Since my father was a physics teacher and I grew up in his lab, I learned metric units early. For some purposes they're great; you absolutely do not want to even try an engineering problem involving multiple SI unit conversions in imperial units. But for some other things, compatibility with infrastructure makes metric units a royal pain. Construction materials are a good example of this; what's the proper height of a ceiling in metric? The width of a door? The thickness of a wall? The dimensions of a framing stud? All those nice round numbers turn into ugly decimal fractions or you get something very noticeably weird and incompatible with normal expectations.
And in electronics you have a similar problem with pin spacings, standoff lengths, mounting hole diameters and spacings, and enclosure sizes. There aren't any good approximations like 750 ml for 1/5 gallon, and in a lot of cases fits have to be exact to work.
A manufacturer my company represents recently came out with a new product that is international in focus, and therefore all metric, including all the hardware. We found that the 7mm nut drivers needed to remove the acorn nuts that hold the back on are completely unavailable locally and we had to order them online.
Did good ol President Carter not try to have us all convert in the 70;s? I seem to remember something like that and it just never caught on. What gets me is when trying to work on a vehicle that was partially built in Canada and partially in the US. Have to have both SAE and Metric wrenches to get anything done. And do the Brits not also have there own system? I remember my brother working on his Triumph chopper several years ago and had to buy special tools. I just forget what they call it.
Even if the USA were to change everything else to metric, it would be slow to convert the power grid from 60 cycle to 50 cycle. The cost would be far to great.
50 cycle current would likely raise some havoc with some of my old retro computers. IIRC the C64 used the 60 cycle AC as part of it's system clock.
not sure about Fahrenheit but the definition of celsius comes from water. 0C is when water freezes and 100C is when water boils. I remember something like 100F is the normal human temperature ...
Anyways Celsius is additive, just one degree celsius is different from one degree Fahrenheit...
So coming from Germany (metric) to the US of is quite a challenge. Lets say nuts and bolts, or drills. Easy. if 8mm is to small try 9mm. But here? 7/56 , 1/8, ? WTF? Why, If you buy some wood, is a 2 by 4 actually 1.95 by 3.75? Another example. I ned some brick-tiles for my driveway. in metric it would be mesured in square meters. Here an MendoMills they ask me - how many YARDS? I feel helpless sometimes...
Enjoy!
Mike
Yes, Fahrenheit is based off of the human body. To me time is the only serious GLOBAL measuring device, but if NASA gets that warp machine going this might change lol.
@Bits
am still on a mission to tell everyone that Black Holes are a spherical phenominom and in no way shaped like a hole. There are no sides to it. It just gets denser and denser. And depiction as getting caught in a vortex is pure movie created nonsense. Like any other core of gravity, you would get caught in a decaying orbit, not a vortex.
Okay, I am a bit mental about this one. But film, science fiction, and TV have managed to trump reality. I fear a serious decline in civilization if popular science can blithely ignore real science.
As far as the warp drive, it may just suddenly disappear and we might spend years trying to figure out if it held together or not. Faster than light does mean that radio communications are no longer available, right?
it is way worse ... a couple of days ago here in the TV (FOX News) they talk about some illness affecting one percent of the population. And then, in big bold letters on the screen:
it is way worse ... a couple of days ago here in the TV (FOX News) they talk about some illness affecting one percent of the population. And then, in big bold letters on the screen:
1 %
1 out of 133
jupp.
and you are worried about cicrular black holes?
Enjoy!
Mike
The Information Age is coming to an end. To be replaces by the Misinformed Age.
As far as I know, Pounds and Ounces are, in fact, units of force. The mass unit is Slugs. 1 slug * 32.15 feet per second squared, is 32 pounds force.
Quote: "The pound-force is equal to the gravitational force exerted on a mass of one avoirdupois pound on the surface of Earth. Since the 18th century, the unit has been used in low-precision measurements, for which small changes in Earth's gravity (which varies from place to place by up to half a percent) can safely be neglected."
Hmm, never ever heard of slug before, but wikipedia believes it exists! (and the blob or slinch too...) Crazy crazy.
The metric system has a lot of merit but consider how nicely the english system of halfs, quarters, eights, etc. relates to the binary number system. I wonder if people will start switching back to the english system at some time haha.
There's a lot to be said for fractional (as opposed to decimal) systems of units for everyday life. It's just too bad that evolution gave us ten fingers, instead of twelve or sixteen. Otherwise, we'd have the best of both worlds!
