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Rocks and Minerals. Quartz. Apatite. Diamond. hardness. color. Topaz. fracture. Gypsum. talc. Minerals. luster. Corundum. density. Orthoclase. Calcite. Fluorite. cleavage. EQ: What is a mineral?. Standard: S6E5.b Investigate the contribution of minerals to rock composition.

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slide2

Quartz

Apatite

Diamond

hardness

color

Topaz

fracture

Gypsum

talc

Minerals

luster

Corundum

density

Orthoclase

Calcite

Fluorite

cleavage

eq what is a mineral
EQ: What is a mineral?

Standard: S6E5.b

Investigate the contribution of minerals to rock composition.

eq how are minerals identified
What are the characteristics of a mineral?

How are minerals identified?

What is the Mohs hardness scale?

What is the major difference between an element and a compound?

EQ: How are minerals identified?
properties of minerals
Properties of Minerals
  • A mineral is a naturally formed, inorganic solid that has a crystal structure and a definite chemical composition.
  • Each mineral has its own set of specific physical properties that can be used to identify it (hardness, color, streak, luster, density, crystal system, cleavage and fracture).
  • An element is a substance composed of a singlekind of atom.
  • A compound is two or more elements combined so that the elements no longer have their original distinct properties.
properties of minerals1
Properties of Minerals
  • Naturally Formed- must form naturally
  • Inorganic- cannot arise from materials that were once part of a living thing
  • Solid- always solid, with a definite volume and a definite shape
  • Crystalline Structure- particles must line up in a pattern that repeats over and over again
  • Definite Chemical Composition- always contains certain elements in definite proportions. NaCl (salt)
identifying minerals
Identifying Minerals
  • Hardness- Mohs hardness scale ranks ten minerals from softest to hardest.
  • Color- Because of factors, such as impurities, used only to identify a few minerals
  • Streak- the color of a mineral in its powdered form
  • Luster- how a mineral reflects light from its surface
  • Density- the ratio of the mass to the volume of a substance
  • Crystal Systems- six groups of structures based on the number and angle of the crystal faces
  • Cleavage – splitting along smooth, flat surface
  • Fracture- breaking apart along curved or irregular surfaces
special properties
Special Properties
  • Some properties are particular to only a few types of minerals:
  • Fluorescence – glow under ultraviolet light
  • Chemical Reactions – reacts to an acid
  • Magnetism – natural magnets that attract iron.
  • Taste – ex. Halite has a salty taste
  • Optical Properties – some can cause a double image
  • Radioactivity – minerals that contain radium or uranium
mohs hardness scale
Mohs Hardness Scale
  • Talc 1 Softest known mineral
  • Gypsum 2 fingernail can scratch it
  • Calcite 3 scratched by copper penny
  • Fluorite 4 easily scratched by steel knife
  • Apatite 5 can be scratched by steel knife
  • Orthoclase 6 can scratch window glass
  • Quartz 7 can scratch steel
  • Topaz 8 can scratch quartz
  • Corundum 9 can scratch topaz
  • Diamond 10 hardest known mineral
quick check
Quick Check
  • 1. Which of the following is NOT a characteristic of a mineral?
    • It is formed in nature.
    • It is a living material.
    • It has a crystalline structure.
    • It is a solid.
quick check1
Quick Check
  • 2. Which of the following properties of minerals does Mohs scale measure?
    • luster
    • density
    • hardness
    • streak
quick check2
Quick Check
  • 3. Pure substances cannot be broken down into simpler substances by ordinary chemical means are called

a. molecules.

b. compounds.

c. crystals.

d. elements.

quick check3
Quick Check
  • 4. Which of the following properties is considered a special property that applies to only a few minerals?

a. luster

b. taste

c. hardness

d. density

quick check4
Quick Check
  • 5. Which of the following substances is a mineral?

a. fluorite, which is a crystalline solid with the chemical formula CaF2

b. coal, which forms from the remains of living things.

c. obsidian, which is a volcanic glass and is not crystalline.

d. brass, which is a metal that is made by humans.

eq what is a mineral1
What is a crystal, and what determines a crystal’s shape?

Describe the two major groups of minerals.

What is a native element?

EQ: What is a mineral?
mineral structure
Mineral Structure
  • A mineral is a naturally formed, inorganic solid that has a define crystalline structure.
  • Minerals may be either elements or compounds.
  • Elements are pure substances that cannot be broken down into simpler substances by ordinary means.
  • A compoundis a substance made of two or more elements that have been chemically joined together.
  • A mineral that is composed of only one element is called a native element.
crystals
Crystals
  • A crystal is a solid whose atoms, ions, or molecules are arranged in a definite pattern.
  • Crystals are solid, geometric forms produced by a repeating pattern of atoms or molecules that are present throughout the mineral.
  • A crystal’s shape is determined by thearrangement of the atoms or molecules within the crystal.
  • All minerals can be grouped into crystal classes according to the kinds of crystals they form.
two groups of minerals
Two Groups of Minerals
  • Minerals are divided into two groupsbased on their chemical composition.
  • Silicate minerals are minerals that contain a combination of the elements silicon and oxygen (quartz, feldspar, mica).
  • Silicate minerals make up over 90% of the Earth’s crust.
  • Nonsilicate minerals are minerals that do not contain a combination of the elements silicon and oxygen ( copper, calcite, fluorite, corundum, gypsum, galena).
quick check5
Quick Check
  • 1. What are the two major groups of minerals?
    • metallic and nonmetallic
    • native elements and carbonates
    • silicates and nonsilicates
    • quartz and mica
quick check6
Quick Check
  • 2. Silicate minerals contain a combination of the elements
    • Sulfur and oxygen.
    • Carbon and oxygen.
    • Iron and oxygen.
    • Silicon and oxygen.
quick check7
Quick Check
  • 3. Which of the following is a nonsilicate mineral?
    • orthoclase, KASi3O8
    • Talc, Mg3Si4O10(OH)2
    • Almandine, Fe3Al2(SiO4)3
    • Magnetite, Fe3O4
the formation mining and use of minerals p 74
Where can you find minerals?

What is an ore?

Compare surface and subsurface mining.

What is reclamation?

What are some examples of minerals and their uses?

The Formation, Mining, and Use of Minerals (p.74)
the formation of minerals
The Formation of Minerals
  • Minerals form in a variety of environments in Earth’s crust.
  • Each of these environments has a different set of physical and chemical conditions.
  • The environment in which a mineral forms determines the mineral’s properties.
  • Environments in which minerals form may be on or near Earth’s surface or deep beneath Earth’s surface.
the environments
The Environments

Evaporating Salt Water

  • When a body of salt water dries up, minerals are left behind.

-gypsum, halite

Metamorphic Rocks

  • When changes in temperature, pressure, or chemical make-up changes a rock, metamorphism takes place.
  • -calcite, garnet, graphite, hematite, magnetite, mica, and talc
the environments1
The Environments

Limestones

  • Surface water and ground water carry dissolved materials to lakes and seas where they crystallize on the bottom

-Calcite, dolomite

Hot-Water Solutions

  • Groundwater works its way downward and is heated by magma. It then reacts with minerals to form a hot liquid solution.

-gold, copper, sulfur, pyrite, galena

the environments2
The Environments

Pegmatites

  • As magma moves upward, it can form teardrop-shaped bodies called pegmatites. The mineral crystals become extremely large.

-many gemstones, such as topaz, tourmaline

Plutons

  • As magma rises upward through the crust, it sometimes stops moving before it reaches the surface and cools slowly, forming millions of mineral crystals. The entire magma body solidifies to form a pluton.
    • Mica, feldspar, magnetite, quartz
mining
Mining
  • An ore is the natural material large enough and pure enough to be mined for profit.
  • Rocks and minerals are removed from the ground by one of two methods-surface mining and subsurface mining.
  • Surface mining is used to remove mineral deposits on or near the Earth’s surface.

