How to save billions of dollars.

[kandrathe]

Best logical anti-penny rant ever!

[Jester]

There are lots of countries that get by without denominations that small. For example, I was just in Uruguay, where the 50 centesimos piece, half an Uruguayan peso, is worth about 2.5 US cents - and even then, nobody uses the damn thing except for obligatory change. Even the single peso isn't a heck of use.

I'm on board - down with pennies!

-Jester

[Concillian]

I agree, while we're streamlining, let's move to the whole 2 timezone thing too: http://www.standardtime.com/index.html

[Taelas]

Such logical, rational ideas.

Of course they will be completely ignored by the masses.

[LennyLen]

There are lots of countries that get by without denominations that small

We got rid of 1 and 2 cent coins here ages ago, and then 5 cent coins a few years ago.

[Taelas]

We had 25-øre coins scrapped last year. An øre is defined as 1/100th of a krone, and ~5 kroner is equal to 1 dollar, so it was the equivalent of a nickel.

Why you guys still have pennies baffles me.

Oh, and while you're at it, switch to metric and centigrade. Even more rational, logical ideas!

[Maitre]

Best logical anti-penny rant ever!

[video style rant]The one thng I didn't hear was the economic projection for the metals industry if the penny goes away. What happens when somebody starts a copper/zinc reclamation business processing the old pennies, and starts selling cheap recycled copper? How does this affect global demand for raw copper mined in Africa? Oh yeah, and what is the estimate of environmental impact when people discover pennies they forgot to redeem during the buy-back period before the coin disappears. What are they going to do? Toss the penny. Then you get heavy metal accumulation in landfills (like there isn't enough of that already). [/video style rant]

To be perfectly honest, I can't disagree with the premise that any denomination more expensive to produce than it is worth is a prime candidate for removal, however, I don' think dropping to the three coin system recomended in the video would fly in the US. With the present state and local tax rates (depending on jurisdiction ranging from 0% - 7.5% or more) small denominations still seem important to me. I would instead propose a four coin system: copper "nickels," dimes, quarters and dollar coins.

Although, maybe we should eliminate hard currency altogether now, rather than waiting until farther in the future when barcodes and scans will be the only currency we need.

[kandrathe]

To be perfectly honest, I can't disagree with the premise that any denomination more expensive to produce than it is worth is a prime candidate for removal, however, I don' think dropping to the three coin system recomended in the video would fly in the US. With the present state and local tax rates (depending on jurisdiction ranging from 0% - 7.5% or more) small denominations still seem important to me. I would instead propose a four coin system: copper "nickels," dimes, quarters and dollar coins.

Although, maybe we should eliminate hard currency altogether now, rather than waiting until farther in the future when barcodes and scans will be the only currency we need.

We have .10, .25, .50, and $1 -- other than fractional change, I don't use pennies or nickels for anything. I would propose a 2 year period of time to allow retailers to reprice their goods without creating additional work in stocking and repricing. By then, people will get used to things being $2 or $1.90 instead of $1.99. Due to taxes, you'd still need to round at the register. Long gone would be the give a penny, take a penny trays. I agree electronic transactions are the best way, but... I like the freedom of currency if I want to stay out of the system of tracking all my purchases...

As for the price of metals... Most of us have more copper in our wire, and pipes in our homes than we could muster up in pennies.

[Jester]

To be perfectly honest, I can't disagree with the premise that any denomination more expensive to produce than it is worth is a prime candidate for removal...

They mention this in the video, and you mention it here. But I don't understand. Coins are not minded for their seignorage rents, at least, not this century. They're produced for their social utility as currency. A nickel will surely generate more than 9 cents worth of use in its total lifetime circulation. The argument for replacing it is that will generate even more in costs, from people having to carry them around and make change with them. The fact that its face value is 5 cents is almost irrelevant.

If you were just concerned about production costs, you'd print $1000 dollar bills until you ran out of ink.

-Jester

[--Pete]

Hi,

They're produced for their social utility as currency.

Indeed. Neither the metallic value nor the production cost have anything to do with the nominal value of a coin. Minting coins from a cheap material, say aluminum, would make more sense than keeping the copper, nickle, silver -- especially since those aren't really used anyway.

