Difficulties encountered by African students’ learning the semiotic representations of the spatial structure of organic molecules. - Archive ouverte HAL Accéder directement au contenu
Proceedings/Recueil Des Communications Année : 2012

Difficulties encountered by African students’ learning the semiotic representations of the spatial structure of organic molecules.

Destin Mangane
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Résumé

This study aims at identifying and analysing the learning difficulties of beginners regarding the semiotic representations of the spatial structure of organic molecules from a visualization perspective. The three-dimensional arrangements of atoms in molecules are depicted by two-dimensional drawings such as Cram representations or Newman projections which constitute two different semiotic systems. Treatment and conversion of semiotic representations need visuospatial abilities such as mental rotation or iconic visualization. A questionnaire was designed to determine to what extent grade 12 students in Benin (Africa) master the transformations of the semiotic representations of organic molecules. A paper-and-pencil test including four questions was administered to 340 students. The analysis of the answers revealed that a great proportion of students do not master the treatments of the Cram's semiotic representations. Most students responded randomly to say whether one or two permutations between atoms of a chiral molecule lead to the same molecule or its mirror image. No student could draw a correct staggered conformation from an eclipsed conformation which shows that the students do not master mental rotation. One third could not identify conformational isomers out of a list of six conformations because the iconic visualization is not operative. Moreover most of those who identified conformational isomers have a limited understanding of that concept. The most difficult task seems to be the conversion of a Cram representation to a Newman projection. The analysis of numerous incorrect answers leads to the assumption that spatial orientation is ineffective in most students.
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hal-02883062 , version 1 (27-08-2020)

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  • HAL Id : hal-02883062 , version 1

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Destin Mangane, Isabelle Kermen. Difficulties encountered by African students’ learning the semiotic representations of the spatial structure of organic molecules.. XXXIV (3), pp.170-174, 2012. ⟨hal-02883062⟩
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