CLASSROOM UPDATE • CHEMISTRY
Misconceptions can mess it up
C
hemistry is one of the core science domains taught in school. In the simplest terms, chemistry deals with materials and their transformations. Thus, it is closely associated with our lives and is important for us to understand this association. However, these connections are not always apparent through the content taught in schools. In fact, chemistry seems very abstract when it is introduced in the syllabus. The abstract nature poses several challenges to learners and teachers. While struggling to understand the concepts, learners often end up having misconceptions. This article aims to help teachers understand why chemistry poses learning challenges and to acquaint them with some of the standard resources available in the public domain.
of modern chemistry, which is the chemistry taught in schools today (see Figure 1). These major components are – a) Macro, b) Sub-micro and c) Representational components.
Learners’ misconceptions in chemistry is an established area in the field of Chemistry Education Research (CER). It is important to not associate negative connotations with the word misconceptions. The suffix 'mis' indicates the variation in the learners’ conceptions from the current scientific understanding of chemistry concepts. We also would like to emphasize that any individual, not just school students, can have misconceptions.
Figure 1: Three components of the modern chemistrychemistry triangle (by Alex Johnstone).
There are several reasons for developing misconceptions. For example, in everyday life, we observe that combustion leads to a massive reduction in volume or mass of materials. Thus, it is a counterintuitive experience for learners to understand that substances can gain mass after combustion. Sometimes language can be a barrier, e.g., ‘salt’ in chemistry is a technical term (a substance produced by the reaction of an acid with a base), but often it is perceived by learners as referring to sodium chloride (namak in the Indian context). Another crucial factor responsible for misconceptions in chemistry is related to wrong instructional practices. It is, thus, important to first understand the characteristics of chemistry as a subject. The late Prof. Alex Johnstone, a renowned chemistry education research expert from the University of Glasgow, has described three major components
Images courtesy: Hanza George and Savita Ladage
Savita Ladage and Hanza George
The macro component of chemistry (that is, descriptive chemistry) represents the concrete experiences that one can gather about the material and their transformations through sense organs, e.g., texture or appearance of materials, changes during chemical reactions such as a change in colour, precipitation, the formation of gases/effervescence and change in temperature during the course of a reaction. The sub-micro component represents concepts such as the particulate model of matter, subatomic particles, etc. There are no direct experiences related to this abstract and theoretical sub-micro component. The explanations in chemistry are in terms of the sub-micro component. The third representational component (the language of chemistry), includes equations, formulae, mathematical/graphical representations, etc., which is equally abstract in nature. When serious engagement with chemistry begins at school, learners have some experiences relating to materials, that is the learners are located at the macro end of the triangle. Soon, they are pushed towards the middle of the triangle with the introduction of the other two components (over grade 7-9). In fact, the learners are not even presented with TEACHER PLUS, SEPTEMBER 2020
49
