My point about the thickness of a saw cut is that in casrpentry you don’t need to measure finer than that (just as you don’t need to measure finer that 1/16 of a inch, which is a bit larger than 1 mm). So you don’t work with fractions: if your division gives you 285.7, then you work with 285 or 286, just as you would not work with 13 7/256 of an inch. (1/256 of an inch is almost exactly 0.1 mm).
The calculations are all easier when you work with one unit, and the plans don’t even need to show the unit if it can be assumed this way. With the American system, you need to calculate in 1/16’s, inches and feet.
I’ll admit the imperial system does feel more natural, and indeed many measurements were standardised in very organic ways originally:
Inch = width of the king’s thumb (or, at a pinch if you weren’t the king, your own thumb)
Foot = The length of a foot of someone with a large foot
Yard = chin-to-outstretched-finger-tip
Acre = The area one man and one horse could plough in a day
…and so on.
I’ll admit to using feet and inches for trivial woodwork, but for more accurate joinery I’ll use metric.
There is a natural feel to metric units too, if you look for them. They were cunningly designed so that originally 1km was 1/40,000th of the circumference of the earth, 1cc of water weighed 1g, and 1 l of water weighed 1kg. The French estimated the earth’s circumference wrong when they did the original survey, so the metre has been redefined somewhat, but the density of water neatness comes in handy.
The vegetable plot I rent is measured in rods. That’s OK, but I want my high tech stuff in metric already.
There’s also pounds-mass. Yes, there is a unit of mass with the same name as the unit of force. IIRC, it’s both a holdover from when there was no distinction between force and mass, and so that you CAN actually convert between pounds and kilograms. Since pounds-force and kg measure two different things, one cannot technicall equal a given amount of the other. Yes, you can do a unit conversion that eliminates that pesky aceleration factor of pounds force, but you still don’t have a given amount of pounds equaling a given amout of kilograms, you just have a given amount of pounds equal to the force thast a given amount of kilograms will provide in earth gravity.
So along comes Mr. Pound-mass, who uses the same conversion factor that one would use to go from pounds-force to kg, so now you CAN have a given amout of pounds equal a given amount of kg.
The tricky part is when you try to get the weight of an object in pounds-force, if its mass is measured in pounds-mass. They are the same number, and the equation is just Newton’s second law (F = ma) but with the dimensionless constant, g[sub]c[/sub] introduced to basically eliminate the fact that otherwise a pound-force would be about 32 times higher than a pound-mass. So to go from pounds-mass to pounds-force, you have:
W = g/*g[sub]c[/sub]**m, where g is the gravitation constant, equal to 32.2 ft/s, and m is the objects mass in pounds-mass.
I think this is where arguments pro-metric invariably fall apart. The suggestion, for instance, that Celcius is better than Fahrenheit. Does it really matter a whit in my day to day life that water freezes at 0 and boils at 100? Is calling a really hot day 35 degrees super easy when calling it 95 is hard? Cooking a roast at 350 is just trouble but 175 is simplicity itself.
That doesn’t make sense.
Similarly, using miles rather than kilometers to plan a trip isn’t exactly a hardship. Using cups and partial cups, tablespoons and teaspoons to cook is fairly straightforward, a bit of 3rd grade arithmetic will get you through. Even inches and feet don’t really cause us that much pain, it just takes a bit of getting used to
I think anyone can see how metric is a boon for manufacturing, where conversions are constant and critically important. Around the house, it’s just not a big enough deal to claim that life would be better if I switched.
Really? I was always taught that there were three teaspoons in one tablespoon, sixteen tablespoons in a cup, four cups in a quart, four quarts in a gallon.
FWIW, Wikipedia says that the way I was taught is the “traditional” way, but it also mentions the federal redefinition.
