This set of multimedia lessons, developed by the American Chemical Society, introduces state change by examining four processes: evaporation, condensation, freezing, and melting. Each process is supported by Flash simulations, related videos, background information for teachers, assessments with answer keys, student reading material, and standards-based lessons. Sample multimedia include Conducting Energy, States of Matter, Water Cycle, Liquid Nitrogen, Specific Heat, and more. Editor’s Note: The authors designed this curriculum to help students understand basic chemistry within a framework of molecular interactions. The molecular models and related animations provide a foundation for understanding states of matter, atomic models and bonding, charge interactions, and chemical change.