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NIST Wants An Electronic Kilogram
Dearing writes "According to the Global Engineering Journal, NIST, those not-so-standard standards people, want to give up the hunk of metal they've been calling a kilogram, even though it never weighs the same twice. In it's place, an electronic kilogram could act as the permanent standard."
Just visited the Greenwhich 'standards' - a bronze bar with two nubs that you could lay a ruler on to measure it's accuracy.
A sad, sad day.
We all now lost 10% of our weight. I just hacked NIST's computers and changed the reference.
Why aren't I thin now? I must hack the electronic tape measure next.
$10 if you want me to make you taller, too.
we've known about gravity for years and we can't agree on a standard for weight?
*nix has no change!!!
Do Unto Others As You Would Have Others Do Unto You - ONLY HARDER!
Why when I was a lad, all we had was a platinum-iridium cylinder, and we liked it. But you damn kids today, with yer newfangled electronic kilogram, why I oughta...
This is sufficient for a 5yh post 8)
It takes 40+ muscles to frown, but only four to extend your arm and bitchslap the motherfucker
They balance it against gravity to measure it? Wouldn't that be really, really inaccurate, since gravity varies by altitude, local density variations, etc? Did I misunderstand what I just read?
Sheeze, why not just define it as 1.498e20 atoms of carbon (or whatever number), and be done with it.
Sometimes it's best to just let stupid people be stupid.
NetInfo connection failed for server 127.0.0.1/local
Why have we been working with actual physical models to provide standards for so long? Didn't there used to be a bar representing the "exact" length of a meter before they switched it over to the distance light can travel in 0.xxx seconds?
If you're going to have standards, at least base them on constants, like the aforementioned speed of light for distance, the mass of certain molecules for mass, and...hmmm...can anyone think of anything for time? (I don't know what they currently use) Keep in mind that speed-of-light is taken.
Last post!
hunk of metal they've been calling a kilogram, even though it never weighs the same twice.
A gram is not a measurment of weight.
A kilogram is a unit of mass not weight. Weight is dependant on gravity. Mass is not.
You're using her as bait, Master!
"As electronic measurement equipment gets better, we can apply it to the experiment to get better results, which may lead to even better equipment, which we can apply to the project, and so on..."
=> as Quake gets better, I can apply it to my hardware, wich may lead to a better quake, and so on
I think I understand ! I'am a potention Nobel Prize, Just as he's a Potential Quake geek !
It takes 40+ muscles to frown, but only four to extend your arm and bitchslap the motherfucker
From the artice: It measures, with great precision, how much current passes through a wire coil in a strong magnetic field to balance the pull of gravity on a one-kilogram mass standard, and how much voltage is generated by moving the coil. Separate systems in the laboratory determine reference levels for voltage and gravity.
Call me a computer scientist, but isn't there something recursive about defining the prototype kilogram with gravity and then measuring gravity at the same time? Or is there something I don't understand about gravity?
Slashdot 's editors are dickheads
You could define a kilogram as the amount of water in a cubic decimeter. Or, you could define it as the mass of 6.02 * 10^23 protons, or any number of other ways. I don't understand how this measurement they intend to make with the device they have will be any more accurate or easier to deal with.
You could even define it as the energy in some huge number of photons of a particular wavelength. :-)
Need a Python, C++, Unix, Linux develop
The late Dr. Dick Deslattes said something like, "If we ever have to communicate from afar with ET aliens, we could explain all our science standards in terms they would understand, but we'd have to throw them the mass standard to explain that."
Yeah, because an advanced species capable of space travel would never understand something so complex as to think of a standard measurement of a physical item that isn't affected by gravity.
(one of) NIST's own web page(s) on this is at http://www.eeel.nist.gov/811/elec-kilo.html. There's a lot more technical detail there than at the link given in the article.
This really does make sense to replace the artifact with something independent -- they have a bunch of "voodoo" every time they measure the current kilo to try to get the same answer.
The standard for the second is:
The second is the duration 0f 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the Caesium atom.
And now I know as much as I did before.
...they're far smarter than me - thanks for the answers.
Last post!
I don't know how to write or communicate using "correct US English".