There's a lot to be said for fractional (as opposed to decimal) systems of units for everyday life. It's just too bad that evolution gave us ten fingers, instead of twelve or sixteen. Otherwise, we'd have the best of both worlds!
Eight would be better. Of the ten we have the pinkies are pretty much useless anyway. Then all our math and computers would be octal based. Address and data bus widths would be in multiples of 3 bits ;- )
And fractional values would also be a better fit with octal.
Twelve is actually a better base for fractional measure, since it's divisible by three, as well as by two and four. That's why "dozen" is a thing. Although it's not so hot for binary circuitry, at least BCD (binary-coded duodecimal) would be more compact.
I wrote a long ironic reply to this thread but it disappeard because I had been logged off. A timeout thing I guess, all gone after the log-in window.
So I give you this instead: http://www.youtube.com/watch?v=rhXqZfTLhPY
When you log in, be sure to click the "Remember me?" box, and you won't automatically get logged out.
Nice video, BTW. But it leaves off the part where the cat then comes into the house, finds a nice clean spot on the carpet, and pukes up a hairball with the grass that it just ate.
Some of the problems with our "system" of measures is evident in this series of posts. For example, a couple of people mentioned a 2x4, but didn't get the size right. In fact, the size of a 2x4 depends on when it was milled. Old ones are larger, new ones are smaller. Currently, it's about 1-1/2 x 3-1/2". And then there's plywood. Is 1/2" plywood actually 31/64" or is it 15/32"? Depends on the grade of 1/2" plywood, but one thing it generally isn't, is 1/2". Measure a piece of 1/2" pipe and you won't find anything on it that's 1/2", but if you measure some 1/2" tubing you'll find it to be exactly that. I deal with a lot of sheet acrylic (plexiglass, Perspex) and in the US, the fractional sizes run undersize. That's because almost none of it is manufactured here, and as one example, nominal 1/4" runs about 0.236" instead of 0.250" as it should be. Why? Some may recognize that 0.236" turns out to be 6 mm. So it's really 6 mm material, but it gets sold as 1/4" because Americans would rather buy undersized imperial stuff than reasonably accurate metric stuff, even though in reality it's the same stuff. As for the gauges someone mentioned, wire has a gauge, as do number drills (as opposed to fractional or letter drills), and sheetmetal has a gauge, and are they the same? Nope. Some of the people I make things for want drawings in imperial units, some metric. Some want common US hardware (e.g. 2-56, 4-40, 6-32, etc) and some want metric (for those who've never figured out our screw sizes, the first number is the diameter [another arbitrary gauge], and the second is the pitch in threads per inch). Incidentally, note that screws get larger as the gauge number gets larger, but the drills used to make the holes for them get smaller as the number gets larger. Strangely, a #10 machine screw will almost fit in a hole drilled with a #10 twist drill, but that's an accident and it's the only combination even remotely close. My machines have micrometer collars in imperial units, so my trusty old HP calculators (10s and 15s) all have 25.4 in memory 0 all the time. Believe me, for someone like me who has to deal with both, and switch back and forth almost moment by moment, this Yankee will take metric every single time. Well, almost every time. Years ago I lived in Japan, and when I went to the market I had to try to figure out just how expensive meat was that was priced in yen per 100g when I was used to dollars per pound. Not yen per gram or yen per kilo, yen per 100g. Made NO sense. And I still can't guesstimate distances in kilometers.
I grew up with the usual American units. There was a year in primary school where they tried introducing metric. That didn't go well. It was mostly forgotten, until I took a physics class in high school. That teacher did it right! On day one, while dealing with the class formalities, he announced that metric units were the only units used for the entire year. No exceptions. He wouldn't even hear a non metric spoken unit, just looking at you patiently. Eventually people would get it, convert, restate and the proceedings would continue whatever they were.
Turns out units work just like language does. You need total immersion for a while. It takes time to build up frames of reference. Once these are established, working with the unit in question isn't a big deal, and that is exactly what we did. Everything. As I built those up, the units solidified fairly well and I don't generally have trouble today, unless it's a unit I have not yet established. I find two things to be important: One are some equivalents so that the units make sense together. I'll learn the conversion factor, then I'll equate a few handy metrics. One cm, for example? That's generally your pinky finger width. One decimeter? Popsicle stick, etc.. What is hot, what is cold, heavy, forceful, whatever. And don't just read the stuff and attempt to remember, experience it multi-sensory just like you learned your primary unit.
If you do that, you won't have a lot of trouble.
