Students teaching students is widely accepted to be one of the most effective teaching methods with benefits for both the students teaching and those that are learning (Sorcinelli, 1991; Stigmar, 2016). Previous studies have found that students acting as instructors experience improved content knowledge and develop skills and confidence in communication of complex subject matter (Swim, 1999). Students learning from other students experience increased enjoyment and enthusiasm in learning science (Hinck, 2013; Rao et al., 2007). We created a cross-age scientific curricular experience program model that utilized hands-on activities with instruction by trained high school students. This study aims to understand how these curricular experiences impact the self-efficacy of student instructors as well as student learner engagement. We found that student instructors commonly have positive teaching experiences and feel more confident about teaching after each curricular experience. Student engagement during all curricular experiences was high and reflections from instructors, students, and classroom-teachers highlighted the benefits of students teaching students. Overall, this study shows support for cross-age instruction and the importance of hands-on activities in scientific education. We hope educators increase cross-age instruction and hands-on activities throughout their science classes.