Adding music to STEM instruction could provide the dual benefits of (1) making STEM content more accessible and (2) enhancing students' engagement in the learning process. Here we explore the extent to which music-oriented high school students achieve these two benefits when they participate in "Songwriting To Learn," a possible variation on the Writing To Learn (WTL) model of instruction. We analysed 81 artist statements, collected over 12 years at an annual science fair, in which students described their music compositions and the compositions' connections to science. Rather than simply reporting scientific facts in song lyrics, these students used an impressive variety of musical elements (Genre, Instruments, Lyrics, and Structure [i.e., chords, dynamics, melody, rhythm]) as metaphors or symbols for science-related elements (Scientific Topic, Conveying Information, Affect, Personal story, Scientific story). Many students demonstrated a sophisticated attention to musical details and nuances, consistent with their frequent self-identification as musicians and/or music fans. Moreover, in composing and performing songs, these students fulfilled some key criteria by which scientific identities are developed, including the forging of personal connections to science. These students may use their practice-linked identities in the domain of music to express their growing understanding in the domain of science.