I'm relating these to children's stories, which have shown a decent persistance.
The point is, that a book or a show can disappear leaving just small marks on society. But given the current techie culture of quoting heavily on certian books and references, we might expect the original Star Wars, The Matrix, and the general feel of Dr Who and Star Trek to suvive, these are doing better than other works, such as Blakes 7 or Babylon 5.
Given the vast material on Dr Who and Star Trek, we might find these surviving in a guise like Noddy, Mickey and Minnie, &c, where people are familiar with the characters, but not any specific plot.
Hitchhicker's Guide, may well be the new Alice in Wonderland, and the Matrix, and Star Wars may well survive as storys that give many quotes to, something like Black Beauty, or the Secret Garden.
Velikovsky says that craters were made during planetry encounters. So that a crater is concurrent with the fall of civilisations does not dosprove Mr Velikovsky.
Certianly, you have not advanced any reason why Velikovsky is a crackpot, and why "crackpots" can not engage in serious science [eg Sir Isaac Newton]. Character attacks are not good science.
Firstly, Velikovsky did submit to peer reviews. This is documented in a number of books. None less than Albert Einstein read the early books favourably.
Secondly, the thing is science, it provides testable ideas, and has made successful predictions. He says that Venus is hot enough to boil petrolium, and that petroluium fires would be burning on Venus were there oxygen there. The then current view was that Venus is 59 degF. His view does not need changing, by virtue that they made so many successful corrections.
I mean, it was not all that long ago, when Shumaker-Levi tumbled into Jupiter, that astronomers conceded that these things DO happen.
That is, in fifty years, Velikovsky remains unchanged and a valid theory, where the accepted theory has undergone a metamorphis due to what we find out there. Is that not enough to reconsider.
Regards your view of pseudo-science rubbish: You must understand that the movements of the planets as posited by Velikovsky is an explanation of the events that he teased out of legends. He successfully predicted that Venus was hot, that Jupiter has a large magnetic field, and quite a number of other things. Whether it is right or wrong, it is still a valid, testable hypothesis, capable of making predictions, and therefore Science.
The collapse of the Roman Empire and other events around the year 300 were discussed in the recent book Catastrophe, the proposition of which is that the Dark Ages were caused by an upset of the world weather around 535, by a large volcano that Krakatoa is in the crater of. The events of 535, as well as those of 1485BC and 687BC, suggest that it was not the work of a local civilisation, but widespread disasters.
You must understand this about Velikovski's theory. He did not posit that the celestial events occured, and then looked for confirmation, but rather, from the study of ancient legends, using his skill as a psychocharist, suggested that the described events happened, and were suppressed (as victims of trauma usually do). That is, Velikovski's wandering planets are an explination, not a cause. Your "Sun Standing Still" is described as a tippletoe movement of the earth.
The great chorus of people who stood up and said it was rubbish sounds similar to those who stood up and said the earth moves in the sky. There were serious objections to a moving earth, that took centries to overcome [like, how can it move and keep its atmosphere].
To date, I have not seen any reasonable attempt to refute Mr Velikovsky, which, if he were such a widely read author, and Science were so sure of their footing, this aught be addressed. Put simply, there is nothing in Velikovsky that is against the reason of physics, and certianly, one must agree that our understanding has changed in the intervening time.
On the other hand, there are perfectly reasonable explinations to most of the events that Velikovski describes. Check out the Abacus book Velikovski Reconsidered.
Also, Velikovski DID submit his books to peer review. But there was an organised campaign by some scientists to prevent the publication of his book by his first publisher, MacMillan.
Velikovsky said that a lot of civilisations came to greif as a result of Venus coming close to Earth around 1500BC. Because of some errors in the calendars (the "Dark Ages" of the ancient time), this could also mean 2000BC.
The relevant books are things like Ages in Chaos, Worlds in Collision and Earth in Upheval.
Transistors are essentially voltage-controlled capacitors.
voltage controlled switches, actually.
CMOS. = Complementry Metal Oxide Semiconductor. This is relatively slow and expensive, but it retains its state when there is no power, hence its use in Bios memory. Most circutry is done in doped silicon.
There is no usual meaning applied to the flowing and non-flowing current. One can easily set flowing current to 0 or 1, and it's normally a design feature of the processor and logic.
