Issues in Earth Science
“Eww, There’s Some Geology in my Fiction!”
Issue 2, Nov 2014
Suggestions for Activities and Discussions to accompany a Reading of
Plate Tectonics and Non-Platonic Relationships by Alicia Cole
Curriculum for the Earth Sciences often includes the Theory of Plate Tectonics as a key element, and often presents Plate Tectonics as the conceptual model for students to hang their new ideas on. However, learning facts and theories in and of itself is not the goal of the Next Generation Science Standards (NGSS). The practices of science, one of three components of learning called 'dimensions of learning' in the NGSS, involve learning how to figure things out—doing science--not merely accepting the facts and theories that someone else has figured out for you. The theory of plate tectonics is a great place for students to consider the various lines of evidence that support this particular scientific theory.
A good starting place for examining evidence with your students is to plot the locations of earthquakes. The epicenters aren’t distributed randomly but predominantly occur in narrow bands, marking the locations where plates meet. Maps showing an earthquake plotting activity to find plate boundaries are found at http://web.mnstate.edu/colson/est/est2b6.html.
You can also examine other lines of evidence such as locations of volcanic activity, the age of the ocean floor, and seafloor topography. Below are some suggested data-driven activities that you can do with your student to engage them in the practices of science as they relate to the different types of plate boundaries mentioned in Plate Tectonics and Non-Platonic Relationships.
Many of these suggested activities, along with comprehensive teacher and student resources, may be found at Tectonics, which is part of the Environmental Literacy and Inquiry (ELI) site at Lehigh University. The six investigations at this site form a coherent instructional sequence in which students consider the data and evidence for the different kinds of boundaries and the multiple lines of evidence that support the theory of plate tectonics. This online resource provides teacher guides, classroom-ready investigations for students and detailed ‘how-to’ supports for using the different map layers included in each of the investigations.
No one has ever seen a subducting plate deep under a mountain range. Sadly, there are no Mole Machines that allow us to go there in real life. So how do we know that subduction zones even exist? One line of evidence that you can examine and consider with your students is the increasing depth of earthquakes as one goes farther inland from a deep ocean trench.
Investigation 6at ELI guides students in exploring earthquake depth and viewing slab profiles across the Aleutian Islands. Below are two sample maps (from the Investigation 6 online GIS activity), one with earthquake depths along the convergent boundary and one showing the profile of earthquake depth across the convergent boundary.
Depth of earthquakes are color coded in this map image. Notice how the earthquakes get deeper as you go north away from the trench where subduction occurs. Earthquakes occur where blocks of rock are moving relative to each other, so the location of the quakes mark the course of the descending plate.