Marguerite Forest (Florida Gulf Coast University), Phil Stokes (University of Arizona), Steve Semken (Arizona State University)

Students in an upper-division undergraduate geology, physical geography, or environmental science course.

Students should have a capacity to estimate numbers based on orders of magnitude. Students should also know terminology for basic landforms and landscapes.

The activity is used at the beginning of a lecture as a baseline assessment to gauge student conceptions of where geomorphic processes fit on a temporal timescale. After misconceptions and naive ideas are addressed by the instructor, the activity is then used to guide students to understand how different geomorphic processes correctly fit into the timescale.

Correctly distinguish geomorphic processes by their timescales.

In terms of cognitive process, the exercise begins with student recognition of features and scaffolds to involve classification of processes and execution of characterization skills to develop a timescale (Anderson et al. 2001).

Students work in small groups to assemble the timescale.

Each student or pair of students is provided with an illustration of a landscape, landform, or geomorphic process and asked to place it in the appropriate location on the timescale answer form (Acrobat (PDF) 8kB Feb28 12) (see the list of landforms and geomorphic processes (Excel 74kB May8 12)). The landforms and processes list includes information on time ranges for each time, time in seconds, and time in years. Note that the time ranges represent approximate values for the processes and that the time in seconds and time in years columns represent low-end values for each respective process. Thus, some processes may fit into multiple locations on the timescale answer form and some revision by students will occur during the initial phase of the activity.

After students have completed their first iteration of the timescale, the instructor will assess the placement of each process on the answer form (Acrobat (PDF) 8kB Feb28 12). The instructor will then determine which processes need further explanation. For some processes, lecture or other learning strategies might be implemented if students do not have a good understanding of the scale in which they occur. For other processes, the instructor may facilitate a discussion to lead students to expand, contract, or alter their perceptions of the time range.

Ultimately, and perhaps towards the end of the lecture period or as a quiz, students will again be asked to complete the timescale answer form.

Students can be assessed on definitions of terminology, ability to identify geomorphic features, and correct placement of features along the timescale. Additionally, instructors can modify the timeline as needed (e.g., add/remove landforms, focus on local themes) to best suit their targeted learners.

Anderson, L.W. (Ed.), Krathwohl, D.R. (Ed.), Airasian, P.W., Cruikshank, K.A., Mayer, R.E., Pintrich, P.R., Raths, J., & Wittrock, M.C. (2001). A taxonomy for learning, teaching, and assessing: A revision of Bloom's Taxonomy of Educational Objectives (Complete edition). New York: Longman.