• Crust
  • Mantle
  • Outer core
  • Inner core
  • Lithosphere
  • Plates
  • Tectonic plates
  • Ocean plate
  • Continental plate
  • Asthenosphere
  • Convection
  • Convection current
  • Magma
  • Divergent plate boundary
  • Theory of Plate Tectonics
  • Convergent plate boundary
  • Transform plate boundary
  • Fault
  • Lava
  • Fissure
  • Geyser
  • Rift
  • Basalt
  • Granite
  • Density
  • Ocean trench
  • Subduction
  • Subduction zone
  • Earthquake
  • Mid-ocean ridge
  • Mountain
  • Rift valley
  • Volcano
  • Volcanic island
  • Undersea canyon


Students know:
  • The layers of the Earth include, from outmost to innermost, the crust, mantle, outer core, and inner core.
  • The crust and upper mantle are broken into moving plates called the lithosphere. These plates are known as tectonic plates and fit around the globe like puzzle pieces.
  • The asthenosphere is located below the lithosphere. The asthenosphere is hotter and more fluid than the lithosphere. Convection occurs in the asthenosphere.
  • Convection is the transfer of heat by the actual movement of the heated material.
  • Through convection, movements deep within the Earth, which carry heat from the hot interior to the cooler surface, cause the plates to move very slowly on the surface.
  • The Theory of Plate Tectonics states that the outer rigid layer of the Earth is divided into a couple of dozen "plates" that move around across the Earth's surface relative to each other.
  • The areas where plates interact are called plate boundaries.
  • The three types of plate tectonic boundaries include divergent (dividing), convergent (colliding), and transform (grinding past each other).
  • Because ocean plates are denser than continental plates, when these two types of plates converge, the ocean plates are subducted beneath the continental plates. Subduction zones and trenches are convergent margins.
  • Subduction zones form when plates crash into each other, spreading ridges form when plates pull away from each other, and large faults form when plates slide past each other.
  • A divergent boundary occurs when two tectonic plates move away from each other. Along these boundaries, lava spews from long fissures and geysers spurt superheated water. Frequent earthquakes strike along the rift. Beneath the rift, magma—molten rock—rises from the mantle. It oozes up into the gap and hardens into solid rock, forming new crust on the torn edges of the plates. Magma from the mantle solidifies into basalt, a dark, dense rock that underlies the ocean floor. Thus at divergent boundaries, oceanic crust, made of basalt, is created.
  • When two plates come together, it is known as a convergent boundary. The impact of the two colliding plates buckles the edge of one or both plates up into a rugged mountain range called a mid-ocean ridge, and sometimes bends the other down into an ocean trench. Trenches are long, narrow, steep-sided depressions in the ocean floor. A chain of volcanoes often forms parallel to the boundary, to the mountain range, and to the trench. Powerful earthquakes shake a wide area on both sides of the boundary. If one of the colliding plates is topped with oceanic crust, it is forced down into the mantle where it begins to melt. Magma rises into and through the other plate, solidifying into new crust. Magma formed from melting plates solidifies into granite, a light colored, low-density rock that makes up the continents. Thus at convergent boundaries, continental crust, made of granite, is created, and oceanic crust is destroyed.
  • Two plates sliding past each other forms a transform plate boundary. Rocks that line the boundary are pulverized as the plates grind along, creating a rift valley or undersea canyon. As the plates alternately jam and jump against each other, earthquakes rattle through a wide boundary zone. In contrast to convergent and divergent boundaries, no magma is formed. Thus, crust is cracked and broken at transform margins, but is not created or destroyed.


Students are able to:
  • Use a model of the flow of Earth's internal energy and the resulting plate movements and identify the relevant components.
  • Describe the relationships between components of the model including how the flow of Earth's internal energy drives a cycling of matter between Earth's surface and deep interior causing plate movements.
  • Articulate a statement that relates a given phenomenon to a scientific idea, including how the flow of Earth's internal energy drives a cycling of matter between Earth's surface and deep interior causing plate movements.


Students understand that:
  • The flow of Earth's internal energy drives a cycling of matter between Earth's surface and deep interior. This cycling of matter causes plate movements.

Scientific and Engineering Practices

Developing and Using Models

Crosscutting Concepts

Energy and Matter