Explain the complex concepts of the expanding universe using the simple models of this two-part teacher demonstration and student lab. The demonstration models how light waves are stretched to greater wavelengths as space expands, while the lab activity allows students to visualize the distance of galaxies, as seen by an observer, by simulating the direct relationship between a galaxy’s distance from the observer and its expansion velocity. Developed by the Contemporary Physics Education Project (CPEP) and aligned to national standards, the set up and procedure for each activity is displayed on the included instructional DVD. Includes materials for 10 lab groups. Grades 9–12.