Perspectives are domain-specific strategies employed by experts in a specific field to formulate and investigate questions. Such strategies may therefore serve as good models for acquiring knowledge. Based on this premise, we developed the perspective of form and function, as used by both biologists and technical designers, into a tool for constructing knowledge in primary science education. Firstly, we developed a model of the perspective of form and function. It proved possible to make one model for both biological and technical practice. In order to ascertain whether primary school students could acquire the perspective of form and function, the model of the perspective of form and function was then developed into a learning tool dubbed the "designer's glasses". During lessons, the students (aged 11) learned to use the tool to translate from function to form and vice versa, for both technical and biological phenomena. The "designer's glasses" helped the students to analyse and compare technical and biological designs and increased their observational skills and understanding of design. However, specific coaching by the teacher was needed to achieve the necessary steps in observation and discussion. (Contains 5 figures and 1 table.)