Using Questioning as an Instructional Strategy for Concept- Based Teaching
Asking the right questions in class is often seen as a way to engage learners in the lesson. However, such questions play another important role of helping students better understand and to relate concepts in the studying of science. One example involves asking higher order thinking questions while carrying out Chemistry experiments, which is especially important to high ability learners who may need to be further challenged in regular lessons. For example, when studying the properties of aqueous solution of aluminium (Al3+), iron (III) (Fe3+) and chromium (III) (Cr3+) ions, students may be asked to compare and derive the similarity in their acid property. Questions such as “Why are they acidic?”, “What happens when solid sodium carbonate (Na2CO3) is added to an aqueous solution containing aluminium (Al3+) ions?” and “Why does the addition of acid cause the precipitate to dissolve?” require learners to explain, analyse and evaluate, thus pushing learners to go beyond mere procedural knowledge. Coming up with answers to these questions requires an understanding and a good grasp of the concepts of bonding, acid-base reaction and equilibrium and making accurate connections in these topics.
Similarly, before carrying out qualitative analysis, students can be asked to predict expected observations and give reasons for their predictions before they carry out the tests. Hence, before aqueous ammonia is added to an aqueous solution of magnesium (Mg2+) ions, learners could be asked “What do you expect to see immediately?” and “What happens when this is followed by the addition of solid ammonium chloride (NH4Cl)?”. Such questions provide high ability learners with opportunities to connect specific experimental phenomena to more theoretical concepts in Chemistry. From experience, when students were required to make such predictions, they had to link what is observed in the experiment with their understanding of equilibrium and solubility product. Additionally, learners’ concepts of equilibria and solubility were reinforced through connections made by what they see in the laboratory.
In laboratory work, besides giving students chances to practise laboratory skills, it was also beneficial for high ability learners to conduct some experiments which extended over a period of two or three weeks. Such extended laboratory investigations required high ability learners to work with multiple concepts or with multistep processes. This challenged high ability learners more, requiring them to integrate concepts into a single laboratory report, and gave them a chance to mirror what mature chemists do in the real world. Having a greater overlap of experiments with lecture topics also reduced the burden of remembering disparate facts for students. Concept-focused instruction given in the laboratory, when it is well developed, can help reduce the lecture time on the topic. Giving learners opportunities to work with interactive software and molecular models at the beginning of the laboratory session also gives learners time to develop fresh insights and ideas, resulting in better synchronisation of the concepts learned in the laboratory and lecture.
While the account so far has described the use of explicit concept-focused instruction, mental models and questioning as it was explored with our group of learners, other concept-building activities such as looking at misconceptions and relevance can be valuable. The next section looks at some examples of their use in the chemistry classroom.