Archive for the ‘Blogs’ Category
domestic arts in the age of digital distribution. RIP, vlorblog. here are some posts mentioning “clean” and “dish”: https://vlorblog.wordpress.com/?s=clean+dish (courtesy of the “search” feature from that blog).
… but i’ve lost control of that one.
so here it is again. with a photo
from “vlorbik unstrung”.
the music isn’t by me, of course. “stealing”
already-well-known tunes was good enough for
joe hill and woody. and dylan. so it’s good
enough for me.
i easily figured out the main “trick” in playing it
but haven’t practiced it enough (even now) for
public performance.
negatively fifth street (2015)
a drifter escaped from a boxcar/ denouncing obviously jive believers/ has a zine about it in the catalog/ but nobody can work the damned randtrievers/ and the cats are praying in the alley/ and the pool shark is chalking up his cue/ an’ i’m out lookin’ for my lady/ down on kirkwood avenue
jesse, he’s round the corner/ buskin in front of the bird/ doesn’t bother him if no-one stops to listen/ doesn’t bother him if they don’t like the words/ and some violence boys might come and beat him down/ and he’ll forgive ’em more than i could ever do/ but that’s nothin compared to what’s goin on/ back on kirkwood avenue
a melancholy cougar/ buys a hoagie from a clown/ there’s a tempest brewing somewhere/ and there’s panthers on the other edge of town/ and the goddess of gloom and the jester/ are doin’, that thing they love to do/ in a video montage/ at the parking garage/ on kirkwood avenue
a cloud of marijuana/ is obscuring the people in the park/ or maybe i’m just losing my eyesight/ or maybe it’s just getting close to dark/ an’ the tournament game was a victory/ so now it’s turnin’ into a zoo/ an’ the riot squad and the thunder god/ are on kirkwood avenue
grading linear algebra again.
so far this quarter, i’ve (1) returned
the text from last quarter (late) and
i’ve (2) gone back and got a different
copy of the same text a week later.
and that’s it… a week and two days
into the semester.
but starting today there’ll be bigfat
envelopes full of homework piling up
in my mailbox. so very likely i’ll be
posting less over in the cooking show
(where i’ve had a pretty good run going
for about a week).
math stood tall: edusolidarity recap at JD’s.
Mathblogging.org looks pretty promising.
(i couldn’t put this in a comment
for this “log laws” post
at f(t); too long.)
it’s the old principles-versus-procedures problem.
students hate general principles.
i’ve had tutees pay me hundreds
to supervise their homework
who very clearly “tune out”
whenever i try to explain
what’s going in in a general way.
it’s worst when it’s about a topic
they’ve been exposed to before…
the famous “math phobia”. panic
sets in when you realize that
you’re going to expose your ignorance
yet again… about fractions, variables, or
vocabulary (“equations” and “expressions”,
for example)… to name some common
weaknesses for *beginning* algebra.
the tendency is to believe that whatever
this “general principle” thing is that
teachers keep wanting to come back to
is secret-math-head *code* for something
that, if we’d only present it in plain english,
then they’d know how to work the problems
on the test (which had darn well better
be *just like the ones we practiced*).
so we give in and show ’em the “procedures”:
FOIL instead of “repeated distributive law”,
for example… and they *pass* the tests
but get *further behind* in the grand scheme.
“i’ve done OK this far by disregarding
all the math-brains-only *theory*…
and now i’m failing. but i’ll *never*
be a math-brain… good heavens,
i’d have to go back and understand
an *awful lot* of stuff i’ve been
given a pass on all these years!…
it’s the pedagogy! it’s my learning
style! it’s my teacher! math sucks!”
the phenomenon persists at all levels
(that i’ve passed through in learning
math up to my published thesis…
when, sure enough, i still felt myself
an imposter compared to the “real
mathematicians” i’d been working
with in grad school).
“logs” are a particularly interesting case:
otherwise-well-prepared calculus students
are often very weak on logs. hell, every
tenth student has decided they’ll just
go ahead and pretend “ln(x)” is to be
replaced with “1/x” somewhere along
the line no matter how many times
it’s marked wrong.
when “should” students learn about
the abstract, proof-heavy style
of math-rightly-so-called?
the typical student will never
*feel* ready for *any* new idea.
(this should be considered in
any discussion of “developmental
barriers”).
do-the-same-thing-on-both-sides.
logs-are-inverse-exponentials.
here’s a common-log equation:
log(4) + log(25) = log(x).
and here’s its solution.
10^[log(4) + log(25)] = 10^[log(x)]
10^[log(4)] * 10^[log(25)] = x
4*25 = x
x=100.
now, kate’s worksheets are great
and i’m not suggesting that anyone
make my approach into their
exhibit A for day-two-of-logs.
so don’t get me wrong.
the point i set out to make when i started…
if i can remember that far back… is that
*no* approach can overcome the simple
fact that our courses are designed to
go *much too quickly* for median-level
students. the good news is that we
can spot talent pretty easily this way:
anybody who can keep up typically
hasn’t “hit the wall” where math
gets *hard*; give ’em an A and
pretend we’ve done something
to be proud of.
my “discrete mathematics” students
last quarter were all calc 2 vets:
future programmers and engineers
and whatnot. and *almost* all of
’em learned quite a bit about
writing proofs. the *easy* thing
here is (of course!) the logic.
(i mean the symbol manipulation;
what all the p’s and q’s have to do
with the “logical structure” of
a given proof is much more obscure
than it appears to non-teachers.)
if *anybody* i’ve ever worked with was
developmentally ready to take on
“show using the definition of logs
that log(a) + log(b) = log(ab)”
as an exercise, it’ll’ve been these
talented hardworking students.
but the resistance was palpable and i folded.
there was… as always… much too much
material (i also had to skip stuff like
“manipulations with sigmas” and
“complete induction”… the class
emerged ready to take on maybe
a third of the exercises in the sections
covered [mostly the easiest ones]).
there *is* no developmental appropriateness
in “real world problem solving”: one needs
a technique that *works* wherever it’s found.
our task as math-teachers-in-schools,
though, is pretty much “preparing students
for yet another class”… and one technique
that “works”, alas, is *hide your weaknesses”.
that idea of “apply some inverse-thingy
on both sides of the equation”? one of
a handful of big ideas in algebra
(along with “variables”, “graphs”,
and “roots of polynomials” and…
well, not much else…)
“look: to undo an *addition*, we do
a *subtraction*… to undo a multiplication,
we do a *division*… and these ideas
were *hard* when we tackled ’em
back in some earlier course.
a little later, we decided that
we wanted to ‘undo’ squares,
and introduced ‘square roots’;
more generally (and about half
the beginning-algebra folks
get lost around the bend in
here somewhere) we’ll need
to undo powers-of-the-variable
like x^K, and introduce Kth roots.
well, then, doggone it, why shouldn’t
the same undo-the-operation
strategy work for K^x?”
i’ve ranted out this mini-lecture
not just to get it out of my system
(for today), but to demonstrate
that one need *not* have any
*formal* understanding of
“inverse function” to use the
never-stop-harping-on-general-principles
method that i’m more or less advocating here.
(indeed, inverses-treated-formally
is a classical crux. “never mind
*why* i solve x = f(y) when i want
a formula for f^{-1}(x)… just show
me *how*!”… one of the most
glaring examples of the
i’ll-never-understand-the-reasons
phenomenon known to me.)
okay. this was fun.
haven’t i got a *job* or something?
UPDATE jun17 2020 (can’t f-ing comment…)
kate nowak’s site is gone. evidently she
has something to do with this mess.
k. nowak