- open pits

- surface coal mines (open-pit)

- quarries

mining1
Mining
  • Subsurface mining is used when mineral deposits are located too deep within Earth to be surface mined.
  • Mine reclamation is the process by which land used for mining is returned to its original state or better.
  • Has been required by law since the mid-1970’s.
  • To reduce the effects of mining, reduce our need for minerals.
  • Recycle!
the use of minerals
The Use of Minerals
  • Some minerals are of major economic and industrial importance.
  • Metallic minerals have shiny surfaces, do not let light pass through them, good conductors of heat and electricity.
  • Nonmetallic minerals have shiny or dull surfaces, may let light pass through them, and are good insulators of electricity.
the use of minerals1
The Use of Minerals
  • Gemstones are highly valuable minerals because of their beauty and rarity rather than their usefulness.
  • Color is the most important characteristic of a gemstone.
  • The more attractive the color is, the more valuable the gem is.
  • Mass of a gem is expressed in a unit known as a carat.
  • One carat is equal to 200 mg.
quick check8
Quick Check
  • In a mineral, the particles line up in a repeating pattern to form
  • A. an element
  • B. a crystal
  • C. a mixture
  • D. a compound
quick check9
Quick Check
  • The term that describes how a mineral reflects light is its __________.
  • A. luster.
  • B. streak
  • C. color.
  • D. weight.
quick check10
Quick Check
  • One characteristic that a substance must have to be considered a mineral is _____.
  • A. to be living.
  • B. to be small.
  • C. to a liquid.
  • D. to be a solid.
quick check11
Quick check
  • A compound is two or more ________ chemically combined.
  • A. atoms
  • B. minerals
  • C. elements
  • D. protons
quick check12
Quick Check
  • An element is a substance composed of a single kind of __________.
  • A. compound.
  • B. atom.
  • C. mineral.
  • D. Mohs hardness scale.
quick check13
Quick Check
  • The groupings silicate and nonsilicate minerals are based on
  • Organic content.
  • Gas and liquid state
  • Chemical composition.
  • Color.
quick check14
Quick Check
  • Nonsilicate minerals
  • Do not contain oxygen.
  • Include native elements.
  • All have a nonmetallic luster.
  • Are all rare substances.
quick check15
Quick Check

Which of the following is NOT a class of nonsilicate minerals?

  • oxides
  • Micas
  • carbonates
  • native elements
quick check16
Quick Check

What is a mineral deposit that is large and pure enough to be mined called?

  • gemstone
  • ore
  • pluton
  • pegmatite
quick check17
Quick Check

Halides form when fluorine, chlorine, or bromine combine with any of the following elements EXCEPT

  • sodium.
  • potassium.
  • calcium.
  • oxygen.
quick check18
Quick Check
  • What is the name for nonmetallic minerals that are valued for their beauty and rarity rather than their usefulness?
  • plutons
  • gemstones
  • ores
  • pegmaites
quick check19
Quick Check
  • What kinds of mines are open pit and quarry mines?
  • shaft mines
  • slope mines
  • surface mines
  • subsurface mines
rock mineral mixtures
ROCK: Mineral Mixtures

sediments

cooling

sedimentary

melting

erosion

magma

igneous

pressure

lava

metamorphic

cementation

heat

eq how are rocks formed

EQ: How are rocks formed?

Standard S6E5.c

Classify rocks by their process of formation.

how are rocks classified
How are rocks classified?

How does igneous rock become sedimentary rock?

How does sedimentary rock become metamorphic rock?

How does metamorphic rock become igneous rock?

How are rocks classified?
rock formation
Rock Formation
  • Scientists classify rocks by the way they are formed.
  • Rocks are composed of minerals and other materials.
  • Minerals are the building blocks of rocks.
  • Rocks are classified into three (3) groups based on how they are formed:
    • Sedimentary rocks
    • Igneous rocks
    • Metamorphic rocks
the rock cycle
What materials are rocks made of?

Describe four processes that change rock from one type to another.

What are the three main classes of rock?

Describe two characteristics of rock that are used to help classify it.

The Rock Cycle
what materials are rocks made of
What materials are rocks made of?
  • Rock is describe as a naturally occurring solid mixture of one or more minerals and organic matter.
  • Rocks are made of mixtures of minerals and other materials, although some rocks may contain only a single mineral. When studying a rock sample, geologists observe the rock’s color and texture and determine its mineral composition.
  • Texture is described with terms based on grain size, grain shape, and grain pattern. Most rocks are made up of tiny particles of minerals or other rocks, which are called grains. A rock’s grains give it its texture.
  • There are three major groups of rocks: igneous rock, sedimentary rock, and metamorphic rock. These terms refer to how the rocks in each group were formed.
the rock cycle1
The Rock Cycle
  • The rock cycle is a series of processes in which a rock forms, changes from one type to another, is destroyed, and forms again by geological processes.
  • Rocks have been used by humans to make tools and weapons and to construct buildings.
processes that shape the earth
Processes That Shape the Earth
  • Certain geological processes make and destroy rock.
  • These processes shape the features of the Earth.
  • Theses processes also influence the type of rock that is found in a certain area of Earth’s surface.
processes that shape the earth1
Processes That Shape the Earth
  • Weathering is the process by which water, wind, ice, and heat break down rock.
  • Erosion is the process by which sediment is removed from its source.
  • Deposition is the process by which sediment moved by erosion is laid down.
  • Uplift is the process by which rock within the Earth moves to Earth’s surface.
illustrating the rock cycle
Illustrating the Rock Cycle
  • Igneous rock is formed when magma or lava is cooled and hardens and solidifies.
  • Sedimentary rock is formed by the process of weathering, erosion, deposition and cementation.
  • Metamorphic rock is formed by heat, pressure or chemical change beneath Earth’s surface.
rock classification
Rock Classification
  • Scientists classify rocks in detail by using two important criteria – composition and texture.
  • Composition is the chemical makeup of a rock; describes either the minerals or other materials in the rock.
  • Texture is the quality of a rock based on the sizes, shapes, and positions of the rocks grains.
classifying rocks
Classifying Rocks
  • Classifying Rocks - How Geologists Classify Rocks = When studying a rock sample, geologists observe the rock’s origin, color and texture, and determine its mineral composition

A. Origin = 3 major groups of rocks

1. igneous rock = forms from the cooling of molten rock

a. lava = above the surface

b. magma = below the surface

2. sedimentary rock = forms in layers from other rocks, plants, and animals that

have been compacted and cemented together

3. metamorphic rock = formed when existing rock is changed by heat, pressure, or chemical reactions

B. Texture = the size, shape, and pattern of the rock’s

grains

1. Grain Size

a. fine-grained (small)

b. coarse-grained (large)

2. Grain Shape

a. smooth and rounded

b. jagged

3. Grain Pattern

a. lie in flat layers

b. wavy, swirling patterns

c. looks like rows of multicolored beads

d. occur randomly

4. No Visible Grain

a. have no apparent grains

b. smooth, shiny texture

C. Mineral Composition =

1. mafic

2. felsic

quick check20
Quick Check
  • Which of the following rocks is not normally used as a construction material?
  • marble
  • halite
  • limestone
  • granite
quick check21
Quick Check

The process in which wind, water, ice, and heat break down rock is called

  • uplift.
  • intrusion.
  • recystallization.
  • weathering.
quick check22
Quick Check

What forms when rock partially or completely melts?

  • limestone
  • reefs
  • ripple marks
  • magma
quick check23
Quick Check

Scientists classify rocks

  • by composition and texture.
  • by volume.
  • by mass.
  • by color and size.
how do igneous rocks form
What characteristics are used to classify igneous rocks?

Describe three (3) ways in which igneous rocks differ?

What is the difference between extrusive and intrusive rocks? Give an example of each.

Why are some igneous rocks dark and others light?

