Download Final Review - 2016 with answers

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8th GRADE EARTH SCIENCE
2nd SEMESTER REVIEW
Directions: Below are terms, vocabulary words, and scientific theories and principles that are a part of
Earth Science. In order to be prepared for your exam, you need to provide as much information as
possible for each. Credit and Extra Credit will be given for this worksheet (exact pages will be assigned)
Chapter 4: Earth’s Chemistry
What is matter? What is mass?

Matter- anything that takes up space and has mass.

Mass- The amount of matter in any object.
What is the difference between a chemical and physical property?

Chemical properties describe how a substance reacts with other substances. Physical properties can
be observed without changing the composition (make-up) of the substance.
What is an element?

A substance that cannot be separated or broken down into simpler substances.
What is an atom?

The smallest unit of an element that has chemical properties of that element.
Draw and describe the Atomic Structure

Protons- particles that have a positive charge
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Electrons- particles that have a negative charge
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Neutrons- particles that are neutral (no charge)
Chapter 5: Minerals of the Earth’s Crust
What is a mineral? What four questions must be answered to know if you have a mineral?

Mineral- a natural, usually inorganic solid that has a characteristic chemical composition, an orderly
internal structure, and a characteristic set of physical properties.
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Is it inorganic? (one that is not made up of once living things)
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Does it occur in nature?
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Is it a crystalline solid? (does it have a regularly repeating pattern?)
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Does it have a consistent chemical composition?
What are the seven properties of minerals and explain each?
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Color- while a good place to start, color alone is generally not a reliable method for mineral
identification.
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Streak- color of the mineral in a powder form.

Luster- how light is reflected from a mineral’s surface. Metallic luster (light reflects like it would off from a
metal surface) or nonmetallic luster (all other minerals).
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Cleavage and Fracture- the tendency of a mineral to split along specific planes to form smooth, flat
surfaces is cleavage. Fracture- if a mineral breaks unevenly into curved or irregular surfaces.
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Hardness- the measure of the ability of a mineral to resist scratching. Hardness is measured using the
Mohs Hardness Scale.
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Crystal shape- six basic shapes form minerals (isometric or cubic, tetragonal, monoclinic, orthorhombic,
hexagonal, triclinic)
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Density- the ratio of the mass of a substance to the volume of a substance.
Chapter 6: Rocks
What are the three types of rocks and how is each made?

Igneous- from fire- forms when magma, or molten rock, cools and hardens.
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Sedimentary- formed from rocks, minerals, and organic matter that have been broken into fragments
and cemented together through pressure.
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Metamorphic- forms when existing rock is altered or changed.
What is the Rock Cycle?

The series of processes in which rock forms, changes from one type to another, is destroyed, and forms
again by geological processes.
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Diagram: create a diagram of the rock cycle. Include all three layers of rocks, the magma, and the eight steps
of the cycle.
How are Igneous Intrusive and Extrusive rocks different? (Give some examples of each type as well)

Intrusive igneous- rock formed from the cooling and solidification of magma beneath Earth’s surface.
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Extrusive igneous- rock that forms from the cooling and solidification of lava at Earth’s surface.
What are the three types of sedimentary rock and explain each?

Chemical Sedimentary- sedimentary rock that forms when minerals precipitate from a solution or settle
from a suspension.
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Organic Sedimentary- sedimentary rock that forms from the remains of plants or animals.

Clastic Sedimentary- sedimentary rock that forms when fragments of preexisting rocks are compacted
or cemented together.
Explain contact and regional metamorphism

Contact- a change in the texture, structure, or chemical composition of a rock due to contact with
magma.
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Regional- a change in the texture, structure, or chemical composition of a rock due to changes in
temperature and pressure over a large area, generally as a result of tectonic forces.
Explain foliated and non-foliated?