Being English, I only know how to use International English - I didn't realise my ignorance was holding back scientific progress.
If they were trying to accurately measure weight, then the variations in Earth's gravity would be a problem. However, a mass balance will always work, regardless of local gravity. Think of a see-saw. If it starts balanced, and then you pull down twice as hard on either end, it stays balanced.
As for why we don't use 6.0221e26 (I think that's right) carbon atoms as the standard kilogram, the only way we have on the macroscopic scale of determining how many atoms are in something is to weigh it. You'ld have to use the kilogram to define the kilogram.
yes.
-
A few years ago, a professor of my mentioned in lecture that a standards body was attempting to define what a kilogram is by using light!
I guess now a meter is defined, not by a steel or platinum rod, but by a multiple of the wavelength of light emitted by Xenon plasma or some other gas. By using the logic that mass can be converted into energy, and light was a form of energy, you could somehow define a kilogram by a multiple of the energy in the form of light, released by an atom of some substance when excited to a certain state.
I think that they probably lost most non-geek people on this, not to mention the engineers that use mass kg all of the time. The extension of this theoretical definition of a kg would spawn a horrible sense of relationships for tomorrow's physics and engineering students. What is heavier, a kg of feathers or a kg of light? Huh?
The Plat-Irid rod is good enough for Gubmint work.
-- Len
...it's the ground that you hit at the end of the gravitational pull that's hard...ouch.
In reality, I'm sure we could at least replace it with a theoretical definition that's more accurate than the cylinder. Even though the current definition of the meter is physical, in practice it's difficult to measure (the distance light travels in 1/299,792,458 of a second).
So, define the kilogram as the amount of mass that one liter of pure water contains at 4C. We already know the definitions of the meter exactly (defined by scientists, thanks very much), electric field permittivity (\epsilon_0), magnetic field permeability (\mu_0), the speed of light (c), etc.
With all these constants defined exactly, it just seems like there would be a better way...
Isn't this a little like trying to use lasers to determine the alcohol content in liquor? What's the point. You can already determine the mass with standard techniques, who needs another method?
mp3's are only for those with bad memories
Wouldn't it make sense to measure the mass of something by accellerating it to a known speed, then measure the amount of energy it takes to stop it?
Or, conversely, the amount of energy it takes to get it to a certain speed?
That would/should provide you with a measurement that's truly gravity-independant, and a scale that
Another idea: Make a vacuum tube. Put the item you want to weigh inside the vacuum tube. (Again, don't put your pets in there!=) Point the tube straight up and down. (we're using gravity for this one) Throw the item to be weighed up the tube, like the ball in a pinball machine, with a known amount of energy. Measure how high up the tube it goes, how long it takes to get there, and how long it takes to fall back down to the bottom.
Should be simple computation to determine the actual mass of the object from there, no matter how much gravity is in effect... no?
They're using the current(physical) standard to establish the new(elctronic) standard.
The new standard is going to be "the ammount of mass properly balanced by XXX volts and YYY amperes in the referenced system." That ammount is expected to be more consistent than "the ammount of mass needed to properly balance that hunk of metal we have in the basement."
The current (physical) standard changes from time to time due to dust, wear(from cleaning), etc.
Do not confuse duty with what other people expect of you; they are utterly different.Duty is a debt you owe to yourself.
So now if I want to buy a kilo of cocaine, some dealer's gonna have to walk up to some two story tall machine and poor in the coke until it's 1 kilogram?
This should be GREAT for police officers. Just look for two story tall electronic kilogram machines to bust all the coke dealers.
mp3's are only for those with bad memories
Wouldn't it be easier to define a kilogram like the mass of 'n' carbon atoms (or whatever).
I thought it said an "electronic kibogram". Make sure your measurements are correct or he who greps will git'ya!
One line blog. I hear that they're called Twitters now.
The gram is a measurment of mass, whereas the Newton is the measurement of force. Mass changes with gravity and something weighing 1 gram here would be significantly less on the Moon. Force, if I remember rightly is universal. Since 99.9999% of Slashdotters live on the planet Earth I would say that it doesn't really matter how much weight I would 'loose' simply by travelling to the moon.
