Invited
The nano-dimension: A suggestion of a new dimension to the Johnstone’s chemistry triangle

Teaching and learning chemistry involves three domains of meaning that together create a comprehensive conceptual understanding (Johnstone, 1991): the macroscopic domain, the submicroscopic domain and the symbolic domain. The macroscopic domain (macro domain) mainly deals with substances and chemical phenomena that can be observed, smelled, and so on. The submicroscopic domain (submicro domain) deals with particle entities, especially molecules, atoms, ions and electrons, and their arrangements. The symbolic domain mainly deals with representations in terms of formulas, reaction equations, charge signs, and the like. In the last 20 years educational links between the context and these three domains of meaning in chemistry education led to the development of context-based chemistry education programs around the world. This pedagogical approach introduced an additional domain to chemistry education – the human dimension (Mahaffy, 2015) that includes the involvement of humans in chemistry as creators, learners and teachers and consumers; and the involvement of chemistry in human life in variety of contexts. However, when the human dimension was added to chemistry education, it was realized that the original three dimensions presented above are not enough in order to explain the chemistry of many real contexts. In the conference, I will suggest a new domain of meaning that mediates between the other dimensions: The nano-dimension. The nano-dimension is essential to the explanation of real contexts because the organization of materials in the nano-scale influences their properties and functions. Several examples of everyday life contexts will be presented in which a same compound that have different forms of organization in the nano-dimension leads to different properties, and therefore different applications. The examples include natural materials (e.g., eggshell), as well as synthetic materials (e.g., fabrics).