As a researcher and teacher, I have a certain understanding of the
affordances and limitations of different energy representations. But I also enjoy hearing some of the teachers’
perceptions of these representations so that I can compare with my own views. That’s what this post starts to explore. There could be important implications for instruction, but I don't get into that here.
Monday, 08/13/2021, table#2, pm
In a previous post (here) I described a particular class context and how
three different groups (tables#2, #3, and #8) each used a different energy
representation on their whiteboard to answer the same prompt.
In this post I will show and analyze an interesting clip from that same
context where the teachers at table#2 explicitly compare their board (Energy
Tracking) to that of table#3 (Energy Bar).
One reason I think this clip is interesting is because the teachers
spontaneous contrast and compare the two boards and quickly pick up the key differences. It’s also interesting because the different
members have very different preferences.
For the video clip, Mary is on the left initially writing on the
whiteboard, Sid has the blond curly hair on the foreground right and Julie has
the straight brown hair at the back right.
The clip starts with table#2 answering several questions on chemical
and thermal energy in lifting and lowering a bowling ball at constant
speed. Since the questions are on the
screen at the front of the room, Mary is frequently looking back over her
shoulder to see if she is getting all the details right. So when, Joe, who has been working with
table#3 on the same problems, brings his whiteboard up to the front of the room,
she sees him do it. (at 0.37 in this clip).
Finally, Mary finishes up and is mentally quite exhausted ,but she is
also very intrigued (troubled?) by what she sees on Joe’s board (1:09). From there follows a brief group discussion
about what table#3 did (Energy Bars) compared to what table#2 did (Energy Tracking):
Mary: …and I’m
done.
Julie: laughs.
Mary: Is looking at Joe’s board at the front of the
room (scratching her neck)
Julie:
I’m so sick of talking ab (Mary
talks over her)
Mary: What do you guys think of those bars?
Julie: I love
the bars.
Mary: Do you
love the bars?
Sid:
Adjusting her view to see the front of the room.
Mary: The
only thing I don’t like about the bars, but
they seem to (garble) (points to
the front of the room), it’s not clear
where they come from (points to her group’s whiteboard to compare), like if you just did bar to bar (gestures
with hands) you don’t have any…transfer
(gestures with hands)
Julie: Yeah, totally, transformation and
conservation is all I see. But I like
it.
Mary: But
they’re showing it though (points again to front of room), with dot dotted lines are they? (folds arms on chest)
Sid:
Yes, but they’re also different
SIZES (squeezing gestures with both hands). In fact we can’t do chemical going to two different things
(garble).
Mary: As far
as (garble)…
Julie:
laughs
Mary: it’s not showing where it’s coming from. It’s not showing the transfer.
Julie: (lays head on table) I like it for conservation.
Sid: It’s
bound by (garble) (gentle pounding motion by right hand)
Julie: (cheering) Go bars, go bars!
Sid: (garble) (head nodding).
Mary: They’re elegant.
Julie: I’m so
burned out on this scenario. I’m burned
out.
2:00-2:20
side conversation
Mary: Looking at Sue (black top, grey skirt) at table#1
and/or the front of the room and mouths something (“what are they doing”??)
Mary: Did
their…
Mary: Gets up to get a better view of Joe’s
board. Tilts head at angle to better
read it. Sits back down.
Mary: I can
not follow that one (pointing to Joe’s board). It’s
too…
Julie: Mary,
let your brain rest. You’re going to
explode..hahaha. You’re going to
explode.
Starting at about 0:40 in this clip, Mary is repeatedly looking at
Joe’s board as she finishes her other task.
It is really interesting (different?) to her and keeps grabbing her
attention. Immediately upon finishing
the task at hand, she is back looking at Joe’s board. Her gestures and facial expressions are very
interesting. Maybe she feels some
intrigue or perhaps puzzlement? She has
a slightly closed body position which might be expressing some uncertainty. She looks a long time and then wants to know
what her group thinks.
I’m fascinated that Julie’s response is immediate. Perhaps this is part of her personality, to
be spontaneous. Clearly she is not as
reserved as Mary. Anyway, she has no
hesitation whatsoever. She loves bars. But Mary is bothered that the bars don’t show
the energy tracking. She can’t see the
specific transfers clearly, and in particular, where each form came from,
although table#3 did put in dotted lines to indicate both some kind of tracking
and that all bars had the same overall heights (see the second photo here). I am interpreting the “they” in “it’s not clear where they come from” to
refer to the different energy forms rather than to the Energy Bar
representation itself. I say that
because of her hand motions (bar to bar) and her reference to the work on their
own whiteboard, which she points to, and which explicitly used an Energy
Tracking Diagram (see first photo here).
