physical features of the united states geography: section 2

44
Physical Features Physical Features of the United of the United States States Geography: Section 2 Geography: Section 2

Upload: linda-barker

Post on 28-Dec-2015

221 views

Category:

Documents


1 download

TRANSCRIPT

Page 1: Physical Features of the United States Geography: Section 2

Physical Features of Physical Features of the United Statesthe United States

Geography: Section 2Geography: Section 2

Page 2: Physical Features of the United States Geography: Section 2

Turn to page 4 in your textbooksTurn to page 4 in your textbooks

What landforms are What landforms are shown?shown?

Mountains, coastlines, Mountains, coastlines, oceans, rivers, gulfs, plains, oceans, rivers, gulfs, plains, basins, and canyons.basins, and canyons.

Page 3: Physical Features of the United States Geography: Section 2

Forces That Have Helped Shape Forces That Have Helped Shape U.S. LandformsU.S. Landforms

Continental DriftContinental Drift- Scientists - Scientists believe that the Earth’s continents believe that the Earth’s continents were once a single land mass (or were once a single land mass (or perhaps two), which began to perhaps two), which began to break up and drift apart some break up and drift apart some 240 million years ago.240 million years ago.

Page 4: Physical Features of the United States Geography: Section 2
Page 5: Physical Features of the United States Geography: Section 2
Page 6: Physical Features of the United States Geography: Section 2

Volcanoes and Earthquakes Volcanoes and Earthquakes

VolcanoesVolcanoes and and earthquakesearthquakes occur frequently along occur frequently along boundaries between shifting boundaries between shifting continental plates.continental plates.

These violent phenomena play a These violent phenomena play a keykey role in shaping of the role in shaping of the landland..

Page 7: Physical Features of the United States Geography: Section 2

VolcanoesVolcanoes occur when hot gases and occur when hot gases and magma (molten, or melted, rock within magma (molten, or melted, rock within the Earth) build up the Earth) build up pressurepressure and spew and spew forth from underground as forth from underground as lavalava..

As volcanoes erupt again and again As volcanoes erupt again and again over many centuries, they can create over many centuries, they can create cone-shaped cone-shaped mountainsmountains..

Page 8: Physical Features of the United States Geography: Section 2
Page 9: Physical Features of the United States Geography: Section 2

Pressure beneath the Pressure beneath the Earth’s surface also causes Earth’s surface also causes earthquakesearthquakes, which can , which can topple buildings and rip up topple buildings and rip up the landscape.the landscape.

EarthquakesEarthquakes

Page 10: Physical Features of the United States Geography: Section 2
Page 11: Physical Features of the United States Geography: Section 2
Page 12: Physical Features of the United States Geography: Section 2
Page 13: Physical Features of the United States Geography: Section 2
Page 14: Physical Features of the United States Geography: Section 2

GlaciersGlaciers Many landforms in the United States Many landforms in the United States

especially in especially in AlaskaAlaska, in mountainous areas, , in mountainous areas, and near and near CanadaCanada have been shaped by have been shaped by movingmoving masses of masses of snowsnow and and iceice..

These These glaciersglaciers, common in polar regions, , common in polar regions, form where more snow falls in winter that form where more snow falls in winter that can melt in summer.can melt in summer.

Page 15: Physical Features of the United States Geography: Section 2
Page 16: Physical Features of the United States Geography: Section 2

IcebergIceberg

Page 17: Physical Features of the United States Geography: Section 2

Glaciers spread out during periods called Glaciers spread out during periods called ice agesice ages, when global temperatures dip , when global temperatures dip sharply.sharply.

During the last ice age, some During the last ice age, some 20,00020,000 years years ago, a ago, a mile high mountain of icemile high mountain of ice stretched stretched from west of what is now Chicago to New from west of what is now Chicago to New York City and south to the Ohio River York City and south to the Ohio River valley.valley.

Page 18: Physical Features of the United States Geography: Section 2
Page 19: Physical Features of the United States Geography: Section 2

ErosionErosion The moving of rocks and soil by glaciers is The moving of rocks and soil by glaciers is

one of many forms of one of many forms of erosionerosion-the wearing -the wearing away of land by wind, rain, or ice.away of land by wind, rain, or ice.

