Students will construct and display models of microbes including viruses, bacteria, and unicellular eukaryotes using a single common scale to demonstrate the diversity of sizes. Viruses may also be modeled at a larger scale to demonstrate greater structural details. This project can be expanded by requiring students to provide written or oral summaries, develop posters, model the length of nucleic acid, and other variations. This activity was designed to improve student understanding of the relative sizes, shapes, and structures found in microbes ranging from viruses to small fungi and protists, and to encourage use of metric units such as nanometers and micrometers.