QWERTY keyboards - why?

[huckelberry]

Moksha,

There are computational advantages to metric but that is not how people normally use the measurement system. How big is a gallon? about this, hefting a gallon jug in ones mind. I never ask myself how many teaspoons in a gallon. Yes if those were metric units the calculation would be easier. It would be unusual for most people to be called upon to make that calculation however.

(of course if you were a chemical engineer you would see this differently)

At an early stage of my science education I made the transition from feet, pounds, poundals and pounds weight and all the rest of them to the delightful simplicity of the International System of Units (SI, abbreviated from the French Système international (d'unités)). From the point of view of mathematical simplicity and lack of arbitrary conversion constants cropping up in equations, there is simply no contest.

I think anyone who has done physics seriously will agree with me.

Chap, in the US physicists and other scientists use the metric for reasons you point out. Nobody prevents that. I see that as perfectly understandable. I learned metric in school long ago. I was making an observation about why it is slow to become common usage in this country. For me all distances or elevations exist in my mind and memory as miles yards or feet. If someone says the mountain is so many meters high I have to do an annoying computation in order to compare it to other mountains I know. The same is true about how long is the drive to such and such a location. If I check how many miles it is to Portland the number is usefull trip planning information. To know how many feet it is would not be helpful.

[Chap]

Chap, in the US physicists and other scientists use the metric for reasons you point out. Nobody prevents that. I see that as perfectly understandable. I learned metric in school long ago. I was making an observation about why it is slow to become common usage in this country. For me all distances or elevations exist in my mind and memory as miles yards or feet. If someone says the mountain is so many meters high I have to do an annoying computation in order to compare it to other mountains I know. The same is true about how long is the drive to such and such a location. If I check how many miles it is to Portland the number is usefull trip planning information. To know how many feet it is would not be helpful.

Umm, the UK has many irrationally conservative people in it (I'm not saying you are one, just to be clear). But when the metric system was adopted for general purposes in 1965, it took hold pretty quickly, helped initially by a system of dual labelling (prices per pound and per kilogram both on the ticket.) It is nowadays used for all commercial and practical measuring purposes. The conversion was surprisingly untraumatic.

There are a few exceptions, where the old units persist in what may be called 'closed systems': for journey distances, vehicle speeds and the sizes of returnable milk containers, beer and cider glasses (though fresh milk is often still sold in multiples of pints, with the metric equivalent also marked). I think the vehicle speed exception was mostly a safety measure to avoid confusion on the roads (is that 100 miles/hour or 100 km/hour??), and beer measures have very strong cultural associations that were thought unnecessary to disrupt.

The US could certainly do the conversion if it wanted to. I suppose that the size of the internal US market in comparison with exports renders it less pressing, thought the retention of the old measures must certainly exercise a 'cognitive drag' effect on science education - which will in turn have economic effects.

[Gunnar]

One thing that adds to the confusion is some American measures differ from British Imperial measures. For example, British gallons are larger than American gallons.

American (confidently) "A pint's a pound, the whole world round!"

British person (diffidently, but rhythmically) "Well, where I come from, a pint of pure water weighs a pound and a quarter."

Thanks for filling another gap in my knowledge. I had from time to time vaguely wondered if there was some physical relationship between a fluid ounce and an ounce of weight, but had never looked it up to confirm that, though it is possible I was once taught that in school and just forgot it. Thanks to you I now know. Here's what I just found. Confirming what you said.

One US fluid pint of water weighs about a pound (16 ounces), resulting in the popular saying, "The pint's a pound, the world around." However, a US pint of water weighs 1.04375 pounds and the statement does not hold the world around because the imperial (UK) pint weighs 1.25 pounds. A different saying for the imperial pint is "A pint of pure water weighs a pound and a quarter."

link http://en.wikipedia.org/wiki/Pint

So, an American pint doesn't weigh exactly one pound, but it's pretty close.