This article describes a new competence-oriented teaching rationale for a science course, developed in Germany through close cooperation between teachers and researchers, that seeks to improve scientific literacy at upper-level secondary school (ages 15-17). Its aim is to help students become independent and competent experimenters by combining scientific inquiry and the principles of self-determination theory to create a learning environment that can promote students' interest, motivation and learning. Consequently, the course concept includes a gradual increase in the degree of experimental self-regulation (stairway to competence). First findings on the effectiveness of the course are presented.