The The Appalachian MountainsAppalachian Mountains of the eastern of the eastern United States are relatively old and eroded United States are relatively old and eroded mountains.mountains.

That is why they are lower and less rugged That is why they are lower and less rugged than the younger than the younger Rocky Mountains of the Rocky Mountains of the WestWest..

Page 20: Physical Features of the United States Geography: Section 2

Mountain Ranges and PlateausMountain Ranges and Plateaus

MountainsMountains are perhaps the are perhaps the most easily identified most easily identified landforms.landforms.

These These elevatedelevated areas of areas of peakspeaks and and crestscrests rise high above the rise high above the surrounding countryside.surrounding countryside.

Page 21: Physical Features of the United States Geography: Section 2

Other elevated landforms, Other elevated landforms, plateausplateaus, are flat or gently rolling , are flat or gently rolling expanding at high attitudes.expanding at high attitudes.

AltitudeAltitude measures the height of a measures the height of a landform above sea level or landform above sea level or another surface, such as the ocean another surface, such as the ocean floor. floor.

Page 22: Physical Features of the United States Geography: Section 2

Interior and Coastal LowlandsInterior and Coastal Lowlands

LowlandsLowlands are valuable are valuable landforms because they are landforms because they are often flat or gently rolling often flat or gently rolling and thus suitable for and thus suitable for agriculture.agriculture.

Page 23: Physical Features of the United States Geography: Section 2

In landforms called In landforms called basinsbasins, , flowing water with no outlet flowing water with no outlet collects to form lakes that collects to form lakes that become very salty as water become very salty as water continually evaporates. continually evaporates.

A A plainplain is a large area of is a large area of level or gently rolling land.level or gently rolling land.

Page 24: Physical Features of the United States Geography: Section 2

Between the lowlands and the Between the lowlands and the mountains lies the mountains lies the PiedmontPiedmont (French (French for “foot” and mountain”).for “foot” and mountain”).

As you travel up a river from the As you travel up a river from the coast, you know you have reached the coast, you know you have reached the Piedmont when you encounter a Piedmont when you encounter a series of series of rapidsrapids and and waterfallswaterfalls; water ; water flowing from the mountains to the sea flowing from the mountains to the sea makes a sharp drop as the elevation makes a sharp drop as the elevation of the land suddenly changes. of the land suddenly changes.

Page 25: Physical Features of the United States Geography: Section 2

This boundary between the This boundary between the Piedmont and the coast Piedmont and the coast plains is called the plains is called the fall linefall line..

Page 26: Physical Features of the United States Geography: Section 2

Major water featuresMajor water features WaterWater is an important natural is an important natural

resource, and so are resource, and so are riversrivers and and lakeslakes (landforms defined by water). (landforms defined by water).

Rivers and lakes are useful for Rivers and lakes are useful for transportationtransportation, , foodfood (fish, shellfish, (fish, shellfish, edible plants such as seaweed), and the edible plants such as seaweed), and the removalremoval of of wasteswastes..

Page 27: Physical Features of the United States Geography: Section 2

Great LakesGreat Lakes

Together, the Together, the five Great five Great LakesLakes make up the make up the largest largest bodybody of of fresh waterfresh water in the in the worldworld..

Lakes Michigan, Superior, Lakes Michigan, Superior, Huron, Erie, and Ontario.Huron, Erie, and Ontario.

Page 28: Physical Features of the United States Geography: Section 2
Page 29: Physical Features of the United States Geography: Section 2

St. Lawrence RiverSt. Lawrence River

The The Great LakesGreat Lakes empty into empty into the the Atlantic OceanAtlantic Ocean through through the the St. Lawrence RiverSt. Lawrence River, one , one of two great rivers that of two great rivers that drain the U.S. interior. drain the U.S. interior.

Page 30: Physical Features of the United States Geography: Section 2
Page 31: Physical Features of the United States Geography: Section 2

A A tributarytributary is a stream or is a stream or river which flows into a river which flows into a mainstream (or parent) mainstream (or parent) river, and which does not river, and which does not flow directly into a sea. flow directly into a sea.