However, let me join the ranks of those who would like to see the penny and nickle (and quarter) removed from circulation. The total inflation from 1913 to now is about 2200%. A penny then is about the equivalent of 22 cents now. We really don't need that fine a graduation of money. As to the quarter, since it is worth 25 cents, and since the objective is not only to get rid of small denomination change, but also to go to 1/10 of a dollar as the smallest increment, it has to go. It could be replaced by a 20 cent coin, but doesn't really need to be replaced at all. We've long made do with pennies and nickles, a factor of five. Dimes and halves would simply replace them.

--Pete

[Lissa]

Best logical anti-penny rant ever!

<snip> Toss the penny. Then you get heavy metal accumulation in landfills (like there isn't enough of that already). <snip>

Zinc is not a heavy metal. And considering that pennies are mostly zinc now with a thin veneer of copper, it's doubtful the actual copper would amount to much anyway.

[Rhydderch Hael]

I thought that, in numismatic terms, what we've been using all this time aren't actually coins, but tokens.

A "coin" is minted with some intrinsic value. We haven't seen the likes of that since clad copper has been used to make our dimes, quarters, half-dollars, and dollars. They have instead become "tokens", which have a represented value— very much like a paper note does.

[--Pete]

Hi,

Oh, and while you're at it, switch to metric and centigrade. Even more rational, logical ideas!

I often hear complaints or jabs about the USA not being on the metric system. Actually, we've been on the metric system since the late nineteenth century (1878). And we were the second country, after France, to use it officially long before we formally adopted it. We've been just a little slow to convert to it -- but all of our units are based on it.

Of course, the metric system itself sucks. It has one thing going for it, a unified set of prefixes for multiples of 1000 (with a few for 100 and 10). Every thing else about it (size of basic units, the fact that ten is only divisible by 2 and 5, the ridiculous size of derived units, etc.) is wrong.

The metric system was conceived by a bunch of ivory tower intellectuals with no practical experience. They worshiped simplicity and regularity, and they sacrificed utility for their dreams. Only a revolutionary French academician could think that the unit used to measure the length of a nail should be (effectively) the same unit used to measure the circumference of the Earth.

Indeed, metric units are arbitrary. Unlike the common units they replaced, they are not based on either accepted usage or convenience for the task at hand. By 1800, it took an amazing amount of geocentricism to base a measuring system on the dimension of the Earth. But that's just what they did. Starting with the meter.

One meter was supposed to be one ten millionth of the distance from the pole to the equator. Now this causes a problem. Traditionally, the earth is divided into degrees, minutes, and seconds. And from Babylonian times, there are 360 degrees in a circle, 60 minutes in a degree, and 60 seconds in a minute. By 1800, there was a large amount of material, from maps to star charts to sailing instructions that was based on the Babylonian system. In addition, there were large numbers of instruments using that system, from sextants to indicators on telescope mounts and more.

The nautical mile is the distance subtended on a great circle of the earth by a central angle of one minute. This makes navigation much easier, since the separation of two points in nautical miles is just their angular difference along a great circle in minutes. To make the meter (actually the kilometer) equally useful, the academicians proposed a new measure for angles, the grad. A complete circle is 400 grads. How that makes sense is not clear, since the circle is the natural basis for angular measurement and 100 grads to the circle would have been more in the spirit of metrication. However, they wanted a circular measure that agreed with their linear measure (which, when you think about it, shouldn’t the unit of length have such that the equatorial circumference was a power of ten?) Regardless, the problem is practical. Since the grad is not a widely accepted unit, finding maps with longitude and latitude in grads is a tad difficult. Also, if available at all, I suspect a sextant in grads will be hard to find and thus, pretty expensive. And I doubt that sight reduction tables in grads are any too common, either. If the grad is forced on the world, then yet one more useful unit would fall to the mindless metricians.

So, we have the meter. An arbitrary unit of no particular value. Had the academicians had the brains of a peacock instead of its pride, they would have used the nautical mile and developed the length unit around it.

