Abstract

The "Sedimentators" activity focuses on helping students observe the relationship between sediment grain size and the energy of the environment that eroded or deposited the grains. The activity uses a Predict-Observe-Explain (POE) pedagogy that solicits students' prior knowledge on a topic, has them observe a scientific phenomenon, and finally has them compare their prior knowledge to what they observed. During this activity, students use sedimentators to observe what grain sizes settle out of a system fastest to slowest. Sedimentators are clear PVC pipes with sediment of varying size (silt-pebble) and water that models the order that grains settle out of a system. The first half of the activity focuses on identifying the order in which grain sizes settle out. The second half focuses on exploring how the order the grains settle out in relates to the energy of the environment and what the grain size in a rock sample or outcrop can tell a geologist about the rock's deposition. The outcome of this activity is for the students to interpret the energy of the environment from the grain size of the sediment.

Context

This activity is used in an introductory, undergraduate geology course that serves non-major students primarily. Students complete the activity in class during the first lecture on sedimentary rocks, taking about 20 minutes.

Why It Works

This activity is effective because it uses the sedimentators, which are models that represent grain size and the energy of the environment that grains settle out. Students shake the sedimentator and mix up the grains and can see order of settling out. The activity provides a hands-on way for students to explore this phenomenon. The activity is also part of a course transformation that implemented 15 POE activities into an introductory course to look at student self-efficacy, interest, and student conceptual understanding. The study has yielded significant improvements in interest and conceptual understanding.