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 – 5 t h G r ad e Sc i enc e
The Natural World
Unit 1 Clarifying Statements
Revised May 2009
The Natural World
In The Natural World, students identify structures and processes of the Earth
and its related systems. A system can include processes as well as things.
Learning about systems requires understanding how parts relate to and influence
one another. Systems often contain other systems that may interact. For
example, the Earth is a system that is composed of subsystems including the crust,
mantle, and core. Each layer is made of different materials, has a different
thickness, and a different temperature. It is important for students to understand
that there are differences within each layer. For example, the crust is composed
of a variety of earth materials including rocks, gravel, and soil. Soil can further be
divided into humus, topsoil, subsoil, and rock. These many systems interact to
create changes in and on the surface of the Earth.
Students should understand how destructive and constructive forces shape the
Earth’s physical features. Destructive forces are responsible for destroying, or
breaking down and wearing away, the Earth’s surface. Weathering is the breaking
down of rocks into smaller pieces by exposure to water, wind, ice, and growing
plants. Erosion is the carrying away (movement) of weathered materials.
Deposition is the dropping of the weathered materials in a new place. Deposition is
a constructive force. Constructive forces are responsible for constructing, or
building up, the earth’s surface. The movement of waves, wind, water, and ice shape
and reshape the Earth’s land surface by eroding rock and soil in some areas and
depositing them in other areas.
Forces on the Earth’s materials create wrinkles, folds, and faults that can
construct mountains and basins. These same forces inside the Earth and on its
surface constantly change one kind of rock into another kind of rock. In third
grade, students learned there are three basic rock types: igneous, sedimentary,
and metamorphic. In this unit students learn that weathering, erosion, deposition,
and forces of heat and pressure are responsible for these changes. Some of these
forces result from heat deep inside the Earth. Temperatures at the bottom of the
Earth’s crust are so hot that rocks melt. Heat flow (convection) and movement of
this melted material cause earthquakes and volcanic eruptions that can create
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 – 5 t h G r ad e Sc i enc e
The Natural World
Unit 1 Clarifying Statements
Revised May 2009
landforms such as mountains and basins. Some changes in the Earth’s surface are
abrupt (such as floods, mudslides, earthquakes, and volcanic eruptions) while other
changes happen slowly over time (such as mountain building and delta formation).
Past events have shaped present day land features. By studying or observing
features such as sedimentary rock sequences, students can draw conclusions about
what happened in the past. Each layer tells the history of the events that took
place. In general the layers on the top tell about the most recent events and the
layers on the bottom tell about the distant past. In between is the history from
past to present. The layers do not tell exactly when an event took place or the
complete story about the event, but they do tell the order in which some events
took place. For example in this diagram of sedimentary rock layers, scientists can
conclude that layer K is the oldest and layer N is the youngest.
N
M
L
K
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 – 5 t h G r ad e Sc i enc e
The Natural World
Unit 1 Clarifying Statements
Revised May 2009
Scientists also use tree-growth rings to learn about the past. In general, each ring
on a tree represents one year of growth. The widths differ due to changes in the
climate and water availability. In the picture below, the thick, inner rings show
conditions were favorable for tree growth, whereas the thin, outer rings indicate
less favorable conditions. Using this information, scientists can conclude what the
climate was like in the past.
In previous grades, students identify, describe, and classify natural resources. In
5th grade, students should understand how past events have led to the formation
of renewable, nonrenewable and inexhaustible resources. Renewable resources
can be replenished over relatively short time spans and may include: plants and
animals for food; natural fibers for clothing; soil for plant growth; and forest
products for lumber and paper. Inexhaustible resources are renewable resources
that are so vast that they cannot be used up in many lifetimes and include: water
energy resulting from the effects of gravity, wind energy resulting from the
uneven heating of the Earth by the sun, and solar energy. Nonrenewable resources
are resources that continue to form; however, the processes that create them are
so slow that significant deposits take millions of years to accumulate. These may
include fossil fuels (such as natural gas, oil, and coal), metals (such as iron,
aluminum, and copper), and minerals (such as quartz, graphite, and topaz). In
addition, students describe the processes responsible for the formation of coal,
oil, natural gas, and minerals. Coal forms when land plants in swamps and marshes
become buried under layers of sediments. Oil and natural gas are formed from
once living microorganisms that were buried under ancient seas. As the
sedimentary layers build up, the pressure increases. This pressure coupled with
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 – 5 t h G r ad e Sc i enc e
The Natural World
Unit 1 Clarifying Statements
Revised May 2009
heat from inside the Earth changes plant matter into coal and organic matter from
ancient seas into oil and natural gas. A mineral is a solid natural material that has a
crystal form and is made by nature in or on the Earth’s crust. Minerals form when
molten rock cools and forms crystals or when water evaporates and leaves crystals
behind. These minerals combine to create rocks.
Three renewable resources, critical to all life on Earth, are carbon, nitrogen, and
water. The Earth has a finite amount of these materials which are cycled (used and
reused) through nature. The Earth has a limited capacity to absorb wastes and
recycle materials naturally. The benefits of the Earth’s resources can be reduced
by using them wastefully or destroying them. Therefore, to assure that these
natural resources are available for use, conservation is essential. The carbon,
nitrogen, and water cycles play a role in Earth’s systems.
**Teacher note: The carbon, nitrogen, and water cycles are introduced in this unit
of study as a method of recycling natural resources. Carbon is found in fossil fuels
and is released back into the Earth system when these fuels are burned. Water is
an agent of weathering and erosion; therefore it helps to shape Earth’s surface.
Water is a renewable resource, recycled through the water cycle. Water flow is an
inexhaustible resource. As long as gravity exists, water will flow. Nitrogen, water
vapor, and carbon dioxide gases are also found in our atmosphere. It is not
recommended to teach the cycles in their entirety during this unit. These cycles
are a better fit in the Cycles and Adaptations unit.
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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