One annoyance I've seen is the move to round off computer units to powers of 10. This is just broken, and I'm just balking on it mostly.
A few years later, I ended up doing a lot of manufacturing. Many of those guys didn't handle metric well just because they worked in the other units so much. I would take them through the same things and have a little fun with it. Non issue after a while. We got a lot of work from Asia, and none of it was inches. I converted exactly one, and that was it. Time to just deal in metric, and we did and it all worked out. The biggest issue was tools. Machine tools ran in inches and retrofitting those was cost prohibitive, meaning some conversion was always going to happen. Old machine tools still work too, with somebody somewhere continuing to use them... I don't see that going away for years. Lots of years.
Good measuring tools are a must. Measuring a lot of stuff helps with the sensory memory and makes all those little associations you made in your primary unit.
I have the biggest trouble with things like drills. Hate that system. Easier to just measure the drill, which is what I will do before drilling anything. I don't care whether or not I measure it metric or inch, but I measure it and understand the desired hole and then go from there. Mostly depends on the tools I've got. My digital devices do both, my older school analogs are inch based.
Soon, what happens is there isn't so much of a primary unit and the question always comes up then. Find common ground, convert non compliant elements, then work in that unit for the project.
A lot of manufacturing is moving to metric now. Multinational companies are driving this more than anything, just so they can work around the world. A whole lot of this will continue to solidify, IMHO, and it won't be inches for the vast majority of things, but it will continue to take a really long time.... And there are factions too. Where investments are big, inertia keeps the unit in place. None of it will be sorted before I check out.
So there you go OBC. Go and just experience the stuff! Walk around with a good measuring tool and do exactly what you did as a kid. Measure everything so that you can map the numbers to the world in a more familiar way. If you keep it just some math abstraction you will always struggle. Better to embrace it and just jump in, get familiar and soon you won't even notice!
The metric system has a lot of merit but consider how nicely the english system of halfs, quarters, eights, etc. relates to the binary number system. I wonder if people will start switching back to the english system at some time haha.
In the USA, 8 bits still make up a dollar. I presume that is where computer bits orginated from and the Byte was just an amusing name that was pulled out of someone's hat to clarrify that one was not talking about money..... along with its amusing companion, the 4 bit Nibble.
In fact, decades ago and the computer age unfolded, the USA stock markets convered from 8ths, 16ths, and even 32nds in their stock prices to decimal. It was perceived that money should be in an all decimal system for the sake of universality (not sure that was really convienence). The British converted to the decimal pense from thier Pounds, shilling, pense system.
It just consumes a lot of computer time to use decimal for pounds and sums of pounds, and other systems for lesser fractions. Along with pocket calculators (we now have one on every computer and cellular phone), the ubiqutous conversion tables of old are disiappearing -- we just use Excel or whatever.
But it there are still Asian units that never got onto the conversion tables - land measurement, Chinese medicine dosage measurements, local food market weights and measures, and so on. I suspect that cultures retain these as a defence of their commerce - thus the long and short tons.
In fact, decades ago and the computer age unfolded, the USA stock markets convered from 8ths, 16ths, and even 32nds in their stock prices to decimal. It was perceived that money should be in an all decimal system for the sake of universality (not sure that was really convienence).
Actually the US stock markets continued to use fractional prices until 2000. Conversion was problematic because often the fractions were often stored as separate numerator and denominator fields and transmitted as text. People on this forum often complain about floating point, but the dirty secret of computers is that they stink at floating point math. When dealing with large sums of money, small truncation and rounding errors can result in big trouble.
They ended up going with a minimum of two, maximum of 4 decimal places to replace fractional stock prices in the transmitted form. Internally many programs need to use double precision with fix up logic to add a small quantity to correct for rounding errors. Binary coded decimal still has a place because of this as well. Actually I wouldn't be surprised if some programs retained separate numerator and denominator fields and went decimal for the display.
The term "bit" is generally attributed to John W. Tukey, who used to write "bit" in his papers as short for "binary digit". Tukey is famous for being one of the inventors of the Fast Fourier Transform.
Turns out the "byte" was born in the same year that I was. Wikipedia has it's history.
I had hear that the term "bit" for money derived from the habit of physically cutting silver coins into shares, of course 4 and then 8 is the easiest way to do that.
I'm shocked to see that the New York Stock Exchange only went decimal in 2000/2001
Oddly here in the very decimalized Scandinavia you can buy 10 eggs in a box. However if you want less than that the next size down is a box of 6 not 5. This clearly shows the superiority of the dozen which is divisible by 2, 3, 4 and 6 not just 2 and 5 as in decimal.
