Common-Sense Chemistry: A Model for Understanding Students’ Alternative Conceptions

Research in science education in the last thirty years has shown that students enter chemistry classes with many preconceived ideas about the behavior of the natural world (1). These ideas, derived from previous physical and social experiences, often lead them to make predictions and build explanations different from those derived by currently accepted scientific theories and practices. Moreover, as learners try to assimilate new information into their existing knowledge structures, a variety of unintended instructional outcomes result. From this perspective, the recognition and characterization of students’ beliefs and prior knowledge seems to be crucial to helping them build scientific understandings (2). Unfortunately, most teachers do not adequately analyze and reflect on students’ thinking about natural phenomena. Instead, classroom assessment is typically designed to determine to what extent a student’s knowledge matches that sanctioned by school science (3). Students’ explanations are judged on a scale of right to wrong, and little analysis is done on the meaning or cognitive implications of the actual answers. Academic failure is normally attributed to either a lack of student effort and motivation or the use of inadequate instructional strategies. This system diverts teachers’ attention away from the actual student work and prevents them from using student thinking to inform their practice (4). My personal experience as teacher educator indicates that, when given the opportunity, most college and secondary school chemistry teachers tend to be interested in the analysis and discussion of research results on students’ alternative conceptions in chemistry. However, they are rapidly overwhelmed by the number and diversity of alternative conceptions that science learners may have. Many teachers are often unable to identify any consistent patterns in the students’ thinking and thus see the vast inventory of students’ alternative conceptions as isolated pieces of information. Moreover, the catalogue of students’ ideas can rapidly become a list of common mistakes that they see as their obligation to fix. Every mistake is quickly judged as a misconception, without further reflection on the actual source of the problem or any analysis of the underlying patterns in the students’ reasoning that might in fact be used as a resource to promote understanding. Most of the literature that describes, reviews, and summarizes research on alternative conceptions in chemistry traditionally organizes the information by topic or subject: states of matter, particulate nature of matter, chemical bonding, chemical equations, etc (5-10). Unfortunately, this “inventory-approach” makes it difficult for teachers to identify any common assumptions or patterns of reasoning that may be guiding students’ thinking about chemical phenomena. The development of such a common “explanatory framework” would be very useful to help chemistry teachers and instructors to identify, understand, and even predict the possible alternative conceptions that their students may hold (11). Said system would allow teachers to organize the important knowledge that they have about student ideas in chemistry in more meaningful ways. This paper discusses the results of a research project guided by the assumption that such common explanatory framework exists and can be described by analyzing the existing research literature on alternative conceptions in chemistry. Based on this assumption, this work was guided by the following research question: What common assumptions about the behavior of the natural world and associated patterns of reasoning underlie many of the alternative conceptions in chemistry as described in the research literature? Although one should recognize that students’ ideas vary with age, personal history, and social background (1), the goal of this research project is to build a model of a typical “naïve” student in an introductory chemistry classroom in a western society. The intention is to develop a useful framework that chemistry teachers and instructors can use to better understand and even predict many of their students’ ideas, and implement instructional strategies that promote learning and understanding. In the following section I describe the theoretical and empirical work that guided my analysis of students’ conceptions about chemical substances and phenomena, and the development of the proposed explanatory framework. Then, I describe the research methodology, and present the central findings. This work represents an effort to utilize well-established results in chemical education research to develop tools and models that can help improve teacher thinking and practice.