Thursday Session B

Thursday 1:30pm-4:00pm Weeks Geo: 140
Teaching Demonstration

Session Chairs

Andrew Goodwillie, Lamont-Doherty Earth Observatory
Laurel Goodell, Princeton University
1:30pm-1:50pm
Connecting magma formation, origin of crust, and the meaning behind igneous rocks using research-based diagrams, analogies, and games in physical geology
Andrea Bair, Delta College

Show Abstract »

This activity aims to: dispel common misconceptions about the origin of magma (i.e., from a liquid layer of Earth), promote understanding of the processes of magma generation, help students see igneous rocks as products of their formation and connected to plate tectonic processes, promote expert-like use and understanding of graphs and other diagrammatic representations, help students connect concepts and phenomena at different spatial and temporal scales. This activity centers on common images used in teaching students about magma generation and plate tectonic processes (cross sections and graphs) specifically modified to avoid common student misconceptions. Connections between processes are emphasized. Outcomes include: Identify which layers of Earth magma comes from, and the nature of magma areas in those layers. Explain how partial melting influences magma composition. List and describe the three main mechanisms for melting rocks. Draw pressure-temperature graphs for each kind of melting. Be able to explain how each igneous rock forms including: source rock composition and layer of Earth, plate boundary (or boundaries) that most likely are the location for melting that layer of Earth, the mechanism(s) for melting that produced the magma, and where the rock formed.
1:50pm-2:10pm
Seafloor Spreading
Andrew Goodwillie, Lamont-Doherty Earth Observatory

Show Abstract »

Plate tectonics forms a fundamental component of our understanding of how Earth works. In this activity, students examine the age of the ocean crust, calculate the rate of seafloor spreading at different locations around the world, and compare the spreading rates within the context of plate tectonics. They do this using GeoMapApp - the free geoscience map-based software developed at Lamont. Spreading rates are calculated for three different ocean basins: South Atlantic across the Mid-Atlantic Ridge, Pacific across the East Pacific Rise, and the area between Australia/Antarctica across the Southeast Indian Ridge. Each area has quite different spreading characteristics. In addition, the ability within GeoMapApp to layer multiple data sets and use a transparency slider to compare layers allows the activity to be expanded to investigate, for example, depth-age relationships of the cooling lithosphere, or global heat flow, or the global geoid anomaly.
2:10pm-2:30pm
Polar wandering or continental drift? It all depends on where you stand.
Karla Panchuk, University of Saskatchewan/ St. Peter's College

Show Abstract »

This activity demonstrates apparent polar wandering by using paper compasses to simulate paleomagnetic records. In the first part of the activity the demonstrator plays the role of a stationary continent. She directs a participant playing the role of the magnetic north pole to stand in different positions, and sets her compass to point at the pole in each case. Compasses are stacked to represent the accumulation of igneous layers recording paleomagnetic signals, and she explains this to students. She then proceeds to "interpret" the "record" in terms of polar wandering by positioning the north pole ahead of her, and then directing him/her again based on the needle on each compass in the stack, while remaining stationary herself. This shows how a polar wandering path can be constructed. Finally, she illustrates the alternative interpretation, that the continent has moved instead. Magnetic north is once again positioned centrally, but this time the demonstrator has volunteers play the position of the continent at different times by using the compasses to position themselves relative to magnetic north. In a larger space a second set of compasses can be used to represent inclination and changes in latitude.
2:30pm-2:50pm
Features of different Volcanos
Charles Czajka, North Carolina State University

Show Abstract »

This is a lesson I use when teaching about the different volcano types. Previously students would have learned about controls on magma viscosity and how viscosity influences volcanic eruptions. They would have also done a pre-class reading assignment related to volcano types. This lesson would begin with a short review of the pre-class assignment and introduce a few new concepts related to volcano types and sizes. From there, students work on a Venn diagram activity where they compare and contrast shield and composite volcanos. Information is then presented on Flood basalts and calderas. Following this, students work together to complete a table outlining various properties of six different volcano types, including their size, magma silica content, viscosity, and gas content. Finally students use their completed table to construct a concept map relating various properties of the different volcanos. At the end of their worksheet activities, student are also asked to reflect on their confidence in completing each of the lesson's learning objectives.
2:50pm
Break
3:00pm-3:20pm
"Jelloea" and Understanding Basaltic Volcanism
Laurel Goodell, Princeton University

Show Abstract »

"Volcanoes" are formed from bowls of gelatin inverted onto pegboard. "GPS stations" (pushpins) are installed and "housing developments" (Monopoly™ houses and hotels) are built. Then, "magma" (colored water) is injected through the pegboard into the bottom of the volcano.* The transparent gelatin enables observation of the formation of dikes that propagate laterally, often far enough to intersect the flank of the volcano and generate "lava flows." With time, new injections tend to feed established dike paths rather than making new ones – thus setting up a "plumbing system" within the volcano. The flanks of volcano can become unstable and generate "landslides." This activity serves as a model for the formation of dikes and dike systems that build up volcanic edifices and feed lava flows. Looking at the final model in plan view, for example, makes the geologic map of Hawaii take on new meaning - especially the rift zones of Kilauea and Mauna Loa. Students are able to investigate and better understand the mechanics of dike formation and propagation; lava flow hazard and risk; and the generation of precursor ground deformation and seismicity. (Activity inspired by http://www.spacegrant.hawaii.edu/class_acts/GelVol.html)
3:20pm-3:40pm
Igneous Cooling Rates, Crystal Size, and NOT Getting the 'Right' Experimental Results
Mary Colson, Moorhead Public Schools
Russ Colson, Minnesota State University-Moorhead

Show Abstract »

The organic compound thymol, with a melting temperature of 48°C, can be used to give students an opportunity to experiment with the effects of cooling rate on crystal size. We examine how a cookbook lab, which was designed to 'confirm textbook information,' can be transformed into an authentic scientific investigation in which students and teacher face unexpected results together. These experimental surprises give opportunity for student-student and teacher-student interactions in which students argue from evidence, develop models for what's happening during crystallization, and revise and redo experiments in response to new understanding. Attendees will examine typical products of thymol cooling-rate experiments, evaluate how well the experiments support the textbook model, and consider possible causes of discrepancies. We will watch videos of cooling-rate experiments and consider how students and teachers together can develop their own models to explain what's going on. We will examine not only how students become engaged in real science investigation when results are unexpected, but how the teacher as a practitioner of science is a necessary ingredient in mentoring students through thinking about those unexpected results.