6th Grd. ---Earth’s Structure---Chp 2 Study Guide
I.
II.
III.
IV.
Vocabulary:
a. Magma: molten, liquid rock material found underground.
b. Crust: thin, rocky outer layer of earth.
c. Mantle: thick middle layer of earth
d. Erosion: the process of wearing away rock
e. Rock: natural mixture of particle, sediments, rocks, crystals.
f. Density: the amount of matter an object has per unit volume.
g. Lithosphere: the crust and the uppermost layer of the mantle.
h. Mineral: naturally occurring generally inorganic solid that has a crystal definite
composition.
i. Uplift: any process that moves Earth’s surface to a higher elevation.
j. Rock cycle: a series of process that change one rock into another.
k. Sediment: rock that is broken down into smaller pieces or dissolved in water.
l. Asthenosphere: solid but plastic layer found in the upper mantle on which the crustal
plates sit.
m. Core: dense metallic center of earth
n. Lava : molten liquid rock material found on Earth’s surface.
o. Landforms: feature sculpted by processes on Earth’s surface or resulting from forces
within Earth.
Complete with the words provided:
Beaches
Landforms
Volcano
Erosion
River
Glacier
Uplift
a. The U-shaped valley in Yosemite National Park was formed by a ____Glacier_______
b. A canyon or a V-shaped valley is carved by a _____River________
c. California’s Great Central Valley was formed by the _____Erosion_______ of the surrounding
mountains.
d. The cone-shaped peak of Mount Shasta was formed by layers of rock material deposited
by a ______Volcano_____
e. Valleys and _______Beaches____________ are common landforms resulting from erosion and
deposition of Earth’s surface materials.
f. Earth’s surface is covered with ______Landforms_ created by internal and external forces.
g. The Sierra Nevada and Coastal Ranges are mountain belts created by ____Uplift__.
Compare how internal and external forces affect mountains.
Internal forces are uplifting and building forces, and External forces are mostly destructive and
erosive.
Compare and contrast how igneous, metamorphic, and sedimentary rocks are formed.
Sedimentary
Sedimentary rocks are formed from particles of sand, shells, pebbles, and other fragments of
material. Together, all these particles are called sediment. Gradually, the sediment accumulates in
layers and over a long period of time hardens into rock
Metamorphic
Metamorphic rocks are formed under the surface of the earth from the metamorphosis (change) that
occurs due to intense heat and pressure (squeezing). The rocks that result from these processes
often have ribbon like layers and may have shiny crystals, formed by minerals growing slowly over
time, on their surface.
Igneous
Igneous rocks are formed when magma (molten rock deep within the earth) cools and hardens.
Sometimes the magma cools inside the earth, and other times it erupts onto the surface from
volcanoes (in this case, it is called lava). When lava cools very quickly, and the rock is small in size
Draw the layers of Earth
V.
VI.
VII.
VIII.
IX.
X.
XI.
Distinguish between the crust, mantle, and core.
Crust: thin, rocky outer layer of Earth.
Mantle: Below the crust, thick middle layer.
Core: dense metallic center of Earth.
Describe three major landforms.
Mountains, Valleys and Beaches (describe from your notes).
Contrast a rock and a mineral
Rock: natural solid mixture of particles.
Minerals: natural occurring, general inorganic solid that has a crystal structure and definite
chemical composition.
What is the difference between cleavage and fracture?
Cleavage- splits easily along flat surfaces.
Fracture- is smooth and curved or jagged with sharp edges.
Why gems are so much more valuable than other minerals?
Gems are rare and beautiful. They are not found as plentiful as other minerals.
What is the Mohs scale?
Measures the hardness of a mineral
What are the physical properties of the minerals and what they mean?
Color: Most minerals have a distinctive color that can be used for identification
Streak : Streak is the color of the mineral in powdered form. Streak shows the true color of the mineral
Hardness : Hardness is a measure of the mineral’s resistance to scratching.
