Introduction

Teaching is an uncertain domain of knowledge. Teachers struggle to strike a balance among competing educational goals. For example, many teachers believe that students learn best when they have opportunities to construct their own meanings in their own language, but teachers also recognise the traditional value placed on formal statements of scientific principles and use of scientific language. Frequently, the attempt to strike a balance presents teachers with insoluble dilemmas. How, for example, to value the language students have and use and to value the language of scientific representation? The tensions inherent in the issue of language and science – like so many other issues in science education – must be worked through, optimised and traded off in practice. Teachers want students to understand that the knowledge of science is conditional and constructed and they want students to know about the canonical explanations found in school science textbooks. Teachers want students to understand that scientific work is a passionate and non-linear activity and they want students to be able to follow the protocols of writing up lab reports. Unlike the issues in more certain domains of knowledge than teaching, these dilemmas admit no permanent solution. Teachers are committed to an enterprise that requires multiple and apparently conflicting outcomes, an enterprise where excellence requires goodhumoured resolution of apparently irreconcilable alternatives.