On Sat, 10 Nov 2012, Thorsten Bonow wrote:
> Therefore solving it symbolically first and inserting the units
> afterwards is exactly what the students shouldn't be doing.
I think the "elegant" answer to this would be that dimensions are not
the same thing as units. The dimensions don't go away just because
the equation is written symbolically, and the optimal time to check
the dimensions are correct is probably while the equation is still in
symbols, before substituting in numbers and units.
I guess you know better than I do how much or how little of that
"elegant" approach can reasonably be applied in high school teaching,
though.
--
HTH,
Dan