COLLEGE STUDENT CONCEPTIONS OF GEOLOGIC TIME

College student conceptions of the scale of geologic time and the relationship between time and geologic or biologic events were evaluated through interviews, open-ended questionnaires, and student generated timelines collected from five institutions. These data were compared to Geoscience Concept Inventory questions related to geologic time collected from over 50 institutions. A range of alternative conceptions and non-scientific models were observed. Our data indicate that while a majority of students believe the Earth is billions of years old, very few understand how the age of the Earth is determined, and most confuse the concepts of absolute and relative dating. Students also hold a number of alternative conceptions about the Earth's formation and the appearance of life, and these ideas are remarkably consistent across institutions. Detailed evaluation of student timelines reveals a notable disconnect between the relative relationships between the age of the Earth, the time required for the evolution and extinction of organisms, and the appearance of dinosaurs and humans. Intriguingly, timelines can be mapped onto ternary diagrams, and the relationship between ternary diagram zoning and specific models of geologic time is being explored.