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help to better structure problem solving tasks.
First, however, our focus was on creating a better
interactive resources for qualitatively understand-
ing the dynamic behavior of electrical circuits-an
animated circuit simulation.
cuits with capacitors, for example, but could not
answer basic qualitative questions such as what
happens in a circuit with a capacitor, light bulb
and DC voltage source. Our circuit simulation
shows them this behavior. Second, our circuit
simulation uses a technique known as enactive
modeling that allows for manipulating variables
in real-time and immediately seeing their effects.
Thus for example students can 'wiggle' the voltage
and see its effects in a circuit with a capacitor or
inductor, thereby helping students induce invari-
ant principles related to the impedance of these
components with respect to frequency changes.
The enactive modeling strategy is described in
more detail below.
tHE dESIgn of An AnImAtEd
cIrcuIt SImuLAtIon
As mentioned above, the outside resources used
in Inductor to provide feedback to students while
they worked on circuit problems were not suf-
ficient. Students still were not given a sense of
how particular circuits behave in real-time. This
motivated the creation of an animated circuit
simulation. An interactive simulation environment
may allow students to develop a more “voltage-
centered” model of circuit behavior that experts
use to understand the flow of current (Frederick-
son and White, 2000). Also, allowing students to
experiment with a simulation will allow them to
develop multiple context-dependent interpreta-
tions of the invariant laws that govern circuit
behavior. Furthermore, from a design perspective,
students can explore the role of circuit components
by adding and removing them from the circuit, or
by changing their values in a circuit. By showing
an animation of current flow through a circuit in
real-time, students can see Ohm's law (voltage
equals current times resistance) in action and see
the effects of more advanced components like
capacitors and inductors on current flow.
This simulation can model DC and AC analog
circuits, including components such as capaci-
tors and inductors and transistors. There are two
major design features however that distinguish
it from existing simulations. One is that current
flow is visualized as a single moving chain of
dashes to help students understand the behavior
of the various circuits they learn in introductory
classes. From interviews we found that students
knew the mathematical formulas related to cir-
Enactive modeling
Scientists have routinely employed causal and
mechanical models to help reason about events
and communicate their understanding to other
scientists (Salmon, 1998; de Regt & Dieks, 2002;
Gooding, 1992), even if they later eschew these
models for purely quantitative/mathematical de-
scriptions. James Clerk Maxwell for example used
a mechanical-fluid analogy for electro-magnetic
fields that may have helped him deduce the quan-
titative relationships now known and taught as
Maxwell's laws (Nersessian, 2002).
Researchers in the learning sciences and
cognitive science are beginning to uncover more
about the underlying basis for people's natural
and informal reasoning about both physical and
social events, and why people show a preference
for causal and mechanical models. There appears
to be a connection between our informal reason-
ing and the embodied nature of our thoughts and
actions. We are beginning to pay attention to the
role of one's body and intentional actions (“em-
bodied cognition”, “enactive learning”) in order
to better characterize the contextual constraints
involved in natural reasoning about events. This
applies to computer simulated events as well.
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