In the physics problems we gave our students, people always had a body
surface area of 2 square meters. Exactly that, of course!
Jim
On 2011-01-02 1509, Paul Trusten wrote:
Dosing some medications in amount of drug per square meter of body
surface area *(BSA) instead of body mass takes into account the
metabolic and drug elimination differences among patients. BSA dosing is
often used for anti-cancer (chemotherapy) drugs.
----- Original Message -----
*From:* Bill Potts <mailto:[email protected]>
*To:* [email protected] <mailto:[email protected]> ; 'U.S.
Metric Association' <mailto:[email protected]>
*Cc:* [email protected] <mailto:[email protected]> ;
'Gentry, Elizabeth' <mailto:[email protected]>
*Sent:* 02 January, 2011 11:34
*Subject:* RE: [USMA:49395] powers of ten--becoming an exponent
proponent
I agree with you, Paul. And, for the grade level at which exponents
should be taught, that seems about right.
The one thing that puzzles me is the milligrams per square meter
dosage. I can only think of this being used for some kind of skin
cream, which leads to the question of how one easily determines a
patient's skin area. I have to assume, though, that an approximation
is probably close enough and that order-of-magnitude errors are
unlikely. :o)
Bill
------------------------------------------------------------------------
*From:* [email protected] <mailto:[email protected]>
[mailto:[email protected]] *On Behalf Of *Paul Trusten
*Sent:* Sunday, January 02, 2011 08:40
*To:* U.S. Metric Association
*Cc:* [email protected]; [email protected]; Gentry, Elizabeth
*Subject:* [USMA:49395] powers of ten--becoming an exponent proponent
The previous discussion of Zimbabwe currency in the article in
question
(http://news.yahoo.com/s/ap/20110102/ap_on_re_af/af_zimbabwe_numbers_game
) reminded me that part of our problem in accepting metrication in
the U.S. is that we Americans are not yet proponents of exponents.
We tend to limit the teaching of exponents to a small part of our
mathematics education and don't apply that education to the
practical subject of measurement. When I stop to consider the metric
system, I sense that I am returning to eighth-grade algebra, when I
should have learned something about exponents /much/ earlier than
that. At least to me, facility in exponential notation makes the
meanings of the SI prefixes easier to understand and manipulate.
I don't know what it's like in metric countries, but, here in the
land of the foot and the mile, even the simplest application of
exponents in connection with SI falls on innumerate ears. For
example, in pharmacy I have yet to hear one of my colleagues look at
the symbol m^2 and pronounce it "square meter." They will pronounce
it "meters squared," which may be good as an exponential statement
but, I think, bad as a measurement unit. Some (usually outside of
pharmacy) can't even get that far, and will state a dose of 50
mg/m^2 as "50 milligrams emm two," reading it out to me with
difficulty, not knowing what it means. Pharmacists use common sense
and can interpret, based on the drug being ordered, that 50
milligrams per square meter is what was meant, but if two people are
communicating purely on the basis of the expression being used, with
nothing else to refer to, who knows? From the resulting confusion,
we may get a medical Gimli Glider.
I remember, in the fourth grade (which, for me, was 50 years ago),
learning "decimal places," and learning the "millions place" and the
"thousands place," but at that time, those places were never
connected to the concept of bases and exponential notation. Had that
been done for us,I think we could have adapted to the metric system
the very next day and become metric citizens.
As I mentioned, I haven't been in the fourth grade for 50 years, and
the timing of the study of exponents may have changed since then
(big grin). I'd be interested in what the teachers on this list
think of the above.
So, my question is:: to what extent do you think a thorough
grounding in exponential notation in the early years of mathematics
education (2nd, 3rd grade?) would improve the ability of the U.S. to
go metric?
Paul T.
--
James R. Frysinger
632 Stony Point Mountain Road
Doyle, TN 38559-3030
(C) 931.212.0267
(H) 931.657.3107
(F) 931.657.3108
