The unit on chemical care wants to enhance the students’ thinking of substances in interaction with their environment. This is a more complex view than just describing substances and their properties. Research on structure-property-relations (summarised e.g. by Scheffel et al., 2009) points out that students often focus only on one criterion instead of the interaction of different criteria influencing a property or a behaviour. Even in complex structures, properties are sometimes referred to as properties of individual atoms. Additionally, macroscopic properties are sometimes transferred onto sub-microscopic structures in a misleading way, such as giving colours to atoms. The approach of this unit is to avoid this narrow thinking right from the beginning by pointing out the use, the behaviour and the consequences of substances in an environment, not isolated from it. The level of complexity develops from sub-unit to sub-unit, but each new sub-unit should be connected to the knowledge already developed before.
Regarding the method or pedagogical teaching and learning approach, all sub-units allow the students to develop their own ideas for experiments and explanations, of course guided by the material. Next to the guideline of IBSE, context-based learning (see a collection of approaches in Bulte, Pilot & Gilbert, 2006, or in Nentwig & Waddington, 2005) is applied in the design of the units and the material.
In sub-unit 1, the students are led through the activities by the story (“storytelling”) of becoming a household detective.
Sub-unit 2 also situates the activities in the students’ home, this time focussing on cleaners and the help of chemical knowledge for a careful treatment of their own and their families’ health as well as of objects at home.
Sub-unit 3 deals with clothes and fibres, both embedded in daily-life situations, and in industrial contexts.
All sub-units can be structured along the following phases (see Nentwig et al., 2007).
References:
Gilbert, J., Bulte, A. & Pilot, A. (2006). Special Issue on Context-based learning. International Journal of Science Education (IJSE) 28/9
Nentwig, P., Demuth, R., Parchmann, I., Gräsel, C., Ralle, B. (2009). Chemie im Kontext: Situating Learning in Relevant Contexts while Systematically Developing Basic Chemical Concepts. Journal of Chemical Education, 84(9), 1439-1444.
Nentwig, P., Waddington, D. (Eds.)(2005). Making it relevant. Context based learning of science. Münster: Waxmann.
Scheffel, L., Brockmeier, W., Parchmann, I. (2009). Historical Material in Macro-Micro Thinking: Conceptual Change in chemistry Education and the History of Chemistry. IN: Gilbert, J., Treagust, D. (Eds.). Multiple Representations in Chemical Education. Dordrecht: Springer.