How do igneous rocks form?
origins of igneous rock
Origins of Igneous Rock
  • Igneous rocks are classified by their origin of formation, texture of the grains, and composition of the rock.
  • Igneous rock forms when magma cools and hardens.
  • Three ways magma can form: heat/rise in temperature, pressure released, rock changes composition.
origins of igneous rock1
Origins of Igneous Rock
  • Igneous rocks form from melted rock, the cooling and hardening of magma and lava.
  • Magma is molten rockbeneath Earth’s surface.
  • Lava is molten rockabove Earth’s surface.
  • When a volcano erupts, magma is released onto Earth’s surface.
  • Once above Earth’s surface, it is called lava.
  • Common igneous rocks: granite, basalt, pumice, obsidian.
composition and texture of igneous rock
Composition and Texture of Igneous Rock
  • Igneous rocks differ from one another in what they are made of and how fast they are cooled.
  • Composition –
  • Igneous rock that is rich in silicon and light-colored are called felsic rock.
  • Igneous rock that is poor in silicon and dark-colored are called mafic rock.
  • Texture –
    • Fine-grained (small) = cools quickly
    • Coarse-grained (large) =cools slowly
origins of igneous rock2
Origins of Igneous Rock
  • Igneous rocks are classified by their origin of formation, texture of the grains, and composition of the rock.
  • Igneous rock forms when magma cools and hardens.
  • Three ways magma can form:
    • heat/rise in temperature
    • pressure released
    • rock changes composition
composition and texture of igneous rock1
Composition and Texture of Igneous Rock
  • Igneous rocks differ from one another in what they are made of and how fast they are cooled.
  • Composition –
  • Igneous rock that is rich in silicon and light-colored are called felsic rock.
  • Igneous rock that is poor in silicon and dark-colored are called mafic rock.
  • Texture –
    • Fine-grained (small) = cools quickly
    • Coarse-grained (large) =cools slowly
origin of formation
Origin of Formation
  • Igneous rock formations are located below and above Earth’s surface.
  • Intrusive igneous rock – from magma (below surface), coarse-grained (large crystals), below Earth’s surface
  • Extrusive igneous rock – from lava (above surface), fine-grained (small crystals), below Earth’s surface
how do igneous rocks form1
How do igneous rocks form?
  • Igneous rocks are classified according to their origin, texture, and mineral composition.
  • Igneous rocks form either from lava, above the earth’s surface or magma, below the earth’s surface. They also differ in texture according to the size and shape of their mineral grains. They differ in mineral composition depending on how much silica and other minerals are present.
  • Extrusive rock (basalt) forms from lava that has erupted onto Earth’s surface.
  • Intrusive rock (granite) forms when magma hardens beneath Earth’s surface.
  • Dark igneous rocks form from magma or lava low in silica content (felsic).
  • Light igneous rocks form from magma high in silica content (mafic).
composition and texture of igneous rock2
Composition and Texture of Igneous Rock
  • The longer it takes for magma or lava to cool, the more time the crystals have to grow.
  • The larger the crystals or grains, the more coarse the texture of the rock.
  • The less time liquid rock takes to cool, the less time crystals have to grow.
  • This type of rock will be fine-grained.
  • Fine-grained rocks contain very small crystals or grains.
  • If the cooling is very rapid, it contains no crystals.
intrusive igneous rock
Intrusive Igneous Rock
  • Igneous rock that forms below the surface of the earth
  • Below = intrusive
  • Usually has coarse-grain texture
  • Cools very slowly
  • Common intrusive igneous rocks are called Plutons.
extrusive igneous rock
Extrusive Igneous Rock
  • Igneous rock that forms above the earth’s surface
  • Extrusive = above
  • Common around volcanoes
  • Cools quickly
  • Usually fine-grained texture
  • Lava cools to form the ocean floor
uses of igneous rock
Uses of Igneous Rock
  • Most igneous rocks are hard, dense, and durable.
  • Ancient Native Americans used obsidian for making very sharp tools for cutting and scraping.
  • Granite is used as a building material such as decorative stonework, curbstones, and floors..
  • Basalt is crushed to make gravel.
  • The rough surface of pumice makes a good abrasive for cleaning and polishing.
  • Perlite is often mixed with soil for strating vegetable seeds.
summary
Summary
  • Igneous rock forms when magma cools and hardens
  • The texture of igneous rock is determined by the rate at which the rock cools
  • Igneous rock that solidifies at Earth’s surface is extrusive. Igneous rock that solidifies within Earth’s surface is intrusive.
quick check24
Quick Check

1. Which of the following are ways magma is formed?

  • by compaction and cooling
  • by melting and cooling
  • by changes in composition
  • by weathering and erosion
quick check25
Quick Check
  • What kind of texture does igneous rock have when magma cools slowly?
  • coarse-grained
  • large-grained
  • fine-grained
  • medium-grained
quick check26
Quick Check

3. What kind of texture does igneous rock have when magma cools rapidly?

  • coarse-grained
  • medium-grained
  • large-grained
  • fine-grained
quick check27
Quick Check

4. What kind of rock is formed when magma intrudes into other rock?

  • extrusive igneous rock
  • sedimentary rock
  • intrusive igneous rock
  • organic sedimentary rock
quick check28
Quick Check

5. What kind of rock is formed from lava that cools on Earth’s surface?

a. organic sedimentary rock

b. sedimentary rock

c. intrusive igneous rock

d. extrusive igneous rock

how is sedimentary rock formed
Describe the origin of sedimentary rock.

Describe the three main categories of sedimentary rock.

Describe three types of sedimentary structures.

How is sedimentary rock formed?
forming of sedimentary rock
Sedimentary rocks are formed when particles of other rocks or the remains of plants and animals are pressed and cemented together.

Rocks undergo weathering to form sediment.

Sediment is transported (erosion), settled out of the windand waterand deposited somewhere.

Usually after burial somewhere, the deposited sediment undergoes lithification.

Forming of Sedimentary Rock
forming of sedimentary rock1
Forming of Sedimentary Rock
  • Lithification is the process that turns sediment into a rock.
  • If the sedimentary rock is buried deep in to the crust under more and more sediment (layered), often due to plate tectonics, the heat and pressure causes metamorphism to occur.
  • This transforms the sedimentary rock into a metamorphic rock.
  • Sediment (weathering) = erosion = deposited = compaction = cementation.
  • Common Sedimentary Rock: sandstone, shale, and limestone.
forming of sedimentary rock2
Forming of Sedimentary Rock
  • Erosion – occurs when running water or wind loosen and carries away fragments of rock.
  • Deposition- the process in which sediment settles out of the water or wind carrying it.
  • Compaction- the process that presses sediment together.
  • Cementation- the process in which minerals crystallize and glue particles of sediment together.
forming of sedimentary rock3
Forming of Sedimentary Rock

Sedimentary rocks are formed when small particles of rock and the remains of plants and animals are compacted and cemented together.

To form sedimentary rocks, sediment is loosened and carried away by water and wind by erosion.

The sediment then settles out of the wind and water during deposition.

The sediment begins to settle out and form layers. As the layers stack up, they become heavier until the weight squeezes the layers tighter during compaction.

composition of sedimentary rock
Composition of Sedimentary Rock
  • Sedimentary rock is classified by the way it forms.
  • Clastic – formed from other rocks and minerals (conglomerate, sandstone, shale)
  • Chemical – forms when minerals crystallize out of solutions (halite)
  • Organic – forms from the remains of once-living things (limestone).
types of sedimentary rock
Geologists classify sedimentary rocks according to the type of sediments that make up the rock.

There are three major groups of sedimentary rocks: clastic rocks, organic rocks, and chemical rocks.

Types of Sedimentary Rock
clastic rocks
A clastic rock is a sedimentary rock that forms when rock particles are squeezed together.

Examples of clastic rocks:

Shale

Sandstone

Conglomerate

Breccia

Clastic Rocks
clastic rock shale
Shale forms from tiny particles of clay.

Shale feels smooth, and splits easily into flat pieces

Clastic Rock: Shale
clastic rock sandstone
Sandstone forms from the sand on beaches, on the ocean floor, in riverbeds, and in sand dunes.

Sandstone is formed when small particles of sand are pressed and cemented together.

Clastic Rock: Sandstone
clastic rock conglomerate and breccia
Conglomerate is a rock made up of large particles with rounded edges.

Breccia is a rock made up of large fragments with sharp edges.

Clastic Rock: Conglomerate and Breccia
organic rocks
Organic rock forms from the remains of plants and animals and are deposit in thick layers.

The term “organic” refers to substances that were once part of living things.

Three important organic rocks:

Coal

Limestone

Chalk

Organic Rocks
organic rock coal
Coal forms from the remains of swamp plants buried in water.

Over millions of years, they slowly change into coal.

Organic Rock: Coal
organic rock limestone
The hard shell of living things produces limestone.

Chalk forms from sediments made of skeletons of microscopic living things found in the ocean.

Organic Rock: Limestone
chemical rocks
Chemical rock forms when minerals that are dissolved in a solution crystallize.

Chemical rocks can also form when mineral deposits left when seas or lakes evaporate.

Examples:

Rock salt

gypsum

Chemical Rocks
sedimentary rock structures
Sedimentary Rock Structures
  • The most important feature of sedimentary rock is stratification.
  • Stratification is the process in which sedimentary rocks are arranged in layers.
  • Strata differ from one another depending on the kind, size, and color of their sediment.
  • Ripple marks(1) are made by the motion of wind and water waves on lakes, oceans, rivers, and sand dues.
  • Mud cracks (2) form when fine-grained sediments at the bottom of a shallow body of water are exposed to air and dry out.
  • Rain-drop (3) impressions can be preserved in fine-grained sediments, as small pits with raised rims.
uses of sedimentary rocks
Uses of Sedimentary Rocks
  • Sandstone and limestone are used as building materials.
  • The White House in Washington, D.C. is built of sandstone.
  • Limestone is also used to make cement.
summary1
Summary
  • Sedimentary rock forms from rock weathering into sediment, erosion, deposition, compaction and cementation.
  • Sedimentary rock forms at or near the Earth’s surface.
  • Clastic sedimentary rock forms when rock or mineral fragments are cemented together.
  • Chemical sedimentary rock forms from solutions of dissolved minerals and water.
  • Organic (limestone) forms from the remains of plants and animals.
quick check29
Quick Check

1. Which process forms sediment/

  • weathering
  • cementation
  • compaction
  • deposition
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2. What are strata?