Jumpstart the tartan drive.
why, exactly, a kilogram [...] never weighs the same twice?
IIRC the idea is to convert the standard of mass to a number of electrons accelerated by some well known voltage.
The electrons since they are moving, produce a magnetic field which pushes against a well known reference magnetic field (which can be measured without concern for mass). This magnetic repulsion is used to balance a 1 kg reference mass against gravity.
Since gravity produces acceleration independant of mass (ma=F=mg => a=g), it's also possible to measure the local gravity to a high precision by means of the acceleration with needing to know something's mass.
Thus we have a way define mass in terms of a number of electrons (and a geometry of the path they take, technically) and other measured quantities which don't use mass in their standards.
You could say mass is so many atoms of some reference substance, but how do you measure it? Since you can't first weigh it and extrapolate from there. Similarly volume would depend on temperature, structural arrangement, and other things. The people at NIST claim this provides a more easily reproducible method of defining mass. (Of course I'd rather just stick with the electronic scale or balance pan since these tend to be accurate enough for me.)
They can send it to me. It would make a nice paperweight and conversation piece, don't you think? And not just because of the value of the precious metals.
The fact is, however, that the most respected science publications in the world require the use of US english.
Friends don't help friends install M$ junk.
NIST, those not-so-standard standards people, want to give up the hunk of metal they've been calling a kilogram, even though it never weighs the same twice.
I think they would want to give it up because it never weighs the same twice.
I hope they invested in a UPS.
LOAD "SIG",8,1
LOADING...
READY.
RUN
That was the idea of a -standard-
Second: The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom.
As mass and energy are equivalent, can't they just define the mass as a certain number of barrels of that cesium 133 light? Right now they just throw away that light each second, but they could recycle it.
I really find it strange that say that the standard mass doesn't always weight the same.
Why do they think that is the mass that changed and not the machine (whatever they use) they're using to measure it that is innacurate. If they believe the machine is more accurate than the standard mass then drop it and use the machine.
A standard must be something that you cannot argue about. If it weights different then ajust what you use to weight it. Because if you don't trust the standard them it doesn't fullfill any purpose.
Just send them a dictionary that "weighs" a kilogram and you kill two birds with one stone.
To settle the debate,
6.022e26 adoms of C12 is 1.200e1 grams
Strive to make your client happy, not necessarly give them what they ask for
we'd have to throw them the mass standard
Wouldn't we have to throw them a dictionary first?
So far you have proposed greeting an alien race by heaving a kilogram weight and a heavy book at them. Some welcome.
"Sheeze, why not just define it as 1.498e20 atoms of carbon (or whatever number), and be done with it."
No problemo - as soon as you figure out a practical method for counting out those atoms on the floor of your typical machine shop. 'Oops - dropped another one. Someone blow the oil off it NO NOT THAT HARD - damm, out the window'.
If you define the number of atoms of a particular element to make up a kilogram, you've made a precise definition measure of mass.
What is the practical concern if the physical reference measure is off by a couple thousand atoms (or has a range of error)???
I find the idea "electrical reference measure" a fascinating idea; I just hope the gov't is not wasting millions of dollars trying to implement it.
"Hmmm, space probe or electrical reference measure... Which do I choose?"
There is no America. There is no democracy. There is only IBM and AT&T and DuPont, Dow, General Electric, and Exxon
..an electronic kilogram...
Sorry, the acronym EKG is already taken. Please try again.
I like to play children's songs in minor keys.
"We're all sons of bitches now." --J. Robert Oppenheimer
Another illiterate Slashdot post bites the dust.
...just like economists talk about the 1974 dollar as being a standard to refer to (when discussing values from different years, to account for inflation) I guess scientists will start having to use "dated kilograms".
For example: "Pluto masses 1.203e12 Kg? Is that in 1993 or 2001 kilograms?"
Mass fool! Mass! "We all now lost 10% of our mass" and as a consequence: "We all now lost 10% of our weight"
F=MA
That would be defining 'mass', not 'weight'.
The problem is a practical one; they are trying to find an easier way to take something, and determine if it is a 'kilogram' or not.
