Two weeks ago, we had temps that were as much as 10 degrees F above normal!

Now, if we was using all that Metric stuff, that woulda been 10 degrees C!!!

Now, to convert between Fahrenheit and Centigrade, (for a ball park conversion!) you double the degrees Centigrade, and add 32. So, if we used that thar Centigrade thingy, and had temps 10 degrees higher than normal, and if you convert that to Fahrenheit, that would be 10 X 2 = 20, 20 + 32 = 52. 52 degrees hotter than normal! That woulda put us at about 150 F! We'da been fried alive when we walked outside! Theyda been spontaneous human constipation all over the place!

Yep! Y'all can just keep that metric stuff!





;)

[Jimbo07]

Now, to convert between Fahrenheit and Centigrade, (for a ball park conversion!) you double the degrees Centigrade, and add 32. So, if we used that thar Centigrade thingy, and had temps 10 degrees higher than normal, and if you convert that to Fahrenheit, that would be 10 X 2 = 20, 20 + 32 = 52. 52 degrees hotter...

;)

So THAT's how you do math in imperial systems!

Ugh!

:D

[This Guy]

So THAT's how you do math in imperial systems!

Ugh!

:D

Just have to remember that Fahrenheits are longer than Centigrades!


:boxedin:

[Jimbo07]

... and Centigrades have less feet than Centipedes. I think I'm getting it now!

:boggled:

[Michael Redman]

Do souls all weight exactly the same? They should, based on my understanding of theology. Let's use them for a standard.

[Jimbo07]

21 grams, no?

I always thought that movie was 'bout drugs...

[Michael Redman]

21 grams, no?

I always thought that movie was 'bout drugs...

OK, simple, a Kilogram is now 47.6190476 souls.

[DRBUZZ0]

So THAT's how you do math in imperial systems!

Ugh!

:D

It's called the STANDARD system. Don't make me go to the hardware store and take a picture of the damn bolt isle. There's a "STANDARD" section and a "METRIC" section. Everybody knows that.

When has the system with feet and pounds and miles ever gone and setup a triangle trade system? or established colonies and taxed them and took their tobacco or sugar or coffee or gold or whatever? Did that system go around making other measure systems use its money and pay a duty to its king or something?

No. And it can't. Because it's just a set of measuring standards. So it can't be imperial.

[Cuddles]

No. And it can't. Because it's just a set of measuring standards. So it can't be imperial.

That's just what it wants you to think.

[balrog666]

I think it's a matter of shrinkage. Everybody know about shrinkage.

[Hindmost]

it sublime.

glenn:boxedin:

[a_unique_person]

The way it's worded, the media would have us think that as a human race, we were stupid enough to have only one reference.

We're not that dumb, right?

Most other standards can be defined in terms of a reproducible reaction, eg, the length of a metre can be defined in terms of


Today, it is defined by the International Bureau of Weights and Measures (http://en.wikipedia.org/wiki/International_Bureau_of_Weights_and_Measures) as the distance travelled by light (http://en.wikipedia.org/wiki/Light) in absolute vacuum (http://en.wikipedia.org/wiki/Vacuum) in 1/299,792,458 of a second (http://en.wikipedia.org/wiki/Second). from wikipedia.

Weight can't be done that way yet, but proposals are being made to rectify the problem as mentioned previously. It will be defined as being x number of atoms of silicon.

[qayak]

BTW, when you, Americans, will get rid of the obsolete system you have?:D

Not soon I hope! I have a business set up at a border crossing where I change the fuel tanks of American tourists coming to Canada. I charge them $500.00 to take out their old tank and install a new one that works with metric litres. Before they leave Canada, I reinstall the old tank for another $500.00.

They are very grateful that for only $1000.00 they can be assured of a safe, trouble free drive through the frozen wasteland of Canada where our temperaturs never getting above 45 degrees.

[dogjones]

Almost... theeeeeeere... (http://www.guardian.co.uk/science/2007/oct/29/sciencenews.uknews)

[mhaze]

Check this out. (http://www.guardian.co.uk/science/2007/sep/13/1)
Hypotheses?

This matter was cleared up once the Theory of Dark Suck was developed.

For some time, scientists thought that when an ordinary person turned a light bulb "ON" in a room, then the bulb emitted photos as a result of it's glowing filament (or other mechanism in flourescents, etc).