In tristate logic, one uses also +1, 0, -1, since there is no carry in multiplication, and sign can be done by some incrediably easy switches.
Imagine the trauma when the poor little dear gets involved in a motor accident. People tend to get attached to things that show emotion, and already to cars.
So a car showing emotions is likely to lead some people into a "deep and meaningful" relationship with their car, and it would cause grief when this is abruptly ended, for example, by an accident.
Over here, they're accepted as a form of proof of identification. For example, it's the mode of identification required to get videos from a video store.
The thing about "driving a car" means that you have to "prove" who you are to these people, and therefore, evidence of that proof can be used elsewhere.
Over here, [Queensland, Aus] we have Age 18+ cards, which are issued by the licencing authorities. They function as licences for identification pruposes only (eg you can use an Age18 card to get drinks in a hotel. Mind you, you can't drive a car on an Age18+ card.
The scheme was set up to get around the teenage drinkers in hotels, even though they're 18, not having a licence.
I recall reading in some book about "Design for the real world" about putting cheap speakers into the faces of a dodecahedron produces good sound. Nothing came of that, and I doubt if anything will come of this.
I think it has more to do with buyer perception than gee-whiz technology, although it could have some application for bands on the road or PA events.
The ulitmate irony was that VB is being used to hack some secret IP. Does M$ proud.
Personally, I think that we should go the VB crowd because of the collapese of Ansett and the WTC. MS is not relenting on their release date for XP, and are probably using the drawn attention as a cover.
It's nice that you argue that the Imperial system is a coherent single system,
The reason that I say the SI is a hodgepodge is that it is not anything like the sorts of systems that arise from theory. Much of theory had to be rewritten to accomidate the features of SI.
The electrical units pre-existed the MKS by many years: that there was a connexion to be made was only found in 1905. That is, the kilogram is a derived unit in the m-J-s system.
The reason that the mole was elevated to a separate base unit, was that the older dimension was M. In the MKS, this would have made the kilomole the base unit. This is what was actually used. SI gets around using gram-moles and kilograms, by making the mole a base unit.
The terms "practical" and "rationalised", bandied around as if they were things to be valued, actually have quite different meanings.
"Practical" is made out to mean that the units are of practical size. In fact, all it means is that the Joule, Watt, Ohm, Volt, etc, are part of it. The centimetre-dekatonne-second system [Mie] is "Practical". I made one out of the foot-Joule-second as well. V, A, ohm, F, H, second, watt, joule, Wb and C are unchanged. Mass=hile, force = trood, length=foot. J=foot^2*hile/s^2. Make the hile represents the "slug", and 100 degC = 140 degT. A new weight "bess" is needed so that trood = bess-force. In this system, J = foot-bess-force, and kJ=bess * degT * joule constant.
"Rationalised" is made out to mean "rational" or "logical". It actually means an adjustment to bring together values. When the 4pi is introduced into coulombs equation, it makes some measures equal. For example, in polarised media, J, M, P were 4pi of the induced fields B, H, D. After rationalisation, they become equal. Displacement originally referred to the displaced electrical charge P [as in the International Critical Tables], but when P=Di, this allowed D to become also displacement.
In any case, rationalisation means the system was fiddled with afterwards, ie not self evident. Gravity and light have not been fiddled with, so the system is incoherent over this respect.
I never said that imperial wasn't coherent (nor did I say it was).
Sorry: my mistake.:(
On the other hand, the metric system called SI, which is used with Litres, is somehow a hodgepodge of different systems.
If it is acceptable to use it with SI, and other units not with SI, then why reject from the system?
You are the one who originally said SI is a hodgepodge, but now you're saying that it's not? Is this now what you meant? It is essentially what this sentence is saying.
That SI has seven base units where other systems need only three or four, is a pretty good sign.
Things that are measured take singular: money is coming in from..., where counted things take plural: cattle are coming in from...
Very well, so what is this in response to? I don't see how this has much to do with what I said...
It's in relation to the difference between a number and a measure
But that did not stop you from demanding the source for the recent status of the mole.
Of course I did.
Fair enough.
Notes on the definition of "ampere". Are these your own definitions and arguments, or taken from the documents you referenced?