The Mohs scale is a set of 10 minerals whose hardness is known. Softer minerals can be scratched by harder minerals
because the forces that hold the crystals together are weaker and can be broken by the harder mineral.
The following is a listing of the minerals of the Mohs scale and their rating:
1.
2.
3.
4.
5.
Talc
Gypsum
Calcite
Fluorite
Apatite
6.
7.
8.
9.
10.
Orthoclase Feldspar
Quartz
Topaz
Corundum
Diamond
Cleavage & Fracture:
Cleavage: Minerals tend to break along lines or smooth surfaces when hit sharply.
Fracture describes the quality of the cleavage surface. Most minerals display either uneven or grainy fracture, conchoidal
(curved, shell-like lines) fracture, or hackly (rough, jagged) fracture.
Crystalline Structure
Mineral crystals occur in various shapes and sizes. The particular shape is determined by the arrangement of the atoms,
molecules or ions that make up the crystal and how they are joined.
Tenacity
Tenacity is the characteristic that describes how the particles of a mineral hold together or resist separation. The chart
below gives the list of terms used to describe tenacity and a description of each term.
Magnetism
Magnetism is the characteristic that allows a mineral to attract or repel other magnetic materials. It can be difficult to
determine the differences between the various types of magnetism, but it is worth knowing that there are distinctions made.
Luster
Luster is the property of minerals that indicates how much the surface of a mineral reflects light. The luster of a mineral is
affected by the brilliance of the light used to observe the mineral surface. Luster of a mineral is described in the following
terms:
Metallic The mineral is opaque and reflects light as a metal would.
Nonmettalic The mineral does not reflect light like a metal.
XII.
Describe the difference between lithosphere and the asthenosphere.
Lithosphere is the rigid, cool part of the earth, which contains the crust and the upper part of the mantle. The asthenosphere is the convecting
part of the mantle which behaves like a plastic.
The lithosphere (crust and attached upper mantle) is less dense but hard and behaves as a brittle
material and floats on top of the asthenosphere, where rock is in a plastic, semi-molten state and
so deforms in a ductile manner.
XIII.
Pyrite and Gold are two minerals golden in color. What physical property would you use to
determine what is what.
Check on the different physical properties of the minerals !
XIV.
XV.
Describe how convection affects other processes on Earth.
The outer core produces Earth’s magnetic field.
The mantle aids on the flow of rocks and plate tectonics.
The heat transfer inside the upper mantle drives the movement of the plates. This movement of
plates can cause earthquakes, and can uplift mountains among other things.
Know the Rock Cycle
The Rock Cycle is a group of changes. Igneous rock can change into sedimentary rock or into
metamorphic rock. Sedimentary rock can change into metamorphic rock or into igneous rock.
Metamorphic rock can change into igneous or sedimentary rock.
Igneous rock forms when magma cools. Magma is a hot liquid made of melted minerals. The minerals can
form crystals when they cool. Igneous rock can form underground, where the magma cools slowly, or
they can form above ground, where the magma cools quickly.When it pours out on Earth's surface,
magma is called lava.
On Earth's surface, wind and water can break rock into pieces. They can also carry rock pieces to another
place. Usually, the rock pieces, called sediments, drop from the wind or water to make a layer. The layer
can be buried under other layers of sediments. After a long time the sediments can be cemented together
to make sedimentary rock. In this way, igneous rock can become sedimentary rock.
All rock can be heated. But where does the heat come from? Inside Earth there is heat and pressure. Rock
does not melt, but it does change. It forms crystals. If it has crystals already, it forms larger crystals.
Because this rock changes, it is called metamorphic. Metamorphosis can occur in rock when they are
heated to 300 to 700 degrees Celsius.
When Earth's tectonic plates move around, they produce heat. When they collide, they build mountains
and metamorphose (met-ah-MORE-foes) the rock.The rock cycle continues. Mountains made of
metamorphic rocks can be broken up and washed away by streams. New sediments from these
mountains can make new sedimentary rock.
The rock cycle never stops.