Now, from this arbitrary unit of length, we get our unit of mass. The gram was originally defined as the mass of one cubic centimeter of water. Why? Why a cubic centimeter? That results in a pretty small unit of mass. Why water? It’s easier to purify mercury, and it would have given a slightly more useful mass to work with. Combined with the length of the meter, the smallness of the gram leads to an unworkable system. More on that later.

Then there was the whole thing with time. Neither the decimal calendar nor decimal time made the grade. Even the French academicians were smart enough to let them die. Had they combined their intelligence with common sense and recognized some of the usefulness of traditional practice, they might have actually come up with a better calendar, perhaps one of thirteen four week months with a non-weekday, non-day-of-the-month new year’s day and (as needed) leap year’s day.

Temperature measurement was only partially their fault. Around 1800, temperature was not well understood and the concept of absolute zero was still some years in the future. However, by the conference of 1875, things had changed quite a bit. The adoption of the centigrade scale at that time was a mistake that has had repercussions to this day. The modern scale is based on the degree centigrade but with its zero at absolute zero. Since two points are needed to establish a temperature scale, the second point was chosen as the triple point of water. This gives us the ugly additive factor of 273.15 to convert from Celsius to Kelvin. What happened to one unit fits all and everything by powers of ten? Indeed, why use a unit based on the freezing point and boiling point of water at all? The Fahrenheit values of zero and one hundred are more useful to the human scale. They are the temperatures (approximately) above and below which humans start to lose efficiency. The triple point of water, at least, makes sense in that it is a precisely defined condition.

Finally, there is the ampere. While not bad in itself, it leads to absurd derived units for induction and capacitance. The unit of capacitance? A Farad. But you typically see micro farads, pico farads, even pico pico farads. Inductance and the Henry is not as bad, but it by no means good.

The remaining two ‘fundamental’ units, the mole and the candela, are anything but. The mole is basically just a conversion factor from atomic mass units to grams. The candela is just the areal power density of a monochromatic light source.

How well were those base units chosen? Well, consider that there has never been a system of units based on them directly. The cgs systems (there were at least two) were based on the second and the gram, but used the centimeter for length because the results of using the meter were ludicrous. Still, it led to a unit of energy, the erg, that is so small that "One hundred million ergs!" (a line from a really bad sci-fi movie) is about the energy content of 1/4 of a PBJ sandwich.

The MKS system, the basis for the SI units, is hardly better. The unit of force, the Newton, is too small for most practical applications. Ask a metric user what he weights, and he'll give you his mass in kilograms instead. Metric torque wrenches are not labeled in N•m or N•cm (which are units of torque), probably because there isn't enough room on the barrel of the wrench to write all the digits. Instead, they're labeled in kg•m, kg•cm, or g•cm. I'm not too sure what a mass times a distance is, but I'm sure it's no torque by any definition I know.

As to the vaunted power of ten multiples, so what? First, if appropriate basis are used to measure things, then not many multiples are ever needed. Second, the unfortunate happenstance of our four fingers and a thumb gave us one of the worst numbering systems possible. Given our bilateral symmetry, it is pretty much inevitable that we would use an even base. Had we had four or six digits on each hand, we'd be a lot better off. Eight would be beautiful in that it would provide fast conversions between bases that are a power of 2. Twelve, though not as useful, at least has the advantage of having 2, 3, 4, and 6 as its factors.

How important is this? The next time you bake a pizza (or other pie) at home, try to cut it into ten pieces. Humans are very good at dividing things into halves, and halves of halves, and so on. They're almost as good at dividing things into thirds. But it's the rare untrained person that can get a division of an object by fifths right.

And, yeah, really nice system of prefixes. There are prefixes that are orders of magnitude apart, but their abbreviation differ only in being capital or lower case. Nice source of potential mistakes. Like peta and pico, zetta and zepto, yotta and yocto, and (before they changed it) deca and deci. Of course, they fixed that last pair by breaking their own rules about one letter abbreviations. And then there's the whole mega and milli and micro mess. Do you know, right off the top of your head, where µ is on you keyboard?

Even trained people screw up all the time. If I were really getting the 0.5 MG daily dose of tacrolimus that my prescription bottle claims, I'd be writing this on a Ouija board instead of a keyboard.