  • mineral fragments
  • minerals crystallized out of solution
  • layers in sedimentary rock
  • fossils in sedimentary rock
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3. What kind of sedimentary rock is made of fragments of rocks cemented together by a mineral?

  • organic
  • stratified
  • chemical
  • clastic
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4. What kind of sedimentary rock is made from solutions of dissolved minerals in water?

  • organic
  • chemical
  • stratified
  • clastic
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5. What kind of sedimentary rock is made from fossils?

  • organic
  • stratified
  • chemical
  • clastic
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Quick Check

6. What is the process called in which sedimentary rocks are arranged in layers?

  • erosion
  • extrusion
  • weathering
  • stratification
how is metamorphic rock formed
How are metamorphic rocks formed?

Describe two ways a rock can undergo metamorphism.

Describe the difference between foliated and nonfoliated metamorphic rock.

How is metamorphic rock formed?
metamorphic rocks
Metamorphic Rocks
  • Metamorphic rock is formed when existing rock is changed by heat, pressure, or chemical reactions.
  • They are classified by the arrangement of their mineral grains.
  • The two types of metamorphic rocks are called foliated and non-foliated.
  • Foliated is when the grains are parallel or arranged in planes or bands.
  • Non-foliated refers to where the grains are arranged randomly.
how do metamorphic rocks form
How Do Metamorphic Rocks Form?
  • Heat and pressure deep beneath Earth’ssurface can change any rock into metamorphic rock.
  • When a rock changes into metamorphic rock, its texture, crystal structure, and mineral content change.
  • The texture or mineral composition of a rock can change when its surroundings change.
  • If the temperature or pressure of the new environment is different from the one in which the rock formed, the rock will undergo metamorphism.
  • Two ways that rock can undergo metamorphism are by contact metamorphism and regional metamorphism.
composition of metamorphic rock
Composition of Metamorphic Rock
  • Metamorphism occurs when temperature and pressure inside the Earth’s crust change.
  • Minerals that were present in the rock when it formed may not be stable in the new temperature and pressure conditions.
  • The original minerals change into minerals that are more stable in these new environment.
  • Some metamorphic minerals form only at certain temperatures and pressures.
  • Common metamorphic rock: slate, schist, marble, and gneiss.
textures of metamorphic rock
Textures of Metamorphic Rock
  • Geologists classify metamorphic rocks by the arrangement of the grains that make up the rocks.
  • Metamorphic rocks that have their grains arranged in layers or bands are foliated.
  • Examples
    • Slate (from shale)
    • Schist
    • Gneiss (from granite)
textures of metamorphic rock1
Textures of Metamorphic Rock
  • Nonfoliated rock’s grains are arranged randomly.
  • Examples:
    • Marble (from limestone)
    • Quartzite (from sandstone)
  • Metamorphic rocks are harder and more dense than sedimentary rocks.
metamorphic rock structures
Metamorphic Rock Structures
  • Metamorphic rock has features that tell you about its history.
  • In metamorphic rocks, these features are caused by deformation.
  • Deformation is a change in the shape of a rock caused by a force placed on it.
  • These forces may cause a rock to be squeezed or stretched.
  • Folds or bends in metamorphic rock are structures that indicate that a rock has been deformed.
uses of metamorphic rock
Uses of Metamorphic Rock
  • Marble and slate are the two most useful metamorphic rocks.
  • Marble can be cut into thin slabs and easily polished (Taj Mahal).
  • Slate , because it is foliated, splits easily into flat pieces.
  • Slate is used for flooring, roofing, outdoor walkways, or chalkboards.
  • Marble and Slate both come in a variety of colors.
summary2
Summary…
  • There are 3 major rock groups: igneous rocks sedimentary rocks and metamorphic rocks.
  • Igneous rocks form when molten rock cools and hardens from magma or lava.
  • Sedimentary rocks form from particles deposited, pressed, and cemented together by water and wind.
  • Metamorphic rocks form from heat and pressure, or a chemical change.
  • Forces inside Earth and at the surface produce a rock cycle that builds, destroys, and changes the rocks in the crust.
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Quick Check

1. How does metamorphic rock form?

  • A. by intense heat and pressure
  • B. erosion, deposition, compaction, cementation
  • C. melting into lava or magma, then cooling into a new rock
  • D. by pressing together and then cementation
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Quick Check

2. Molten rock beneath Earth’s surface is called

  • A. Lava.
  • B. Magma.
  • C. Sedimentary rock.
  • D. Igneous rock.
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Quick Check

3. If you wanted to duplicate conditions in a laboratory that produced metamorphic rock from sedimentary rock, what would you need to do?

  • A. apply pressure to the rock
  • B. apply high temperature to the rock
  • C. apply high pressure and high temperature to the rock
  • D. let the rock stand under water for a long time
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Quick Check

4. Which of the following is a metamorphic rock?

  • A. Granite
  • B. Sandstone
  • C. Limestone
  • D. marble
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Quick Check

5. Metamorphic rocks can be formed from

  • A. igneous rocks.
  • B. sedimentary rocks.
  • C. metamorphic rocks.
  • D. all rock groups.
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Quick Check

6. The rock formed when granite changes to a metamorphic rock is

  • A. marble.
  • B. basalt.
  • C. gneiss.
  • D. pumice.
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Quick Check

7. Metamorphic rocks that have their grains arranged in parallel bands or layered are said to be

  • A. jagged grained.
  • B. foliated.
  • C. nonfoliated.
  • D. coarse grained.
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Quick Check

8. The heat that changes a rock into metamorphic rock comes from

  • A. friction of plate movement.
  • B. the sun.
  • C. the heat of the mantle.
  • D. chemical rocks in the crust.
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Quick Check

9. Geologist classify metamorphic rock according to

  • A. the exterior color of the rock.
  • B. the overall shape of the rock.
  • C. the arrangement of the grains that make up the rock.
  • D. the degree of hardness of the rock.
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Quick Check

10. Which type of rock is MOST LIKELY to form layers?

  • A. Sedimentary
  • B. Igneous
  • C. Metamorphic
  • D. magma
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Quick Check

11. The _________ of a rock is determined by the sizes, shapes, and positions of the minerals the rock contains.

12. ________ metamorphic rock contains minerals that are arranged in plains or bands.

13. The most characteristic property of sedimentary rock is __________.

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Quick check

14. Sedimentary rock is classified into all of the following main categories except _________.

a. clastic sedimentary rock

b. chemical sedimentary rock

c. nonfoliated sedimentary rock

d. organic sedimentary rock

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Quick Check

15. An igneous rock that cools very slowly has a __________ texture.

a. foliated

b. fine-grained

c. nonfoliated

d. coarse-grained

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Quick Check

16. Igneous rocks forms when

a. minerals crystallize from a solution.

b. sand grains are cemented together.

c. magma cools and solidifies.

d. mineral grains in a rock recrystallize.

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Quick Check

17. A __________ is a common structure found in metamorphic rock.

a. ripple mark

b. fold

c. sill

d. layer

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Quick Check

18. The process in which sediment is removed from its source and transported is called ____________.

a. deposition.

b. erosion.

c. weathering.

d. uplift.

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Quick Check

19. Mafic rocks are

a. light-colored rocks rich in calcium, iron, and magnesium.

b. dark-colored rocks rich in aluminum, potassium, silica, and sodium.

c. light-colored rocks rich in aluminum, potassium, silica, and sodium.

d. dark-colored rocks rich in calcium, iron, and magnesium.

processes of change
Processes of Change

weathering

mechanical weathering

chemical weathering

moving water

deposition

waves

glaciers

gravity

wind

erosion

the crust mantle and core lesson 16

The Crust, Mantle, and CoreLesson 16

How do the forces within the earth affect the formations of the Earth’s surface?

the crust mantle and core
The Crust, Mantle, and Core
  • Earth is divided into four layers: the crust, the mantle, the outer core, and the inner core.
  • Each layer is made up of different materials.
  • It takes 6,380 kilometers to get to the center of the Earth’s inner core.
  • Each layer has a different thickness.
thickness of earth s layers
Thickness of Earth’s Layers
  • Crust: 8-32 kilometers
  • Mantle: 2900 kilometers
  • Outer Core: 2250 kilometers
  • Inner Core: 1300 kilometers
the crust
The Crust
  • The crust is the thin outer layer of Earth.
  • Earth’s crust is made of two layers.
  • The top layer is made of granite; the bottom layer is made of basalt.
  • The continents are made of both granite and basalt.
  • The ocean floors are made of basalt.
the mantle
The Mantle
  • The makeup of the mantle’s rocks is similar to that of the crust.
  • The Moho boundary is located between the crust and the mantle.
  • Currents of the mantle’s molten rock can move whole continents and ocean floors.
  • Molten rock from the mantle burst through the crust to create islands and volcanoes.
  • The top layer of the mantle is liquid rock that we call the asthenosphere.
the outer and inner cores
The Outer and Inner Cores
  • Earth’s core is made up of two parts: a shell called the outer core and a sphere called the inner core.
  • Both cores are made up of the metals iron and nickel.
  • The outer core is liquid metal; the inner core is solid metal.
  • Tremendous pressure keeps the inner core a solid.
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Quick Check

The very top layer of Earth, found under soil and water is which of the following:

a. upper mantle

b. crust

c. asthenosphere

d. outer core

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Quick Check

Which of the following causes the difference between the upper mantle and lower mantle?

