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Last modified: Tuesday, February 28, 2012

IU course about geologic time featured in the Journal of College Science Teaching

Feb. 28, 2012

BLOOMINGTON, Ind. -- Faculty and staff at Indiana University Bloomington have shown how integrating course learning outcomes with active learning techniques and course assignments can help students gain an understanding of geologic time, the division of Earth's history into units that stretch many millions or even billions of years.

They suggest the approach can help students overcome similar "bottlenecks" that prevent in-depth learning in other fields -- just as students in an undergraduate class in environmental geology gained basic understanding of geologic time and grew confident in their ability to use the concept.

Professor Chen Zhu's Environmental Geology course

Students Alicia Pardoski, Adelye Seng and Bayli Payne, from right, confer with associate instructor Will Simmons, left, during a recent lab in professor Chen Zhu's environmental geology course.

Print-Quality Photo

Their article, "Looking Back to Move Ahead: How Students Learn Geologic Time by Predicting Future Environmental Impacts," was published in the current issue of the Journal of College Science Teaching. Authors are professor Chen Zhu and associate professor Claudia C. Johnson of the Department of Geological Sciences; George Rehrey, a consultant with the Center for Innovative Teaching and Learning; and Brooke Treadwell, a graduate student in the School of Education.

Zhu said comprehending geologic time is often a big challenge for students, especially those without a strong science background. It's hard for them to make sense of processes that take place outside the scope of their own lives, much less over many thousands of lifetimes.

The problem presents a "bottleneck," a term coined by IU scholars David Pace and Joan Middendorf and colleagues in their Scholarship of Teaching and Learning research on "decoding the disciplines" to describe the place where many students get stuck and can't progress to expert-level thinking on a given topic or key concept.

"In this case, if students can't understand and apply the immensity of geologic time, they aren't going to succeed in the course," Rehrey said.

In the environmental geology course, designed for non-science majors, Zhu used labs and projects in which students created "distance metaphors" to visualize the immensity of geologic time: that the Earth is nearly 4.6 billion years old, that dinosaurs and other organisms evolved and went extinct over periods of hundreds of millions of years, etc. For example, students used rolls of toilet paper and paper towels to represent units of geologic time, demarcating events in the Earth's past.

While the idea of visualizing geologic time wasn't particularly new, what was novel was the way the course integrated real-world issues with other assignments in order to actively engage students as they extended their thinking about geologic time into the future instead of the past. The students assessed issues related to the Yucca Mountain waste repository in Nevada, required to secure high-level nuclear waste for at least 1 million years. And they studied the contribution to global warming of IU Bloomington's coal-fired Central Heating Plant in the context of glacial cycles and background levels of greenhouse gases prior to industrialization.

"The idea is to introduce environmental concerns that students can relate to in their daily lives, and that are very much tied up with the concept of geologic time," Zhu said.

Learning of geologic time was assessed through a series of test questions, surveys and assignments, including a final case-study problem in which students advocated a position on closing the campus heating plant, making use of the concept of geologic time and using scientific data and graphs to make an evidenced-informed scientific argument.

Almost two-thirds of students demonstrated basic understanding of geologic time through the assessment. Also, surveys administered at the start and end of the semester showed that students' self-reported confidence in their understanding of geologic time increased dramatically during the course.

"A remarkable feature of this research is the collaboration of geologists with a faculty development specialist and a graduate student from education," said Craig Nelson, professor emeritus of biology and a longtime leader at IU Bloomington of the Scholarship of Teaching and Learning, which uses research and scholarship to improve the teaching of undergraduates.

"This breadth really increased the depth and significance of the paper," Nelson said. "Although still quite rare elsewhere, such collaboration grows naturally out of the nationally leading Scholarship of Teaching and Learning program at IU Bloomington, which Rehrey directs."

The Journal of College Science Teaching article is available through IU Libraries. Rehrey can be reached at 812-856-4231 or To speak with Zhu, please contact Steve Hinnefeld at IU Communications, 812-856-3488 or