It is a paraphrase of the actual definition, and considerations in the construction of reproducable resistences, as I quoted
A definition, can only be true for a specific case.
You can only define, for example, that a pound-force is the gravity acting on a pound. You can define a function, as well: for example, square ~ as the area of a square of side ~. But you can not then having defined a foot=12 inches, and the relation of square to linear measure, then define a square foot as 144 square inches.
You can not define an equation.
If all the elements of an equation are defined, the equation can not also be defined. The equality is either true or false, or irrelevant.
Define in what sense? I can make up an arbitrary, meaningless equation that has no real world correlation. It's not very useful, but I defined it.
True. That's how most quantities start out: someone defines a measure that is sort of useful.
With the conversion factors placed in the appropriate locations I'm sure they are (I don't see why they wouldn't be), but then again I don't know for certain.
Flux from a charge Q, in SI flux=Q; in CGS; flux = 4.pi.Q
Capacity and Volume
Capacity and volume are the same concept: space, but there the distinction is needed because there are a lot of measures that are not derived from the linear dimensions of the vessel. Is not the imperial gallon derived from the pound?
History is important, because it decides the evolving patterns[...]
Historical ideas are important, because the way we see measures change over time, as does our use of number. For example, around 1900, the style was to use large numbers of small units: CGS, grains and inches. In 1980, the style is to use small numbers of large units, MKS, pounds and feet. You would miss that if you were not aware of it.
Relying on historical wreckage can lead you into the same mistake I heard of about women's feet in China. The servey merely looked at their feet and ages, and noted a movement of the feet in certian trends. This reflects changing customs, not biological presures.
Any unit intended to be used as part of a system is part of the system.
It's nice that you argue that the Imperial system is a coherent single system, despite the different capacitity systems between the US and UK, and when the Russians used the foot, they did not use the pound. On the other hand, the metric system called SI, which is used with Litres, is somehow a hodgepodge of different systems.
Quanties are measured, and change when the units do. Numbers are counted, and do not change.
Things that are measured take singular: money is coming in from..., where counted things take plural: cattle are coming in from...
I never argued any history with you, but argued statements you made about SI. Therefore discussing SI as it currently stands is the issue on the table.
But that did not stop you from demanding the source for the recent status of the mole. Historical prospective makes metrology easier to understand.
Notes on the definition of "ampere".
Unlike the other definitions, the ampere is defined to set the permeability of free space to a fixed value. Specifically, it can be written so that it is 1e-7 H/m.
The practical electrical units were defined to be a decade multiples of the theoretical EMU, for "practical applications". Any system that has an energy unit of a Joule, and a time unit of a second, can absorb them. In SI terms, this means a length of k metres, and a mass of 1/k^2 kg, the resultant permeability constant is (1e7)/k Henry/Length.
Maxwell puts k=1e7, which makes L=Quadrant [of the earth, = 10,000 km (hence the old name of the Henry), and M = 1e-14 kg.
. The system derived is coherent with the EMU equations.
In order to have k != 1e-7, you have to rewrite the EMU and divide quanities (eg B from H). You could define k or L. Gustav Mie defined L=1 cm, and hence k=0.01, M=10 tonnes. Giorgi puts L=1 metre, so k=1. This is the basis of the MKSA, and hence the SI.
If you chance to visit your NIST site, download sp330.pdf, and look at the adobe page 67 of that. You will see they talk of a new value for the von Klitzing constant of 25812.807 Ohms. This is 137.036*2pi*29.9792458 Ohms. 29.979&c is the speed of light. The reason that this can not be made the new definition of the Ohm is because it would upset the intended definition of the ampere, as seen on adobe page 68 of that pdf.
Therefore, we are entitled to regard the ampere defined to preserve the permeability of space, and that the H/m as the most important fixed value.
base units, definitions and dimensional analysis.
A definition, can only be true for a specific case. You can not define an equation. There is nothing inherent in the definition of any of the base units, or even in the derived units, that imply the relationships involved.
Units can not be intrinictly coherent. They are coherent to a body of equations. CGS units are coherent, as are SI units. But they are not coherent to the other's equations. And, as a result, the dimensions are not strictly equatable; hence the "equates to" in the conversions.
