Download Chapter 21- Planet Earth

2nd Semester Earth Science Ch 21- Planet Earth & Ch 22 Climate
Chapter 21- Section 1: all; Section 2: p 709-710, 714 middle; 716-717; Section 3: all
Chapter 22- Section 3 Climate 760-762
Section 1: Earth’s Interior and Plate Tectonics
What is Earth’s Interior Like?
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The Earth is made up of three layers: the crust, the mantle and the core.
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_________ the thin and solid outermost layer of Earth above the mantle
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_________ the layer of rock between Earth’s crust and core
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_________ the center part of the Earth below the mantle
Structure of the Earth
DRAW AND LABEL your own diagram
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Earth’s interior gets ____________________________________.
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Geologists believe that the mantle is much hotter than the crust, reaching
temperatures higher than 1250° C (2280° F).
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The core is hotter than the mantle, reaching temperatures higher than 6000° C
(10,800° F).
Radioactive elements contribute to Earth’s high internal temperature.
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The breakdown of ______________________________ uranium, thorium and
potassium ________________________ that contributes to Earth’s
_____________________________________________________________.
Plate Tectonics
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Around 1915, German scientist Alfred Wegener proposed the idea that the continents
were once united as a _____________________________________________________.
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He pieced the continents together like a ________________ and called the
supercontinent they formed _____________________________.
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Evidence for Wegener’s ideas came later.
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Wegener’s theory of continental drift was ignored until structures discovered on
the ocean floor provided evidence for a mechanism for the movement of
continents.
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Symmetrical bands on either side of a mid-ocean ridge indicate that the two sides
of the ridge were moving away from each other and new ocean floor was rising
up between them.
_________________________________________ supports the theory of moving plates.
• Iron in molten rock aligns itself with Earth’s magnetic field as it cools.
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The Earth’s magnetic field reverses polarity about every 200,000 years
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The process is recorded as magnetic bands in rock, based on the age of the rock.
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Symmetrical bands on either side of the Mid Atlantic Ridge suggest that the crust
was moving away from the ridge.
Earth has _____________ that ______________________________________________.
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Wegener found ___________________________ on widely separate continents,
which supported his idea.
The crust and upper portion of the mantle are divided into about seven large
pieces called ___________________________.
____________________________ the solid, outer layer of Earth, that consists of the
__________ and the rigid ___________________
Plate tectonics
the theory that explains how the outer parts of Earth ______________________________,
and that explains the relationships between _______________________________, sea-floor
spreading, ____________________________, and volcanic activity
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It is unknown exactly why tectonic plates move.
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One hypothesis suggests that plate movement results from __________________
in the asthenosphere, the hot, fluid portion of the mantle.
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Another hypothesis suggests that plate movement results from the ___________
________________ acting on the plates.
Plate Boundaries
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Mid-ocean ridges result from ____________________________________________.
• The border between two plates is called a boundary.
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Divergent boundary a place where two plates are ______________________________
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_____________________ forms between divergent boundaries.
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Magma __________________ produced under Earth’s surface
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Oceanic plates ______________________continental plates at convergent boundaries.
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Plates ______________________________________ at a convergent boundary.
_______________________the process by which one lithospheric plate moves
______________________________ as a result of tectonic forces
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The area where one plate slides over another is called a subduction zone. Subduction
zones produce ________________________, ____________________, and
___________________.
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Subduction of ocean crust generates __________________________.
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Chains of volcanoes form on the upper plate in a subduction zone.
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These volcanoes can form far inland from their associated oceanic trench.
Colliding tectonic plates create __________________________.
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When two _________________________, mountains are formed at the boundary
of the collision.
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The ____________________ formed during the collision between the continental
tectonic plate containing India and the Eurasian continental plate.
Transform fault boundaries can ___________________________.
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Plate movement can cause ___________________________________________.
_________ a crack in Earth created when rocks on either side of a break move
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Plate movement at transform fault boundaries is __________________________
______________________________.
Section 2 Earthquakes and Volcanoes
What are Earthquakes?
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Earthquakes _____________________________________________________.
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Earthquakes are ___________________ resulting from rocks ______________________
each other at __________________
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Seismic waves are _______________________________________during an earthquake
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Focus= the area along a fault at which the _________________of an earthquake occurs
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___________________= the point on Earth’s surface directly above an earthquake’s
focus
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Energy from earthquakes is ________________________________________.
• Earthquakes generate three types of waves:
• ________________________________________
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________________________________________
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________________________________________
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Longitudinal waves travel by _____________________ and _________________ crust,
also called primary waves (P waves) (SLINKY!)
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Transverse waves travel in an ________________________________movement, also
called secondary waves (S waves)
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Surface waves seismic waves that can _____________________________________,
move in a ___________________________ motion
DRAW!
Longitudinal Wave
Transverse Wave
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Volcanoes
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_______= an opening at the surface of Earth through which volcanic material passes
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A volcano is ___________________ in Earth’s _____________through which
magma has reached Earth’s surface.