Ah, but conversion is so much easier say the metrification supporters. That’s their big bad bugaboo. Sure, to convert the width of the Atlantic from miles to nails is a lot harder than from kilometers to centimeters. But why would anyone want to? Or, except as a stupid exercise in primary school, how often does anyone actually do it? How often does someone need to convert barrels (any of them) to ounces (any of them)?

Consider the hand. You're out in the paddock, looking over some horses. One catches your eye. You look in its eyes, you check its ears, you examine its teeth for rings and wear, you then want an idea of how tall it is. Realizing you've left your meter stick at home, you jump into your car, go get the stick, and drive back to the paddock. By then, the horse is no longer qualified to run as a two year old. Me? I've got my measuring sticks with me at all times. I simply walk them up, hoof to withers, counting as I go and estimating the last to the nearest 1/2 hand. If I get 16 or so hands, I know I've got a reasonable size horse. No Clydesdale, but no pony, either. I compare hands to hands. I don't convert them to inches or fathoms or millimeters.

If a 16 hand horse runs a 7 furlong race, does anyone in their right mind convert that to 64 inches and 55,440 inches to find that the horse has run 866 times its height?

When you're driving do you convert your speedometer reading from km/hr to cm/s? If you're running the 100 meter sprint, do you convert that to 0.1 km or 10^5 mm? The reason the metric system needs easy conversions is the one size fits all mentality. If one is going to measure the width of a nucleus with the same ruler used for the diameter of the universe, he’s gonna need a lot of powers of ten. But in real applications, the metric system buys nothing. It is no easier nor harder to calculate gas usage by dividing some number of miles by some number of gallons than to divide some number of kilometers by some number of liters.

And yes, one unit per dimension is easy. On paper. But when you are talking about the mass of stars, is it reasonable to use the same unit that you use to measure the mass of the hydrogen atom? (Hint: the first is usually given in solar masses, the second in atomic mass units. And neither have an exact conversion factor to SI units).

There are a lot of conversion factors in the traditional units. My point is that all of those conversions don't matter. First, most people have no need of most of those units, they're specific to surveying, or navigation, or jewelry. Second, even for when they're used, conversion is seldom if ever necessary. There are few, if any, recipes that call for 16 ounces of flour and 2 ounces of gold making it necessary to convert from troy to avoirdupois.

So, yes, the metric system has a certain simplicity in definition. But one pays for that simplicity in many ways, including unnecessary conversions and the introduction of many zeros either before or after the decimal point. I'm not saying the metric system should not be used. I'm not even saying that it shouldn't be the basis for all measuring systems (as it is in the USA). I'm saying that demanding that everything be measured in SI units just for the sake of a trivial consistency is wrong. Discarding utility for elegance is a stupid, elitist attitude. Appropriate for academicians during the French revolution, possibly, but not for a modern society that has expanded its lengths and masses by orders of magnitude in both directions.

The imperial units are not arbitrary. Quite the opposite, they were developed as they were needed and they were convenient for the quantities they measured. So, terrestrial distances can be measured in miles in five digits or less. An arrow shot can be stepped off in yards, the width of a wall in feet. Originally, each unit stood alone, and no one would have thought of measuring a bolt of cloth with a surveyor's chain.

Consider how things are measured. For instance, atmospheric pressure. You take a glass tube with one end sealed and fill it with mercury and stand it up in a bowl of the same, open end down. Then you measure the height of the mercury in the tube relative to that in the bowl. That gives you a direct measurement of the pressure in some unit of length (usually mm of Hg or inches of Hg). Now, atmospheric pressure is usually just compared to atmospheric pressure, not to the pressure it takes to form diamonds nor that in intergalactic space. Just what is gained from converting from mm-Hg to Pa? It makes the useful comparisons no easier, and simply adds one unnecessary and potentially error causing step to the process.

