This article offers an outline of 3D science that conceptualises science around three dimensions: domain knowledge, evidence-management procedures and psychological energy. We propose that this model could underpin a rigorous, effective and motivating approach to science education in schools. We show how self-determination theory offers useful insights into motivation in 3D science and discuss the benefits of this for teachers and students. As proof of concept we sketch out clear assessment objectives for a 3D-compliant science course and develop outline assessment criteria to show the possibility for progression.