I like to present the metric system to college students by first getting them to see the value of a decimalized system of accounting. I tell them that Thomas Jefferson asked Congress in the 1790s (as Sec of State, not as Prez) to decimalize the dollar when it was adopted as the nation’s currency, as opposed to the 1 pound=20 shillings=240 pence system used by Britain. I’ve typically let them see the utility of this system of counting, by taking our year (2013), and asking them if we had 2013 pennies, how much money would we have, expressed in terms of dollars and cents? The exercise is designed to show people how easy it is, to recon 2013 pennies in blocks of 100. You don’t even have to do any multiplication or division, you just move the decimal and arrive at $20.13. I then tell them how easy it is to convert 1000 grams to kilograms, etc.
The last time I tried this, I received a shock. I had 3 students volunteer an answer, and the first two got it wrong. Fortunately, the third student did state that 2013 cents was equal to 20 dollars and 13 cents, but I was shocked that the rest of the class was either silent or guessed wrong. I’m wondering if this is symptomatic of the group of students as a whole (college freshmen). Now I’m sure that some knew, but simply didn’t feel like voicing their opinion in a large group of people; some others might have been bored (has been known to happen in classes!)—but I’m still thinking that quite a few didn’t know. I think in the spring, I’ll give my students a short, anonymous survey to see if they can understand mathematical concepts like this. But in the meantime, my suspicions remain strong that many adults are close to being innumerate, if not already there. And I’m wondering how to present the metric system to them—to students who have no desire or ability to convert inches to feet to yards to miles, etc. If they don’t even bother with that, what difference would the metric system make to them? What attracted me to it was the standardization of it (there was only one kilometer, one gram, etc.), which made remembering statistics much easier. Of course students wouldn’t see this as much of an advantage. But apart from the ease of converting among units, what other benefits can be presented to the man in the street?
