Results from Interviews on the Radioactive Atom -
Informed by the results described in part A, we shifted
the emphasis of this investigation to examine students'
ideas about the role that the atom plays in connection
with the concept of radioactivity, including the process
of decay. As a first step, we conducted a series of six
individual demonstration interviews in which students
were asked to perform specific tasks, and answer
conceptual questions, designed to provide insight into
their beliefs about concepts related to radioactivity. A
combination of both open-ended and pre-determined
protocols was used with each of these interviews, which
averaged 1/2 - 3/4 hour in length. Each interview was
videotaped for later analysis of students' responses and
actions. These interviews were conducted with two
students that were enrolled in the introductory
calculus-based physics course, two students enrolled in
the introductory algebra-based physics course and two
undergraduate physics majors who had completed the
year long introductory calculus-based physics series and
a sophomore level modern physics class in which they
had specific instruction on radiation and radioactivity.
The information obtained from these interviews was
then used to guide the design of open-response and
multiple-choice questions administered on pre- and
post-instruction questionnaires.