Now we know that the active mechanism is the latent "Dark Suck" of energy that occurs when the switch is turned "OFF". This should have been obvious, after all, when the sun goes down it gets colder. That's because the Dark Suck takes all the photons out of the air and tells the molecules to be quiet, not to dance around.

This weight, kept under lock and key, is most likely in a room in which the light switch is normally in the "OFF" (activating DarkSuck forces). In such a case, who would not expect the item to lose weight?

In interstellar space, DarkSuck can become a very powerful force, known as Black Holes (obselete terminology of course).;)

[nw843x]

BTW, when you, Americans, will get rid of the obsolete system you have?:D

Why Americans cling to the inferior measurement system is beyond me .....
http://ts.nist.gov/WeightsAndMeasures/Metric/pub814.cfm

..... they were one of the original signitories to the Treaty of the Meter of 1875. :boggled:

§ 205a. Congressional statement of findings. - TheCongress finds as follows:

(1) The United States was an original signatory partyto the 1875 Treaty of the Meter (20 Stat. 709), which establishedthe General Conference of Weights and Measures, the InternationalCommittee of Weights and Measures and the International Bureau ofWeights and Measures.(2) Although the use of metric measurement standards in the United States has been authorized by law since 1866 this Nation today is the only industrially developed nation which has not established a national policy of committing itself and taking steps to facilitate conversion to the metric system.
(3) World trade is increasingly geared towards the metric systemof measurement.
(4) Industry in the United States is often at a competitive disadvantagewhen dealing in international markets because of its nonstandardmeasurement system, and is sometimes excluded when it is unableto deliver goods which are measured in metric terms.
(5) The inherent simplicity of the metric system of measurementand standardization of weights and measures has led to major costsavings in certain industries which have converted to that system.
(6) The Federal Government has a responsibilityto develop procedures and techniques to assist industry, especiallysmall business, as it voluntarily converts to the metric systemof measurement.
(7) The metric system of measurement can provide substantial advantagesto the Federal Government in its own operations.

[Soapy Sam]

I think it makes more sense to try to define the kilogram directly, simply because the errors of measurement will be less.

Think about it. A 1kg sphere is about six inches across (fifteen cm for you civilized types). A 1g sphere is about six-tenths of an inch across. A 1mg sphere is about six hundredths of an inch across, and a 1ug sphere is about six thousandths of an inch across. The "few tens of atomic diameters" of imperfection is a thousand times more significant an error on the 1ug sphere. What they would really like to do, I suspect, would be to make a 60-inch sphere that weighed a metric tonne, but they don't have the fabrication or machining capacity....


Yes, but the gram is the fundamental unit - hence the prefix "kilo" in "kilogram". Doing it this way means defining the gram in terms of fractions of multiples of itself.
Plus ca change...

[Jimbo07]

Yes, but the gram is the fundamental unit

Only in cgs reckoning. In mks reckoning, the kilogram is the fundamental unit. The SI units are generally taken from mks, meaning that the kilogram is the reference unit.


[/I]- hence the prefix "kilo" in "kilogram". Doing it this way means defining the gram in terms of fractions of multiples of itself.
Plus ca change...

That's the way it goes. C'est la vie...

[Soapy Sam]

Rarely a day I don't learn something here.


ETA-http://www.unc.edu/~rowlett/units/cgsmks.html

[shadron]

http://www.guardian.co.uk/science/2007/sep/13/1
The low amount of mass lost plus the bolded above seems to make this loss not such a big deal does it not?

Such a small amount could be explained by handling and occassional (however short a time period) exposure.

Yes, it is a big deal: if the difference is measurable, then what is the standard? Did the standard loose the 50 ug or did the others gain (on the average)? If scales are getting sensitive enough to measure the difference, then do they need adjustment upwards? How do you handle a shifting standard?

It's not that any of these standards are ever handled. They are stored under the equivalent physical security of Fort Knox, in a dry inert atmosphere and are never ever exposed to anything as crass as a human breathing the same air. In fact, the standard is almost never moved; national standards (like the one the US owns) are compared to the standard in situ, I believe.

What is desirable is to define the standard kg in terms of something universal. Length is standardized as so many wavelengths of a certain color of light, time by counting the atomic vibrations of a certain molecule. Standards gurus are working on something like that that can be reproduced in any suitable laboratory anywhere. In the meantime they are constructing a new kg standard from a perfectly formed sphere of silicon.

