N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t
6th Grade Science
Unit 4
Earth Systems Land Rev. Spring 2008
EARTH SYSTEMS: LAND
Sixth graders will understand that the Earth is a set of closely linked systems. A
system can include processes as well as things. Learning about systems requires
understanding how parts relate to and influence one another. Students have
explored simple systems in elementary. In middle school, students begin thinking
about systems more explicitly – analyzing parts, subsystems, and interactions.
Complex systems often contain other systems that may interact. Examples of
complex systems include the human body, the solar system, and the universe.
Because changes in any one system affects the others, Earth is thought of as a set
of interrelated systems. Energy from within and outside the Earth provides the
force that creates these changes. The 6th grader will be able to identify forces
that shape features of the Earth including uplifting, movement of water, and
volcanic activity as processes within Earth systems. Students will also be able to
summarize the rock cycle, a concept introduced at 6th grade, as a system of
continual constructive and destructive changes.
Structure of the Earth
Students were introduced to the different layers of the Earth in 5th grade. The
6th grade student will revisit this information in order for them to understand the
origin of earth materials involved in the rock cycle. The 8th grade student will
learn about the layers in more detail. At the 6th grade level, it is sufficient for
students to understand there are four basic layers: crust, mantle, outer core and
inner core.
The crust is the thinnest layer of the Earth. It is also the layer we walk on. It is
made up of soil and rocks. The layer below the crust is called the mantle. This is
the thickest layer, making up most of the Earth’s mass. Magma that flows to the
surface of the earth as lava originated in this layer. The core is the innermost
layer of the Earth. The outer core is made of molten materials while the inner
core is solid. The following diagram illustrates the layers of the Earth:
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
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N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t
6th Grade Science
Unit 4
Earth Systems Land Rev. Spring 2008
Minerals and Rocks
The rocks that compose the Earth’s crust are themselves made up of minerals.
Minerals are naturally occurring, crystalline substances. Students should be
exposed to some of the basic properties of minerals, such as luster, streak and
hardness. Moh’s scale of hardness does not need to memorized, but students
should understand how to interpret the scale and use it to assign a relative value of
hardness to a mineral.
Concepts from the properties of matter unit should be reviewed through this
content.
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
2
N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t
6th Grade Science
Unit 4
Earth Systems Land Rev. Spring 2008
The Rock Cycle
The rock cycle describes how the form and structure of rocks is constantly
changing. There are 3 basic types of rocks: igneous, sedimentary and metamorphic
Each type of rock is formed through different processes. The processes that are
a part of the rock cycle are as follows:

Melting: Heating within the Earth causes rock to melt and form magma.

Cooling and Hardening: Magma rises towards/to the surface, cools and
hardens.

Weathering, Erosion and Deposition: Weathering is the breakdown of rock
into sediment. Erosion is the movement of that sediment. Deposition is the
process by which the sediment is dropped in a new location.

Compacting and Cementing: Pressure compacts sediment together. Water
between particles evaporates, leaving minerals that cement sediments
together.

