Most young children love a good song and dance, an enticing story, and gorgeous illustrations. How could this staple of the early childhood classroom--music and literature--access children's ideas about physical science? How can young children communicate their knowledge of unseen science concepts that are not easily represented in pictures? These questions were central to the design of a six-day first-grade science unit for the "Next Generation Science Standards" (NGSS) that "sound can make matter vibrate, and vibrating matter can make sound." This article describes the first-grade assessments of investigation into sound and vibration, began by designing and building rubber band instruments, using differentiated materials and planned extensions. The next lesson discussed student theories about the bee's buzz. In addition to the explicit formative assessment activities, students also maintained journals to capture their emergent thinking about vibrations and sounds. Through the use of hands-on activities, well-selected children's literature, and physical response in assessments, students were provided opportunities to learn and to communicate their understanding of these difficult, unseen concepts in physical science.