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Earth's Physical

Geography

Unit 2

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Our Planet, the Earth

• How does the Earth move in space?

• Why do seasons change?

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Days and Nights

• The Earth travels around the sun in an oval-shaped orbit.

The Earth and the Sun

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• It takes _________________ year, for the Earth to complete one revolution around the sun.

• As the Earth revolves, it is also spinning on its __________________.

• Each rotation (or complete spin on the axis) takes about _____________.

• It is daytime on the side facing the sun and night on the side away from the sun.

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The Earth and the Sun

Understanding SeasonsWhy are the days longer in some parts of the year?• The Earth’s axis is at an ___________________. • In about half of the Earth’s orbit, the tilt causes a

region to face toward the sun for more hours than it faces away from the sun.

• _______________________. • In other regions that face away from the sun for

more hours, days are shorter.

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Why does the temperature change during the seasons?

• The warmth you feel at any given time of year depends on how directly the sunlight falls on you.

• Some regions receive a great deal of direct sunlight, while others receive very little.

• _________________________________________________________________.

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Line of Latitude Where is it?Gets Direct Sunshine on Seasons

Tropic of Cancer 23 1/2º N June 21

Arctic Circle 66 1/2º N Never

Antarctic Circle 66 1/2º S Never

Tropic of Capricorn 23 1/2º S December 21 First day of winter, or winter solstice, in Northern Hemisphere

Equator March 21September 23

Spring and fall equinoxes: Days and nights are almost equal everywhere

0º

Looking at LatitudesLooking at Latitudes

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Zones of LatitudesZones of Latitudes

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Low Latitudes: The Tropics

• Area between the Tropic of Cancer and the Tropic of Capricorn

• In this region, it is almost ____________.

Looking at Latitudes: Zones

Looking at Latitudes: Zones

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Middle Latitudes: The Temperate Zones

• Area between the Tropic of Cancer and the Arctic Circle

• AND the area between the Tropic of Capricorn and the Antarctic Circle

• In this region, there are ______________, each with a distinct pattern of _________, _______________, and _____________.

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High Latitudes: The Polar Zones• Area between the Arctic Circle and the

North Pole

• AND the area between the Antarctic Circle and the South Pole

• In this region it is very cool to ________ _______________.

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Land, Air, and Water

• What forces shape the land?

• What are the Earth’s major landforms?

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Forces Inside the Earth

What is the Earth made of?________________________________________________________________________.

Continents are unique, in part because of their landforms, which include mountains, hills, plateaus, and plains.

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Pangaea: The Supercontinent

• Geographers theorize that millions of years ago the Earth had only ____________ ________________, which they call Pangaea.

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• They believe that 200 million years ago, some force made Pangaea split into _____________ ___________ and begin to move apart, forming separate continents.

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• The theory of plate tectonics explains why the continents separated.

• Continents are part of plates that shift over time.

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The Movement of the Continents

_______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________.

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Volcanoes, Earthquakes, and Shifting Plates

The world’s plates move in different directions, causing a variety of effects:

Ridges: In some places, plates move apart, and magma leaks through the cracks in the crust. In the oceans, over time, the cooling rock builds up to form lines of _______________________ called ridges.

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Volcanoes: In other places, the plates push against one another, forcing one plate under the other. Tremendous _____________________ builds up causing molten rock to explode on the surface.

Earthquakes: – Along plate boundaries, there are many __________

places in the Earth’s crust. – When plates push against each other, the crust

cracks and splinters from pressure. – These cracks are called ______________________. – When the crust moves along faults, it releases great

amounts of ______________________ in the form of _____________________.

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Forces on the Earth's Surface

Forces like volcanoes slowly build up the Earth. Other forces slowly break it down. These forces may not be as dramatic, but they have important and long-lasting effects.

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The Two Effects of Weathering:1. Weathering breaks down rocks

into tiny pieces, wearing away the Earth’s landforms. Many once-steep mountains are now low and rounded. Three things cause weathering: _________________.

