Atoms in need

As any teacher will testify, there are many questions to which the answer might be ‘because it wants a full outer shell’ or ‘so it becomes more stable’, raising the hackles of those seeking the development of a deeper level of understanding in students. Many teachers (including the author of this summary) have resorted to anthropomorphism, building explanations around the wants and needs of atoms and molecules to help students to overcome difficulties in answering questions relating to bonding and properties of matter. However, such teleological explanations can prevent students from developing the deeper understanding required for success in more advanced study, and are often the foundation of the most deep-rooted misconceptions that students carry through their studies.

Talanquer has investigated the explanatory preferences of students at different stages in order to probe the impact of this issue.

It is noted that teleological explanations plague other disciplines, notably biology, where phrases such as ‘eagle wings are designed for soaring’ can convey a meaning far removed from that which was intended. In chemistry, teleological explanations are commonly found in textbooks, with, for example, Le Chatelier’s principle being explained by the system’s intention to re-establish equilibrium. The article also draws on research in developmental psychology, which indicates that teleological interpretations are pervasive in childhood, and that this way of thinking can persist into adulthood.

Students were asked a number of questions in different ways, with an example relating to the tendency of oxygen atoms to form two bonds in covalent compounds. Analysis showed that 74% of 2nd semester general chemistry students preferred the teleological explanation that this happens to satisfy the octet rule rather than being explained as oxygen atoms having two semi-filled valence orbitals which can accommodate electrons from other atoms. The data indicated that students across the whole range, including postgraduates, showed a strong preference for teleological over causal explanations. The reasons for this preference may relate to the simplicity and comprehensibility of teleological explanations, which lull students into a false comfort zone of misconception. Other suggestions are that students’ frequent exposure to such explanations leads to a familiarity that influences their answers in high pressure situations and the fact that teleological explanations help students to correctly predict chemical properties. A proposed solution is that instruction could aim to develop students’ metacognitive skills to help them to moderate their responses through analytical reasoning.