Useful units arise as needed, and go when no longer needed. They don't get handed down from ivory towers nor are they mandated by politicians. Consider atomic cross sections in barns. Or look at the league. The origin was how far an average person could walk in an hour. Now that people seldom walk farther than from the couch to the refrigerator, it is of little use. But when shank's mare was most people's form of transportation, then it was a very useful unit. If someone told you it was 5 leagues to town, you knew right away how long it would take to get there. If they told you it was 24 km, you'd have to go through "Hm, I can walk about 5 km in an hour, so it'll take me about 5 hours." The league came about because it was useful. If it was ever formally defined in terms of other lengths, then that is a relatively modern (and useless) innovation. And it didn't need to be legislated away. Along with the knowledge of how to saddle a horse, it simply slipped into obscurity when it was no longer needed.

So, no. I'm not sold on the metric system. It is a poor system that, like the Jack of all trades, does many jobs, but none of them well. The one real advantage it has is that it is the closest thing the world has to a unified measuring system. But don't take that too far. When I was still working on cars, I discovered that German, French, and Italian metric nuts and bolts were not interchangeable. Oh, yeah, they all had the same nominal size heads and shafts, but they used different pitches and different thread shapes. My tools have been gathering dust since about '85, so that may have changed with the EU and all. But remember, standards are important. That's why every company, every country, every union has their own.

Now, if you really want a great system of units, consider a set of natural units.

--Pete

[Jester]

Indeed, why use a unit based on the freezing point and boiling point of water at all? The Fahrenheit values of zero and one hundred are more useful to the human scale. They are the temperatures (approximately) above and below which humans start to lose efficiency.

While I agree with most of what you've written, this makes no sense to me, and indeed seems to be in contradiction to the spirit of the rest of your argument.

The Fahrenheit values of zero and one hundred are worth nothing. One, or five degrees above or below zero, or one hundred, and nothing special at all happens. It is not a threshold of any relevant kind, practical or theoretical. I don't even know what to make of "start[ing] to lose efficiency" - are you saying that humans operate with no loss of efficiency between these points? How do you know when you "start" to lose efficiency? And why would that be a relevant marker even for a practical temperature system?

The freezing and boiling points of water, OTOH, are of enormous practical, everyday usage. People are mostly water. Our planet is mostly water. We consume water. Water falls from the sky. We travel across water (without which the nautical mile wouldn't have been a hell of a lot of historical use). We drink water drinks, and both freeze and boil water for consumption. Water is a very natural, practical reference point. Zero and one hundred are physical thresholds - you can tell when you've reached them (suitably adjusted for pressure) pretty much immediately by its effects on the water surrounding us. It is precisely defined (in theory, if only roughly in practice), it is observable in everyday life, and it has practical value. Fahrenheit has... uh... well, nothing, really.

Kelvin is no doubt more useful for scientific measurements, because it starts in the ultimate physically justifiable point, absolute zero. But it is damned annoying to use numbers from 250-350 to describe everyday temperatures, and if we have to use a compromise system, Celsius/Centigrade seems like a good one.

-Jester

[--Pete]

Hi,

The Fahrenheit values of zero and one hundred are worth nothing. One, or five degrees above or below zero, or one hundred, and nothing special at all happens. It is not a threshold of any relevant kind, practical or theoretical. I don't even know what to make of "start[ing] to lose efficiency" - are you saying that humans operate with no loss of efficiency between these points? How do you know when you "start" to lose efficiency? And why would that be a relevant marker even for a practical temperature system?

Thank you. That is indeed correct and I've deleted it from the Standard Metric Rant of which this post was version 0.0.1. The US military uses those two numbers (0 F and 100 F) as indicators for when additional manpower is needed. For every degree below 0 F, the military considers a 2% loss of efficiency. There's a similar correction for above 100 F, though I can't remember the actual ratio.

The freezing and boiling points of water, OTOH, are of enormous practical, everyday usage.

The freezing point, yes, for the difference between solid and liquid is critical. But there is no particular advantage to labeling it 0 or 32 or 273. The boiling point, no, for water does not boil naturally except in a few spots. That water boils and generates steam and can be used for cooking are all fine and good. But the *number* at which that phenomenon happens is of no practical use. For thermodynamical calculations, only an absolute scale works. And for everyday use, then pasta comes out the same at 100 C as it does at 212 F -- and no cook that I know of measures it anyway.