Page 32: Physical Features of the United States Geography: Section 2

Acquiring Acquiring New OrleansNew Orleans as part as part

of the of the Louisiana PurchaseLouisiana Purchase was was

considered important to the considered important to the

development of the Mississippi development of the Mississippi

and Ohio River valleys because and Ohio River valleys because

the city served as a port for the city served as a port for

American American agriculturalagricultural goods. goods.

Page 33: Physical Features of the United States Geography: Section 2

Extensive Ocean CoastlinesExtensive Ocean Coastlines

Access to oceans is a great Access to oceans is a great advantage for advantage for tradetrade and and traveltravel, and 23 of the 50 , and 23 of the 50 United States benefit from United States benefit from ocean coastlines.ocean coastlines.

Page 34: Physical Features of the United States Geography: Section 2

Hawaii: An ArchipelagoHawaii: An Archipelago

HawaiiHawaii is the only state is the only state completely surrounded by completely surrounded by ocean waters.ocean waters.

An An archipelagoarchipelago, or chain of , or chain of islands, was created over the islands, was created over the centuries by volcanic activity.centuries by volcanic activity.

Page 35: Physical Features of the United States Geography: Section 2

Mineral and Energy ResourcesMineral and Energy Resources

Associated with the U.S. landforms are a Associated with the U.S. landforms are a variety of variety of mineralmineral and and energyenergy resources. resources.

They were first tapped by early They were first tapped by early Native Native AmericansAmericans, who learned to use them in , who learned to use them in their daily lives.their daily lives.

Today, such resources are crucial to the Today, such resources are crucial to the operation of the operation of the U.S. economyU.S. economy..

Page 36: Physical Features of the United States Geography: Section 2

True MineralsTrue Minerals Most Most mineralsminerals lack lack inorganic matterinorganic matter by by

products of living organisms.products of living organisms. These minerals are These minerals are solidsolid substances substances

occurring in nature, each with its own occurring in nature, each with its own distinctive chemical composition.distinctive chemical composition.

Since minerals do not replicate Since minerals do not replicate themselves as animals and plants do, themselves as animals and plants do, they are called they are called nonrenewable resourcesnonrenewable resources. .

Page 37: Physical Features of the United States Geography: Section 2

Energy ResourcesEnergy Resources EnergyEnergy is vital in every aspect of modern is vital in every aspect of modern

life. life. The The United StatesUnited States has a variety of resources has a variety of resources

that can be used to produce energy.that can be used to produce energy. Coal, petroleum, and natural gas are Coal, petroleum, and natural gas are fossil fossil

fuelsfuels: They originated from a combination : They originated from a combination of ancient organisms and ancient minerals.of ancient organisms and ancient minerals.

Page 38: Physical Features of the United States Geography: Section 2
Page 39: Physical Features of the United States Geography: Section 2
Page 40: Physical Features of the United States Geography: Section 2

Alternative EnergyAlternative Energy Solar powerSolar power- energy from the sun.- energy from the sun. AlcoholAlcohol- produced from plants such as - produced from plants such as

corn.corn. MethaneMethane- economical substitute for - economical substitute for

natural gas. Created by allowing natural gas. Created by allowing inorganic matter such as manure to rot inorganic matter such as manure to rot which emits gases.which emits gases.

Geothermal EnergyGeothermal Energy- heat from within - heat from within the earth.the earth.

WindmillsWindmills- Used to generate electricity - Used to generate electricity from the wind. from the wind.

Shale oilShale oil- fossil fuel obtained by heating - fossil fuel obtained by heating and crushing oil-bearing rocks.and crushing oil-bearing rocks.

Page 41: Physical Features of the United States Geography: Section 2

WindmillsWindmills

Page 42: Physical Features of the United States Geography: Section 2

WindmillsWindmills

Page 43: Physical Features of the United States Geography: Section 2

Many of these alternative sources of Many of these alternative sources of energy are renewable resources.energy are renewable resources.

The United States also has many sites The United States also has many sites that are suited to producing that are suited to producing hydroelectric powerhydroelectric power, which is , which is generated when falling water turns generated when falling water turns turbines.turbines.

Page 44: Physical Features of the United States Geography: Section 2