Canada adopted the metric system officially in 1970, but it was too late for me. I still can’t instinctively picture anything in metric: I have to translate a kilometre into a fraction of a mile before I know for sure whatever the stated distance is. Temperatures mean nothing, other than 30 is hot so 25 is nearly so. The Celsius scale is too course a measurement, anyway. There’s too big a difference over one degree, let alone five.
I know what 30 or 20 or 7 miles to the gallon means as soon as it’s uttered. But 12.3 litres over 100 kilometres? WTF!?
A trip to the States is like hopping into a time machine. I instinctively know the highway speeds, the distance to travel and how long it will take to get anywhere (but figuring out gas mileage in the States has always been goofy. What is this quaint U.S. gallon thing the locals insist on using?)
My two nephews were educated in metric and grew up with it. They know nothing else, other than intellectually. Neither of them know, care to know or have any reason to know that 90 is hot (since we’re still breathing, it must be Fahrenheit). When in the U.S., they have to translate everything to metric to get a feel for how fast they are travelling and the time it will take to get somewhere.
So, yeah, the dinosaurs have to die before Fahrenheit stops being used on old-fart radio stations. And since I’m among the youngest members of the last generation educated in imperial (metric was an afterthought), all things being equal those radio stations will use Fahrenheit for a long time yet.
As someone who lives in the US, and vacations in Canada every year, I would say that it isn’t that difficult for the average person to adapt to the metric system in every day life. Some things are more descriptive (millimeters of rain rather than inches), and some are less (degrees of temperature).
I work in an engineering firm, and I agree with Anaamika, the cost of converting does bear a stiff price, especially with historical engineering information. Holding on this due to cost isn’t like holding on immediate environmental concerns; no real harm is done by not taking action right now. (Oh yeah, the Hubble… :smack: )
BTW, Massachusetts Department of Transportation chose to adopt metric, and eventually caved in and went back to Imperial units (I believe that **groman ** was first here in using this correct term for the system that US uses now). Massachusetts USGS maps were the only ones in the US (that I know of) in 1:25000 scale rather than the 1:24000 scale in every other map (presumably in order to conform the intended (and abandoned) conversion to metric).
That said, I don’t see much reason to change. George Orwell said it best in 1984:
" 'E could 'a drawed me off a pint," grumbled the old man as he settled behind his glass. “A 'alf liter ain’t enough. It don’t satisfy. And a 'ole liter’s too much. It starts my bladder running. Let alone the price.”
But, if the oil companies see the profit in it, you can bet that we will be buying liters of gasoline :rolleyes:
Don’t know if this warrants a thread to itself, but while we’re on the topic of the metric system, for those who advocate complete conversion:
Why not convert time to metric? Why convert all other means of measurement, and then have to deal with 60 seconds per minute, 60 minutes per hour, 24 hours per day? And then all those pesky weeks and months? Days and years are both quantifiable; any thing else is arbitrary.
OK, you’re making cookies. But it’s for a big bake sale at your kid’s school, so you’re making ten times the amount in the recipe. It’s kind of annoying to measure out 10 teaspoons of baking soda, though… Would be much easier to use a measuring cup.
So, how many teaspoons are there in a cup? Do you know? I sure don’t. But I can tell you how many milligrams there are in a gram, or milliliters in a liter.
We were taught metrics in high school too, I just put my college time in there to peg my generation. And it is the college edumikated folk that usually get to make the decisions.
I forgot to mention 'til others did that I can do temperatures in both scales, 22-25 is room temp, 37.5 is body temp, 100 is boiling, 0 is freezing, 4 is your frige and everything else is relative.
I took some timber to be cut down at our factory sawmill, the dimensions being 75.6cm x 105.5cm.
The saw operator coudn’t do it, he only worked in millimetres!
An imperial pint is about 0.568 litres, so if that 10% difference is the worst thing in that old man’s life under Big Brother. … And there’s a bigger difference between the Imperial pint and the US pint (0.473 litres) than there is between an Imperial pint and a half litre.