Julie completely agrees with Mary, but still likes bars. She is able to immediately comprehend the two
key features of the bars and the missing one – “There is no tracking, just
transformation and conservation”. Sid’s
comments and tone of voice seem to indicate she doesn’t prefer Energy Bars
either, but she doesn’t ever say so explicitly.
And Mary states even more unequivocally that the bars don’t show the
energy transfers. Julie knows why she
likes bars – the conservation of energy is very clear in them for her (all bars
are the same height, which can be seen in one quick glance).
Here is a hypothesis about why Julie might prefer bars (or see energy
conservation so clearly in them compared to tracking). Conservation in energy tracking comes from
counting the number of letters in two or more snapshots and comparing
them. The letters might be scattered
across several different objects spatially arranged on the whiteboard, or, as
in the case of table#2’s whiteboard for this problem, there are many different
snapshots, with different length arrows showing the transforms. So it is a little jumbled and perhaps
difficult at first glance to see, although counting the number of transition
“rows” in their diagram is also a way to see conservation, and the number
neither increases nor decreases from beginning to end. This is speculation on my part why Julie
might like bars. And she never really
says she likes them better than tracking, so that is also speculation on my
part.
Julie is totally psyched now (actually totally burned out if we believe
her self-report, though her body language shows fatigue too I think) and starts
cheering for the bars: “Go bars! Go
bars!” almost like it IS a competition between bars and tracking, and that she
DOES like bars better than tracking. And
Mary certainly agrees that bars are “elegant” - aesthetically pleasing.
It’s clear that Mary is totally engrossed by the bars, working hard to
try to figure them out. Even though the
other two pull her off-topic after she
sits down, after 20 seconds she is right
back at it, even getting up to go look
around people in the way, and tilting her body sideways to view the bars a
different way. At last she states a
reason for all this querying and behavior – she can’t follow them. So perhaps this whole time, since first
glancing at them when Joe brought them up, she is puzzled and has been trying
to figure them out, but her group doesn’t really explain them to her when she asks. And possibly she can’t quite figure them out
on her own. And Julie just really
doesn’t want to do any more on this scenario, so Mary stops after trying this
second time.
Something curious about Julie’s response to loving bars is that she
never draws them. I’ve been watching the
group all week and at least in the afternoons, only Sid and Mary have been
drawing on the whiteboard. And table#2
never had bars on any of their whiteboard photos that we have. Apparently only table#3 ever does bars. One possible reason that table#2 never did
bars is that Julie never felt strongly enough about bars over tracking to
insist on taking the pen and drawing bars.
But perhaps also she does not understand them in enough detail to draw
them (they were never formally introduced in class, and only appeared in a
Diagnoser question on-line, which table#3 took and ran with in at least three
different cases).
What follows next is absolutely hilarious (to me and table#2) but I
won’t say much about it. I just thought
it was so great that I wanted to share it with the public. Mary tries one more time (her 3rd
attempt) to ask her group about how the bars compare to their tracking, but
Julie shuts her down, apparently for health and/or safety reasons:
Mary: laughing (garble, asking something pointing
to their WB)
Julie: You may
not look at this (whiteboard) again.
Mary: Hand motions of heat from her head.
Sid:
Thermal energy, thermal energy.
Julie: What’s
that smell? It’s like her hair is smoldering…Gosh,
Mary, take a break. (fanning Mary with her hand to cool her off).
Mary: Slouched with her arm grabbing her neck and
laughing uproariously.
Sid:
She’s got too much thermal energy
(gently fanning Mary with the whiteboard)…(garble) too much chemical, breaking their bonds. That’s the evidence we have.
Mary:
Relaxed sitting.
Julie: Mary is, all of a sudden Mary is…kapoo
(makes blowing up sound and gestures with hands), her head explodes. Ohhh…take a
break Mary, walk it off.
Mary: Waves hands in front of chest to cool herself
off.
Notice the excellent evidence-based reasoning that Sid is using to
justify her statement about which energy transfers she thinks are going on in
Mary’s head.
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