Water is a very natural, practical reference point. Zero and one hundred are physical thresholds - you can tell when you've reached them (suitably adjusted for pressure) pretty much immediately by its effects on the water surrounding us.

Actually, water is a terrible substance to use as a standard. First, its property of dissolving nearly everything (which earns it the title of the universal solvent) means that any water you start with is going to contain many impurities. It also means that whatever apparatus you use to purify it will probably partially dissolve, introducing its own impurities. Second, the relatively steep lines of its phase transitions mean that small errors in the pressure yields a larger error in the temperature than would be the case with other materials. I shared an apartment at Los Alamos with a chemist that needed precise and accurate measurements of temperature. After two months, he quit trying to use water and went to the Peltier effect and a large brass slug.

Kelvin is no doubt more useful for scientific measurements, because it starts in the ultimate physically justifiable point, absolute zero. But it is damned annoying to use numbers from 250-350 to describe everyday temperatures, and if we have to use a compromise system, Celsius/Centigrade seems like a good one.

Well, first, my point is that the Kelvin and Celsius systems are compromises. Compromises exactly for the reason of convenience and nothing more. Unlike some of the other compromises (Angstrom units, for one), the relation between the two scales is additive and not based on a factor of ten. So, I'm not so much saying that they are inferior to Fahrenheit as that they are inconsistent with the concept of metrication.

And, second, the right thing to have done would have been to make the triple point of water (or some other unique point in the pressure temperature plane) a single digit and multiple of ten. Like 300. Then, at least, a scale based on absolute zero and one handy for common use would at least have a simple conversion.

--Pete

[DeeBye]

In this thread, Pete composed a huge post. I haven't read it because it is too huge. I bet it is full of science stuff.

[--Pete]

Hi,

In this thread, Pete composed a huge post. I haven't read it because it is too huge. I bet it is full of science stuff.

I'd say mostly history.

--Pete

[weakwarrior]

I thought zero F was the temperature at which water fully saturated with salt freezes. It's not a terribly useful zero but it is precisely defined. I think 100 F is actually quite useful. Although this was not the original definition it is the temperature at which you can officially be called sick.

On the general rant - I think you exaggerate how little we convert units. I'm 5 foot 6 inches. My baby was born 9 lbs 4 oz. Stuff like that.

[Zenda]

Actually, we've been on the metric system since the late nineteenth century (1878).

No, the US may have been one of the signing nations of the Metre Convention, but up to this day does not officially use or mandate a metric system of units, making it one of only three countries that still use customary units.

Indeed, metric units are arbitrary. Unlike the common units they replaced, they are not based on either accepted usage or convenience for the task at hand.

Yeah, maybe we should have kept the Stunde, which represents the distance a person walks in a hour

So, we have the meter. An arbitrary unit of no particular value. Had the academicians had the brains of a peacock instead of its pride, they would have used the nautical mile and developed the length unit around it.

The original Nautical mile was not suitable for a standardized unit of length, because it varied from equator (1843 m) to poles (1862 m). It wasn't until 1929 that the (average) value of 1852 m was used internationally, and the US kept using it's own version (1853 m) until 1954.

Now, from this arbitrary unit of length, we get our unit of mass. The gram was originally defined as the mass of one cubic centimeter of water.

The base unit of mass in the Metric system is Kg, nog gramms.

The cgs systems (there were at least two) were based on the second and the gram, but used the centimeter for length because the results of using the meter were ludicrous. Still, it led to a unit of energy, the erg, that is so small that "One hundred million ergs!" (a line from a really bad sci-fi movie) is about the energy content of 1/4 of a PBJ sandwich.

The international system of units is developed from the MKS system, not the CGS system, so I'm not sure why you bring that up. CGS has hardly been used since 1940, except in the US (where it is still popular in the fields of electrodynamics and astronomy, for some reason).

The MKS system, the basis for the SI units, is hardly better. The unit of force, the Newton, is too small for most practical applications. Ask a metric user what he weights, and he'll give you his mass in kilograms instead.