Balancing it against a reference weight is one way.
What they are saying is, doing this electronically is more accurate and easier, using magnetic fields and measured currents and such rather than a classical balance.
The definition of a kilogram of mass isn't going to change. They're just finding a better way to measure it.
One last note: "I dream that it would be especially neat if the experiment didn't work as planned and we could prove that it was interference from an extraterrestial transmission of some sort.... Did I mention that I like science fiction?"
Oh Doc, you had me until right here...now I think you may just be a quack. Someone should really have shut off the tape recorder on this interview about 20 seconds earlier.
--trb
Huh? You mean to tell me that there is another country outside of the one I live in? Now you're really pulling my leg!
C'mon everybody knows that the United States is the only country and that we are the supreme elite hand crafted by the divine one in his own image. Everyone else is simply a bunch of subhuman under-evolved monkey-men!
When the US says "jump!" The rest of the world asks "How high?" And we all know that these Anglo-saxons should go back to speaking their "own" language and leave the advanced English stuff to those whom god deemed worthy of speech, the United Statesmen!
Everyone else is just pastry tarts compared to us, we rule, and all others must follow our trail eating up the feces and detritus that we leave in our wake.
Oh yeah...SARCASM on BAY_BEE!
Love ya!
The majestical sarcasmotron.
He was legally arrested by the Serbian Police.
They then legally sent him to face the charges.
I'll see your Constitution and raise you a Queen.
Hello ? Anybody home?
Reading the posts on slashdot is like listening to my grandmother talk about the reason mankind is doomed is because we went to the moon.....
Anyone here actually know anything about metrology? It doesn't sound like it.
This is the informed society? Good grief!
That's odd, I don't understand how this question relates to an article about an electronic standard for mass. And before you flame me for nitpicking, let me remind you that Mars has some very expensive upper-atmospheric dust right now thanks to imprecise communication about units of force. Ordinary people can blithely confuse mass and weight without causing problems. Engineers can't, and this article appears in an engineering publication. When are we going to learn to be more precise about this sort of thing?
When all you have is a hammer, everything looks like a skull.
Sigh... Reading these responses fills me with doubt about the future of computers in general since half the people posting are posting with ignorance of the simplest physics concepts that should have been learned in Grade 10 science class. Maybe these posters are drop outs? Or maybe they think they are hot IT people because they installed linux a few times?
I predict that software design (open source and closed source) will decline further as too many unknowingly ignorant people make decisions. More crashes, more bad designs, more strange problems.
You are on your way to becoming a Pointy Haired Programmer!!! Stop and question yourself before you post!!!!
The ultimate goal is to derive all measures from
the fundamental constants of physics.
The two most popular are "c" the special of light
and "h" Planck's quantum of action.
A recent Physics today suggests a using
E=mc^2 and E=hv, where v is a frequency.
Frequencies are the most accurately measurable
item in the universe, at a current accuracy of
one part in 10^19. So the proposal is to choose
a "kilogram frequency" that precisely defines
the kilogram. There is already a "meter frequency"
that precisely defines the meter length in terms
of light velocity. And a "second frequency"
which some frequency count close to an astronomical
second.
The least well-known constant is the gravitational
constant, measured only to four decimal places.
The probably is instrumental error, because
everything pulls on everything else.
At least twice in the past decade someone has
proposed changing the law of gravitation because
of funny measurements, but every time an
experiment error was found. The constant "G"
doesn't fit into many physics equations,
so it isn't as easy to bootstrap equations
as for the other constants and measurement units.
Similarly, the kg could be defined as "the mass of 4.32415234895 x 10^33 protons (or whatever -- pulled that number out of you know where).
There's nothing "circular" about that definition at all.
That that is is that that that that is not is not.
"And in space, 1 kilogramme (s)till weighs one kilogramme"
No, it doesn't "weigh" on kilogram. It "is" one kilogram, but it "weighs" much less, due to reduced gravitationl force.
You almost made a good point but screwed it up with lazy communication.
This new apparatus is a very elaborate, and I'm sure very accurate, way to weigh their reference mass -- but the reference mass is still right at the heart of it. So how is this a fundamental change in the definition of the kg?
