The experiments reported here provide a perceptual analysis of the first movement of Mozart's Piano Sonata in Eb Major, K. 282. The listeners, who varied in the extent of their musical training, performed three tasks while listening to the piece as it was reproduced from an expert performance. The first task determined how the music is perceived to be segmented, the second task determined how the experience of tension varies over time, and the third task determined what listeners identify as new musical ideas in the piece. These tasks were performed first on the entire piece and then on smaller sections from the beginning. These three aspects of music perception are coordinated with one another and correlate with various musical attributes. Judgments of section ends co- occurred with peaks in tension and slow tempos. Judgments of new musical ideas co- occurred with low tension levels and neutral tempos. Tension was influenced by melodic contour, note density, dynamics, harmony, tonality, and other factors. Judgments of large-scale section ends were less frequent than judgments of new musical ideas, but these were more nearly one-to-one on smaller time scales. A subsidiary experiment examined the extent to which tension judgments were influenced by performed tempo and dynamics. Listeners made tension judgments for four different versions of the piece: as performed, constant dynamics (with tempo as performed), constant tempo (with dynamics as performed), and constant tempo and dynamics. The tension curves were generally very similar, deviating only in a few regions containing major section ends. The results are considered in light of the metaphor of tension applied to music and the analogy between music and linguistic discourse.