Promoting understanding of chemical representations: Students' use of a visualization tool in the classroom

Abstract

Many students have difficulty learning symbolic and molecular representations of chemistry. This study investigated how students developed an understanding of chemical representations with the aid of a computer‐based visualizing tool, eChem, that allowed them to build molecular models and view multiple representations simultaneously. Multiple sources of data were collected with the participation of 71 eleventh graders at a small public high school over a 6‐week period. The results of pre‐ and posttests showed that students' understanding of chemical representations improved substantially (p < .001, effect size = 2.68‐. The analysis of video recordings revealed that several features in eChem helped students construct models and translate representations. Students who were highly engaged in discussions while using eChem made referential linkages between visual and conceptual aspects of representations. This in turn may have deepened their understanding of chemical representations and concepts. The findings also suggest that computerized models can serve as a vehicle for students to generate mental images. Finally, students demonstrated their preferences of certain types of representations and did not use all types of three‐dimensional models interchangeably. © 2001 John Wiley & Sons, Inc. J Res Sci Teach 38: 821–842, 2001

The influence of prior knowledge on viewing and interpreting graphics with macroscopic and molecular representations

“…Research on multiple representations has been of particular interest in the area of chemistry (Kozma, 2003;Kozma & Russell, 1997;Rohr & Reimann, 1998;Treagust, Chittleborough, & Mamiala, 2002;Wu, Krajcik, & Soloway, 2001). Visual representations play a critical role in chemistry, where complex phenomena are not always directly observable (Kozma, 2000).…”

“…Macroscopic representations depict observable phenomena, whereas molecular and symbolic representations describe invisible and abstract phenomena. Molecular representations illustrate chemical processes by the arrangement and movement of molecules, whereas symbolic representations present formulas, equations, and structures (Wu et al, 2001).…”

“…However, much of the research also indicates that the influence of domain knowledge cannot be overlooked (Kozma, 2003;Kozma & Russell, 1997;Wu et al, 2001;Wu & Shah, 2004). Learning from multiple representations at the macroscopic and molecular level can be a difficult process, especially for novices.…”

“…Students with little domain knowledge generally focus on surface features to make links across representations. However, little about surface features is related to the underlying themes of the representations (Wu et al, 2001). Because they have difficulty finding more abstract similarities across representations, novices are misled by surface similarities among macroscopic and molecular representations.…”

Explorando as percepções de professores em serviço sobre as visualizações no ensino de química

“…Outros estudos, [9][10][11][12] reforçaram o princípio de que a visualização ocupa um papel central na aprendizagem, uma vez que os estudantes do ensino médio e superior apresentam dificuldades para interpretar fenômenos e transformações químicas em termos de modelos representacionais atualmente aceito. 13 De qualquer perspectiva que se investigue, é fato que professores pesquisadores e profissionais de química necessitam ter o domínio de expressar os conhecimentos químicos pela articulação das três dimensões da realidade: macroscópica, submicroscópica e representacional.…”