Foliated- metamorphic rock texture in which mineral grains are arranged in planes or bands (ex. Slate,
schist, gneiss)
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Non-foliated- metamorphic rock texture in which mineral grains are not arranged in planes or bands (ex.
Marble)
Ch 8: The Rock Record
Explain the principles of Uniformitarianism, Law of Superposition, relative age, absolute age, and Principle of
Original Horizontality.
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Uniformitarianism- a principle that geologic processes that occurred in the past can be explained by
current geologic processes.
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Law of Superposition- a sedimentary rock layer is older than the layers above it and younger than the
layers below it if the layers are not disturbed.
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Relative age- the age of an object in relation to the ages of other objects.

Absolute age- the actual numeric age of an object or event, often stated in years before the present, as
established by an absolute-dating process, such as radiometric dating.

Principle of Original Horizontality- sedimentary rocks, left undisturbed, will remain in horizontal layers.
Rock that is not in horizontal layers have been tilted or moved by movements that occurred after the
layers were deposited.
Explain half-lives and radiometric dating. Also, what elements would you use to date humans or the Earth?

Radiometric dating- a method of determining the absolute age of an object by comparing the relative
percentages of a radioactive, or parent, isotope with a stable, or daughter, isotope.

Half-lives- the time required for half of a sample of a radioactive isotope to break down by radioactive
decay to form a daughter isotope.
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Dating humans- use carbon dating
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Dating Earth- use uranium, potassium, rubidium, argon
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Diagram: Draw, label, and explain the three types of unconformities.
Know and understand graphs similar to pg 223 #34-36.
Chapter 9: View of the Earth’s Past
What is the geologic column?
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An ordered arrangement of rock layers that is based on the relative ages of the rocks and in which the
oldest rocks are at the bottom.
How is the history of the Earth divided?
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Eras (a unit of time that includes two or more periods), periods (a unit of time that is longer than an
epoch but shorter than an era), epochs (a subdivision of time that is longer than an age but shorter than
a period.
Explain the Paleozoic Era, Mesozoic Era, and the Cenozoic Era.
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Paleozoic Era- the geologic era that followed Precambrian time and that lasted from 542 million to 251
million years ago. First vertebrates appear; modern, oxygen-rich atmosphere formed; first amphibians
appeared; first reptiles appear; formation of Pangaea is complete.

Mesozoic Era- the geologic era that lasted from 251 million to 65.5 million years ago; also called the
Age of Reptiles. Pangaea begins to break apart; first mammals appear; first primitive birds; last
dinosaurs become extinct.

Cenozoic Era- the current geologic era, which began 65.5 million years ago; also called the Age of
Mammals. Most modern mammals; first grasses; India collides with Asia, Antarctica drifts over South
Pole; first early human ancestors; modern Ice Age began; modern human appeared.
Ch 10: PLATE TECTONICS
Explain the Theory of Continental Drift and give some evidence which supports it.

Theory of Continental Drift- hypothesis that a single, large landmass broke up into smaller landmasses
to form the continents, which then drifted to their present locations.
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Fossil evidence- if continents were connected, fossils of plants and animals should be found on both.
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Rock formations- ages and types of rocks in the coastal areas matched closely to prove they had once
been connected.
Explain Sea-Floor Spreading and describe the relationship of the older crust and newer crust.