Ireland has been offially(-ish) metric for ages now, with road distances shown in kilometres (except on the traditional, white finger-posts, which still show miles…). However, until 20th January this year, all speed limits were in miles per hour. Confusion or what?
Beer, I am glad to say, is still served in pints (as in the UK), thanks to a get-out clause in the relevant EU Directive.
I started school in 1964 and was largely taught in Imperial - I still have somewhere an old arithmetic book for under 11’s printed in the 50’s which contains horrors like “divide £12-18-8 by 5/6½”. Thank f*ck those days are over!
If someone tells me that they weigh 56 kilos, it takes me ages to work out what they are in stones (for American viewers, a stone is 14 pounds) before I can call them a fat git or a skinny runt. And if they said they were 1 metre 75 tall, I wouldn’t have a clue if they were a giant or a midget. Nor would I have the faintest idea how big a field would be if someone told me it was 43 hectares - but equally, I’d be in the dark if it were 6 acres.
But talk to anyone over here of generation just below mine - say, someone born in the mid-60’s even - and they haven’t a clue about Imperial stuff. It’s easy to convert: just start teaching nothing but metric in schools and in about 30 years, everyone still using Imperial will have retired or died. Sure there’ll be about 20 years of confusion, but that’s a small price to pay - unless you work for NASA, I suppose…
3 teaspoons in a tablespoon
4 tablespoon in 1/4 cup
for 10 teaspoons of baking soda, I’d do 3Tbs + 1tsp. Mostly because spoons are easier to use with baking soda. You could also do 1/4cup - 2tsp
Metrically, it would be 50ml, which is pretty handy, but 9x is 45ml and 8x is 40ml, which has to be made up of various combinations of 15ml and 5ml spoons anyway, unless metric cooks have a massive variety of cups and spoons in every possible 5ml increment.
Easier metrically? Maybe somewhat, but as long as you can stuff my first two lines here into your brain, imperial isn’t that tough, even in the odd circumstance where you’re really sizing up a recipe.
When I was getting my civil engineering degree in the 1990s most classes were still taught in English units. Then for one of my reinforced concrete classes the professor taught in all metric units. It took 5 minutes of “An apple is about .1kg. That’s one Newton of force. Turn it into applesauce and spread it over a card table, which is about 1 meter on a side. That’s one Pascal of pressure.” and that was it, made no difference to how the class was taught or what we learned except that the mental arithmetic was easier.
I’m with Giles on the woodworking; I do it for a hobby and working with mixed powers of two is a major PITA. Lessee, 1 7/16 inches plus 3/32 inches, minus 1/8 inch saw kerf, then divide by two…too easy to screw up. Now imagine that your tape measure and meter stick and saw fence and whatnot are marked in millimeters and your tablesaw blade is 3mm thick (2mm for a thin-kerf blade). No fractions, math is much easier. I’ve seen the owner of one American cabinet shop talking about how he switched everything over to metric and everyone is much happier, far fewer math errors.
And I don’t buy that “pounds are more convenient than kilograms” - “a pound” is more convenient than “half a kilo” of sugar? Does that mean that “two pounds” is less convenient than “one kilo”?
You’ve never worked in a commerical kitchen, have you? Being the math whiz :rolleyes: that I am, I found myself always having to do conversions for the baker’s assistant at one shop. “So, how much is 3-1/3 pounds by 6? And how much is 4-3/4 tsp by 12? What is that in cups?” It makes one wonder if someone doesn’t make a baker’s slide rule.
As anachronisms, they are indeed delightful. As working units, they are a pain in the ass.
I like playing with slide rules and sextants, but if I have to calculate something or measure my position quickly and accurately I’d rather use an electronic calculator and an GPS receiver
That’s because the conversion is being achieved by government statute and our typical reaction to such legislation is to grumble, but comply. This may not hold true for other countries (the term ‘cold, dead hand’ springs immediately to mind).