IMPROVING STUDENT UNDERSTANDING OF GEOLOGIC TIME THROUGH INQUIRY BASED ACTIVITIES

The ability to think beyond human time scales and into deeper time is fundamental to understanding gradual geologic and biologic processes that occur over vast time spans. Research demonstrates that while students of all ages are adept at ordering key biologic events in Earth’s history, most struggle with the scale of time between events. Students often underestimate the length of time between the origin of life and Phanerozoic events while exaggerating the time between events within the Phanerozoic. These misrepresentations display a naïve conception of Earth’s geologic history.

North Carolina State University’s Physical Geology labs have traditionally taught geologic time with an analogic activity where students place sticky notes with events of known ages on a 46-foot tape measure representing Earth’s 4.6 billion year history. In the spring of 2013, the geologic timeline activity was rewritten, converting a confirmation inquiry exercise to a mixed structured and guided inquiry activity that required students to take a greater role in analyzing and communicating the results. In the new iteration, each student is given an actual fossil and has to predict the first appearance of the organism by placing it on the timeline tape measure. The class timeline is then corrected and students analyze the spatial distribution of fossils and create their own geologic boundaries or periods. During the spring and summer semesters, half the sections of the course were taught using the original lab exercise and half with the revised version. To assess the effect of the lab changes on conceptual understanding, a new summative question was written for the lab course’s final examination at the application level of Bloom’s taxonomy. The question asks students to place tick marks on a line to represent the relative timing of five key events in Earth’s history. The average score for students (n=112) in the revised sections was 10% higher (p=0.0005) than for those in the original sections (n=113). This study provides evidence for the efficacy of using higher levels of inquiry and prediction coupled with analogic thinking to increase student understanding of the timing of key events in Earth’s geologic history.