One has a series of relationships that define things. For example, Force=mass*acceleration, or F=ma. This gives a definition that defines a unit force in terms of unit mass and unit acceleration, under specific conditions. [A definition can not infer a relation, but must infer the things it depends on].
There are units that depend on force, eg power, energy and pressure.
Gravity is easy to use: mass can be converted to force fairly easily. The term "weight" translates variously to a mass "net weight" or statistics, or a force as in mechanics. This leads to mass being used as a force unit or mass force indifferently: eg pounds per sq in.
In the case of the fps system, one can derive an absolute system based on the f=ma relation. Kelvin makes the pound mass, and the f=poundals. Perry makes f=pound, and derives a mass="slug". The practical system is a mix of Perry and Kelvin systems, as gaussian = mixed ESU, EMU.
One can diffirentiate the (mass,force), like Stroud (pound, Pound), or the german style (gram, pond), the US style (M-mass, M-force) or the new style (M, M-force). cf Kennelly's ab-, stat-
One can make all systems coherent by rejecting F=ma as a derived equation, and defining F as a base unit. So you would have ft-lb-pdl-s or f-slug-lbf-s or ft lb-lbf-s, which is how the fourth, electical quantity appeared (as ESU and EMU are cm-g-s-Fr and cm-g-s-Bi).
Alternately, one can divide the force into "force = f=ma" and "g-force=mg". This is how D gets split from E.
Dimensions arrise from a putting the base units as variables, eg L M T F, or L-M-T-g. The number of dimensions is quite arbitary. It's an open algebra. This means, that I can take your dimensions and use it as if I derived it. But if I want to use it in a dead-end calcualtion, I can substitute L, M, T as 0.3048, 0.4536 and 1, to convert fps to MKS, or even put L, M, T as L^1, L^3, T if this needs to be done. It's an algebra, and I can substitute the values.
Young had an algeba that allowed exact conversions between SI and CGS. He had six base units, adding S and U to the LMTI set. U basically corresponds to a turn in "ampere-turn". The HLU and Gaussian has a curl here, ie a Bi = Fr/s - curl. 1 curl= 29979245800 turns. S is the space factor: 1 Coulomb produces 1 C-sur of flux, or 4pi C-sun of flux.
He has a body of equations, and six free variables, or six base units. You can fold the equations to get the SI or CGS equations by substituting for S and U beforehand, or leave the equations unfolded and add two extra base units to SI and CGS.
So how many base units for electricity? four or six?
There is no reason that in future some compelling reason will evolve for us to associate the candela with the watt. I mean, they used to measure resistances in miles (of copper wire).
Capacity
I'm sorry, but I'm failing to see why one would be more accurate than the other.
You are looking at the number, not the practical implication of measurement. Have you ever tried to construct a cube of a specific volume. It's easy to do a cylinder, since these can be turned on a lathe, which is why you see lots of cylinder measures. But a cube?
Technical vs Scientific measurement
The thing that the technical people brought into SI is that every unit should have a name. In science, one can say "in cgs units, and give just the number.
The thing that the scientific people brought into SI is coherence, the idea that one can say: the SI unit of X is Y. In some fields of science, they simply say "in xyz units" and drop the units completely. That's why the CGS units did not have names until Kennelly gave then ab- and stat- names in 1904.
History is important, because it decides the evolving patterns, the candela may be the current "pound-force".
The current SI definitions, except for the Ampere, represent the latest constructions for the units. In practice, the second is seen as a second division of the minute, this a division of an hour.
The definition of the second has changed to more stable measures as the ability to create clocks got more accurate.
The second as a fraction of a year is never intended to be a second of arc, as applied to a year=360 degrees, This is about 24 seconds long, and the sort of unit used by the Babylonians.
The ampere is defined to make the constant in Ampere's equation equal to 2e-7 N/A^2.
The older style of fractions and relation is to say something like 2 deg 8 min of arc. I have seen a temperature given as 38 deg 22 min Fahr.
Gallon = cube side 6.522 inches. But I don't need to work in cubes by itself. I fl oz = cube side 0.1 feet.
Kilogram: the mass of one litre of pure water. How much does a gallon of water weigh???
One gallon is 10 lb water.
How many Imperial Tons does your swimming pool weigh?
An imperial ton is very nearly 36 cu ft: ie 1 fathom * 1 fathom * 1 foot. If you insist on a cube, try 3.3 ft or 39.6 in, or 5 links, they're all the same.
