Learners Ideas and Misconceptions - Essentials of Chemical Education - page 21

Fig. 1.11 Chemical structure and bonding with regard to the chemical reaction [ 21 ]
Tetrahedral-ZPD metaphor . Last but not least Sileshi [ 25 ] formulated a “Tetra-
hedral-ZPD” chemistry education metaphor as another framework to prevent
students' misconceptions (see Fig. 1.12 ). This metaphor rehybridizes the very
powerful 3D-tetrahedral chemistry education concept proposed by Johnstone [ 26 ]
and Mahaffy [ 27 ]: macroscopic, molecular, representational level, and human
element. With the idea of the “Zone of Proximal Development (ZPD)” of social
constructivist Vygotsky [ 28 ], ZPD should describe “the distance between the actual
development level as determined by independent problem solving and the level of
potential development as determined through problem solving under adult guidance
or in collaboration with more capable peers” [ 28 ].
The basic elements of this metaphor are what Shulman [ 29 ] has labeled “Pedagog-
ical Content Knowledge (PCK)” integrated with contextual and research knowledge:
“Pedagogy-Content-Context-Research Knowledge (PCCRK). Content knowledge
refers to one's understanding of the subject matter, at macro-micro-representational
levels; and pedagogical knowledge refers to one's understanding of teaching-learning
processes; contextual knowledge refers to establishing the subject matter within
significant social-technological-political issues; and research knowledge refers to
knowledge of 'what is learned by student?', that is, findings and recommendations
of the alternative conceptions research of particular topics in chemistry” [ 28 ].
Sileshi further conducted an empirical study to evaluate the effects of the
Tetrahedral-ZPD metaphor on students' conceptual change (see Fig. 1.12 ). Know-
ing by own experiences that high school students in Ethiopia are mostly
memorizing chemical equations without sufficient understanding, that they are
not used to think in models or to develop mental models according to the structure
of matter, new teaching material and worksheets for the application of the particle
model of matter and Dalton's atomic model were prepared [ 25 ].
In pilot studies lasting for 6 weeks, the research was carried out with an experi-
mental-control group design: pretests and posttests were used to collect data before
and after the intervention. First results from the posttests indicated that the students in
the experimental group, taught with the new teaching material concerning the struc-
ture of matter, show significantly higher achievements compared with the students in
the control group: students' misconceptions in the experimental group after they were
taught using the new teaching material are less than in the control group [ 25 ].