9th Grade Earth Science Mid-Term Study Guide
BEDROCK GEOLOGY:
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Key Concept: The geologic history of the Earth is determined by Earth Science principles such as differing
rocks and sediments in different locations, forces inside the Earth and basic geologic principles.
Sub-Concepts:
**Geologic maps show the surface geology of an area, region or a larger land area. They are constructed
using a variety of methods and contain generalizations.
**There are three types of rocks: sedimentary, igneous and metamorphic and the rock cycle explains the
relationships that can occur between them.
Geologists interpret the rock record using four principles: superposition, horizontality, original lateral
continuity and crosscutting relationships.
Forces inside the Earth can create folds or faults over time. Different types of faults (reverse, normal and
strike-slip) are formed by different forces (compression, tension or shearing).
**Different regions in the United States have different land uses based on the underlying geology.
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Know the three basic types of rocks and how they are formed
Know Rocky the rock cycle with all arrows and be able to draw it
Know how the different kinds of sedimentary rocks are formed
Know the relationship between cooling time and crystal size in igneous rocks
Know fault types and what kind of forces create them
Know what type of plate boundaries create the different types of forces
Be able to put a geologic cross section in order from youngest to oldest features
Know the Geologic principles of superposition, lateral continuity, crosscutting relationships, original
horizontality
VOLCANOES:
Key Concept: Volcanoes are an important part of Earth’s systems which have both hazards and benefits
associated with them.
Sub-Concepts:
a)
Earth scientists use a variety of maps, depending on the information being investigated. Topographic maps,
Mercator projections and geologic maps are used often.
b) Most volcanoes on land form at the edges of continents and in island chains around the edges of the Pacific
Ocean’s Ring of Fire. Volcanoes also occur on land in rift valleys and at hot spots.
c) **The topography of the land influences volcanic flows.
d) **The silica content, volume, temperature, slope and channelization affect the flow of lava and the
formation of volcanoes.
e) **Volcanic hazards include tephra, lava, lahars, pyroclastic flows, ashfall, and gasses.
f) **Volcanoes can influence all of Earth’s systems – including the water cycle and global climate – both
positively and negatively.
g) **Earth science information helps us make decisions and mitigate natural hazards.
1. Know where volcanoes form and why
2. Know the different types of volcano shapes and what type of magma is associated with each, and know
what kind of eruptions these volcanoes cause
3. Be able to draw and explain a contour map
4. Know the major hazards of volcanic eruptions: lahars, CO2 gas, lava, ash, tephra, pyroclastic flow, and
what makes them all so dangerous
5. Know what factors can change the viscosity of lava
PLATE TECTONICS:
Key-Concept: Plate Tectonics is the result of matter and energy flow in the Earth which causes specific
topography
Sub-Concepts:
a) GPS technology helps us measure and predict plate motion over time.
b) **The modern theory of plate tectonics is supported by evidence from paleomagnetism, age of ocean floor
sediments, and ocean floor topography along with Wegener’s pieces of evidence.
c) **There are three main types of plate boundaries, divergent, convergent and transform. Convergent is
further classified as ocean-ocean, ocean-continent and continent-continent.
d) The average density of the Earth provides evidence of the relative densities of the different layers of Earth –
crust, mantle and core. The theory of plate tectonics breaks the layers into lithosphere, asthenosphere and
core.
e) **The current, most accepted mechanism for plate motion is convection in the asthenosphere.
f) **The interactions of plates at their boundaries create specific landforms such as trenches, mountains,
volcanoes, island arcs, rift valleys, and mid-ocean ridges and explains the global pattern of earthquakes.
g) **Wegner supported his hypothesis of continental drift with evidence from the puzzle fit of the continents,
rock units, geologic structures, fossils and glacial evidence.
1. Know the different layers of earth
2. Know the relationship between temperature and density of substances
3. Know what happens when plates of different densities collide
4. Know the features of Pangea
5. Know what geologic features are caused by plate tectonic movement
6. Know where lithospheric plates are being created and destroyed
7. What do hot spots and mid-ocean ridges have in common?
EARTHQUAKES:
Key-Concept: Earthquakes are a result of plate motion and have inherent hazards.
Sub-Concepts:
a) **Earthquakes produce 3 main types of waves, primary (P), secondary (S) and surface which are caused by
different particle motion the Earth.
b) **Seismic evidence explains the different layers of Earth.
c) Magnitude and intensity are two ways that geoscientists make observations about earthquakes.
d) **Earthquakes mostly occur along plate boundaries, but can also occur in the interior of a continent.
e) **Local geology can change the amplitude of earthquake waves and also result in liquefaction.
f) **An understanding of the direct and indirect hazards of earthquakes allows us to mitigate damage from
earthquakes.
g) **Many factors affect the amount of damage caused by an earthquake, including the type of building, the
characteristics of the building site and the characteristics of the earthquake.
1. Know what causes rocks to split and what we call it when it happens
2. Know the difference between s waves and p waves and what they can tell us about the location of an
earthquake
3. General vocab: focus, epicenter, wavelength, frequency, intensity
4. Know where earthquakes are most likely to occur and why
WATER RESOURCES:
Earth resources include the nonrenewable and renewable supplies of water resources upon which
individuals and communities depend in order to maintain quality of human life. (Water)
Sub-Concepts:
a) **Identify and explain the interaction of water within all Earth systems (for example: the biosphere,
lithosphere, and atmosphere) at both the global and regional levels.
b) **Identify and explain the natural and man-made factors within the hydrologic cycle that influence the quality
and amount of water.
1. Know the basic components of the water cycle, and how water moves through it
2. Know where Denver gets most of its drinking water
3. Know and understand how humans affect the quality and quantity of surface and ground water