I can easily visualize things in terms of metric units... but it's very difficult to do so with Imperial units. I see this as a great aid in any sort of mental gymnastics.
You must have went to sleep during the arithmetic lessons.
My views were based on Technet articles, the Windows NT resource kit, and actually seeing NT4 and Win2K in action. Can't get more official than that.:)
Slashdot Mirror
I'm relating these to children's stories, which have shown a decent persistance.
The point is, that a book or a show can disappear leaving just small marks on society. But given the current techie culture of quoting heavily on certian books and references, we might expect the original Star Wars, The Matrix, and the general feel of Dr Who and Star Trek to suvive, these are doing better than other works, such as Blakes 7 or Babylon 5.
Given the vast material on Dr Who and Star Trek, we might find these surviving in a guise like Noddy, Mickey and Minnie, &c, where people are familiar with the characters, but not any specific plot.
Hitchhicker's Guide, may well be the new Alice in Wonderland, and the Matrix, and Star Wars may well survive as storys that give many quotes to, something like Black Beauty, or the Secret Garden.
The thing to understand, is that if the problem is not giving the right solution, then you may be asking the wrong question...
Velikovsky says that craters were made during planetry encounters. So that a crater is concurrent with the fall of civilisations does not dosprove Mr Velikovsky. Certianly, you have not advanced any reason why Velikovsky is a crackpot, and why "crackpots" can not engage in serious science [eg Sir Isaac Newton]. Character attacks are not good science.
Firstly, Velikovsky did submit to peer reviews. This is documented in a number of books. None less than Albert Einstein read the early books favourably.
Secondly, the thing is science, it provides testable ideas, and has made successful predictions. He says that Venus is hot enough to boil petrolium, and that petroluium fires would be burning on Venus were there oxygen there. The then current view was that Venus is 59 degF. His view does not need changing, by virtue that they made so many successful corrections.
I mean, it was not all that long ago, when Shumaker-Levi tumbled into Jupiter, that astronomers conceded that these things DO happen.
That is, in fifty years, Velikovsky remains unchanged and a valid theory, where the accepted theory has undergone a metamorphis due to what we find out there. Is that not enough to reconsider.
The collapse of the Roman Empire and other events around the year 300 were discussed in the recent book Catastrophe, the proposition of which is that the Dark Ages were caused by an upset of the world weather around 535, by a large volcano that Krakatoa is in the crater of. The events of 535, as well as those of 1485BC and 687BC, suggest that it was not the work of a local civilisation, but widespread disasters.
You must understand this about Velikovski's theory. He did not posit that the celestial events occured, and then looked for confirmation, but rather, from the study of ancient legends, using his skill as a psychocharist, suggested that the described events happened, and were suppressed (as victims of trauma usually do). That is, Velikovski's wandering planets are an explination, not a cause. Your "Sun Standing Still" is described as a tippletoe movement of the earth.
The great chorus of people who stood up and said it was rubbish sounds similar to those who stood up and said the earth moves in the sky. There were serious objections to a moving earth, that took centries to overcome [like, how can it move and keep its atmosphere].
To date, I have not seen any reasonable attempt to refute Mr Velikovsky, which, if he were such a widely read author, and Science were so sure of their footing, this aught be addressed. Put simply, there is nothing in Velikovsky that is against the reason of physics, and certianly, one must agree that our understanding has changed in the intervening time.
On the other hand, there are perfectly reasonable explinations to most of the events that Velikovski describes. Check out the Abacus book Velikovski Reconsidered.
Also, Velikovski DID submit his books to peer review. But there was an organised campaign by some scientists to prevent the publication of his book by his first publisher, MacMillan.
The relevant books are things like Ages in Chaos, Worlds in Collision and Earth in Upheval.
voltage controlled switches, actually.
CMOS. = Complementry Metal Oxide Semiconductor. This is relatively slow and expensive, but it retains its state when there is no power, hence its use in Bios memory. Most circutry is done in doped silicon.
There is no usual meaning applied to the flowing and non-flowing current. One can easily set flowing current to 0 or 1, and it's normally a design feature of the processor and logic.