That that is is that that that that is not is not.
Yes, but it is fairly acurate. I'm not sure destroying it completely is a good idea, and I don't mean that it should just be put in a museum or something. It would be kind of creepy if someone was able to slowly 'change' the national kilogram. I guess I could see the next level down going electronic, the ones they distribute, but the national kilogram, which they only use something like two or three times a year to check out the duplicates/make new ones should remain I think. Heh. I can just see someone 'hacking' the National Kilogram, talk about a weight-loss program I like ;)
[Something witty and intelligent should have appeared here.]
{Traicovn}
In the spirit of free-as-in-chaos, I have instituted my own private moderation system. You get +1 Insightful for this. You're right, of course, but not many people would spot the distinction.
-- MarkusQ
"NIST, those not-so-standard standards people, want to give up the hunk of metal they've been calling a kilogram, even though it never weighs the same twice."
of course it weighs different every time, it's a standard kilogram, which is a measure of mass. the weight of the Kg will differ as gravity differs - which is a fun little trick having to do with the mass of the earth and the nearby celestial bodies.
the whole point of the new measuring device is (basically) to more accurately measure the force of gravity on the standard mass - by doing some magic with a magnet keeping the whole thing in balance. this is really just getting at a better measurement of gravity than anything else.
the crux of the situation is that the only standard for a kilogram is the actual lump of platinum itself. other things, like the standard second, are based on fun stuff like exactly how many times a cesium atom vibrates at a particular temperature. it might be fun to try and define a kilogram as Exactly This Many platinum atoms and be done with it, but that's kinda tricky for the moment.
it might be a better "standard" to accelerate the "standard" mass at a "standard" rate and measure the forces. say, by swinging the thing around in a calibrated centrifuge at whatever we're calling one Gee. then you can get to the bottom of the whole "weight" issue (in terms of newtons, i suppose).
besides, unless the standard mass is made of something that's decaying (radioactively - it's not like they'd make the thing out of, say, beef), it'll be pretty much the same mass for quite some time. it's just those nitpickety scientists at the NIST (on which i read a very interesting article recently, i believe in National Geographic Magazine) who want it to be defined in terms of something that will never change
and secondly, since when is the NIST "not-so-standard"? they are the national frickin' institution for the damned things, so they should be an authority on the subject...
- Entertaining Bits from the Ancient Kernel Tree
Gimme SI any day!
And Taco, WTF is the "postersubj compression filter?" Why can't you just explain in plain English what the fuck you do or do not like in the comment boxes?
It doesn't mean much now, it's built for the future.
The new standard is going to be "the ammount of mass properly balanced by XXX volts and YYY amperes in the referenced system."
SI standards based on absolute numbers (as opposed to chunks of metal) include the second (9192631770 ticks of a cesium atom) and the meter (the distance light travels in 1/299792458 second). But you can't define kilogram in terms of volt or ampere because they're already based on the kilogram. A volt is one watt per ampere. A watt will raise a 1N weight at 1m/s, while a newton will accelerate a 1kg mass at 1m/s^2. An ampere is the current in two parallel wires 1m apart that produces 2e-7N per meter of length. Therefore, defining a kilogram in terms of a volt or ampere would be circular (unless NIST skillfully arranges the equation to solve for kg); NIST must define its new version of the kilogram in terms of the second and meter.
Sources include NIST's current definitions.
Will I retire or break 10K?
There's a guy on the corner what can measure out quarter and half ounces with amazing consistancy... dunno why they have to go to all that trouble, when they could hire this guy cheaper.
Betcha if scientists were wont to shoot NIST people if their measurement vehicle was wonky because NIST's dumbell was off, you'd see some pretty accurate measuring going on over there...
Potato chips are a by-yourself food.
We should all be using proper measurements, anyway: pounds and ounces. Not this Euro sissy crap.
The onoe thing the article doesn't mention is the real goal which is what is causing a lot of confusion. The real goal is to be able to calibrate all measuring devices against some common standard. The current standards that I know of are:
1) The length of a second as defined by a certain number of oscillations of a Cesium atom.