Also it's odd that despite being metric there is nothing metric in colloquial talk about speed. I mean "kilometers per hour". There is nothing metric about hours. Never mind minutes, days, weeks etc.
I never imagined people had such a hard time with conversions, even quick estimations or the "feel" of the dimensions. As a teenager at school we had a machine shop with lathes, mills and all other tools calibrated in inches and fractions of an inch. That's what industry used. We also had a science lab where everything was done in SI units and metric. So we grew up with a feel for both systems and I assumed the rest of the modern world was doing so as well.
Comments
And in electronics you have a similar problem with pin spacings, standoff lengths, mounting hole diameters and spacings, and enclosure sizes. There aren't any good approximations like 750 ml for 1/5 gallon, and in a lot of cases fits have to be exact to work.
A manufacturer my company represents recently came out with a new product that is international in focus, and therefore all metric, including all the hardware. We found that the 7mm nut drivers needed to remove the acorn nuts that hold the back on are completely unavailable locally and we had to order them online.
50 cycle current would likely raise some havoc with some of my old retro computers. IIRC the C64 used the 60 cycle AC as part of it's system clock.
Jeff
-Phil
Actually, that was signed off by good ol Gerry Ford.
http://en.wikipedia.org/wiki/Metric_Conversion_Act
OK, At least I got the Era correct!!!
Yes, Fahrenheit is based off of the human body. To me time is the only serious GLOBAL measuring device, but if NASA gets that warp machine going this might change lol.
am still on a mission to tell everyone that Black Holes are a spherical phenominom and in no way shaped like a hole. There are no sides to it. It just gets denser and denser. And depiction as getting caught in a vortex is pure movie created nonsense. Like any other core of gravity, you would get caught in a decaying orbit, not a vortex.
Okay, I am a bit mental about this one. But film, science fiction, and TV have managed to trump reality. I fear a serious decline in civilization if popular science can blithely ignore real science.
As far as the warp drive, it may just suddenly disappear and we might spend years trying to figure out if it held together or not. Faster than light does mean that radio communications are no longer available, right?
it is way worse ... a couple of days ago here in the TV (FOX News) they talk about some illness affecting one percent of the population. And then, in big bold letters on the screen:
1 %
1 out of 133
jupp.
and you are worried about cicrular black holes?
Enjoy!
Mike
-Tor
The Information Age is coming to an end. To be replaces by the Misinformed Age.
Hmm, never ever heard of slug before, but wikipedia believes it exists! (and the blob or slinch too...) Crazy crazy.
-Phil
Eight would be better. Of the ten we have the pinkies are pretty much useless anyway. Then all our math and computers would be octal based. Address and data bus widths would be in multiples of 3 bits ;- )
And fractional values would also be a better fit with octal.
-Phil
So I give you this instead:
http://www.youtube.com/watch?v=rhXqZfTLhPY
When you log in, be sure to click the "Remember me?" box, and you won't automatically get logged out.
Nice video, BTW. But it leaves off the part where the cat then comes into the house, finds a nice clean spot on the carpet, and pukes up a hairball with the grass that it just ate.
-Phil
Obviously not a pianist / guitar player / typist.
Or nose picker.
I grew up with the usual American units. There was a year in primary school where they tried introducing metric. That didn't go well. It was mostly forgotten, until I took a physics class in high school. That teacher did it right! On day one, while dealing with the class formalities, he announced that metric units were the only units used for the entire year. No exceptions. He wouldn't even hear a non metric spoken unit, just looking at you patiently. Eventually people would get it, convert, restate and the proceedings would continue whatever they were.
Turns out units work just like language does. You need total immersion for a while. It takes time to build up frames of reference. Once these are established, working with the unit in question isn't a big deal, and that is exactly what we did. Everything. As I built those up, the units solidified fairly well and I don't generally have trouble today, unless it's a unit I have not yet established. I find two things to be important: One are some equivalents so that the units make sense together. I'll learn the conversion factor, then I'll equate a few handy metrics. One cm, for example? That's generally your pinky finger width. One decimeter? Popsicle stick, etc.. What is hot, what is cold, heavy, forceful, whatever. And don't just read the stuff and attempt to remember, experience it multi-sensory just like you learned your primary unit.
If you do that, you won't have a lot of trouble.
One annoyance I've seen is the move to round off computer units to powers of 10. This is just broken, and I'm just balking on it mostly.
