Students' visualisation of chemical reactions – insights into the particle model and the atomic model

Abstract

This paper reports on an interview study of 18 Grade 10–12 students’ model-based reasoning of a chemical reaction: the reaction of magnesium and oxygen at the submicro level. It has been proposed that chemical reactions can be conceptualised using two models: (i) theparticle model, in which a reaction is regarded as the simple combination and rearrangement of reactant particles and does not involve any change in the identity of the reactants, and (ii) theatomic model, wherein a reaction involves the transformation of one chemical species into another. This paper suggests that although theparticle modellooks simpler than theatomic model, it can help to support the learning of some advanced chemical concepts such as energetics and collision theory. Therefore, it is postulated that students who reason using theparticle modelare able to demonstrate some advanced ideas about chemical reactions. The conceptualisation of reactions in terms of theatomic modeland theparticle modelallows a flexible understanding of students’ learning. Students’ representations of the reaction between magnesium and oxygen were analysed with reference to the two models. The models were found to be useful in assessing the students’ understanding of the reaction and revealing the novel ways that the students reasoned the chemical reaction. In addition, a student who used theparticle modelto represent the reaction was found to explain the reaction in terms of some energetics and kinetics concepts. The study offers insights for curriculum planners and teachers into the potential of these two models to help students understand chemical reactions.

Sketching, not representational competence, predicts improved science learning

“…Most recently, Cheng (2018) has demonstrated that as representational competence develops, it does not generalize across science domains or even among science concepts. In the study, Cheng assessed 40 students' RC and conceptual knowledge related to the topics of particulate nature of matter and the carbon cycle.…”

“…A close examination of the activity structures in each of the studies regarding RC indicate that these studies have yet to fully explore the efficacy of specific interventions designed to support RC while engaged in content learning. In the majority of the RC studies (e.g., Cheng, 2018; Hubber et al, 2010; Nitz et al, 2014), RC was measured in the context of learning environments that only incidentally addressed RC as a target of instruction. For example, Nitz et al looked at the relationship between RC and content knowledge as they developed in classrooms where teachers varied their explicit emphasis on teaching students how to interpret various disciplinary representations.…”

“…Various researchers have demonstrated that drawings provide important insight into learners' developing mental models of scientific phenomena as well (see Van Meter & Firestone (2013) for a review). The bulk of research on drawing activities have focused on the role of drawing to support assessment (e.g., Cheng, 2018; Cooper, Williams, & Underwood, 2015; Harle & Towns, 2013; Kelly, Barrera, & Mohamed, 2010) or to facilitate scientific modeling (e.g., Cooper et al, 2015; Quillin & Thomas, 2015). Such work has demonstrated that drawing provides an external representation that affords students the opportunity to evaluate their developing understanding of a scientific model and that most drawings are close approximations of the last pedagogical model students viewed in their curriculum (Coll & Treagust, 2003).…”

Una herramienta para el análisis del nivel de comprensión del modelo de materia de los alumnos de 4º de ESO

“…Algunas de las representaciones visuales también proporcionaron detalles como la idea del movimiento continuo de partículas, mediante el uso de comillas en los tres estados de la materia. Por lo tanto, nuestros resultados respaldan las afirmaciones de que las visualizaciones son una forma muy útil de acceder a las concepciones de los estudiantes (Cheng 2018, Cheng y Gilbert 2017y 2009, Adadan, Irving y Trundle 2009.…”

Penilaian Kualitas Media Audio Visual Tentang Karakteristik Larutan Asam Basa Untuk Siswa Sma/Ma

“…(2006) menyebutkan bahwa audio visual juga mampu mengurangi kesalahan siswa dalam memahami konsep dalam kegiatan praktikum. Hal ini menegaskan bahwa media audio visual sangat penting untuk mencapai keberhasilan pembelajaran karena mampu menampilkan model dan simulasi materi berukuran mikroskopik (Cheng, 2017). Media ini sangat tepat untuk mengurangi kesulitan belajar siswa pada subjek-subjek abstrak seperti kimia.…”