  • a. heat
  • b. pressure
  • c. erosion
  • D. weathering
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Quick Check

The pressure on the inner core can be compared to which of the following:

a. The same pressure as the pressure around an exploding bomb.

b. The same pressure as the pressure of a volcano erupting.

c. The same pressure as the pressure of hurricane wind.

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Quick Check

The inner core is made of

a. liquid metal

b. liquid rock

c. solid metal

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Quick Check

The reason we have a magnetic field is due to the:

a. gravitational pull of the sun.

b. gravitational pull of Earth.

c. movement of the inner core.

d. movement of the outer core.

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Quick Check
  • From the lowest to highest temperature, which is the correct order of Earth’s layers?
  • A. inner core, outer core, mantle, crust
  • B. mantle, crust, outer core, inner core
  • C. crust, mantle, outer core, inner core
  • D. crust, mantle, inner core, outer core
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Quick Check
  • In general, how does the density of material in Earth’s layers change with depth?
  • a. density increases with depth
  • b. density decreases with depth
  • c. density does not change with depth
  • d. density increases, then decreases with depth
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Quick Check

In Earth’s crust, what type of rock is found under the oceans?

a. only granite

b. only basalt

c. granite on top, basalt underneath

d. basalt on top, granite underneath

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Quick Check

The thickest layer of the Earth is the

a. crust.

b. mantle.

c. outer core.

d. inner core.

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Quick Check

The Moho is the boundary between the

a. inner and outer core.

b. the outer core and the mantle.

c. the crust and the mantle.

d. the crust and the atmosphere.

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Quick Check

What is the composition of the core?

A: ______________________________

What is the composition of the asthenosphere and where is it located?

A: ________________________________

_________________________________

_________________________________

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Quick Check

Compare the temperature of Earth’s four (4) layers.

Crust ______________________________

Mantle _____________________________

Outer Core _________________________

Inner Core __________________________

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Quick Check

Inside the Earth, What increases with depth?

A: ______________________________

_______________________________

_______________________________

slide148

EQ:

How does weathering

occur?

weathering
Describe three ways abrasion occurs in nature.

List three things that cause chemical weathering of rocks.

Describe the similarity in the ways tree roots and ice mechanically weather rock.

Describe five (5) sources of chemical weathering.

Weathering
weathering1
Weathering
  • Weathering is the process by which rock materials are broken down by the action of physical or chemical processes.
  • Mechanical weathering is the breakdown of rock into smaller pieces by physical means. (ice, wind, water, gravity, plants, animals)
  • Chemical weathering is the process by which rocks break down as a result of chemical reactions. Water, weak acids, and air can cause chemical weathering.
6 agents of mechanical weathering
6 Agents of Mechanical Weathering
  • 1. Ice – water seeps into cracks during warm weather. When the temperature drops, the water freezes and expands, causing the ice to push against the sides of the crack. This causes the crack in the rock to widen.
    • Abrasion – the grinding and wearing away of rock surfaces through mechanical action of other rock or sand pebbles.
    • The three ways that can cause abrasion are wind, water, and gravity.
three causes of abrasion
Three Causes of Abrasion
  • 2. Water – as rocks and pebbles roll along the bottom of flowing water, they bump and scrape against each other, causing these rocks to become rounded and smooth.
  • 3. Wind – wind blows sand and silt against exposed rock eventually wearing away the rock’s surface.
  • 4. Gravity – rocks grind against each other during a rock slide, creating smaller and smaller rock fragments. Anytime one rock hits another rock, abrasion takes place.
plants and animals
Plants and Animals
  • Some plants (#6) can easily break rocks. The roots grow through existing cracks in rocks.
  • The growth causes the root to expand, forcing the crack to widen. The force can eventually split the rock apart.
  • 7. Animals that live in the soil (moles, prairie dogs, insects, worms, gophers), cause a lot of weathering. By burrowing in the ground, these living creatures brake up soil and loosen rocks to be exposed to further weathering.
5 agents of chemical weathering
5 Agents of Chemical Weathering
  • Common agents of chemical weathering are water, acids, and air.
  • These agents weaken the bonds between minerals grains of the rock.
  • 1. Water – can cause rock to be broken down and dissolve. Can take thousands of years to take place.
  • 2. Air – the process of oxidation is a chemical reaction in which an element (iron) combines with oxygen, causing rust.
    • (Weak Acids) - acid precipitation, acids in groundwater, acids in living things.
three sources of weak acids
Three Sources of Weak Acids
  • 3. Acid Precipitation – rain, sleet, or snow that contains a high concentration of acid. Normal precipitation is acidic, acid precipitation contains more acid than normal.
  • 4. Acids in Groundwater – carbonic acid or sulfuric acid reacts with rocks in the ground, causing a chemical reaction, eating away at the rock.
  • 5. Acids in Living Things – Lichens produce acids that slowly break down rock.
summary3
Summary
  • Ice wedging is a form of mechanical weathering in which water seeps into rock cracks and then freezes and expands.
  • Wind, water, and gravity cause mechanical weathering by abrasion.
  • Animals and plants cause mechanical weathering by turning the soil and breaking apart rocks.
  • Water, acids, and air chemically weather rock by weakening the bonds between mineral grains of the rock.
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Quick Check

1. Which of the following things cannot cause mechanical weathering?

  • A. water
  • B. acid
  • C. wind
  • D. animals
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Quick Check

2. Which of the following is a type of frost action?

  • A. abrasion
  • B. oxidation
  • C. ice wedging
  • D. gravity
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Quick Check

3. Which of the following types of chemical weathering causes a karst landscape, such as a cavern?

  • A. lichens
  • B. acid precipitation
  • C. acids in groundwater
  • D. water
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Quick Check

4. How do lichens slowly break down a rock?

  • A. by abrasion
  • B. by mechanical means
  • C. by ice wedging
  • D. by chemical means
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Quick Check

5. Which of the following will most likely experience oxidation?

  • A. tennis ball
  • B. aluminum can
  • C. wooden fence
  • D. Bicycle tire
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The grinding and wearing away of rock surfaces through the mechanical action of other rock or sand particles

Rain, sleet, or snow that contains a high concentration of acids

The process by which rocks break down as a result of chemical reactions

The breakdown of rock into smaller pieces by physical means

A chemical reaction in which an element, such as iron, combines with oxygen to form an oxide

The process by which rock materials are broken down by the action of physical or chemical processes

a. mechanical weathering

b. oxidation

c. weathering

d. acid precipitation

e. abrasion

f. chemical weathering

Quick Check
rates of weathering
What is differential weathering?

How does surface area affect the rate of weathering?

How does climate affect the rate of weathering?

Why do mountaintops weather faster than rocks at sea level?

Rates of Weathering
differential weathering
Differential Weathering
  • Differential weathering is a process by which softer, less weather resistant rocks wear away and leave harder, more weather resistant rocks behind.
  • Hard rocks weather more slowly than softer rocks.
the shape of rocks
The Shape of Rocks
  • Weathering takes place on the outer surface of rocks.
  • The more surface area exposed to weathering, the faster the rock will be worn down.
  • As the surface area increases, the rate of weathering also increases.
  • If a large rock is broken into smaller pieces, weathering of the rock happens much faster.
  • The rate of weathering increases because a smaller rock has more surface area to volume than a larger rock.
  • More of the smaller rock is exposed to the weathering process.
weathering and climate
Weathering and Climate
  • The rate of chemical weathering is faster in warm, humid climates than cold, dry climates because of oxidation.
  • Oxidation happens when the temperature is higher and when water is present.
  • Water increases the rate of mechanical (physical) weathering (ice wedging).
  • Repeated changes in temperature (freeze, thaw, freeze, thaw) is a major factor in mechanical weathering.
weathering and elevation
Weathering and Elevation
  • Mountaintopsweather faster than rocks at sea level because they are exposed to more wind, rain, andice than rocks at sea level or lower elevations.
  • The increase in wind, rain, and ice increases the effects of mechanical and chemical weathering. This increase in elevation causes peaks of mountains to weather faster.
  • Gravity affects the rate of weathering:
    • Steepness
    • Rainwater
    • Removal of sediment exposes new rock to weathering
    • Abrasion
    • Increased surface area of mountain
summary4
Summary
  • Hard rocks weather more slowly than softer rocks.
  • The more surface area of a rock that is exposed to weathering, the faster the rock will be worn down.
  • Chemical weathering occurs faster in warm, humid climates.
  • Weathering occurs faster at high elevations because of an increase in ice, rain, and wind.
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Quick Check
  • A process by which softer, less weather-resistant rocks wear away and leave harder, more weather-resistant rocks behind is called
  • A. differential weathering
  • B. mechanical weathering
  • C. chemical weathering
  • D. ice wedging
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Quick Check
  • Which of the following statements describe a rock change after it is in a riverbed for a long period of time?
  • A. The rock rapidly breaks into smaller pieces.
  • B. Chunks of the rock break off, and the rock becomes rougher.
  • C. The edges of the rock are worn away, so its surface becomes smoother.
  • D. The rock absorbs water from the riverbed and becomes softer.
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Quick Check
  • Small rocks weather more quickly than larger rocks because their surface area is
  • A. thinner.
  • B. larger.
  • C. smaller.
  • D. thicker.
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Quick Check

