1. Differentiation of rhythm: In music, strong beats and weak beats appear alternately, and bar lines can clearly show the relationship between the strength and weakness of rhythm, helping players and listeners to better understand and feel the rhythm of music.
2. Music structure: Bar lines can divide a song or music into several relatively independent bars, thus forming the music structure of music. Music structure is an important part of music creation, which can help musicians better organize and express their musical ideas.
3. Music balance and symmetry: Many music works need to maintain balance and symmetry, and the existence of bar lines can help composers better grasp this balance and symmetry in the process of creation.
4. Convenient sight-reading and singing: For performers and singers, bar lines can be used as an important reference to help them better grasp the speed and rhythm of music, and also help them understand and express music accurately.
5. Human natural perception: Human beings have a natural perception of order and law. The existence of bar lines makes the rhythm and organization of music more regular, more in line with human perception, and makes music easier to understand and accept.
Therefore, dividing a song into several sections is not only to better express the rhythm and musical structure of music, but also to help players, singers and listeners better understand and feel music.