STUDY GUIDE 8: EARTH’S LAND
REPORTING CATEGORY 3: EARTH AND SPACE
Earth’s Land: Vocabulary
1. Crust
the outer layer of Earth made of solid rock
2. Mantle
the layer of rock beneath Earth’s crust
3. Core
Earth’s hottest layer; the center layer of Earth
4. Magma
hot, soft rock from Earth’s lower mantle
5. Minerals
naturally-occurring substances within the Earth
6. Rock Cycle
the cycle in which rocks change over time and
under certain conditions
7. Fossil
remains, impressions, or traces of an animal or
plant of a former time period
8. Cast
to form an object by pouring into a mold
9. Mold
a hollow form in a rock that provides the shape of
an object once trapped there
Earth’s Land: Concepts
10. Earth’s Layers
 Rocks are made of minerals.
 Three layers of rocks make up Earth. The outside surface layer is called the
crust. The middle layer of soft melted rock is called the mantle. The center
layer of Earth is called the core. There is an inner core and outer core.
inner core
crust
outer core
mantle
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The Earth’s crust is made up of layers of rock.
The layers near the surface are younger than the layers farther down.
Each layer tells us about the history of the land.
The last layer or top tells us about the present.
The bottom layer tells us about the distant past.
The layers in between give us information from the past to the present.
Basalt
volcanic rock
Shale
sedimentary rock
Sandstone
sedimentary rock
Limestone
sedimentary rock
11. Minerals
 No two minerals are exactly alike.
 Minerals are described by their properties. A property is a feature that is used
to identify something. These properties describe hardness, color and/or
shape.
 Minerals are useful. They are found in glass, salt, pencil lead, steel, and
jewelry. Your body needs small amounts of minerals that you get from eating
food.
12. Rocks
 Rocks are formed from a mixture of minerals and sometimes other materials.
 Rocks are classified into groups by how they are formed.
 Sedimentary rocks are formed from sediments that include minerals, remains
of living things, and other dissolved minerals such as lime.
 Sediments are moved by water and wind and new layers build up over time,
pressing down on the older layers underneath.
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Type of Rock
Examples of Rock
Sedimentary
Rock
limestone
sandstone
Characteristics of Rock
These rocks are formed over a
period of time in layers. They
are made of the hardened
sediments of broken rocks or
other materials.
1. Limestone – formed
underwater, made up of
shells and skeletons of
animals
2. Sandstone – formed
underwater when tiny grains
of sand become cemented
together
13. Fossils
 Fossils often form in sedimentary rocks when what’s
left of a plant or animal is trapped in the layers of
sediments that form the rock.
 Some fossils are body parts, such as bones or teeth,
that have turned to stone.
 A mold is an imprint or cavity in rock left by an organism. When the cavity is
filled with sediments, it forms a replica of the original called a cast.
 Other fossils are only marks left by plants or animals, such as footprints.
These fossils are called trace fossils.
 Fossils can help scientists understand how plants and animals of long ago
looked and lived.
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Resource: Vocabulary
14. Natural Resource
any of the useful minerals or other materials that
people use or take from Earth
15. Nonrenewable Resource
resource that cannot be easily replaced once it is
used (takes millions of years)
16. Renewable Resource
a resource that is replaced by nature as it is used
17. Conservation
the wise use of natural resources
18. Fossil Fuel
a fuel formed from the remains of once-living plants
and animals that are nonrenewable
(examples are coal, oil, and natural gas)
Resource: Concepts
19. Natural Resources
 Natural resources are materials from the environment used by people.
 There are two main groups of natural resources: energy resources and
material resources.
 Energy resources provide people with energy such as sunlight, wind, moving
water, and fuels such as wood, coal, oil, and natural gas.
 Material resources are minerals, rocks, soil, water, plants, and animals. These
material resources make other products for people such as using a tree to
make paper, pencils, and lumber.
20. Renewable Resources (Replaced By Nature When Used)
 soil
 oxygen
 plants and animals
 water and ocean tides
 wind
 sunlight
21. Nonrenewable Resources (Cannot Be Replaced Easily)
 rocks and mineral resources
 aluminum, iron, copper, silver, gold
 oil, coal, and natural gas
 gems and precious stones
22. Fossil Fuels
 Some energy is still stored in dead plants and animals.
 These layers of dead organisms build up over millions of years and become
concentrated into energy rich materials such as oil, coal, and natural gas.
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23. Conservation of Resources
 People must find ways to conserve natural resources. The first step is to
reduce the use of a natural resource. People could use public transportation
instead of driving their own car, turn off lights and other products that use
electricity, don’t let the water run while brushing your teeth, taking shorter
showers, repairing leaky faucets, purchase energy efficient appliances, and
insulate your house.
 Reusing material resources involves not throwing them away, but finding
another use for that item. Many containers and bags can be used more than
once. A compost pile can be started for discarded food materials, yard
clippings, and other plant materials.
 Many types of wastes can be recycled. When we recycle, we need fewer new
resources to make new products. Things that can be recycled are paper,
plastic, aluminum, glass, and steel.
Soil: Concepts
24. Three Layers of Soil
 Topsoil is a layer containing rotting plant and animal materials called humus.
 Subsoil is the layer made mostly of small rocks formed by weathering of large
rocks due to temperature changes.
 Bedrock is the layer made mostly of solid rock.
25. Soil Concepts
 Soil is made from weathered rocks and humus.
 Soil is an important renewable natural resource. Soil contains minerals that
plants and animals need for growth.
 However, soil also needs to be conserved because soil formation is not a fast
process.
 Soil properties such as color and texture, fertility, and ability to hold water
make some soil types better than others for growing plants.
 Planting the same crop year after year uses up certain nutrients. Farmers
rotate crops to prevent this from happening.
 Farmers practice conservation of soil by strip cropping, contour plowing, and
terracing
 Removing plants and trees from the soil allows it to be washed away.
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26. Soil Properties
 Soil is a nonliving part of an ecosystem.
 Water absorption affects the amount of water available to plants and animals
during dry periods. Potting soil with more humus absorbs more water. Dry,
packed clay soil blocks water while wet clay soil holds water so well, plants
cannot use it all. Sandy soil allows water to pass through it without any water
being absorbed.
 Color is the way that the soil looks. The color of the soil tells whether the soil
contains minerals. Dark soils contain the most decaying plant and animal
matter. The color also can tell how warm the soil will get. Darker soils will
absorb more sunlight and get warmer and lighter soils reflect more sunlight.
 The texture is the way the soil particles feel. Course soils are made of large
grains and feel rough, like sand. Fine soils are made of dust or other powdery
substances and feel smooth, like clay.
 Fertility is the ability of the soil to support plant growth. A mixture of humus,
sand, and clay is best for plant growth. Fertilizers make soil richer by adding
decaying plant matter or minerals.
27. Farming Methods That Conserve Soil
 Contour plowing is the process of plowing and planting around a hill rather
than up and down.
 Strip cropping is the process where one or more crops are planted between
rows of other crops.
 Terracing is used on steep hills by cutting broad, flat areas at different heights,
like a huge stairway.
 Crop rotation is planting different crops in a field on a seasonal or yearly
rotation. It helps replace soil nutrients without using as much chemical
fertilizer.
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