Next, we proceed to explicitly justify the chosen content and its sequence. As we
have indicated previously, many of the design-based research proposals do not
explicitly justify the decisions made regarding the content program and its sequence.
The design of a TLS based on the DBR methodology must show the most outstanding elements of epistemological analysis—paradigm shifts, justification of new
theories, events of the emergence of new interpretive models—in order to show
the relationships between the theoretical framework of the discipline and the objectives chosen to teach the subject. In the example we are considering different
discussions in the Physics Education literature about teaching the concepts involved
in the explicative model of how DC circuits work (Closset 1983; Liegeois and
Mullet 2002; Smith and van Kampen 2011).
The mentioned studies show empirical evidences on the difficulties that students
have in learning a scientific model of fundamental of DC circuits with resistors. A
summary of the literature is indicated below:
– The fact that most of the students who participated in the aforementioned studies
avoid using the concepts of potential to analyze the current in a circuit, indicates
confusion in the meaning of this concept.
– A significant percentage of students indicate as a cause of the current the
difference in the amount of charge or sign of charges, between the ends of the
battery.
– Students often use reasoning based on the “formula” in their description of how a
circuit works.
– Many students consider Ohm’s law as the general law of the circuit that explains
its current and energy balance.
– Most of the students do not relate the macroscopic phenomena (current, potential
measurements, resistances ...) and the microscopic phenomena (movement of
electrons, action of the electric field on the electrons ...).
The beginnings of electrical theory in the eighteenth and nineteenth centuries are
linked to electrostatic phenomena. In this way, one of the first theories on the flow of
current in a closed circuit refers to the “electrical conflict” based on the model of the
two fluids that leave the battery and are neutralized along the wire. During the
eighteenth century, studies were carried out in transient current discharges, in
accordance with the development of experimental (Leyden jar) (Bensheguir and
Closset 1996). After Volta’s discovery, the experimental base expands and new
explanatory theories of electric current appear. The concepts of “degree of electrical
tension” of a charged conductor and “electromotive force” were introduced by Volta
to explain the voltage in electrical conductors that caused the movement of current.
During the 1920s, Ohm investigated the conductivity of materials and their resistance to current flow. In this context, Ohm explained the different roles of the current
and the potential at a time when they were both quite confused. Ohm used the
analogy of the temperature gradient that drives heat transfer to explain the flow of
electricity in a circuit through lead wires (Schagrin 1963; Taton 1988). Kirchhoff
synthesized Ohm’s work and went further by proposing a theory for current flow in
electrical circuits. This theory was based on the development of the concept of
13 Designing Teaching Learning Sequences Based on Design-Based Research
167
have indicated previously, many of the design-based research proposals do not
explicitly justify the decisions made regarding the content program and its sequence.
The design of a TLS based on the DBR methodology must show the most outstanding elements of epistemological analysis—paradigm shifts, justification of new
theories, events of the emergence of new interpretive models—in order to show
the relationships between the theoretical framework of the discipline and the objectives chosen to teach the subject. In the example we are considering different
discussions in the Physics Education literature about teaching the concepts involved
in the explicative model of how DC circuits work (Closset 1983; Liegeois and
Mullet 2002; Smith and van Kampen 2011).
The mentioned studies show empirical evidences on the difficulties that students
have in learning a scientific model of fundamental of DC circuits with resistors. A
summary of the literature is indicated below:
– The fact that most of the students who participated in the aforementioned studies
avoid using the concepts of potential to analyze the current in a circuit, indicates
confusion in the meaning of this concept.
– A significant percentage of students indicate as a cause of the current the
difference in the amount of charge or sign of charges, between the ends of the
battery.
– Students often use reasoning based on the “formula” in their description of how a
circuit works.
– Many students consider Ohm’s law as the general law of the circuit that explains
its current and energy balance.
– Most of the students do not relate the macroscopic phenomena (current, potential
measurements, resistances ...) and the microscopic phenomena (movement of
electrons, action of the electric field on the electrons ...).
The beginnings of electrical theory in the eighteenth and nineteenth centuries are
linked to electrostatic phenomena. In this way, one of the first theories on the flow of
current in a closed circuit refers to the “electrical conflict” based on the model of the
two fluids that leave the battery and are neutralized along the wire. During the
eighteenth century, studies were carried out in transient current discharges, in
accordance with the development of experimental (Leyden jar) (Bensheguir and
Closset 1996). After Volta’s discovery, the experimental base expands and new
explanatory theories of electric current appear. The concepts of “degree of electrical
tension” of a charged conductor and “electromotive force” were introduced by Volta
to explain the voltage in electrical conductors that caused the movement of current.
During the 1920s, Ohm investigated the conductivity of materials and their resistance to current flow. In this context, Ohm explained the different roles of the current
and the potential at a time when they were both quite confused. Ohm used the
analogy of the temperature gradient that drives heat transfer to explain the flow of
electricity in a circuit through lead wires (Schagrin 1963; Taton 1988). Kirchhoff
synthesized Ohm’s work and went further by proposing a theory for current flow in
electrical circuits. This theory was based on the development of the concept of
13 Designing Teaching Learning Sequences Based on Design-Based Research
167