Posted by: thebylog | January 10, 2005

Finally some pressure is beginning to lessen. In a way. In other ways, there’s other things – different things – that could just be heating up. And you know what happens when you heat something up: it expands. If there’s nowhere for it to go, guess what? Pressure.

I wrote an Energy Recommendation report recently at the IAC, one of the few (energy as opposed to productivity) that I’ve ever done. There were lots of numbers to crunch and I, naive about industrial applications as I am, wrote it using SI units. My boss called me on it and we discussed how SI is not used in American industry, how that it would drive them crazy trying to get their head around a temperature difference of 13.4 degrees Celcius or a mass flow rate of 170,000 grams/minute. He laughed (I was chuckling just a bit ago as I thought about it) and wondered that no switch had gone off in my head about this. But no, not at all. I was delightfully unencumbered by convention.

However, to show the superiority of SI, answer me this: Is a “pound” (lb) a unit of force or mass?

To be fair, though, to show the superiority of English units, how many centimeters across is your thumb and how many meters long is your foot?



  1. Pound is force of gravity on an object of x mass, yes? Or have I forgotten? But I’m not sure what you’re saying about cm/thumb, m/foot… I have blonde moments. how is that an “eprop” for the English?

  2. oh yeah, and you know what’s odd? The proverbial blue skies and picture-perfect summer weather is actually HIGH (atmospheric) pressure. where’s the lesson to that one?

  3. The “pound” can be used to refer to either mass or force, thus the confusion. Technically, there is a unit called “slugs” that measure mass in English units, but you definitely want to stay away from those in most cases.

    The good thing about the English system is that it’s physically intuitive, i.e. my thumb is about 1 inch across, my foot is about a foot long, my step is about a yard.

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