The US is officially a metric nation; all our English system units are defined in terms of metric standards. We are just retards about going the final mile.

[shadron]

Hmmm, your argument has weight.

Uhhhh, no. Mass. :)

[dudalb]

Why Americans cling to the inferior measurement system is beyond me .....
http://ts.nist.gov/WeightsAndMeasures/Metric/pub814.cfm

..... they were one of the original signitories to the Treaty of the Meter of 1875. :boggled:

§ 205a. Congressional statement of findings. - TheCongress finds as follows:

(1) The United States was an original signatory partyto the 1875 Treaty of the Meter (20 Stat. 709), which establishedthe General Conference of Weights and Measures, the InternationalCommittee of Weights and Measures and the International Bureau ofWeights and Measures.(2) Although the use of metric measurement standards in the United States has been authorized by law since 1866 this Nation today is the only industrially developed nation which has not established a national policy of committing itself and taking steps to facilitate conversion to the metric system.
(3) World trade is increasingly geared towards the metric systemof measurement.
(4) Industry in the United States is often at a competitive disadvantagewhen dealing in international markets because of its nonstandardmeasurement system, and is sometimes excluded when it is unableto deliver goods which are measured in metric terms.
(5) The inherent simplicity of the metric system of measurementand standardization of weights and measures has led to major costsavings in certain industries which have converted to that system.
(6) The Federal Government has a responsibilityto develop procedures and techniques to assist industry, especiallysmall business, as it voluntarily converts to the metric systemof measurement.
(7) The metric system of measurement can provide substantial advantagesto the Federal Government in its own operations.


We were supposed to go metric back in the mid 80's,and there even a campaign about it,but the Government backed down because of the cost of converting would be so great.
The consensus seems to be it's a good idea, but no one wants to pay the cost of conversion.

[tracer]

You guys living in metric-speaking countries really have no idea how bad the "other" system is.

Particularly since there's more than one of them:

http://www.rogermwilcox.name/measures.html

[Schneibster]

Errrmmm, the SI system (the international scientific system of weights and measures) specifies the kilogram as the precise mass of a cubic decimeter of pure water at 4C (the temperature at which liquid water achieves its highest density). The meter is defined as a certain number of wavelengths of a particular line in krypton's spectrum (this is convenient because krypton lasers are relatively easy to construct to use this line).

Or at least that's the way it was supposed to be. It seems that some politicians got involved with science again and so now we have this weird piece of metal that no one can duplicate that people call a "kilogram." The guys who made it in the nineteenth century made it as close as they could to the exact mass of a cubic decimeter of water at maximum density. They were off by 25 ppm. But instead of correcting their error (and it's pretty impressive that they were able to get it that close that long ago), now we have a cluster **** to define it in some other terms than the most obvious ones imaginable that anyone could duplicate anywhere anytime to any desired degree of precision given the precision of their equipment.

The "prototype kilogram" is medieval. The original definition was fine. Of course, if we're going to tweak it, we'll need a 1kg diamond (they want to define the kilogram in terms of an exact number of C12 atoms).

Science always starts to suck when the politicians get involved. Anyone but an idiot would make the standard be defined as a certain volume of an easily-obtainable substance under easily duplicated conditions. Which is what it originally was.

[drkitten]

The "prototype kilogram" is medieval. The original definition was fine. Of course, if we're going to tweak it, we'll need a 1kg diamond (they want to define the kilogram in terms of an exact number of C12 atoms).

No, they can use the silicon crystal to infer the properties of the hypothetical diamond crystal. Once they know how many atoms there are, which is the big question. Once they know how many atoms there are in a mole of silicon, there are the same number in a mole of C12....

[Yllanes]

The meter is defined as a certain number of wavelengths of a particular line in krypton's spectrum (this is convenient because krypton lasers are relatively easy to construct to use this line).

Actually since 1984 the metre is defined as the distance light travels in vacuo in 1/299 792 458 seconds. So now the speed of light is exact by definition. If you want, a more precise measurement of c would change the length of a metre, but the number 299 792 458 m/s will never change. We do this because we can measure times much more precisely than lengths. Nowadays a standard metre is a 500 kg optical table with some precise atomic clock.

[Dilb]

The meter is defined as a certain number of wavelengths of a particular line in krypton's spectrum (this is convenient because krypton lasers are relatively easy to construct to use this line).