MKS stands for Metre-Kilogramm-Second, so I see no problem with measuring my mass in Kg. I know you asked for weight, but noone is really interested in how hard the earth pulls at me in my current location, is it?

Given our bilateral symmetry, it is pretty much inevitable that we would use an even base. Had we had four or six digits on each hand, we'd be a lot better off. Eight would be beautiful in that it would provide fast conversions between bases that are a power of 2. Twelve, though not as useful, at least has the advantage of having 2, 3, 4, and 6 as its factors.

Yeah, maybe we should all go binary. No more silly conversions for computers. Should make them a lot faster.

Apparantly you are having a problem with the decimal numbering system as well as the metric system. I'll readily agree that binary would be better, but there are plenty of higher-priority issues, don't you think?

Even trained people screw up all the time. If I were really getting the 0.5 MG daily dose of tacrolimus that my prescription bottle claims, I'd be writing this on a Ouija board instead of a keyboard.

A normal daily dose of tacrolimus happens to 0.5 mg. If you think that's wrong for you, you should contact your doctor and not blame the metric system.

It is no easier nor harder to calculate gas usage by dividing some number of miles by some number of gallons than to divide some number of kilometers by some number of liters.

That's true, but beside the point. Metrification is about standardisation and unification. If you want to compare gas usage between a European and American car, for example, you will need to choose one set of units. In other words, one of us has to do a conversion. Since you claim to be 'metric', why don't you drop the miles and gallons and give me the numbers in kilometres and liters? (btw, if you insist on miles, which one is it?)

And yes, one unit per dimension is easy. On paper. But when you are talking about the mass of stars, is it reasonable to use the same unit that you use to measure the mass of the hydrogen atom? (Hint: the first is usually given in solar masses, the second in atomic mass units. And neither have an exact conversion factor to SI units).

The metric system is not limited to 7 base units. It doesn't say you can't use your own convenient units. It only requires you to define such units in SI units. That's why solar mass and atomic mass units are so popular around the world, and noone needs to guess how much it actually is.

The US military uses those two numbers (0 F and 100 F) as indicators for when additional manpower is needed. For every degree below 0 F, the military considers a 2% loss of efficiency. There's a similar correction for above 100 F, though I can't remember the actual ratio.

I hope you are not suggesting to conduct scientific experiments using numbers defined by the US military. The exact values are propably classified

Actually, water is a terrible substance to use as a standard. First, its property of dissolving nearly everything (which earns it the title of the universal solvent) means that any water you start with is going to contain many impurities. It also means that whatever apparatus you use to purify it will probably partially dissolve, introducing its own impurities.

Water can easily be obtained in a pure enough form to measure its freezing and boiling point accurately, no worries there. Actually, there aren't many other readily available liquids that would do.

Besides, you need to distinguish between the definition of a unit and its realisation. SI is about definition, while actual measurement of the units is left to scientists.

Second, the relatively steep lines of its phase transitions mean that small errors in the pressure yields a larger error in the temperature than would be the case with other materials.

You got that backwards. A sharp phase transition is needed for accurate measurements. If ice would melt gradually between 0 and 5 degrees, how would you ever determine the exact freezing point of water?

the relation between the two scales is additive and not based on a factor of ten. So, I'm not so much saying that they are inferior to Fahrenheit as that they are inconsistent with the concept of metrication.

Your factors of 10 find their use in the prefixes of units. The metric system says nothing about conversions having to be based on factors of 10.

[weakwarrior]

Even trained people screw up all the time. If I were really getting the 0.5 MG daily dose of tacrolimus that my prescription bottle claims, I'd be writing this on a Ouija board instead of a keyboard.

A normal daily dose of tacrolimus happens to 0.5 mg. If you think that's wrong for you, you should contact your doctor and not blame the metric system.

Note that you used the lower case m = milli and he used the upper case M = mega.

The metric system is not limited to 7 base units. It doesn't say you can't use your own convenient units. It only requires you to define such units in SI units. That's why solar mass and atomic mass units are so popular around the world, and noone needs to guess how much it actually is.

If that's all it takes: 1 foot = 0.3048 meters. So now can America keep using feet? Same goes for pounds and everything else.