Saturday, September 13, 2008

BMI & The Metric System

I recently crossed the 100 kilogram mark. For my fellow American-educated friends, that is just a hair* over 220 pounds. I am also just a little over 6'7" tall, which puts me right at 2 meters. This makes BMI calculation easy, because it is (mass in kilograms) divided by (height in meters) squared. This puts me right at a body mass index of 25. This easy math got me thinking about how horrible the English units of measure are. I imagine that BMI is a recent creation and that its ties to the metric system are somewhat arbitrary, but it was still a reminder.

Working in engineering, almost everything is metric, and I love it. I want to pull my hair out when I come across something in a weird English unit. For example we use microns, that's one millionth of a meter, as a unit of length all the time at work, but every once and awhile somebody will document something in "mils" which is thousandths of an inch.

This somehow made me think about facebook groups and how I could start one for people who thought America should switch to the metric system. Of course, such a group existed already.

I joined.

But for the foreseeable future, our children will probably just have to learn that BMI is their weight in pounds divided by their height in inches squared, multiplied by some conversion factor that few of them will ever be able to remember.

*note: a "hair" is not a metric unit, but I like it. Does that make me a hypocrite?

2 comments:

janinabean said...

if it makes you feel any better, we measure everything in metric (grams and centimeters) in my job, too

KateGladstone said...

Re:

"a 'hair' is not a metric unit, but I like it. Does that make me a hypocrite?"

Hmmm ... according to Yahoo Answers, the diameter of human hairs ranges from 0.000017 meter to 0.000181 meter: http://answers.yahoo.com/question/index?qid=20061128121906AASNZKv . Therefore, some human hairs probably measure 0.0001 meter = 0.1 millimeter. If you change "hair" to "0.1mm", nobody can call you unmetricated.