2) The standard for a Volt (probably related to the charge on an electron) I don't know this one.
3) The standard for mass. (i.e. that hunk of metal)
From these three things and some phenomena based on physical constants (speed of light...) all other units can be referenced. The experiment described in the article pretty much defines the mass standard in terms of the volt standard. So, instead of having 3 standards whose accuracy limits the accuracy of all other standards. There will be only two, and any work to improve the accuracy of a second and the volt will improve the accuracy of all standards.
This reminds me of something my friend and I were talking about. It feels like experimental physics is almsot entirely electronic these days. Almost every single property in the lab is inevitably measured electronically, then that voltage/current/whatever is converted into whatever it was that you wanted. I guess it's only natural that they'd try to take away the last non-electronic measurement.
This reminds me of when a previous physical-object based basic measurement standard was updated, the meter. Instead of being "one/ten-millionth of the distance from the equator to the north pole along a meridian through Paris" (http://www.surveyhistory.org/the_standard_meter.h tm), the measure was eventually (after a couple of rounds of revisions) standardized to be the distance light travels, in a vacuum, in 1/299,792,458 seconds with time measured by a cesium-133 atomic clock.
When people asked if it was the measurement that was being changed, the answer was no, just the precision and accuracy that we can replicate the measurement.
Same goes here, the sea-level weight of 1 kg of mass is not being changed, just its precision and accuracy.
sarchasm: The gulf between the author of sarcastic wit and the person who doesn't get it.
Of course, you americans will have to convert from pounds to kilograms or vice versa to be able to use such a thing.
still, the best (only?) way to measure mass is by weighing it.
Whether it is gravity or some other force, you are still applying an external force and measuring the difference in the object at hand with a standard.
The speed of light, as far as we can tell, is unvarying. It makes a perfect tool for measuring time and length. The light emitted by Cesium oscillating between two excitation states is pretty constant, and not dependent on variances. If you excite Ce to State A, and your excitation energy (freq) drops below that, it's gonna drop back to state B, emitting light at a given frequency, that is not altered by gravity or temperature (and, by the way, that light, due to interferometry, makes an insanely accurate measuring stick). Great.
Mass... Hmm... The only way we have of measuring mass is by moving it, or comparing the movement of one thing with another. The "electronic" device proposed just looks like a more accurate balance scale. One hasn't really defined in terms of an unwavering physical property what a test mass should be.
Why not the deflection of a test surface by a mass, since we can optically measure the flatness of a surface to insane amounts? We can verify the "flatness" of a surface differentially and yet establish its flatness independent of the device measuring it, and with laser interferometry, we could optically detect any changes to to minute deflections, no?
Then how about defining the kg as "the rest mass of 2.1421235313 x 10^29 deterium atoms" (or whatever). That gets around your concern about whether to use the bound or unbound proton mass.
Point is, it can be defined in this manner, and it's not a circular definition.
That that is is that that that that is not is not.
sure we can define a Kg as X number of X element's atoms. but we cannot use that standard. (How exactly do you count out X number of atoms?) what they are trying to do is make a standard that is actually useable. The standard for time and length are actually useable. the standard for volume is actually useable. the standard for mass is not useable and has needed a replacement for decades.
Do not look at laser with remaining good eye.
If you don't like my opinion, I really don't care.
NetInfo connection failed for server 127.0.0.1/local
how much does a kilogram weight?
From the article:
;-)
"We asked Dr. Steiner where he expected the Electronic Kilogram to "go." He replied, "Consistent results from experiments like this could show that quantum and atomic theories are correct and consistent. Or not. "
Let's redefine a kilogram to add more uncertainty to the pursuit of science!
While I appreciate your candor in bringing scientific news to the British public, I must complain about the following misleading comment:
While it is obvious that we have mastered the art of communicating with the dead, it should not be difficult speaking with aliens or other silly people. Our resources would be better spent on hypnotizing bricks, building salons on Mount Everest and confusing cats.
Sincerely,
J. Edgar Hoover
Deceased
Culture is more than commerce
These are the wanks who own the government contract to extort hundreds of dollars from anyone wishing a copy of a standard developed by the government.
