In the present studies, we  assessed college undergraduate research participants' models  of the earth’s composition and dynamics, both without and with access to a web site on plate tectonics.  In previous studies, it has been found that argument writing tasks promote better understanding from web pages, with the best comprehension of texts observed when students write arguments using a two-window browser.  In the present investigation, we are interested in whether or not students in this condition acquire more advanced conceptual models of the subject matter than naïve students, or students in other reading/ writing conditions