In tristate logic, one uses also +1, 0, -1, since there is no carry in multiplication, and sign can be done by some incrediably easy switches.
I was thinking more in terms of solid as opposed to flat: 3D vs 2D, not solid vs gaseous [valve], or solid vs flexiable [relay].
When you're on a good thing -- stick to it. At least I'm not a Windoze fan, but support the alternatives. :)
But would it not be better to work on 3D chips: actual "solid state circuitry"
So a car showing emotions is likely to lead some people into a "deep and meaningful" relationship with their car, and it would cause grief when this is abruptly ended, for example, by an accident.
Maybe they're going to reduce the BeOS kernel into something that runs on a Palm Pilot. I thought on the same token, Win CE is based on Win NT.
One might hope for a BeOS desktop and palmtop along the same lines as Windows.
Just a thought.
The thing about "driving a car" means that you have to "prove" who you are to these people, and therefore, evidence of that proof can be used elsewhere.
The scheme was set up to get around the teenage drinkers in hotels, even though they're 18, not having a licence.
I think it has more to do with buyer perception than gee-whiz technology, although it could have some application for bands on the road or PA events.
It's been nice talking to you. Thanks
Personally, I think that we should go the VB crowd because of the collapese of Ansett and the WTC. MS is not relenting on their release date for XP, and are probably using the drawn attention as a cover.
The reason that I say the SI is a hodgepodge is that it is not anything like the sorts of systems that arise from theory. Much of theory had to be rewritten to accomidate the features of SI.
The electrical units pre-existed the MKS by many years: that there was a connexion to be made was only found in 1905. That is, the kilogram is a derived unit in the m-J-s system.
The reason that the mole was elevated to a separate base unit, was that the older dimension was M. In the MKS, this would have made the kilomole the base unit. This is what was actually used. SI gets around using gram-moles and kilograms, by making the mole a base unit.
The terms "practical" and "rationalised", bandied around as if they were things to be valued, actually have quite different meanings.
"Practical" is made out to mean that the units are of practical size. In fact, all it means is that the Joule, Watt, Ohm, Volt, etc, are part of it. The centimetre-dekatonne-second system [Mie] is "Practical". I made one out of the foot-Joule-second as well. V, A, ohm, F, H, second, watt, joule, Wb and C are unchanged. Mass=hile, force = trood, length=foot. J=foot^2*hile/s^2. Make the hile represents the "slug", and 100 degC = 140 degT. A new weight "bess" is needed so that trood = bess-force. In this system, J = foot-bess-force, and kJ=bess * degT * joule constant.
"Rationalised" is made out to mean "rational" or "logical". It actually means an adjustment to bring together values. When the 4pi is introduced into coulombs equation, it makes some measures equal. For example, in polarised media, J, M, P were 4pi of the induced fields B, H, D. After rationalisation, they become equal. Displacement originally referred to the displaced electrical charge P [as in the International Critical Tables], but when P=Di, this allowed D to become also displacement.
In any case, rationalisation means the system was fiddled with afterwards, ie not self evident. Gravity and light have not been fiddled with, so the system is incoherent over this respect.
I never said that imperial wasn't coherent (nor did I say it was).
Sorry: my mistake. :(
On the other hand, the metric system called SI, which is used with Litres, is somehow a hodgepodge of different systems.
If it is acceptable to use it with SI, and other units not with SI, then why reject from the system?
You are the one who originally said SI is a hodgepodge, but now you're saying that it's not? Is this now what you meant? It is essentially what this sentence is saying.
That SI has seven base units where other systems need only three or four, is a pretty good sign.
Things that are measured take singular: money is coming in from ..., where counted things take plural: cattle are coming in from ...
Very well, so what is this in response to? I don't see how this has much to do with what I said...
It's in relation to the difference between a number and a measure
But that did not stop you from demanding the source for the recent status of the mole.
Of course I did.
Fair enough.
Notes on the definition of "ampere". Are these your own definitions and arguments, or taken from the documents you referenced? It is a paraphrase of the actual definition, and considerations in the construction of reproducable resistences, as I quoted
A definition, can only be true for a specific case.
You can only define, for example, that a pound-force is the gravity acting on a pound. You can define a function, as well: for example, square ~ as the area of a square of side ~. But you can not then having defined a foot=12 inches, and the relation of square to linear measure, then define a square foot as 144 square inches. You can not define an equation.
