Jani Sparks, Stable Isotope Specialist at the Purdue University Stable Isotope Facility, discusses the process of analyzing samples for Professors at Purdue University. Isotopes can be thought of as chemical tracers. The Stable Isotope Lab looks for differences between stable isotopes over time, such as the relationship between Carbon-12 and Carbon-13. Dr. Sparks advises high school students to check out stable isotope facilities, either at Purdue or other large Universities.