This lesson is a writing assignment focussed on the use of data to support the theory of plate tectonics. It includes a scoresheet that was created for a calibrated peer review assignment. The assignment directs students to determine the plate boundary types using elevation, age, earthquake and volcano data at a subduction zone and at a spreading center. Learners access data using the "Our Dynamic Planet" CDROM, capture images of the data plots, and incorporate them into their writing.