As part of my gear-shifting to get ready for my new position as Physics Lab Manager at the College of Charleston, I subscribed recently to a mail list provided for the exchange of ideas, hints, solutions to problems, and so forth for science teachers. I have just posted the message below.
Jim I'm new to this list so perhaps I've missed previous discussion on this point. Why are people on this list using non-SI units? It seems rather archaic to me. People on this list aren't teaching their science lessons in those units are they? Of course, it would be natural if one were refering to a six-inch crescent wrench purchased at Sears, since that's a trade size and that's the way the catalog describes them. This perhaps relates to a recent experience I had as part of the judging team for the local regional science fair. I noticed that the vast majority of high school projects were metric (though not always SI) but very few of the middle school projects used metric units. The students told me that their teachers spent a week or two on the SI and then used "normal units" for the rest of the lessons that year. And that leads to another mental connection -- American middle schoolers suck swamp water when it comes to international competitions such as the TIMSS and TIMSS-R. Evaluators of those tests have included the observation that this relates to lack of effective teaching and use of the SI in American schools, among other factors. While I'm going out on a limb and risking the possibility that my questions might anger someone, I'll gratuitously add that I shudder when I see what I call "nekkid decimal points" in numbers. I very strongly favor preceding them with a zero. Apologies in advance if I've stepped in anybody's ancestral rice bowl. Yes, I'm competant in such units and can even deal with poundals, slugs and slinches if need be. I'll hush now and go downstairs for a couple of gills (U.S. gills, of course) of coffee. Jim On Saturday, 2002 April 27 1129, you wrote: > Well, I am really not (I must admit) trying to make a slide wire pot. > What I really want to do is use the wire as a transducer for > measuring the position of an object that moves along a meter stick. > (I know, there are better ways to do this. But my idea will be > educationally valuable.) > So, I'd like 100 ohms/ft or 1000 ohms/foot or even 10,000 ohms/foot > for easy measurement. > > ************************************** > > I recommend to use 18 gauge Chromel-A wire. It is .408 Ohms per foot. > That is what I use. It is excellent. Jerry -- James R. Frysinger University/College of Charleston 10 Captiva Row Dept. of Physics and Astronomy Charleston, SC 29407 66 George Street 843.225.0805 Charleston, SC 29424 http://www.cofc.edu/~frysingj [EMAIL PROTECTED] Cert. Adv. Metrication Specialist 843.953.7644