Sea-Floor Spreading- the process by which new oceanic lithosphere (sea floor) forms when magma
rises to Earth’s surface at mid-ocean ridges and solidifies, as older, existing sea floor moves away from
the ridge.
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Older lithosphere crust spreads apart, new magma rises and fills in the gaps. When this solidified, new
lithosphere forms. The newest crust will be in the middle, the oldest will be furthest out.
What are Plate Tectonics? What layers of the Earth are involved? Give two things that has helped to identify
plate Boundaries
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Plate Tectonics- the theory that explains how large pieces of the lithosphere, called plates, move and
change shape.
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Layers of the Earth involved- lithosphere and asthenosphere
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Earthquakes and Volcanoes
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What are the three types of plate boundaries, how do they move, and give a real world example.
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Divergent boundary- the boundary between tectonic plates that are moving away from each other.
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Convergent boundary- the boundary between tectonic plates that are colliding.
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Transform boundary- the boundary between tectonic plates that are sliding past each other horizontally.
Explain the three possible causes of plate motion. Include a diagram.
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Convection- the movement of heated material due to differences in density that are caused by
differences in temperatures
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Ridge Push- Newly formed rock at a mid-ocean ridge is warmer and less dense than older rock nearby.
The warmer, less dense rock is elevated above nearby rock, and older, denser rock slopes downward
away from the ridge. As the newer, warmer rock cools and becomes denser, it begins to slide down the
slope between the lithosphere and the asthenosphere.
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Slab pull- Where plates pull away from each other at mid-ocean ridges, magma from the
asthenosphere rises to the surface. The magma then cools to form new lithosphere.
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Name: _________________
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Explain the supercontinent cycle.
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The process by which supercontinents form and break apart over time. Over time, all the continents
collide to form a supercontinent. Then, heat from Earth's interior builds up under the supercontinent, and
rifts form in the supercontinent. The supercontinent breaks apart, and plates carrying separate
continents move around the globe.
Ch 11: DEFORMATION OF THE CRUST
Explain Isostasy, Stress, Strains, and Folds.

Isostasy- The other force is the buoyant force of the asthenosphere pressing up on the lithosphere.
When these two forces are balanced, the lithosphere and asthenosphere are in a state called isostasy

Stress- The amount of force that is exerted on each unit of area
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Strain- When stress is applied to rock, rock may deform. Any change in the shape or volume of rock that
results from stress is called strain.
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Fold- When rock responds to stress by deforming in a ductile way, folds commonly form.
What are the three types of faults, describe which way they move, and what each creates.

Normal fault- is a fault in which the hanging wall moves downward relative to the footwall. Normal faults
commonly form at divergent boundaries, where the crust is being pulled apart by tension.
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Reverse fault- When compression causes the hanging wall to move upward relative to the footwall
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Strike-slip fault- the rock on either side of the fault plane slides horizontally in response to shear stress.
Strike-slip faults commonly occur at transform boundaries, where tectonic plates grind past each other
as they move in opposite directions.
What types of mountains are created by tectonic plate collisions and explain each?
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Continental-Oceanic- When the moving plates collide, the oceanic lithosphere subducts beneath the
continental lithosphere
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Oceanic-Oceanic- Volcanic mountains commonly form where two plates whose edges consist of
oceanic lithosphere collide. In this collision, the denser oceanic plate subducts beneath the other
oceanic plate
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Continental-Continental- Because the two continents have equally dense lithosphere, subduction does
not occur but the collision continues. The intense deformation that resulted from the collision uplifted the
mountains.
Ch 12: EARTHQUAKES
Explain elastic rebound, focus, and epicenter.
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Elastic rebound- the sudden return of elastically deformed rock to its undeformed shape
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Focus- The location within Earth along a fault at which the first motion of an earthquake occurs
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Epicenter- The point on Earth’s surface directly above the focus
Describe Seismic Waves (Body Waves and Surface Waves)
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Seismic waves- As rocks along a fault slip into new positions, the rocks release energy in the form of
vibrations
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Body waves- waves that travel through the body of a medium
o
P waves- called primary waves or compression waves, are the fastest seismic waves and are
always the first waves of an earthquake to be detected
o
S waves- secondary waves or shear waves, are the second-fastest seismic waves and arrive at
detection sites after P waves.
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Surface waves- form from motion along a shallow fault or from the conversion of energy when P waves
and S waves reach Earth’s surface. Although surface waves are the slowest-moving waves, they may
cause the greatest damage during an earthquake.
Describe how Earth’s interior layers affect seismic waves.
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Waves travel through different material at different speeds. By studying the speed and direction of
seismic waves, scientists can learn more about the makeup and structure of Earth’s interior. Scientists
have been able to locate boundaries between other internal layers of Earth.
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Name: _________________
Hour: _____
What are a seismograph and a seismogram?
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Seismograph- an instrument used to detect and record vibrations in the ground
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Seismogram- A tracing of earthquake motion that is recorded by a seismograph
How do earthquakes affect humans? Magnitude, tsunamis.
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An earthquake whose epicenter is on the ocean floor may cause a giant ocean wave called a tsunami.
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Magnitude- the intensity of an earthquake as measured by a seismograph. Magnitude is assigned a
number based on the Richter scale.
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Most buildings are not designed to withstand the swaying motion caused by earthquakes. Buildings
whose walls are weak may collapse completely. Very tall buildings may sway so violently that they tip
over and fall onto lower neighboring structures
Ch 14: WEATHERING AND EROSION
What is weathering?
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The physical breakdown or chemical decomposition of rock materials exposed at Earth's surface
Explain mechanical weathering and give a few types.
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The process by which rock is broken down into smaller pieces by physical means. Mechanical
weathering is strictly a physical process and does not change the composition of the rock