The average weather condition in an area over a long period of time is called

A. temperature.

B. climate.

C. weather.

D. humidity.

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Quick Check
  • Chemical weathering is most rapid in areas that are
  • A. hot and dry.
  • B. warm and wet.
  • C. cold and dry.
  • D. cool and wet.
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Quick Check
  • Which rocks are exposed to more wind, rain, and ice?
  • A. rocks at a lower elevation
  • B. rocks at a higher elevation
  • C. rocks in streams
  • D. rocks in warm, humid climate
from bedrock to soil
What is soil (loam) formed from?

What is bedrock?

What is soil structure?

What is humus?

What are soil horizons?

From Bedrock to Soil
the source of soil
The Source of Soil
  • Soil is a loose mixture of small mineral fragments, organic matter, water, and air that can support the growth of vegetation.
  • Bedrock is the layer of rock beneath soil.
  • Parent rock is the rock formation that is the source of soil.
  • Wind, water, and movements of glaciers can transport or move soil from one place to another.
soil properties
Soil Properties
  • Soil is made from different-sized materials.
  • Soil texture is the soil quality is based on the proportions of soil particles.
  • Soil texture can influence the ability of water move through the soil.
  • Soil structure is the arrangement of soil particles.
soil properties1
Soil Properties
  • Some soils are rich in nutrients, some are poor in nutrients.
  • A soil’s ability to hold nutrients and to supply nutrients to a plant is describe as soil fertility.
  • Humus is the dark, organic material formed in soil from the decayed remains of plants and animals.
soil horizons
Soil Horizons
  • Soil horizons are the horizontal layers of soil.
  • The top layer of soil is called topsoil, containing more humus than the other layers of soil, rich in nutrients plants need to be healthy.
  • Good topsoil is necessary for farming.
summary5
Summary
  • Soil (loam) is formed from the weathering of bedrock.
  • Soil texture affects how soil can be worked for farming and how well water passes through it.
  • The ability of soil to provide nutrients so that plants can survive and grow is called soil fertility.
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Quick Check
  • Soil quality based on the relative size of soil particles is called
  • A. residual soil.
  • B. soil structure.
  • C. soil texture.
  • D. soil particles.
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Quick Check
  • What is the arrangement of soil particles called?
  • A. soil structure
  • B. soil texture
  • C. soil particles
  • D. infiltration
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Quick Check
  • What is the organic material formed in soil from the decayed remains of plants and animals called?
  • A. bedrock
  • B. parent rock
  • C. residual soil
  • D. humus
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Quick Check
  • Soil is important because it provides
  • A. housing for animals
  • B. Nutrients for plants
  • C. storage for water
  • D. All of the above
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Quick Check
  • Naomi made the pie graph during a laboratory experiment in which she analyzed the composition of loam (soil) found in Georgia. Based on this chart, which of the following is a valid conclusion?
  • A. Approximately 95% of the material that makes up loam is useless to plants.
  • B. Decayed organic matter is the least abundant component of loam.
  • C. Only about 90% of loam’s composition is useful to plants.
  • D. Only about 16% of loam’s composition is useful to plants.
soil conservation
Why is soil important?

How can human activity affect soil erosion?

What are three important benefits that soil provides?

List five methods of soil conservation.

Soil Conservation
soil conservation1
Soil Conservation
  • Soil can be endangered, just like plants and animals.
  • It takes thousands of years for soil to form, it is not easy to replace.
  • Soil conservation is a method to maintain the fertility of the soil by protecting the soil from erosion and nutrient loss.
the importance of soil
The Importance of Soil
  • Soil provides minerals and other nutrients for plant life.
  • All animals get their energy from plants.
  • Soil also provides a place for animals to live.
  • The region a plant or animal lives is called a habitat.
  • Soil holds water for plants to get the moisture or nutrients they need.
processes of change 5
Processes of Change (5)
  • Weathering and erosion wear down, deposition fills in Earth’s surface.
  • Weathering is the slow wearing away or breaking down of objects exposed to Earth’s atmosphere
  • Two kinds of weathering act on Earth’s surface
    • Mechanical weathering
    • Chemical weathering
mechanical weathering 4
Mechanical Weathering (4)
  • When objects are broken down into small pieces but their chemical makeup doesn’t change
  • Wind and moving water are two main causes of mechanical weathering
  • Repeated changes in temperature (freeze, melt, freeze, melt again)
chemical weathering 5
Chemical Weathering (5)
  • Material of an object is changed
  • Produces underground caverns
  • Statue of Liberty needed repairs because of chemical weathering
  • Examples:
    • Rust
    • Acid rain
erosion 5
Erosion (5)
  • The natural moving of material from one place to another
  • Erosion transportsweathered rock material
  • Causes of Erosion:
    • Moving water
    • Gravity
    • Wind
    • Glaciers (moving rivers of ice)
    • Waves
deposition 5
Deposition (5)
  • Land torn down in one place is “deposited” in another place
  • Gravity can cause a landslide moving mud, rock and soil down a hill
  • Wind erosion can move sand and deposit it in another area
  • Glaciers (rivers of ice) scrape rocks off the land and moves them downhill
deposition 51
Deposition (5)
  • Glaciers will stop moving and even retreat and cut a steep U-shaped valley in the land
  • Erosion caused by mountain rivers form V-shaped valleys
  • Hurricanes create waves that erode beaches and cliffs
  • Breaking of waves on a beach can wear it away. The larger the waves, the faster is the rate of erosion.
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Quick Check

Which of the following processes was responsible for producing the Grand Canyon?

A. only weathering

B. only erosion

C. weathering and erosion

D. Movement of a glacier

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Quick Check

The wearing away of the ancient Egypt’s Great Sphinx is an example of

A. weathering

B. mechanical weathering

C. erosion

D. deposition

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Quick Check

A landslide is an example of erosion caused by

A. wind

B. running water

C. the movement of a glacier

D. gravity

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Quick Check

What causes a sand dune to move from one place to another?

A. wind

B. waves

C. tides

D. running water

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Quick Check

About how many years does it take to change flat land into a very deep canyon like the Grand Canyon in Arizona?

A. tens of years

B. hundreds of years

C. thousands of years

D. millions of years

lithospheric plates
Lithospheric Plates

hypothesis

lithosphere

continental drift

Volcanic Mountains

fossil

oceanic plate

Volcanic Islands

continental plate

Mountain Ranges

Ring of Fire

earthquakes

volcanoes

slide203

EQ:

How do the lithospheric plates affect Earth’s surface?

Lesson 19

lithospheric plates1
What features of Earth are produced by the movement of lithospheric plates?

What was Alfred Wegener’s hypothesis?

What is a scientific hypothesis?

What does the collision of two continental plates produce?

