The relative movements of tectonic plates can be used to explain the formation and location of many geologic features at the Earth's surface, such as earthquakes, volcanoes, mountains, hot spots, and oceanic ridges. Convergent boundaries occur where one plate moves underneath another and cause earthquakes and the formation of volcanoes on the overriding plate. Divergent boundaries occur where two plates are spreading apart from each other, commonly seen in the ocean accompanied by the formation of new oceanic crust. Transform boundaries occur where plates are sliding past one another and form fracture zones. In the Earthscience curriculum, plate tectonics provides an important context that is used to explain both topography and geohazards.

This article describes a series of six tectonics investigations we developed to enhance the middle school Earth-science curriculum. These investigations include spatially enabled learning technologies that use freely available web GIS, which is compatible with any desktop computer, laptop, or mobile device, including tablets such as the Apple iPad. Web GIS is a visualization tool in the form of web-based application software that can be used to store, retrieve, and manipulate georeferenced scientific data. Students can use web GIS to view and explore data entirely online (Kulo et al. 2013). Studies have shown that the use of spatial technologies such as GIS in the classroom can improve students' analysis and spatial-thinking skills and increase understanding of the material being covered (Baker and White 2003; Demirci 2008; Bodzin and Cirucci 2009).

The web GIS investigations can be accessed for free at www.ei.lehigh.edu/eli/tectonics. Computers or tablets with internet connections are the only materials needed to complete the investigations. Students can work individually or, depending on computer availability, in groups of two or three. Four of the investigations (1, 2, 3, and 5) can be completed in one 45-minute class period, and two investigations (4 and 6) can be completed in two class periods. The investigations' instructional materials have been effectively used in eighth-grade classrooms with students of varied ability levels, including English language learners. The website includes a series of support materials designed to assist with classroom implementation--detailed teacher guides, video tutorials, content background materials, and assessments for each investigation. (To access the assessments, use login eliteacher and password 87dja92.) In addition to the six investigations described below, there is a web GIS for open-ended investigations that students can use to answer their own questions about tectonics or that can be implemented with teacher-provided guiding questions for students to further explore additional geospatial relationships and patterns in tectonics data.

The investigations are aligned to the disciplinary core idea Earth and Space Science from A Framework for K-12 Science Education (NRC 2012), with a primary focus on core idea ESS2.B: Plate Tectonics and Large-Scale System Interactions. The investigations also incorporate crosscutting concepts, including Cause and Effect; Scale, Proportion, and Quantity; and Energy and Matter. Cause and Effect is a common thread throughout the tectonics investigations. The plate-tectonic causes of earthquakes and volcanoes are placed in the context of their effects in terms of natural hazards. Scale, Proportion, and Quantity are key aspects of tectonics using our GIS-based approach. Learners delve into scale and proportion issues with map zoom in various activities and use quantitative means to assess the relative motions of tectonic plates. The crosscutting concept of Energy and Matter is integral to the tectonics learning material, in which the relation between plate motions (kinematics) and forces (dynamics) results in interactions that release energy in the form of earthquakes and volcanoes.

Each investigation uses a series of design principles to promote geospatial thinking and includes motivating entry points to engage learners, personally relevant and meaningful examples, and learning activities that apply to diverse geographical contexts. …