Eleanor Sayre
University of Maine
Department of Physics

Resource development and justification: Examples from damped harmonic 
motion

As part of ongoing research into cognitive processes and student thought 
at the University of Maine, we have investigated the interplay between 
mathematics and physics resources in intermediate mechanics students. In 
this talk, I present two examples from one student working on the signs of 
the forces in damped harmonic motion.  As the student builds his reasoning 
about the sign of the air resistance force, I identify a chain of 
reasoning in which a request for reasoning is followed by elaborative 
sense-making and checks for consistency, finishing with an optional appeal 
for group consensus.  To analyze the interaction more fully, I draw from 
two theoretical perspectives, Resource Theory[1] and Process/Object[2], 
and extend them to more explicitly treat issues of idea development, 
justification, and durability. My analysis provides evidence for a 
description of student thinking in terms of this extension, termed 
"Plasticity".

[1] D. Hammer. American Journal of Physics 67 (Physics Education Research
Supplement), S45 (2000).
[2] A. Sfard. Educational Studies in Mathematics 22, 1 (1991).