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ECPS Mod6
Apologia Phys Sci Module 6
Question | Answer |
---|---|
Earth’s crust | Earth’s outermost layer of rock |
Earthquake | Vibration of the earth that results either from volcanic activity or rock masses suddenly moving along a fault |
Epicenter | The point on the surface of the earth directly above an earthquake's focus |
Fault | The boundary between two sections of rock that can move relative to one another |
Focus | The point where an earthquake begins |
Igneous rock | Rock that forms from molten rock. |
Metamorphic rock | Igneous or sedimentary rock that has been changed into a new kind of rock as a result of great pressure and temperature |
Plastic rock | Rock that behaves like something between a liquid and a solid |
Sediment | Small, solid fragments of rock and other materials that are carried and deposited by wind, water or ice. Examples would be sand, mud or gravel. |
Sedimentary rock | Rock formed when chemical reactions cement sediments together, hardening them |
The earth is divided into five layers: | atmosphere, hydrosphere, crust, mantle, and core |
We can directly observe these three layers: | atmosphere, hydrosphere, and crust |
The Moho | separates the crust from the mantle |
the Gutenberg discontinuity | separates the mantle from the core |
the Lehmann discontinuity | separates the inner core from the outer core |
how is sedimentary rock formed? | when sediments are solidified through chemical reactions |
how is igneous rock formed? | when molten rock solidifies |
how is metamorphic rock formed | starts out as either igneous or sedimentary rock and is then transformed by high temperature and pressure |
why do we call it plastic rock? | extremes in temperature and pressure make it behave sometimes like a liquid and sometimes like a solid. |
what are seismic waves usually generated by | earthquakes |
what does the behavior of seismic waves teach us? | it tell us a lot about the makeup and properties of the mantle and core |
Why is the inner core solid | because of pressure freezing. Even though the inner core is hotter than the outer core, it remains solid because the pressure is so great that it forces iron atoms close enough together to be solid |
where is the earth's magnetic field generated? | in the earth's core |
what is the magnetic field caused by? | a large of amount of electrical flow in the core |
What is the dynamo theory | The dynamo theory says that the motion of the core is due to temperature differences in the core and the rotation of the earth. This motion causes the motion of electrical charges in the core, which creates electrical current. |
what does the rapid decay theory state? | that the electrical current in the core started as a consequence of how the earth formed and is decreasing over time |
how has the rapid-decay theory been used? | to accurately predict the magnetic fields of other planets. The dynamo theory fails miserably at this. |
what makes the rapid-decay theory more scientifically valid than the dynamo theory? | everything the rapid decay theory has declared was scientifically proven right while everything the dynamo theory declared was wrong. |
would would happen without the magnetic field? | cosmic rays from the sun would hit the earth, killing all life |
what are plates? | large "islands" of the earth's lithospace that float around on the plastic rock of the asthenosphere. This theory is called plate tectonics. |
how can plates move? | one plate can slide under another and form a trench; the plates can move away from each other, allowing magma to rise and create new crust; the plates can push against each other, causing the crust to fold; or the plates can slide along each other |
what is pangaea | is a hypothetical supercontinent that might have existed in earth's past with all the continents fitting together |
what are earthquakes caused by? | the motion of rock masses along a fault or by volcanic activity |
four types of mountains? | volcanic, domed, fault-block, folded |
how have we learned about the lowest regions of the earth | indirect observation through seismic waves |
according to the Richter Scale, how much is the energy multiplied in each step? | 32 (review OYO 6.9) |
what is required for the formation of the fault-block mountain | one rock mass along a fault line is moving up and the other is stationary or moving down, the upward moving mass will form a mountain. |
what is required for the formation of the folded mountain | two rock masses pushing against each other with extreme force causing the crust to bend in an up and down rolling pattern |
what is required for a volcanic or domed mountain | magma pushing up |
seismology | the study of earthquakes |
seismographs | instruments that can measure vibrations that are too small for us to notice |