| A | B |
|---|
| crust | the outer most and thinnest of earth's layers |
| mantle | the layer of earth between the crust and the core |
| lithosphere | the top part of the mantle and the crust above it, covers all of Earth like a thin shell, but is not a solid sheet of material |
| outer core | near the center part of the earth which is made of a liquid iron that is not stationary, it flows in currents that make the Earth's magnetic field |
| seismograph | an instrument to record earthquake waves |
| plate | a large section of earth's crust and upper mantle |
| plate boundaries | edges of plates |
| gravity | one of the reasons plates move, pulls down on the plate towards the mantle |
| tsunami | earthquakes under the ocean can lead to these large destructive waves |
| magma | hot liquid rock below the surface of the earth, sometimes this hot liquid rock can forced to the surface through a weak spot in the crust. |
| continental crust | makes up the land of the continents and generally meets the oceanic crust 100 kilometers from a coast |
| oceanic crust | lies beneath most ocean floors and made mostly of basalt, which is dark green or black rock |
| volcanoes | form near colliding plate boundaries, can ooze fountains of lava and create gases such as water vapor and carbon dioxide |
| converging boundary | when two faults collide |
| spreading plate boundary | when two plates move away from each other |
| sliding plate boundary | when two plates move past each other in different directions |
| earthquake | caused when two plates move or shift at a fault (crack in the Earth's crust), the plates eventually jerk into place causing movement and vibrations that people feel . |
| convection currents | one of the reasons plates move, the force in the mantle that pushes and pulls on the plates. |