Examples: ice, plants and animals, gravity, running water, and wind.
Explain chemical weathering and give a few types

The process by which rock is broken down because of chemical interactions with the environment.
Chemical weathering, or decomposition, occurs when chemical reactions act on the minerals in rock.

Chemical weathering changes both the chemical composition and physical appearance of rock.
Oxidation, hydrolysis, and carbonation are examples.
Ch 15: RIVER SYSTEMS
Explain the 8 steps of the Water Cycle and then draw it.
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Evaporation- water turns to vapor
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Condensation- the change of state from a gas to a liquid
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Precipitation- any form of water that falls to Earth’s surface from the clouds and includes rain, snow,
sleet, and hail
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Transpiration- the process by which plants release water vapor into the atmosphere.
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Evapotranspiration- The total loss of water from an area, which equals the sum of the water lost by
evaporation from the soil and other surfaces and the water lost by transpiration from organisms
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Run-off- when the ground cannot hold any more water, the excess water runs downhill to a larger water
body.
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Infiltration- the process by which water enters the ground
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Percolation- water that has entered the ground travels down through the ground to the water table
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In a river system, what is a drainage basin, tributary, and divide?
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Drainage basin- a region that collects streams (surface runoff) that then become part of a body of water,
such as a lake or a river.
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Tributary- all of the feeder streams that flow into the main stream
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Divide- the ridges or elevated regions that separate watersheds
When discussing stream erosion, what are gradient, discharge, and load?

Gradient- the change in elevation of a stream over a given horizontal distance, the steepness of the
stream’s slope
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Discharge- the volume of water moved by a stream in a given time period
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Load- The materials carried by a stream. Stream load takes three forms: suspended load, bed load,
and dissolved load
Ch 16: GROUNDWATER
Explain ground water, water table, aquifer, porosity, permeability, and recharge zone:

Ground water- Water that fills and moves through these spaces in rock and sediment
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Aquifer- A body of rock or sediment in which large amounts of water can flow and be stored
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Porosity- the percentage of the rock or sediment that consists of open spaces
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Permeability- The ease with which water passes through a porous material. For a rock to be
permeable, the open spaces must be connected
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Recharge Zone- anywhere that water from the surface can travel through permeable rock to reach an
aquifer
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Water Table- The zone of saturation is the lower of the two zones of groundwater. The upper surface of
the zone of saturation is the water table.
Explain the zone of aeration and zone of saturation and draw them

Zone of Aeration- The zone that lies between the water table and Earth’s surface
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Zone of Saturation- The layer of an aquifer in which the pore space is completely filled with water
Draw working wells, dry wells, cone of depression, water table.
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Name: _________________
Hour: _____
Ch 23: OCEAN BASINS
How many oceans are in the world? List them in order from Largest to Smallest

These major oceans are the Atlantic, Pacific, Indian, Arctic, and Southern Oceans.
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Pacific (biggest), Atlantic, Indian, Southern, Arctic (smallest)
What is the difference between a sea and an ocean?

