During physics instruction with mini-projects, four upper secondary school girls decide to plan how to teach electric circuits to younger children. Their group discussions result in a conceptual change related to the concepts resistance and current. Their prior conception, built on current consumption, leads them into conceptual conflicts, and by exploratory talks they reach a new view based on current as movement with different speed. Students’ ownership of learning (SOL) is increased by an instructional design with mini-projects. This gives students the opportunity to choose a unique question, to determine their own learning process, to increase their motivation and to enhance development of competence and self-confidence.