Lithospheric Plates
lithospheric plates 8
Lithospheric Plates (8)
  • Earth's surface is like a jigsaw puzzle in motion
  • The pieces in the puzzle are made of large chunks of Earth’s lithosphere
  • Lithosphere is the solid outer layer of Earth
  • It includes the crust and the top of the mantle
  • The moving chunks of the lithosphere are called lithospheric plates
  • Continents and the ocean floor rest on these plates
  • Where these plates collide or separate, events take place that shape Earth’s surface
continents in motion 6
Continents in Motion (6)
  • German scientist, Alfred Wegener, hypothesized that all land masses on Earth had once made up a single, giant continent.
  • A hypothesis is a proposed explanation for one or more observations.
  • As millions of years passed, pieces of this giant continent separated and moved to their present positions
  • This process is called continental drift
  • Continents move about 2 cm a year
fossils 7
Fossils (7)
  • Fossils can show evidence of continental drift
  • For example, mesosaurus was a reptile that lived more than 250 million years ago
  • It lived in freshwater lakes and rivers
  • Scientists found its fossils in both South America and Africa
  • These continents are now separated by the salty Atlantic Ocean
  • How did their remains end up on both continents?
events caused by moving plates 5
Events Caused by Moving Plates (5)
  • Scientists divide Earth’s lithospheric plates into two groups-
    • Less dense continental plates
    • More dense oceanic plates

The collision of these plates produce different events on Earth’s surface

oceanic plate vs continental plate 3
Oceanic Plate vs. Continental Plate (3)
  • When an oceanic plate runs into a continental plate, the more dense plate slides under the less dense plate
  • This causes volcanic mountains like Mount St. Helens in the state of Washington to form.
oceanic plate vs oceanic plate 4
Oceanic Plate vs. Oceanic Plate (4)
  • When two oceanic plates meet, one slides under the other
  • A deep trench in the ocean floor forms and volcanic islands may pop through the ocean’s surface.
  • The Aleutian islands between Alaska and Russia were formed this way
continental plate vs continental plate 5
Continental Plate vs. Continental Plate (5)
  • When two continental plates collide, neither slides under the other
  • The plates buckle upward where they meet
  • This buckling produces mountain ranges
  • Example: the Himalayas in Asia
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Earthquakes! (5)
  • Some plates get stuck as they push intoeach other or slide past each other.
  • When they become unstuck, a sudden jolt happens.
  • Energy is released and energy sends waves through the ground.
  • This causes the ground to shake…It’s an earthquake!
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Earthquakes Part 2 (5)
  • Earthquakes occur more frequently alongplate boundaries than anywhere else.
  • This accounts for the “Ring of Fire” that curves around the Pacific Ocean.
  • The “Ring of Fire” is a belt where volcanoes and earthquakes are very common.
  • The belt follows the borders of plate boundaries.
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Quick Check
  • What features of Earth are produced by the movement of lithosphere plates?

A. solid masses of iron and nickel

B. liquid masses of iron and nickel

C. red-hot magma

D. mountains ranges, volcanoes, and volcanic islands

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Quick Check

What was Alfred Wegener’s hypothesis?

A. The continents have always been where they are now.

B. Today’s continents were once part of a single land mass that split apart.

C. The continents are made of rock.

D. The continents will one day join to form a single continent.

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Quick Check

Earthquakes are MOST LIKELY to occur at the borders of

A. continents.

B. lithospheric plates.

C. countries.

D. oceans

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Quick Check
  • A scientific hypothesis is
    • A. a fact.
    • B. an explanation that has been supported by repeated observations and experiments.
    • C. a proposed explanation for one or more observations.
    • D. a guess that is not based on observations.
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Quick Check
  • The collision of two continental plates can produce
    • A. volcanic islands.
    • B. a mountain range.
    • C. a single mountain
    • D. a trench.
effects of physical processes
Effects of Physical Processes
  • Just as there was once a single great land mass, there was also a single great ocean around that land mass.
  • The separate oceans we now know were formed as the land masses separated.
  • These separations produced amazing features on the ocean floor, such as the longest mountain range on Earth.
plate tectonics part 1
Plate Tectonics Part 1
  • Many physical processes have shaped Earth’s surface.
  • The physical process of plate tectonics have shaped Earth’s oceans.
  • Plate Tectonics describes how Earth’s lithospheric plates move and how their movements shape Earth’s crust.
  • The continents and ocean floor of Earth ride on 13 lithospheric plates
plate tectonics 2
Plate Tectonics, 2
  • In the 1950s, scientists discovered that rocks on the floor of the oceans were younger than rocks on the continents.
  • Harry Hess, an American geologist, suggested that the sea floor was spreading.
  • As it spread, from an opening in its middle, magma from Earth’s mantle oozed from the opening onto the surface of the ocean floor.
  • When the magma came in contact with seawater, it hardened into new rock.
plate tectonics
Plate Tectonics
  • This rock formed a huge mountain range that snakes through all of Earth’s oceans.
  • This undersea mountain range is called the midocean ridge.
  • As distance from the opening increased, the age of the rocks also increased.
  • Because the spreading has been constant throughout history, the formation of the South Atlantic Ocean can be traced back to a time when South America and Africa were once part of the same landmass.
convection currents 1
Convection Currents, 1
  • Lithospheric plates move due to convection currents in Earth’s mantle.
  • A convection current is a current formed by heated liquid that moves along a circular path.
  • Warm liquid moves upward and across a surface because it is less dense.
  • It cools at the surface, becomes more dense, and moves downward.
  • Then it warms again, becomes less dense, and moves upward.
convention currents 2
Convention Currents, 2
  • As long as heat is applied from below, the liquid will move around and around in convection currents
  • Heat from Earth’s mantle sets up convection currents.
  • These convection currents are made up of liquid rock.
  • The liquid rock rises to a place under the lithospheric plates.
  • The currents move in opposite directions, pushing plates apart in one place, and together in another place.
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Quick Check

Plate tectonics describe movements MAINLY in

  • A. Earth’s crust.
  • B. Earth’s mantle.
  • C. Earth’s outer core.
  • D. Earth’s inner core.
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Quick Check
  • Which ocean was produced by seafloor spreading between Africa and South America?
    • A. Pacific Ocean
    • B. Indian Ocean
    • C. North Atlantic Ocean
    • D. South Atlantic Ocean
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Quick Check
  • As distance increases from a mid-ocean ridge, the rocks
    • A. grow younger
    • B. grow older.
    • C. do not change in age.
    • D. become liquid.
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Quick Check
  • Assume a sea floor has been separating at an average rate of 5 cm a year. The sea is presently 8000 km wide. How long ago did the sea begin to form?
  • A. 1,600 years ago
  • B. 40,000 years ago
  • C. 160,000,000 years ago
  • D. 4,000,000,000 years ago
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Quick Check
  • A convection current of magma is made up of
    • A. a rising more dense liquid and a sinking less dense liquid.
    • B. a rising less dense liquid and a sinking more dense liquid.
    • C. liquids of the same density.
    • D. solids of different densities.
fossils
Fossils
  • A fossil is the remains or evidence of a once-living thing.
  • Most fossils are found in sedimentary rocks.
  • Fossils can reveal what an area on Earth looked like millions of years ago.
  • They also can help us understand the type of climate that area experienced millions of years ago.
  • The upper layers of rock are younger than the lower layers of rock.
changing climates
Changing Climates
  • Scientists have found evidence of fossils of corals in Arctic waters.
  • Corals can live only in warm water.
  • The fossils indicate that a long time ago the Arctic was a warm place.
  • Scientists found fossils of alligators in Canada.
  • Alligators live in warm swampy areas.
  • Conclusion is that Canada was once warm and swampy.
changing surfaces
Changing Surfaces
  • Fossils also provide clues to how Earth’s surface may have changed over thousands and millions of years.
  • Scientists have found seashells high in the foothills of the Andes Mountains.
  • Two hypotheses:
  • - Either, the sea once rose to cover the hills
  • - Or, the hills rose from under the sea.
  • Regardless of which hypothesis is correct, we know that the surface of this part of the world has changed over time.
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Quick Check

What can fossils reveal about Earth’s past?

A. Only changes in Earth’s climate over time

B. Only changes in Earth’s surface features over time

C. Changes in Earth’s climates and surface features over time

D. Present climates and surface features of Earth

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Quick Check

A seashell on top of a hill MOST LIKELY indicates that

A. The hill was once under the sea.

B. Sea animals once lived on land.

C. Seashells are not parts of living things.

D. All hills were once under water.

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Quick Check

What can fossils reveal about Earth’s past?

A. Only changes in Earth’s climate over time

B. Only changes in Earth’s surface features over time

C. Changes in Earth’s climates and surface features over time

D. Present climates and surface features of Earth

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Quick Check

Finding a fossil of a palm tree in Alaska could be explained if the climate of Alaska

A. was once colder than it is now.

B. has always been the same as it is now.

C. was once warmer than it is now.

D. is warming up now.

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Quick Check

If you found a fossil of a freshwater animal in a desert, what could you conclude?

