Electron spin resonance experiments with a JEOL RE-1X instrument will be incorporated in an innovative project-based laboratory program. Students will investigate the structure and reactivity of unstable chemical species having odd numbers of electrons - free radicals and radical anions and cations - that are implicated in many chemical and biochemical reactions. The project will upgrade the research-style ESR projects for students in their junior and senior years. It will replace a 30-year old vacuum tube instrument with a solid-state spectrometer that is 100 times more sensitive and much easier to operate. The combination of enhanced spectrometer sensitivity and easy operation will permit all chemistry majors to study free radical species of chemical and biochemical importance.