The purpose of this article is to share a learning-cycle sequence of lessons designed to convey the particulate nature of matter through use of physical models and analogical thinking. This activity was adapted from Conceptual Chemistry, a long-running professional development program for teachers of grades 4-9. Conceptual Chemistry's approach is to emphasize broad conceptual understanding, students' ideas about science, and content-focused literacy skills. As a result of engaging in this series of lessons, students will observe macroscopic properties of matter and begin to develop scientific models to explain the particulate nature of matter. (Contains 2 figures.)