If all the elements of an equation are defined, the equation can not also be defined. The equality is either true or false, or irrelevant.
Define in what sense? I can make up an arbitrary, meaningless equation that has no real world correlation. It's not very useful, but I defined it.
True. That's how most quantities start out: someone defines a measure that is sort of useful.
With the conversion factors placed in the appropriate locations I'm sure they are (I don't see why they wouldn't be), but then again I don't know for certain.
Flux from a charge Q, in SI flux=Q; in CGS; flux = 4.pi.Q
Capacity and Volume
Capacity and volume are the same concept: space, but there the distinction is needed because there are a lot of measures that are not derived from the linear dimensions of the vessel. Is not the imperial gallon derived from the pound?
History is important, because it decides the evolving patterns[...]
Historical ideas are important, because the way we see measures change over time, as does our use of number. For example, around 1900, the style was to use large numbers of small units: CGS, grains and inches. In 1980, the style is to use small numbers of large units, MKS, pounds and feet. You would miss that if you were not aware of it.
Relying on historical wreckage can lead you into the same mistake I heard of about women's feet in China. The servey merely looked at their feet and ages, and noted a movement of the feet in certian trends. This reflects changing customs, not biological presures.
Have a nice evening. :)
Could end up like the bars on the television. Didn't think of that - ha ha ha. :)
It's nice that you argue that the Imperial system is a coherent single system, despite the different capacitity systems between the US and UK, and when the Russians used the foot, they did not use the pound. On the other hand, the metric system called SI, which is used with Litres, is somehow a hodgepodge of different systems.
Quanties are measured, and change when the units do. Numbers are counted, and do not change.
Things that are measured take singular: money is coming in from ..., where counted things take plural: cattle are coming in from ...
I never argued any history with you, but argued statements you made about SI. Therefore discussing SI as it currently stands is the issue on the table.
But that did not stop you from demanding the source for the recent status of the mole. Historical prospective makes metrology easier to understand.
Notes on the definition of "ampere".
Unlike the other definitions, the ampere is defined to set the permeability of free space to a fixed value. Specifically, it can be written so that it is 1e-7 H/m.
The practical electrical units were defined to be a decade multiples of the theoretical EMU, for "practical applications". Any system that has an energy unit of a Joule, and a time unit of a second, can absorb them. In SI terms, this means a length of k metres, and a mass of 1/k^2 kg, the resultant permeability constant is (1e7)/k Henry/Length.
Maxwell puts k=1e7, which makes L=Quadrant [of the earth, = 10,000 km (hence the old name of the Henry), and M = 1e-14 kg.
. The system derived is coherent with the EMU equations.
In order to have k != 1e-7, you have to rewrite the EMU and divide quanities (eg B from H). You could define k or L. Gustav Mie defined L=1 cm, and hence k=0.01, M=10 tonnes. Giorgi puts L=1 metre, so k=1. This is the basis of the MKSA, and hence the SI.
If you chance to visit your NIST site, download sp330.pdf, and look at the adobe page 67 of that. You will see they talk of a new value for the von Klitzing constant of 25812.807 Ohms. This is 137.036*2pi*29.9792458 Ohms. 29.979&c is the speed of light. The reason that this can not be made the new definition of the Ohm is because it would upset the intended definition of the ampere, as seen on adobe page 68 of that pdf.
Therefore, we are entitled to regard the ampere defined to preserve the permeability of space, and that the H/m as the most important fixed value.
base units, definitions and dimensional analysis.
A definition, can only be true for a specific case. You can not define an equation. There is nothing inherent in the definition of any of the base units, or even in the derived units, that imply the relationships involved.
Units can not be intrinictly coherent. They are coherent to a body of equations. CGS units are coherent, as are SI units. But they are not coherent to the other's equations. And, as a result, the dimensions are not strictly equatable; hence the "equates to" in the conversions.
One has a series of relationships that define things. For example, Force=mass*acceleration, or F=ma. This gives a definition that defines a unit force in terms of unit mass and unit acceleration, under specific conditions. [A definition can not infer a relation, but must infer the things it depends on].
There are units that depend on force, eg power, energy and pressure.
