For many years, when music was integrated into the curriculum it was done by the primary classroom teacher weaving music throughout the school experiences of the children. With careful planning, social studies, spelling, maths, art, physical education, and other curricular components were enhanced by having music contribute to broader understanding of them, and by helping to make experiences within those curricular components more interesting. The children would have opportunities to sing songs of the countries being studied in social studies, to learn spelling words and number combinations through chants or songs, to develop works of art while listening to music, to develop physically while doing movement activities in time to music, and so on.
Harrison, L. N.
United States Experience with Music the Arts Curriculum and Implications for Teacher Education.
Australian Journal of Teacher Education, 9(1).