In music and arts education, a central question is how teachers can best facilitate the creativity of their students, Most research on primary school students' creativity, however, focuses on creativity at the level of the person or product rather than at the level of the creative process. Precisely this knowledge on how creativity emerges in interaction between teacher and student (s) is needed to answer this question. Therefore, we combined detailed quantitative and qualitative analyses of teacher and student actions and reactions to understand emergent creativity during a musical composition task. Five music teacher - student dyads participated in this study. Student turns were coded in terms of levels of novelty and appropriateness while teacher turns were labeled as convergent (aimed at instructing, providing information and evaluation) divergent (aimed at idea generation) or neutral. We found that the levels of novelty and appropriateness of student turns had highly skewed distributions, with high levels of novelty and low levels of appropriateness being especially rare. With sequential analyses, we found for all five dyads that convergent turns often lead immediately to student turns with no novelty and rarely to highly novel turns. However, we saw no immediate relationship between divergent turns and student levels of novelty. In qualitative analyses of longer interactional patterns, we saw how novel ideas can emerge from interactions where the teacher alternates between convergent and divergent behavior, but also how a teacher and student can become 'stuck' in exchanges with no novelty and repeated convergent turns.