You and you're new-fangled metre definitions. It's supposed to be one ten-millionth of the length of the Earth's meridian along a quadrant, or the length of a pendulum with a period of 1 second.

[Schneibster]

Actually since 1984 the metre is defined as the distance light travels in vacuo in 1/299 792 458 seconds. So now the speed of light is exact by definition. If you want, a more precise measurement of c would change the length of a metre, but the number 299 792 458 m/s will never change. We do this because we can measure times much more precisely than lengths. Nowadays a standard metre is a 500 kg optical table with some precise atomic clock.Ahhh, yes. I'd forgotten that. I had heard it had been redefined in terms of c, but only in the last year or so doing some research on something or another. Thanks for reminding me.

[Schneibster]

No, they can use the silicon crystal to infer the properties of the hypothetical diamond crystal. Once they know how many atoms there are, which is the big question. Once they know how many atoms there are in a mole of silicon, there are the same number in a mole of C12....I guess I'm just being curmudgeonly. It's probably best to base it on an exact number of atoms of a particular isotope. My complaint is, you can't just create a prototype right there and check it.

[greymatters]

BTW, when you, Americans, will get rid of the obsolete system you have?:D

* As soon as the units become easier to mentally estimate and relate to: When I hear a "foot", I can instantly think of the rough distance of a human foot. When I hear cup, I can instantly picture a standard cup. What the heck is a "meter"? I'm supposed to think of 2/3 the average human height? It's a little hard to picture a room measured in dismembered bodies! Heck, even Denmark uses tablespoons!

* As soon as metric units can be evenly divisible by 3 and 6: Dividing things into 3rds and 6ths (and 9th for that matter) comes up quite often in construction. Feet and miles are evenly divisible by this, while in metric all you get are repeating decimals.

* As soon as it's useful outside of a scientific lab for something more than a 2-liter bottle.

[a_unique_person]

* As soon as the units become easier to mentally estimate and relate to: When I hear a "foot", I can instantly think of the rough distance of a human foot. When I hear cup, I can instantly picture a standard cup. What the heck is a "meter"? I'm supposed to think of 2/3 the average human height? It's a little hard to picture a room measured in dismembered bodies! Heck, even Denmark uses tablespoons!

* As soon as metric units can be evenly divisible by 3 and 6: Dividing things into 3rds and 6ths (and 9th for that matter) comes up quite often in construction. Feet and miles are evenly divisible by this, while in metric all you get are repeating decimals.

* As soon as it's useful outside of a scientific lab for something more than a 2-liter bottle.

I have lived with both (Australia did the change over years ago.)

Metric is easily better.

Just look at the USA deciding to go dollars and cents a few years ago. I bet no-one has looked back since that change over. :)

[greymatters]

I have lived with both (Australia did the change over years ago.)

Metric is easily better.

It isn't illegal to use metric in the United States. Go ahead, use it all you want when you visit the US! We use both. Why other countries demand only one system of measurement be used is beyond me. Also, if you're trying to market something in just metric in the U.S., you might want to consider whether your potential market would agree with that.

Just look at the USA deciding to go dollars and cents a few years ago. I bet no-one has looked back since that change over. :)

I can only assume you're an astronomer, since you consider 1793 (http://en.wikipedia.org/wiki/Chain_cent) to be "a few years ago". :)

[Dorian Gray]

How many centipedes in a klingon? Who knows - I'll just stick with feet and inches - several inches.

[TX50]

* As soon as it's useful outside of a scientific lab for something more than a 2-liter bottle.

Metric is plenty useful:
People of the European persuasion safely, comfortably and happily buy all
sorts of goods measured in kilograms, metres and centimetres. They also
manage to reliably get to their destinations despite having roadsigns marked
in Kilometres (although many of them still cannot pronounce the word
correctly; it's KIlometre, not KilOmetre!).

European engineers have built the biggest passenger aeroplane, the most
capable air-defence fighter, the biggest and most luxurious ocean liner, the
only space probe ever to land on Titan, and much more - all using metric. :)

Actually many of us British-Europeanites can easily and comfortably think in
both systems. I myself do refuse to use the completely illogical Fahrenheit
system though.

[OnlyTellsTruths]

I myself do refuse to use the completely illogical Fahrenheit
system though.

0 is too cold, time to seek shelter, likewise 100 is too hot..... Often times things that are illogical are useful in their simplicity. Oh and water boils at 200 (well, only if you're in the mountains or have a thermometer from 1807).