A. The ocean once covered the desert.

B. The desert rose from the sea.

C. The desert sank beneath the ocean.

D. A river once flowed through the desert.

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Quick Check
  • The fossil of a tiny horse is found in a layer of rock below the fossil of a larger horse. What can you conclude?
  • A. The tiny horse fossil is younger than the larger horse fossil.
  • B. The tiny horse fossil and the larger horse fossil are the same age.
  • C. The tiny horse fossil is older than the larger horse fossil.
  • D. The larger horse fossil is older than the tiny horse fossil.
the composition of soil
The Composition of Soil
  • Soil is a combination of :
    • Weathered rock
    • Decayed parts of plants
    • Decayed parts of animals
    • Water
    • Air
  • It takes thousands of years to form.
  • Without soil, life on Earth as we know it would not be possible.
formation of soil 1
Formation of Soil, 1
  • Begins when exposed rock starts to weather
  • Wind, moving water, and changes in temperature break rock into tiny pieces
  • Organisms like bacteria and fungi begin to grow in the young soil
  • These organisms produce acids that further break down particles of rock
  • This process produces minerals and the nutrients plants need for growth
formation of soil 2
Formation of Soil, 2
  • Soon small plants take hold in the new soil with their roots.
  • Plants grow and die, along with animals, and soil bacteria and fungi break these organic materials down
  • Organic material is a substance that was originally part of a living thing
a soil profile 1
A Soil Profile, 1
  • Soil that has developed over thousands of years is called mature soil.
  • A soil profile is made up of three layers called horizons.
a soil profile 2
A Soil Profile, 2
  • The top horizon, or A horizon, is very rich in nutrients. It is called topsoil.
  • The middle layer, or B horizon, is known as subsoil. This is where you find clay and minerals washed down by water

seeping through the A horizon

(topsoil)

Deep roots reach into the subsoil.

The last horizon, C, you will find solid bedrock

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Quick Check

What is the last stage in the production of soil?

A. Fungi and bacteria produce acids that break down rock

B. Exposed rock weathers

C. Plants begin to grow in the ground

D. Fungi and bacteria break down organic material

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Quick Check

Soil is made up of

A. only weathered rock

B. only organic material

C. weathered rock and organic matter

D. only animals and plants

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Quick Check

What process is MAINLY responsible for producing minerals and nutrients in very young soil?

A. decay of animals and plants

B. production of acids by bacteria and fungi

C. growth of plants

D. weathering

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Quick Check

From top to bottom, what are the horizons of soil?

A. Bedrock, subsoil, topsoil

B. Subsoil, bedrock, topsoil

C. Topsoil, subsoil, bedrock

D. Topsoil, bedrock, subsoil

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Quick Check

Which of the following contains organic material?

A. grass

B. unweathered rock

C. water

D. air

human activity and erosion
Human Activity and Erosion

Natural agents of erosion:

  • Wind
  • Moving water
  • Gravity (landslides)
  • Waves
  • Glaciers (rivers of ice)

Humans add to the erosion process:

  • Logging
  • Mining
  • Farming
  • Construction
logging
Logging
  • People use trees to build homes, make furniture and paper.
  • In a method called clear-cutting, all the trees in an area are cut down.
  • Roots that used to hold the soil in place die and decay.
  • Rain washes the soil away.
  • Soil has been robbed of nutrients and minerals needed for plants to grow.
mining2
Mining
  • To get minerals from the ground, miners strip away the surface of the land.
  • Strip-mining and open-pit mining remove plants from an area.
  • Plants prevent soil erosion by flowing waters and wind.
  • Without plants, erosion speeds up.
  • Thousands of years may pass before enough topsoil builds up to support plant life.
farming
Farming
  • Planting crops can benefit many people.
  • Planting crops and an unexpected natural event can produce a disaster.
  • From 1930 to 1937, a drought struck the mid-western part of the U.S.
  • Grasses could have protected the soil during the drought.
  • Winds picked up the topsoil and blew it 100s of miles eastward.
  • This event is known as the “Dust Bowl.”
construction
Construction
  • Building of roads, buildings, and communities removes natural barriers, such as plants, to erosion.
  • Erosion speeds up and the land becomes barren and ugly.
  • Today, city officials consider erosion when they plan new construction plans.
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Quick Check
  • What is MAINLY responsible for preventing erosion?

A. mining

B. farming

C. rooting of plants

D. logging

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Quick Check
  • Which human activity is related to logging?

A. strip mining

B. clear-cutting

C. drought

D. open-pit mining

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Quick Check
  • A landslide is an example of

A. erosion

B. a mining process

C. A logging process

D. A farming process

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Quick Check

In what part of the United States was the “Dust Bowl” located?

  • A. northern
  • B. eastern
  • C. western
  • D. central
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Quick Check

What was the MAIN cause of the “Dust Bowl”?

A. floods

B. Storms

C. wind

D. drought

conserving natural resources
Conserving Natural Resources
  • Vital resources in danger:
    • Soil has become unfit for growing crops
    • Water unhealthy to drink, cook with, wash in
    • Air has become polluted with substances

Natural resources can be kept healthy in two

ways:

    • Conserved - saved before it turns bad
    • Reclaimed - made healthy again after it has turned bad
soil conservation2
Soil Conservation
  • Methods used to keep topsoil from being swept away by flowing water and wind.
  • Rolls of trees, called windbreaks, are planted along the edge of farmland to block winds.
  • In terracing, farmers cut level areas into the sides of mountains to block or slow down the downward rushing water.
soil conservation3
Soil Conservation
  • To make land healthy again, people can plant grasses that can live through a drought.
  • Grasses will die and decay and add nutrients to the soil.
  • The roots of the living grasses hold the soil in place.
water conservation
Water Conservation
  • The main threats to our supply of healthy water are pollution and waste.
  • To conserve water:
    • Replace old showerheads and faucets with water saving showerheads and faucets
    • Replace old toilets with water-saving toilets that uses less water per flush
    • Turn off the faucet while you brush your teeth.
    • Turn on the dishwasher only when you have a full load of dishes.
water conservation1
Water Conservation
  • Water pollution comes from different sources:
    • Sewage treatment plants should not pour untreated sewage into bodies of water.
    • Factories and mines must be prevented from dumping harmful chemicals into bodies of water.
    • Methods must be used to prevent fertilizers from washing off of farmlands into bodies of water.
air conservation
Air Conservation
  • Air is made up of 78% nitrogen, 21% oxygen, and 1% other gases.
  • We need oxygen to live.
  • Human activities put gases into the air that can harm you.
  • Air pollution describes air that holds harmful gases.
  • Harmful substances in air, water, or soil are called pollutants.
air conservation1
Air Conservation
  • Two sources of air pollutants:
    • vehicles that burn gasoline or oil
    • Industries whose smokestacks pour chemicals and bits of dirt into the air

Passed laws to protect air from pollution.

Put filters on smokestacks.

air conservation2
Air Conservation

Laws require car manufactures to put in exhaust systems.

State laws require the use of fuels in vehicles that lessen the amounts of pollutants that enter the air.

States require steps to reduce harmful vehicle emissions.

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Quick Check

Terracing is a method used to conserve

  • water.
  • air.
  • soil.
  • fuel.
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Quick Check

A windbreak conserves

  • wind.
  • soil.
  • water.
  • air.
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Quick Check

For a family of four, what indoor use of water consumes the MOST water per day?

  • Washing dishes
  • Doing laundry
  • Drinking and cooking
  • Flushing toilets
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Quick Check

What would reduce automobile air pollution the MOST?

  • Putting filters on car exhaust systems
  • Driving fewer miles
  • Switching to cars that run on electricity
  • Driving cars that use less fuel
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Quick Check

How is farming MOST LIKELY to produce water pollution?

  • A. Fertilizers may enter bodies of water.
  • B. Foods may enter bodies of water.
  • C. Soil may enter bodies of water.
  • D. Gases may enter bodies of water.
summary of plate tectonics
Summary of Plate Tectonics

earthquakes occur

creates mtns

Folds

two plates slide past each other

two plates move apart

Faults

convergent

divergent

transform

Plate Boundaries

two plates pushed together

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Quick Check

When two plates converge, one plate is usually forced to slide under the other. Oceanic plates are more dense than continental plates. If an oceanic plate collides with a continental plate, what will be the likely result?

A. The continental plate will slide under the oceanic plate, generating an oceanic trench.

B. The oceanic plate will slide under the continental plate, generating an oceanic trench.

C. The continental plate will slide under the oceanic plate, generating an earthquake.

D. The oceanic plate will slide under the continental plate, generating an earthquake.

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Quick Check

If two plates meet at a convergent boundary and do not form a subduction zone, they may

A. fold.

B. fault.

C. weather.

D. erupt.

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Quick Check
  • The process of seafloor spreading occurs at what kind of plate boundary?

A. divergent

B. convergent

C. transform

D. at both convergent and transform boundaries

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Quick Check

Where does magma come from?

  • A. the inner core
  • B. the outer core
  • C. the mantle
  • D. the lithosphere
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Quick Check

The ancient supercontinent, Pangea, once contained

A. all of the Earth’s tectonic plates.

B. all of Earth’s crust.

C. all of Earth’s continental crust. D. all of Earth’s oceanic crust