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Definitions
Plate tectonics
The concept that describes and explains how the most significant features on the Earth's surface are produced by processes within the Earth when it acts units at the Earth's surface called plates. As a result, the plates to move around, and change in size and number over time. Although there are other planets that are tectonically active, "plate tectonics" is unique to Earth within our solar system. The more general term "tectonics" refers to processes operating within any rocky planet to form their most significant surface features. Earth is the only planet in the solar system with tectonic activity dominated by structural units called plates. The portions of the Earth's surface along plate boundaries are the most exposed to deformation due to collision and being pulled apart. Distinctive features associated with specific kinds of tectonic activity form at plate boundaries. Tectonic activity is fueled by sources of energy within the Earth's interior, and driven by the temperature difference between the interior and exterior. The key processes of plate tectonics are seafloor spreading that takes place at midocean ridges, and subduction into trenches. Our current understanding of plate tectonic processes explains the existence and location of oceans, continents, large mountain ranges, volcanoes, earthquakes, and other large structures such as folds and faults. Note: At the end of the unit, do the students have a clear concept of this difficult to define topic? It is often defined by example or by definitions that are slightly off the mark - as a force, scientific theory, mountain-building, structural feature of the Earth, concept, or other process. Just what is it? Note: Do students have a sense of Earth's most "significant" features rather than just its largest features? Most of the significant features are large; however, small features can also be significant. Assigning significance takes judgment and knowledge, but that is a key transferable skill. Tectonic Pertaining to large-scale structural formation and deformation of the Earth’s surface (or the surface of other planets). Large-scale structures that form as a result of deformation include folds, domes, basins and faults. Note: Plate tectonics is a subset of the wider range of tectonics exhibited by other rocky planetary bodies.
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