[Mashuna]

The US is officially a metric nation; all our English system units are defined in terms of metric standards. We are just retards about going the final mile.

I'm sure one day you'll be able to go the final kilometer.

[Soapy Sam]

I guess I'm just being curmudgeonly. It's probably best to base it on an exact number of atoms of a particular isotope. My complaint is, you can't just create a prototype right there and check it.

Which is precisely why "the foot" is so, eh... handy.
All you need is a one legged king and you're up and..em,...hopping.

[sphenisc]

How many centipedes in a klingon?

About a plateful, if they're anything like qagh.

[TjW]

Well, with all this hotter weather and stuff going on, I hope never!

See, I done figured it out! Two weeks ago, we had temps that were as much as 10 degrees F above normal!

Now, if we was using all that Metric stuff, that woulda been 10 degrees C!!!

Now, to convert between Fahrenheit and Centigrade, (for a ball park conversion!) you double the degrees Centigrade, and add 32. So, if we used that thar Centigrade thingy, and had temps 10 degrees higher than normal, and if you convert that to Fahrenheit, that would be 10 X 2 = 20, 20 + 32 = 52. 52 degrees hotter than normal! That woulda put us at about 150 F! We'da been fried alive when we walked outside! Theyda been spontaneous human constipation all over the place!

Yep! Y'all can just keep that metric stuff!





;)

This is an explanation for global warming I hadn't heard before.

[a_unique_person]

I can only assume you're an astronomer, since you consider 1793 (http://en.wikipedia.org/wiki/Chain_cent) to be "a few years ago". :)

Just my idea of a joke. :o I was pointing out that the USA was very progressive in a lot of it's thinking back then. For some reason, the metric system cannot be adopted two hundred years later.

[shadron]

* As soon as the units become easier to mentally estimate and relate to: When I hear a "foot", I can instantly think of the rough distance of a human foot. When I hear cup, I can instantly picture a standard cup. What the heck is a "meter"? I'm supposed to think of 2/3 the average human height? It's a little hard to picture a room measured in dismembered bodies! Heck, even Denmark uses tablespoons!

* As soon as metric units can be evenly divisible by 3 and 6: Dividing things into 3rds and 6ths (and 9th for that matter) comes up quite often in construction. Feet and miles are evenly divisible by this, while in metric all you get are repeating decimals.

* As soon as it's useful outside of a scientific lab for something more than a 2-liter bottle.

I think I understand your response here is in the manner of a joke, but as a English system user from the heartland who has been converted to the true way, I would like to respond in turn.

+ Had you been born in a metric using community, you would have the concept of meter/liter/kilogram down in your psyche in the same way you do the foot, cup and pound. I, a user of English for 60 years and a user of metric for 45, still do rough tranlations from metric to English for comprehension's sake; were it not for other factors, English would win. But then, I'm no good at languages, either; perhasp that has somethign to do with it.

+ Oh? How do you do that with the pint/quart/gallon, or the ounce/pound/ton? Besides, how many fingers do you have? Our number system is based on ten, I assume you know. :)

+ Come, come. Europeans use it *all* the time and have no problems - lengths, volumes, mass, temperature. All things considered, the English system only has the factor of daily use by everyone in the US going for it. They do just fine with centigrade temperatures, kilometers from here to there and kilos of body weight (not quite correct usage there, but close enough).

I have a special interest is in architectural plans; it is a pain in the fundament to have to work with 3' 2-5/8" rather than 981 (metric plans always assume millimeters in all except land measurement).

[shadron]

Just my idea of a joke. :o I was pointing out that the USA was very progressive in a lot of it's thinking back then. For some reason, the metric system cannot be adopted two hundred years later.

Conservatives lurk everywhere, and they all have a stake in King Henry's shoe size. We almost had education doing metric in the eighties (which is where it all has to start), but we backed away. Too bad - that will just make it more painful the next time.

[shadron]

I guess I'm just being curmudgeonly. It's probably best to base it on an exact number of atoms of a particular isotope. My complaint is, you can't just create a prototype right there and check it.

The only problem with such an approach are the practical difficulties of counting atoms when the count runs to 24 digits. It takes a long time and it's boring. :) If your idea of exactness might be +/- 10^16 atoms, and you had a practical way to still do it, then that might be the way to go. You'd have to worry about not allowing isotopes to sneak in in significant amounts (1 part in 10^8, for example); little hurdles like that.