They get rich selling the public its own property.
They can go pound sand.
--Blair
"NIST, on the other hand, is a national treasure."
Not true... There is no fixed number given to the mole, that number varies with respect to the kilogram, which varies with respect to that block of metal.
in my day we didn't have water. we had to take some hydrogen and oxygen atoms and pound them with our fists until they turned into water
maybe the mass of the cylinder changed because some elements in it are radioactive, and by decaying reduced the mass?
The Stone Age did not end for lack of stones, and when the oil age ends it will not be for lack of oil. --Bjorn Lomberg
The experiment described in the article pretty much defines the mass standard in terms of the volt standard.
Except a volt is a watt per ampere, and a watt is N*m/s, and N = kg*m/s^2, making a volt a kg*m^2/s^3 per ampere. Now an ampere is the current in two long thin parallel wires 1 m apart that produces a force of 2e-7 N, and again N = kg*m/s^2. This is where it starts to go over my head, but I can see that dividing this out cancels out the kilograms, leading roughly in the direction of the experiment.
Will I retire or break 10K?
with a known amount of energy.
The energy unit (joule) depends on the mass unit (kg), as 1J = 1N*m = 1kg*m^2/s^2, where "kg" represents the mass of the old kilogram in France.
Will I retire or break 10K?
the "mole" is a CONSTANT which is a separate animal entirely from "units" and "quantities"
your analogy is flawed... constants are hybrid entities which in the end must be defined in terms of a unit. that's why the definition for mole is "some integer related to the definition of a kilogram"
Don't blame me - I voted for Howard Dean. http://dean2004.blogspot.com
nickels, dimes and quarters are accepted units for such things.
What we call folk wisdom is often no more than a kind of expedient stupidity.-Edward Abbey
People, what's the density of water? Is it not one kilogram per litre? One of the reasons this definition was chosen is because water is available to even the most ill-equipped of chemists! Certainly ET would have access to a fair quantity of it.
Water has a molar mass of 18.016, meaning that one mole (6.0221367 X 10^23) of water molecules has a mass of 18.016 grams. Get the little green men to divide the 1000 grams in a kilogram by 18.016 to whatever degree of precision they wish, and have them assemble that many moles of water. Call it a kilogram. End of problem.
(My admittedly imperfect monkey-man calculations tell me that 3.334 X 10^25 water molecules has a mass of approximately one kilogram)
Am I the only one who heard Roxette to sing "I'm gonna get blitzed for some sex"?
We don't have enough good old-fashioned Mad Scienists in America anymore. If we don't do something to increase the ranks of Mad Scientists soon, we're going to fall behind Europe in the Mad Science Race.
Fortunately, I have no doubt that Dr. Richard Steiner will make a fine example of an American Mad Scientist. According to his biography, he's devoted the last seven years of his professional life to replacing a hunk of metal with a hunk of metal surrounded by a two-story high machine! Even the project's name is brilliant in its silliness. Imagine meeting this guy at a party:
You: So, what do you, Richard?
Richard: I'm building the ELECTRONIC KILOGRAM! BWAHAHAHAHAHAHAHAHAHAHAHAHAHA! Igor, fetch me a drink!
Mark my words: In ten years, he'll be swinging from a balcony on the side of the Electronic Kilogram screaming "At the Academy, they called me mad! Mad? I'll show them!", as superstitious anti-Metric villagers storm the lab.
I, for one, feel better about America knowing we have men like Richard Steiner and his colleagues on the job. After all, even cold fusion and Raelian clones pale in comparison to the might of the ELECTRONIC KILOGRAM! BWAHAHAHAHAHAHAHAHAH!
Proud to be / Smiley-free / Since Nineteen / Ninety-Three
Actually, I read somewhere that college football players are responsible for like 13% of college rapes while only composing 3% of the class.
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http://www.interactivetheatre.org/resc/athletes
http://www.now.org/nnt/fall-99/campus.html
http://www.apbnews.com/media/celebnews/superbow
So they finally attacked the kilogram, but what about the meter. When is there going to be a change to the meter bofore the physical meter is changed drastically by cosmic particles, degredation, etc...?