Gravity is easy to use: mass can be converted to force fairly easily. The term "weight" translates variously to a mass "net weight" or statistics, or a force as in mechanics. This leads to mass being used as a force unit or mass force indifferently: eg pounds per sq in.
In the case of the fps system, one can derive an absolute system based on the f=ma relation. Kelvin makes the pound mass, and the f=poundals. Perry makes f=pound, and derives a mass="slug". The practical system is a mix of Perry and Kelvin systems, as gaussian = mixed ESU, EMU.
One can diffirentiate the (mass,force), like Stroud (pound, Pound), or the german style (gram, pond), the US style (M-mass, M-force) or the new style (M, M-force). cf Kennelly's ab-, stat-
One can make all systems coherent by rejecting F=ma as a derived equation, and defining F as a base unit. So you would have ft-lb-pdl-s or f-slug-lbf-s or ft lb-lbf-s, which is how the fourth, electical quantity appeared (as ESU and EMU are cm-g-s-Fr and cm-g-s-Bi).
Alternately, one can divide the force into "force = f=ma" and "g-force=mg". This is how D gets split from E.
Dimensions arrise from a putting the base units as variables, eg L M T F, or L-M-T-g. The number of dimensions is quite arbitary. It's an open algebra. This means, that I can take your dimensions and use it as if I derived it. But if I want to use it in a dead-end calcualtion, I can substitute L, M, T as 0.3048, 0.4536 and 1, to convert fps to MKS, or even put L, M, T as L^1, L^3, T if this needs to be done. It's an algebra, and I can substitute the values.
Young had an algeba that allowed exact conversions between SI and CGS. He had six base units, adding S and U to the LMTI set. U basically corresponds to a turn in "ampere-turn". The HLU and Gaussian has a curl here, ie a Bi = Fr/s - curl. 1 curl= 29979245800 turns. S is the space factor: 1 Coulomb produces 1 C-sur of flux, or 4pi C-sun of flux.
He has a body of equations, and six free variables, or six base units. You can fold the equations to get the SI or CGS equations by substituting for S and U beforehand, or leave the equations unfolded and add two extra base units to SI and CGS.
So how many base units for electricity? four or six?
There is no reason that in future some compelling reason will evolve for us to associate the candela with the watt. I mean, they used to measure resistances in miles (of copper wire).
Capacity
I'm sorry, but I'm failing to see why one would be more accurate than the other.
You are looking at the number, not the practical implication of measurement. Have you ever tried to construct a cube of a specific volume. It's easy to do a cylinder, since these can be turned on a lathe, which is why you see lots of cylinder measures. But a cube?
Technical vs Scientific measurement
The thing that the technical people brought into SI is that every unit should have a name. In science, one can say "in cgs units, and give just the number.
The thing that the scientific people brought into SI is coherence, the idea that one can say: the SI unit of X is Y. In some fields of science, they simply say "in xyz units" and drop the units completely. That's why the CGS units did not have names until Kennelly gave then ab- and stat- names in 1904.
History is important, because it decides the evolving patterns, the candela may be the current "pound-force".
Have a nice day. :-)
The definition of the second has changed to more stable measures as the ability to create clocks got more accurate.
The second as a fraction of a year is never intended to be a second of arc, as applied to a year=360 degrees, This is about 24 seconds long, and the sort of unit used by the Babylonians.
The ampere is defined to make the constant in Ampere's equation equal to 2e-7 N/A^2.
The older style of fractions and relation is to say something like 2 deg 8 min of arc. I have seen a temperature given as 38 deg 22 min Fahr.
Gallon = cube side 6.522 inches. But I don't need to work in cubes by itself. I fl oz = cube side 0.1 feet.
Kilogram: the mass of one litre of pure water. How much does a gallon of water weigh???
One gallon is 10 lb water.
How many Imperial Tons does your swimming pool weigh?
An imperial ton is very nearly 36 cu ft: ie 1 fathom * 1 fathom * 1 foot. If you insist on a cube, try 3.3 ft or 39.6 in, or 5 links, they're all the same.
I can easily visualize things in terms of metric units... but it's very difficult to do so with Imperial units. I see this as a great aid in any sort of mental gymnastics.
You must have went to sleep during the arithmetic lessons.
On the other hand, you offer me a MEGO ad.