A sea is a body of water that is smaller than an ocean and that may be partially surrounded by land.
Explain Sonar and how it helped start modern Oceanograhpy?

Sonar- a system that uses acoustic signals and returned echoes to determine the location of objects or
to communicate.
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Scientists measure the time that the sound waves take to travel from the transmitter, to the ocean floor,
and to the receiver in order to calculate the depth of the ocean floor. Scientists then use this information
to make maps and profiles of the ocean floor.
Ch 24: OCEAN WATER
How does each of the following affect the oceans: Salinity, Temperature, Density

Salinity- a measure of the amount of dissolved salts and other solids in a given liquid. The higher the
salinity of water, the better its conductivity.

Temperature- ocean temperature varies depending on depth and location on the surface of the ocean.
The range of ocean temperatures is affected by the amount of solar energy an area receives and by the
movement of water in the ocean.
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Density- Two factors affect the density of ocean water: salinity and the temperature of the water.
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Ch 25: MOVEMENTS OF THE OCEAN
What affects surface currents and how?

Air currents

Earth’s rotation

Location of the continents
Chapter 7: Resources and Energy
Explain the four types of mining.

Subsurface mining- These minerals are mined by miners who work underground to recover the deposits

Subsurface mining- overlying rock material is stripped away to reveal the mineral deposits

Placer mining- large buckets are attached to a floating barge. The buckets scoop up the sediments in
front of the barge. Dense minerals from placer deposits are separated from the surrounding sediments.
Then, the remaining sediments are released into the water.

Undersea mining- because of their location, these deposits are very difficult to mine
What are fossil fuels? How is each formed and how is energy produced from each?

These natural resources—coal, petroleum, and natural gas—formed from the remains of living things.
Because of their organic origin, coal, petroleum, and natural gas are considered fossil fuels.

Coal- Carbonization occurs when partially decomposed plant material is buried in swamp mud and
becomes peat. Pressure over time turns this to coal.

Petroleum and natural gas- Petroleum and natural gas are most often mined from permeable
sedimentary rock. As sediments accumulate and sedimentary rock forms, pressure increases. This
pressure forces fluids, including oil and gas, out of the pores and up through the layers of permeable
rock. Petroleum that accumulates beneath the cap rock fills all the spaces to form an oil reservoir.
Because petroleum is less dense than water, petroleum rises above any trapped water. Similarly,
natural gas rises above petroleum, because natural gas is less dense than both oil and water.
Diagram: Show and label oil and natural gas traps (p. 173)
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What are the two types of Nuclear Energy? Explain how each works and what power it creates.

Nuclear fission- One form of nuclear energy is produced by splitting the nuclei of heavy atoms. This
splitting of the nucleus of a large atom into two or more smaller nuclei
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Nuclear fusion- All of the energy that reaches Earth from the sun is produced by a kind of nuclear
reaction, called nuclear fusion. During nuclear fusion, the nuclei of hydrogen atoms combine to form
larger nuclei of helium. This process releases energy. Fusion reactions occur only at temperatures of
more than 15,000,000 °C.
What are the renewable energy resources? Give each and explain how they work.

Geothermal- water flows far beneath Earth’s surface. This water may flow through rock that is heated by
nearby magma or by hot gases that are released by magma. This water becomes heated as it flows
through the rock. The hot water, or the resulting steam, is the source of a large amount of heat energy.

Solar energy- source of renewable energy is the sun

Hydroelectric energy- One of the oldest sources of energy comes from moving water. Energy can be
harnessed from the running water of rivers and streams or from ocean tides.

Biomass- Renewable energy sources that come from plant material, manure, and other organic matter,
such as sawdust or paper waste

Wind energy- Wind turbines use the movement of air to convert wind energy into mechanical energy,
which is used to generate electricity.
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