Trail of Time


May 24th, 2012

Funded by the National Science Foundation (NSF), the Trail of Time (ToT) is a three-mile-long and fully accessible, interpretive walking timeline trail located on the South Rim of the Grand Canyon. Fifteen years in the making by the Grand Canyon National Park, University of New Mexico, and Arizona State University, the ToT features bronze markers scaled such that each long step (1 meter) on the trail represents one million years of the 4.56 billion-year-age of the Earth.  Those who walk the entire trail get a visceral feel for the age of the Earth and how human timescales interface with geologic time.

Along the ToT, the bronze markers and exhibits convey wayside geologic information to help the Canyon’s 5 million annual visitors uncover stories encoded by rocks and the Grand Canyon landscape.  The project’s goal is to help visitors frame their inquiry, foster a greater passion for science and geology, and gain an understanding of geologic time and key processes of the regions geologic evolution. The ToT aims to stimulate questions like, “How did something the size of the Colorado River (way down at the Canyon’s bottom) carve a 10-mile-wide and 1-mile-deep canyon?” and “How long did it take the Grand Canyon to form and how old are the rocks in the Canyon’s walls?”

From the “TODAY” marker near Yavapai Museum, to Grand Canyon’s oldest rock, at the east end of the Grand Canyon village is a 1.1-mile-long (1,840 meters) walk along the timeline trail that covers 1.84 billion years. Amazingly, it’s another 1.7 miles (2,720 meters) along the timeline to the 4.56-billion-year-old age of the Earth, near Maricopa Point. After walking these distances visitors are heard saying: “It’s a long time, the Earth is really old!” or “I knew that the oldest rock was1.8 billion years old, but you don’t really get a grasp of how much that is until you’ve walked 1.8 billion years!”

In addition to building place-based wayfinding exhibits and activities for public audiences, the ToT team held an NSF-funded workshop for professional stakeholders who met to explore the topic of Innovations in Geoscience Education in the National Park System. Numerous ideas were formulated that build on the ToT exhibition’s interpretation themes of geologic time and earth processes that have the potential to impact interpretation at other sites within the National Park Service system. Ideas that emerged included construction of other Time Trails specific to the age of rocks at different parks and a “passport” system to encourage regional and national geoscience education integration across the National Park System.

The ToT effort involved informal science education research and evaluation to contribute to our knowledge about how public audiences come to understand geologic time and methodologies for outdoor interpretation that increase interest and knowledge. ToT benefitted from a multi-year evaluation process conducted by Selinda Research Associates, using naturalistic methodologies and involving formative, summative, and remedial evaluations.  Evaluation showed that the positioning of slabbed and polished rock exhibits “at their birthday,” along the Trail for touching and discovery, promotes excellent visitor engagement. Conversational sign headings, and the reinforcement of main ideas in different ways along the Trail, were also found to effectively promote informal science learning.

Research undertaken by Steve Semken at Arizona State University aimed at understanding and helping improve public cognition of geologic time informed the design of the ToT.  This research examined cognitive challenges in using the distance-for-time timeline trail analogy for deep time. The concepts that vertical layering in the Canyon walls (oldest at the bottom) corresponds to position along the timeline and that time-gaps in the rock record correspond to sections with no rocks along the Trail were challenging, but understood by some visitors. Additional cognition research using the Trail of Time should be useful in identifying and understanding many underlying misconceptions visitors have about Earth history and geologic processes.

The ToT received about $2 million in 2005 from the National Science Foundation to fund its full-scale development.  In 2011, the Trail received a First Place Award for Wayside Exhibits from the National Association for Interpretation.The team hopes to generate similar efforts at other Colorado Plateau Parks, as they feel that understanding the science of geology is assuming increasing importance as human populations exceed 7 billion on one small planet. The National Park Service and National Science Foundation are filling an essential role to provide improved informal geoscience education to the public.

Trail of Time Team (*= Principal Investigators)

Karl Karlstrom*, Laura Crossey*, and Ryan Crow, University of New Mexico
Steve Semken*, Arizona State University
Mike Williams, University of Massachusetts
Judy Bryan, Ellen Seeley, and Carl Bowman, Interpretation Division, Grand Canyon National Park
Deborah Perry and Eric Gyllenhaal, Selinda Research Associates
Jim Sell, Sue Sell, Matt Blakely, Brian Williamson and Mickey Shilling, Jim Sell Designs

Publications About the Trail of Time

1. Karlstrom, K., Semken, S., Crossey, L., Perry, D., Gyllenhaal, E. D., Dodick, J., Williams, M., Hellmich-Bryan, J., Crow, R., Bueno Watts, N., & Ault, C., 2008, Informal geoscience education on a grand scale: the Trail of Time exhibition at Grand Canyon. Journal of Geoscience Education, v. 56, no. 4, p. 354-361.
2. Crow, R., Karlstrom, K.E., Crossey, L.J., Semken, S., Perry, D., Williams, M., and Bryan, J., 2011, It’s about time: Innovations in geoscience education at Grand Canyon: Legacy, v. 22, p. 26-27.
3. Semken, S., Dodick, J., Ben-David, O., Pineda, M., Bueno Watts, N., & Karlstrom, K., 2009,  Timeline and time scale cognition experiments for a geological interpretative exhibit at Grand Canyon.  Proceedings of the National Association for Research in Science Teaching, Garden Grove, California, 8 p.
4. Semken, S., Dodick, J., Frus, R., Perry, D., Wells, M., Bryan, J., Williams, M., Crow, R., Crossey, L., and  Karlstrom, K., 2010, Studies of Informal Geologic Time Learning at the “Trail of Time” in Grand Canyon National Park: Informal Learning Review.