A few years later, I ended up doing a lot of manufacturing. Many of those guys didn't handle metric well just because they worked in the other units so much. I would take them through the same things and have a little fun with it. Non issue after a while. We got a lot of work from Asia, and none of it was inches. I converted exactly one, and that was it. Time to just deal in metric, and we did and it all worked out. The biggest issue was tools. Machine tools ran in inches and retrofitting those was cost prohibitive, meaning some conversion was always going to happen. Old machine tools still work too, with somebody somewhere continuing to use them... I don't see that going away for years. Lots of years.
Good measuring tools are a must. Measuring a lot of stuff helps with the sensory memory and makes all those little associations you made in your primary unit.
I have the biggest trouble with things like drills. Hate that system. Easier to just measure the drill, which is what I will do before drilling anything. I don't care whether or not I measure it metric or inch, but I measure it and understand the desired hole and then go from there. Mostly depends on the tools I've got. My digital devices do both, my older school analogs are inch based.
Soon, what happens is there isn't so much of a primary unit and the question always comes up then. Find common ground, convert non compliant elements, then work in that unit for the project.
A lot of manufacturing is moving to metric now. Multinational companies are driving this more than anything, just so they can work around the world. A whole lot of this will continue to solidify, IMHO, and it won't be inches for the vast majority of things, but it will continue to take a really long time.... And there are factions too. Where investments are big, inertia keeps the unit in place. None of it will be sorted before I check out.
So there you go OBC. Go and just experience the stuff! Walk around with a good measuring tool and do exactly what you did as a kid. Measure everything so that you can map the numbers to the world in a more familiar way. If you keep it just some math abstraction you will always struggle. Better to embrace it and just jump in, get familiar and soon you won't even notice!
In the USA, 8 bits still make up a dollar. I presume that is where computer bits orginated from and the Byte was just an amusing name that was pulled out of someone's hat to clarrify that one was not talking about money..... along with its amusing companion, the 4 bit Nibble.
In fact, decades ago and the computer age unfolded, the USA stock markets convered from 8ths, 16ths, and even 32nds in their stock prices to decimal. It was perceived that money should be in an all decimal system for the sake of universality (not sure that was really convienence). The British converted to the decimal pense from thier Pounds, shilling, pense system.
It just consumes a lot of computer time to use decimal for pounds and sums of pounds, and other systems for lesser fractions. Along with pocket calculators (we now have one on every computer and cellular phone), the ubiqutous conversion tables of old are disiappearing -- we just use Excel or whatever.
But it there are still Asian units that never got onto the conversion tables - land measurement, Chinese medicine dosage measurements, local food market weights and measures, and so on. I suspect that cultures retain these as a defence of their commerce - thus the long and short tons.
Actually the US stock markets continued to use fractional prices until 2000. Conversion was problematic because often the fractions were often stored as separate numerator and denominator fields and transmitted as text. People on this forum often complain about floating point, but the dirty secret of computers is that they stink at floating point math. When dealing with large sums of money, small truncation and rounding errors can result in big trouble.
They ended up going with a minimum of two, maximum of 4 decimal places to replace fractional stock prices in the transmitted form. Internally many programs need to use double precision with fix up logic to add a small quantity to correct for rounding errors. Binary coded decimal still has a place because of this as well. Actually I wouldn't be surprised if some programs retained separate numerator and denominator fields and went decimal for the display.
Turns out the "byte" was born in the same year that I was. Wikipedia has it's history.
I had hear that the term "bit" for money derived from the habit of physically cutting silver coins into shares, of course 4 and then 8 is the easiest way to do that.
I'm shocked to see that the New York Stock Exchange only went decimal in 2000/2001
Oddly here in the very decimalized Scandinavia you can buy 10 eggs in a box. However if you want less than that the next size down is a box of 6 not 5. This clearly shows the superiority of the dozen which is divisible by 2, 3, 4 and 6 not just 2 and 5 as in decimal.
Also it's odd that despite being metric there is nothing metric in colloquial talk about speed. I mean "kilometers per hour". There is nothing metric about hours. Never mind minutes, days, weeks etc.
I never imagined people had such a hard time with conversions, even quick estimations or the "feel" of the dimensions. As a teenager at school we had a machine shop with lathes, mills and all other tools calibrated in inches and fractions of an inch. That's what industry used. We also had a science lab where everything was done in SI units and metric. So we grew up with a feel for both systems and I assumed the rest of the modern world was doing so as well.