Unit 3 Review, Study Guide- Earth’s Structures PDF

Name: ____________________________________________________ Date: _______________ P#: _____ Unit 3 Review, Study Guide: Earth’s Structures Layers of the Earth: Layers of Earth o Crust: The outermost layer, which is thin and less...

Name: ____________________________________________________ Date: _______________ P#: _____ Unit 3 Review, Study Guide: Earth’s Structures Layers of the Earth: Layers of Earth o Crust: The outermost layer, which is thin and less dense. The oceanic crust is denser than the continental crust. o Mantle: The layer beneath the crust, where convection occurs. o Core: The innermost layer, which is denser, hotter, and made mostly of iron. Convection: Density 3-D Model o Convection: It causes large amounts of rock to Model rise from and sink into Earth’s mantle. o Heat from the core and the mantle itself causes convection currents in the mantle. Models: o Density Model: This model shows the relative positions of the Earth's layers based on their density. o 3-D Model: This model shows the relative position Seismic Waves of layers and relative sizes. Seismic Waves: o Seismic waves: waves of energy that travel through the Earth and are used by scientists to learn about the Earth's internal structure. Plate Tectonics: Continental Drift: o The theory of plate tectonics explains how the Earth's plates move and interact at their boundaries. o It is considered a scientific theory because it is based on observations and evidence from various scientific studies. o The movement of tectonic plates can lead to earthquakes and volcanic eruptions. Continental Drift: o The Theory of Continental Drift: States that the continents have not always been in their current positions; they have shifted over millions of years. o Evidence: Similar fossils of plants and animals have been found on continents that are now far apart, suggesting they were once connected. Plate Boundaries: Plate Boundaries 1. Divergent Boundary: The boundary between two plates that move away from each other. 2. Convergent Boundary: The boundary between two plates that move toward each other. 3. Transform Boundary: The boundary between two plates that slide past each other Subduction: Subduction o Subduction: Occurs when one tectonic plate sinks below another. o Oceanic crust: It is denser than continental crust, which is why it sinks. Earth Changes due to Plate Movement: Mountains 1. Earthquakes o Subduction: When a crustal plate is pushed down into the mantle, it can cause earthquakes. o Transform Boundaries: Earthquakes can also occur when plates slide past each other. 2. Mountains o Mountains are formed at convergent boundaries where two plates collide. 3. Seafloor Spreading Mid-ocean Ridge o New oceanic crust is created at mid-ocean ridges as tectonic plates pull apart. o Builds ocean basins over millions of years. 4. Mid-Ocean Ridge o A mid-ocean ridge is an underwater mountain range formed by rising convection currents in the mantle. o Occur at divergent boundaries where plates move away from each other. Plate Tectonics Pattern: Earthquake and Volcano Distribution Map o Tectonic activity such as earthquakes, volcanic eruptions and the formation of mountain ranges commonly occurs along the boundaries of the moving plates.