Volcanoes generally have one central vent, but they can also have several smaller
vents.
Magma that reaches Earth’s surface is called ____________.
Shield volcanoes have ________________________________.
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Lava from shield volcanoes is _________________________and forms a gently
sloping mountain.
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Shield volcanoes are some of the _________________________ volcanoes.
Composite volcanoes have ___________________________.
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Composite volcanoes are made up of alternating layers of ash, cinders, and lava.
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The lava is thicker than that of shield volcanoes.
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Gases are trapped in the magma, causing eruptions that alternate between ______
and _____________________________ that produces cinders and ash.
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Composite volcanoes are typically _____________________________________.
Most volcanoes occur at ________________________________________ boundaries.
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75% of the active volcanoes on Earth are located in an area known as the
______________________________.
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The Ring of Fire is located along the edges of the ______________________,
where __________________ tectonic plates are ______________________ with
____________________plates.
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Underwater volcanoes occur at ____________________ plate boundaries.
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As plates move apart at divergent boundaries, magma rises to fill the gap.
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This magma creates the volcanic mountains that form ocean ridges.
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________________ is a volcanic island on the Mid-Atlantic ridge that is growing
outward in opposite directions.
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Volcanoes occur at __________________________.
• Some volcanoes occur in the middle of plates.
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___________________________ are mushroom shaped trails of hot rock that rise from
deep inside the mantle, melt as they rise, and erupt from volcanoes at hot spots at the
surface.
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The plumes remain in the same place as the tectonic plate moves, creating a trail
of volcanoes.
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The _____________________________ are an example of this type of volcanic
activity.
Section 3 Minerals and Rocks
Structure and Origin of Rocks
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All rocks are composed of ____________________________.
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There are about 3500 known minerals in Earth’s crust.
Each combination of rock-forming minerals results in a rock with a unique set of
properties.
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___________________ 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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Molten rock cools to form igneous rock.
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Nearly all igneous rocks are made of crystals of various minerals.
________________________________ rock that forms with magma cools and solidifies
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Extrusive igneous rock cools _____ Earths surface
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Intrusive igneous rock cools while ___________________________ Earth’s surface
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Remains of older rocks and organisms form _________________________________.
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All rock breaks down over thousands of years.
______________________ the natural process by which atmospheric and environmental
agents, such as _________, ____________, and ___________________________,
disintegrate and ________________________ rocks
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As pieces of rock accumulate, they can form another type of rock.
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______________________________ a rock formed from compressed or cemented layers
of sediment
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Sediment= accumulated pieces of rock and other particles
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Loose sediment forms rock in two ways.
1. Layers of sediment ________________________________ from weight above,
forming rock.
2. ____________________________________ seep between bits of sediment and
“________” them together.
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Sedimentary rocks are named according to the size of the fragments they contain.
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Rocks that undergo pressure and heating without melting form ________________ rock.
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Heat and pressure within Earth cause changes in the texture and mineral content
of rocks.
Metamorphic rock= a rock that forms from other rocks as a result of intense __________,
______________________, or _________________________________
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__________rocks in the rock cycle form _________ rocks.
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The sequence of events in which rocks can be weathered, melted, altered, and
formed is described by the ___________________________.
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Rock formation occurs _________________________, often over tens of
thousands to millions of years.
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How Old Are Rocks?
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The relative age of rocks can be determined using the
_________________________________________________.
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The principle of superposition states the following:
• Assuming no disturbance in the position of the rock layers, the
________________will be on the ____________________, and the
________________ will be on ___________.
Law of Superposition
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____________________________ can determine a more exact, or _____________, age
of rocks.
• The radioactive elements that make up minerals in rocks _____________ over
billions of years.
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Physicists have determined the ______________ at which these elements decay.
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Geologists can use this data to determine the ___________________________.
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CHAPTER 22 Section 3: Pages 760(climate) – 762
Climate
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Climate the _______________________________________________ in an area over a
_________________________ of time.
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Temperatures tend to be higher close to the _________________________.
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Sunlight strikes the earth ___________________________ close to the equator.
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The suns rays are less concentrated at __________________________, and do
not warm the atmosphere as much.
Earth’s ____________________________________ account for our ________________.
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When the North Pole is tilted toward the sun, the ________________________
Hemisphere experiences ________________.
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When the South Pole is tilted toward the sun, the
_________________________________________ experience summer.
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Summer solstice the ______________________________of the year
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Winter solstice the _______________________________ of the year
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Vernal equinox the point in the __________ when the ___________________________
are ________________________________
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Autumnal equinox the point in the _______ when the _____________________are
_____________________________
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Global climate changes over time.
• Many factors produce changes in Earth’s climate, such as:
• _______________________________________
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slight changes in Earth’s ________________
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_______________________________________
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changes in the _______________________________________
Earth’s climate is likely to continue changing over the millennia to come.
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