Heat and Pressure: Heat comes from either direct contact or nearby
contact with magma. Pressure from overlying rock layers squeezes minerals
in rocks. These two processes may work to actually change the identity of a
rock.
Igneous rocks form from either magma or lava. Both of these are molten rock.
Magma is found underground. When it comes to the surface, it undergoes a
chemical change as it is exposed to the atmosphere. At this point, the molten rock
is referred to as lava. Some igneous rocks, such as granite, form from magma that
has cooled underground. Other igneous rocks, such as pumice, form from lava that
has cooled more quickly on the surface of the earth.
Sedimentary rocks form from the weathered sediments of other rocks.
Weathering occurs through forces such as wind, water, ice, organisms, etc.
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
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N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t
6th Grade Science
Unit 4
Earth Systems Land Rev. Spring 2008
Erosion carries the resulting sediment from one place to another. Deposition of
the sediment occurs in layers. Over time, the pressure of overlying layers causes
the sediment to become compacted and cemented together. As a result of this
process, many sedimentary rocks appear to have strata. Sedimentary rocks are
made from the compaction and cementation of different materials. Common
examples of sedimentary rock include limestone, conglomerate and sandstone.
Metamorphic rocks form from other rocks being heated and put under tremendous
pressure. Students should understand rocks that undergo metamorphosis are not
melted. In order for a rock to change, it must first be buried. Exposure to a heat
source and the weight of overlying rock layers then begins the metamorphic
process. Marble is an example of a metamorphic rock that forms from limestone.
The following is a diagram of the rock cycle. Students should become familiar with
a model such as this. They should understand this is a summary of the rock cycle
and that not all materials will go through all processes contained within the cycle.
Processes are not linear, but dynamic and influenced by heat, pressure and location.
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
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N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t
6th Grade Science
Unit 4
Earth Systems Land Rev. Spring 2008
The rock cycle shows many pathways that rocks can go as they change from one
form to another. A rock may go through all the changes or only some of the
changes.
Forces that Shape the Earth
Forces that shape the earth are the result of a combination of constructive and
destructive forces. Constructive forces include deposition of sediment, volcanic
eruptions, and uplift of the earth’s crust. Destructive forces include weathering
and erosion. The earth’s forces that are seen today are similar to the forces that
have occurred in the past.
Uplifting is a process that happens when a force under the earth’s crust causes the
crust to rise to a higher elevation. Uplifting is one of the ways that mountains are
created. The highest mountain on land is Mt. Everest at over 29,000 feet above
sea level. This mountain is a part of a chain of mountains called the Himalayas.
This mountain range was caused by two tectonic plates colliding together. Millions
of years ago the continents were not found as they are today. Instead they were
one landmass. The earth’s crust is broken into large pieces called tectonic plates.
These plates move slowly and are still moving today. The 6th grade student should
not receive an extensive lesson on plate tectonics, but they should understand that
pieces of the earth’s crust do move and earth’s features are affected by this
movement. Plate tectonics will be studied in detail in 8th grade. The 6th grade
student should understand that when tectonic plates collide, uplifting is the result.
Another example of a mountain range caused by uplifting is the Appalachian
Mountains which are found in the eastern United States. They are not nearly as
high as the Himalayas because they are many millions of years older and have been
worn down by weathering and erosion.
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
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N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t
6th Grade Science
Unit 4
Earth Systems Land Rev. Spring 2008
Uplift
Sometimes the heat inside the Earth will cause its surface to lift
upward like in this dome shaped mountain.
The force behind volcanic activity is the pressure caused by the build-up of
magma from deep inside the earth . Volcanic mountains form as a result of this
build-up of magma and as a result, they add new material to the earth’s surface.
Volcanic mountains are most often found at tectonic plate boundaries. Often one
plate is pushed under another. The plate that is being pushed downward may
eventually melt causing a source of magma that is near the surface. If the magma
finds a way to rise up through cracks in the crust it can harden into rock called
lava, and a volcanic mountain is born. Volcanoes have created some of the most
amazing landforms on Earth.
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
6
N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t
6th Grade Science
Unit 4
Earth Systems Land Rev. Spring 2008
Movement of water is one of the most powerful forces on earth. Water moving
over the land will flow downward in elevation due to gravity. As it does, it makes
channels, canyons, valleys, caves, and can change coastlines. Moving water also
carries sediment to the ocean or drops it off along the way. The moving water of
rivers and oceans has tremendous force and can move sediments great distances
and even break solid rocks. When soil and bits of rock or sand collect at the mouth
of a river a land feature called a delta is formed. This land is very rich in nutrients
and extremely good for growing crops. Weathering, erosion, and deposition are all
process which are affected by the movement of water. Weathering is the process
by which rock is broken down into sediment. Erosion carries this sediment away.
Deposition is the process by which these sediments are laid down in a new location.
Other forces that are responsible for the same processes include ice (glaciers),
wind and gravity.
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
7
N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t
6th Grade Science
Unit 4
Earth Systems Land Rev. Spring 2008
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
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