We describe a laboratory experiment that employs the Nanoceria Reducing Antioxidant Capacity (or NanoCerac) Assay to introduce students to portable nanoparticle-based paper sensors for rapid analysis and field detection of polyphenol antioxidants. The experiment gives students a hands-on opportunity to utilize nanoparticle chemistry to develop their own devices to test antioxidant-containing solutions, such as tea and other beverages, for polyphenolic content, a characteristic likely correlated with health benefits. The method utilizes sensing nanoparticles of cerium oxide that respond visually to antioxidant compounds. Due to ease of use of these sensors, inexpensive materials, and short time requirement (~1 h), this lab is appropriate for primary, secondary, and undergraduate courses. The lab and lesson expose students to the fields of nanotechnology, analytical chemistry, antioxidant chemistry, and antioxidant characteristics of botanicals and food constituents.