PS Module 6 Flashcards
Earth’s crust
Earth’s outermost layer of rock
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
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
Earthquake
Vibration of the earth that results either from volcanic activity or rock masses suddenly moving along a fault
Fault
The boundary between two sections of rock that can move relative to one another
Focus
The point where an earthquake begins
Epicenter
The point on the surface of the earth directly above an earthquake’s focus
Mantle
The layer of the earth between the crust and the core.
Core
The very hot center of our planet.
Core (Inner)
The deepest layer of the Earth, beneath the outer core.
Core (Outer)
The layer of the Earth between the mantle and the inner core.
Soil
The top layer of the earth’s surface, consisting of rock and mineral particles mixed with organic matter.
Magma
Hot, liquid rock underneath the earth’s crust.
Lava
Molten rock, or magma, that erupts from volcanoes or fissures in the Earth’s surface.
Seismic waves
An earth vibration generated by an earthquake or explosion.
Seismographs
Vibration detectors used to analyze the vibrations at different oints of the earth. Scientists can determine the speed at which the seismic waves travel, how much energy they lose as they travel and how their courses are changed in different parts of the earth.
Mohorovicic discontinuity (Moho)
Discovered by a Croatian scientist, Andrija Mohorovicic, this is the boundary between the earth’s crust and the beginning of the earth’s mantle.
Lithosphere
The outer, solid portion of the Earth which includes the upper part of the mantle and the crust above it.
Asthenosphere
Located below the lithosphere, this is part of the mantle. The rock is not completely solid.
Gutenberg discontinuity
Discovered by the seismic studies of German geologist Beno Gutenberg,it is the boundary between mantle and core.
Lehmann discontinuity
Discovered by the seismic studies of Danish scientist Inge Lehmann, it marks boundary between outer core and inner core
Pressure freezing
This occurs when the force of pressure is great enough to counteract the effect of high temperature and the atoms actually get pushed closer together.
Magnetic field lines
Lines that map out how the earth’s magnetic field interacts with other magnets.
Dynamo theory
The theory that the motion of fluid in the outer core of the earth is caused by temperature differences in the outer core as well as the rotation of the earth. This motion causes the motion of electrical charges in the core, which creates electrical current.
Rapid-decay theory
The theory that the electrical current of the earth is a consequence of how it was created.
Plate tectonics
The idea that the earth’s lithosphere is fractured and broken. These places move about on the plastic rock of the asthenosphere.
Pangaea
The theory that in the past all the continents were connected into a giant supercontinent.
Elastic rebound theory
The idea that when forces acting on rocks are pushing them in different directions the rocks can “bend”. This bending occurs very slowly until the forces become too great and the moving rock breaks free and the rocks return to their original shapes. This results in vibrations observed as earthquakes.
Seismology
The study of earthquakes.
Richter scale
Developed by seismologist, Charles Richter, this scale measures the strength of an earthquake based on the nature of the seismic waves it produces. This scale runs from 0 to 10.
Folded mountains
When two moving rock masses push against each other with extreme force causing the crust to bend in an up-and-down, rolling pattern.
Volcanic mountain
A mountain formed by accumulated lava. Also called a volcano.
Volcano
A mountain formed by accumulated lava. Also called a volcanic mountain.
Volcano - active
Volcanos that have erupted recently.
Volcano - dormant
Volcanoes that have not erupted in a long time, but could possibly erupt in the future.
Volcano - extinct
Volcanoes that scientist think will never erupt again.
Domed mountain
A mountain formed when molten rock builds up but does not pierce the surface.
Name the five distinct sections of the earth.
atmosphere, hydrosphere, crust, mantle, and core
Of the five distinct sections of the earth, which of these can we observe directly?
atmosphere, hydrosphere, and crust
What is the difference between the ways that igneous rock and sedimentary rock form?
Sedimentary rock is formed when sediments are solidified through chemical reactions. Igneous rock forms when molten rock solidifies.
Which of these types of rocks starts out as a different kind of rock: igneous rock, sedimentary rock, or metamorphic rock?
metamorphic rock
What is unique about the rock in the asthenosphere?
The temperature extremes make the rock behave as a liquid sometimes, and as a solid sometimes.
What is the main thing scientists observe in order to learn about the makeup of the earth’s interior?
Seismic waves
Which is solid: the inner core or the outer core? Why is it solid when the other is liquid?
The inner core. Even though the inner core is hotter than the outer core, it remains solid because the pressure is so great.
Where is earth’s magnetic field generated?
The earth’s core
What causes earth’s magnetic field?
the large amount of electrical flow in the core
What are the two main theories that try to explain the earth’s magnetic field.
dynamo theory and the rapid-decay theory
What makes the rapid-decay theory more scientifically valid?
The rapid-decay theory has been used to accurately predict the magnetic fields of other planets, whereas the dynamo theory fails at this.
Why is a catastrophe like the worldwide flood in Noah’s time an essential part of the earth’s history if the rapid-decay theory is true?
The rapid-decay theory requires a global catastrophe in order to be consistent with the data that indicate the magnetic field of the earth has reversed several times.
What two reasons make otherwise good scientists ignore the more scientifically valid rapid-decay theory?
that rapid decay theory requires a catastrophe like the Noah flood, and that rapid-decay indicates a young earth tend to make many scientist shy away from it.
Why would life cease to exist without the earth’s magnetic field?
Without a magnetic field, the sun’s cosmic rays would reach the earth.
What are the “plates” in plate tectonics?
plates are large “islands” of the earth’s lithosphere
What can happen when plates collide with one another?
- One plate can slide under another and form a trench.
What causes earthquakes?
the motion of rock masses along a fault, or by volcanic activity
A seismologist detects an earthquake that measures 4 on the Richter scale. Later, he detects one that measures 8. How many times more energy does the second earthquake release as compared to the first?
For every 1 step up the Richter scale, the energy of the earthquake multiplies by 32. The first earthquake measured 4, and the second measured 8. The second earthquake was 4 units higher, which means it released 32 x 32 x 32 x32 = 1,048,576 times more energy than the first.
Name four kinds of mountains and tell what is required for the formation of each.
Volcanic mountains, domed mountains, fault block mountains, and folded mountains. Volcanic and domed need magma from the earth’s mantle; fault block need vertical motion along a fault; folded mountains need rock masses pushing against each other.
