  Research has shown that both high school and university students' reasoning
patterns regarding direct current resistive electric circuits often differ from
the currently accepted explanations. At present, there are no standard
diagnostic examinations in electric circuits. Two versions of a diagnostic
instrument called Determining and Interpreting Resistive Electric circuits
Concepts Tests (DIRECT) were developed, each consisting of 29 questions. The
information provided by the exam provides classroom instructors a means with
which to evaluate the progress and conceptual difficulties of their students
and their instructional methods. It can be used to evaluate curricular packages
and/or other supplemental materials for their effectiveness in overcoming
students' conceptual difficulties. The analyses indicate that students,
especially females, tend to hold multiple misconceptions, even after
instruction. During interviews, the idea that the battery is a constant source
of current was used most often in answering the questions. Students tended to
focus on current in solving the problems and to confuse terms, often assigning
the properties of current to voltage and/or resistance. Results indicated that
students do not have a clear understanding of the underlying mechanisms of
electric circuit phenomena. On the other hand, students were able to translate
easily from a "realistic" representation of a circuit to the corresponding
schematic diagram.