But it is an elegant approach - I'll give it that.

[greymatters]

Why the push to "convert"? In the U.S., we use both systems. Once again, metric isn't illegal here.

We use it, we just don't use it exclusively.

[BenBurch]

Just speculation here, but back at the time this bar was made, radioactive elements were unknown. Is it possible that there were some radioisotopes in the original alloy and that these have decayed since? That absolutely could result in a loss of mass. Any alpha particles would become helium atoms and eventually slip out of the mass as they are so small and unreactive.

[Dan O.]

When I was a kid, the excuse was that switching to the metric system would be an unbearable cost for auto mechanics that would all need to have two sets of tools.

Now, because we didn't switch to the metric system, every auto mechanic needs to have two sets of tools because many parts metric.

[Blue Mountain]

Why the push to "convert"? In the U.S., we use both systems. Once again, metric isn't illegal here.

We use it, we just don't use it exclusively.
(bolding mine)

Three words: Mars Climate Orbiter

[Blue Mountain]

People interested in the various units of measure used in Europe and North America will find the data file for the Linux program units interesting reading. A copy is available online here.

[Schneibster]

I never looked, will it convert to and from furlongs per fortnight?

[Dan O.]

google will (http://www.google.com/search?q=1+meter+per+second+in+furlongs+per+fortni ght)

[Blue Mountain]

I never looked, will it convert to and from furlongs per fortnight?
But of course! :D


bluemountain@hobbit$ units
2084 units, 71 prefixes, 32 nonlinear units

You have: furlong/fortnight
You want: mm/hour
* 598.71548
/ 0.0016702424

[my_wan]

BTW, when you, Americans, will get rid of the obsolete system you have?:D

I'm with you. The idiots at Lockheed Martin that crashed the Mars probe because they were using English units should all be fired and made to repeat 100 times on national news, "I'm an idiot".
http://www.cnn.com/TECH/space/9909/30/mars.metric.02/

It may be difficult to change internally here for carpenters and such but I wouldn't mind throwing my English socket set away one bit.

[Schneibster]

I'm sure I'll find that useful. For something or other. Still, nice to know I can download it if I want to have it around.

[DavidS]

[Mars Climate Orbiter
Well, that's more of an argument for using a system of units than it is for using a particular system of units. A similar problem would occur if a device speaks in grams to one listening in kilograms.

[Diagoras]

Stephen Colbert did a bit on this:
http://www.comedycentral.com/motherload/index.jhtml?ml_video=103200

[danielk]

I can sympathize with the request for easy divisibility by three. In my view we would have been better off switching to the duodecimal system entirely instead of redesigning egg cartons and pruning our language of words like "dozen". If I had been in god's place I would have created humans with twelve fingers. Hm, maybe the FSM just didn't consider that these stupids would depend on their fingers to count.

I like neat. The SI is the best we have, but not neato neatidy enough for me. Must be my genetic heritage: I'm actually proud to have been born in the country where A4 paper was invented. (Don't you agree that the case for square-root-of-two-based paper sizes is even more compelling than the case for the SI, if that's possible?)

Anyway -- Americans, you already won in the language category. Don't ya be getting greedy now, and generously leave the measurement category to us, will ya? You know how politics are traditionally played in Europe. :p

And your paper sizes suck. So there. A6 for toilet paper!

[Diagoras]

I can sympathize with the request for easy divisibility by three. In my view we would have been better off switching to the duodecimal system entirely instead of redesigning egg cartons and pruning our language of words like "dozen". If I had been in god's place I would have created humans with twelve fingers. Hm, maybe the FSM just didn't consider that these stupids would depend on their fingers to count.
It's actually quite trivial to count in base twelve with your fingers. Just count the three segments on each of your four main fingers, using the thumb as a pointer. If you use the other hand to count dozens, you can easily count up to a gross. Furthermore, your finger segments are arranged in a handy 4×3 grid (pardon the pun), which makes it easy to divide it up any way you want.

[Anders W. Bonde]

FWIW, a slight detour: In aerospace the US system of measure still dominates, and has even had a resurgence. Whereas an old all-French airliner such as the Mercure was all-metric, today's European Airbuses fly knots airspeed at feet altitude over nautical miles distance using pounds of fuel in aircraft held together by fasteners with dimensions measured in inches and threads ditto and number of threads per inch (fasteners are often so-called "bastardized metric", e.g. a 6,35 mm bolt with 28 threads per 25,4 mm of length - a 1/4" UNF to the rest of us...).

The Swedish SAAB Draken and Viggen were all-metric, whereas the newer Gripen is a mix of metric and 'imperial' as far as fasteners go - and the cockpit for the export version reads feet, knots etc, whereas the home-market aircraft read meters, km/h etc.

IIRC, French military aircraft are still all-metric. Almost.

Having worked with both SI and US systems on aircraft, I have to say that I actually prefer the US system, though my only 'rational' reasons being that typical 'imperial' measurements can usually by precisely sussed at simply by dividing by two and adding fractions to get the required fraction, and I do find the millimeter too small as a 'base' measure for things the size used on an aircraft (inches relate better to the dimensions and tolerances). The Pascal is a ridiculously small unit of measure of force per area, hence 1 MPa for the sturdy 1 N/mm2 - it's much easier to relate to a 1 liter carton of milk having a weight of approximately 1 daN (the good ole kilopond...)

(BTW: I am a European, born and raised in Europe)

There is one thing we should have kept that the Americans use (and many Europeans in aerospace, too): Third angle projection on engineering drawings - much more logical than the European first angle projection, IMHO, and the ANSI way of dimensioning drawings is IMHO much clearer and neater than the ISO systems (you have to tilt your head to read dimensions, not so in ANSI).

[69dodge]

When I was a kid, the excuse was that switching to the metric system would be an unbearable cost for auto mechanics that would all need to have two sets of tools.

Now, because we didn't switch to the metric system, every auto mechanic needs to have two sets of tools because many parts metric.


The square drive of ratchets is measured in inches. And therefore so is the the square hole in all sockets, including metric ones.

I find this amusing.

I am easily amused.

Anyway, personally speaking, I'm glad mechanics don't only have metric tools. :D

[69dodge]

Must be my genetic heritage: I'm actually proud to have been born in the country where A4 paper was invented. (Don't you agree that the case for square-root-of-two-based paper sizes is even more compelling than the case for the SI, if that's possible?)


Definitely.

Cut a big piece of paper in half to get two small pieces that are the same shape as the original one.

It's very clever. I like it.

[CapelDodger]

OK, simple, a Kilogram is now 47.6190476 souls.

47.6190476 souls at rest.

[CapelDodger]

The "prototype kilogram" is medieval. The original definition was fine.

Not for practical purposes, and the reference weights were used for practical purposes - verifying other weights and calibration of equipment. Preparing a perfect litre of water at 4C is not practical on a regular basis. Handling a reference mass with kid gloves in a controlled environment is a lot easier and much more dependable.

The kilogram is Napoleonic, the focus on standards and exact measurement came into its own in the early Victorian era - driven in part by the interests of industrialists, but also by the rapidly-maturing scientific world as we know it (and love it) today. It was the Age of the Anal - they never had it so good.

[CapelDodger]

[quote=madurobob;2958728]The pound (as a unit of measure) was around before the gram (or kilogram) so it was not defined in terms of grams originally. English units of measure (foot, yard, pound, etc.) were often defined by the king, using his foot for example, and often varied from place to place. This is before international standardization of course. Maybe someone knows when the English system was standardized? Thanks.

The British :rolleyes: system was standardised in the early 18thCE, but certain English measures - such as the pennyweight - were standardised in the 12thCE because they related to coining and taxes.

Standard measures were never established by the monarch's proportions. Most local measures were all over the place until the the Railway Age, but people knew what they were. Long after that a measure which the US hasn't embraced - stones - continued in use, particularly in the fishing industry. And yes, it involved big stones. Standardised now at fourteen pounds, there was a Hull stone, a Yarmouth stone, a Lowestoft stone, and prices to fit. Everybody in the trade understood it - the knowledge was passed from father to son, so it was a closed-shop.

[Dan O.]

The square drive of ratchets is measured in inches. And therefore so is the the square hole in all sockets, including metric ones.

I find this amusing.

I am easily amused.

One day I was walking through the tools section of Sears with a couple of friends and we thought we would have a bit of fun with the clerk. We asked where we would find the metric crescent wrenches. He walked over to the isle with the grey packaging and showed us several crescent wrenches with the handle lengths clearly marked in metric.

[69dodge]

I wrote "the the", and now it's too late to edit it.

I find this annoying.

Apparently, I am easily annoyed, too.