2. Weathering helps create _______. Tiny pieces of _____ combine with ___________________________ material to form soil.

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Erosion• Once this breaking down has taken

place, small pieces of rock may be ______________________ by erosion. Erosion, together with weathering, help slowly create new landforms.

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Air and Water: Two Ingredients for Life

Air• The thick layer of gases that surrounds the

Earth is called the __________________.• It provides life-giving oxygen for people and

animals and life-giving carbon dioxide for plants.

• It also acts as a _____________________ ______ from the sun to make life possible.

• Winds distribute this heat around the globe.

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Water• Roughly ____________ of Earth’s water is

found in the oceans.• The rest is _________________________

______. • Most of that is frozen at the poles.• Fresh water comes from lakes, rivers, and

rain. • Much fresh water, called groundwater, is

stored in the _________________.• People need fresh water—the Earth has

enough, but ____________________, and _________________________________.

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Climate and What Influences It

• What is climate?

• How do landforms and bodies of water affect climate?

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Weather or Climate?

Weather• What you check before you go

outside in the morning• _______________ changes in the air• Measured primarily by temperature

and precipitation

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Climate• What you know from experience

happens from year to year• The __________ weather over _____

______________• The Earth has many _____________.• Climates are different in low, middle,

and high altitudes because latitude affects temperature.

• Landforms, wind, and water also affect climates.

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The Blowing Winds

• Wind and water help spread the sun’s heat and keep the Earth from _____________________.• Winds blow east–west and west–

east in part because of ________ _______________.

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Winds blow north–south and south–north because:• Hot air rises and circulates toward

regions where the air is not as hot. • Hot, moist air from the Equator rises

and moves toward the North Pole or South Pole.• Cold air sinks and moves toward

regions where the air is warmer. • Cold, dry air from the poles moves

toward the Equator.

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Ocean Currents: Hot and Cold

The Earth’s rotation creates ocean currents. Warm water from the Equator flows north or south to colder parts and cold water from the poles flows toward the warm areas near the Equator.

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The Ocean's Cooling and Warming Effects

Bodies of water affect climate in another way too:

Why is a beach on a hot summer day cooler by the ocean?

• Water takes __________________than land.

• In the summer, a place near the ocean or a lake will be cooler than an area farther away.

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Raging StormsWind and water can make climates milder, but they also can create _____. Some storms create great destruction.

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Hurricanes• Wind and rain storms that form in the

tropics in the Atlantic Ocean • The winds at the center travel over 73

miles per hour. • They produce huge waves called storm

surges, ____________________ and can destroy _________________.

Typhoons• Similar to hurricanes, they take

place in the Pacific Ocean.

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Tornadoes• _____________________________________

_____________________________________.

• The powerful winds can wreck almost anything in a tornado’s path.

• However, they only average about one half mile in diameter.

• Therefore they affect a more limited area than hurricanes.

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How Climate Affects Vegetation

• Where are the Earth’s major climate regions?

• What kinds of vegetation grow in each climate region?

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Climate and Vegetation• Plants have features, called adaptations, that

enable them to live in a particular climate.

• Over a very long time, small, accidental changes in a few individual plants made them better able to survive in a particular place.

• Therefore, geographers can predict the kinds of plants they will find in a climate.

• ____________________________________________________________________________.

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Geographers discuss five broad types of climates:

1. ________________________2. Dry3. Moderate4. ________________________5. Polar

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Tropical and Dry Climates

AridSemiarid

Tropical WetTropical Wet and DryTypes

Sparse: Because there is so little rain, plants grow far apart and have shallow roots adapted to absorb scarce water before it evaporates. Some plants flower only when it rains.

Tropical rain forest: Because there is so much light, heat, and rain, thousands of kinds of plants grow here. The uppermost branches of tall trees create a canopy, and plants more adapted to shade grow beneath.

Vegetation

DryWetMoisture

HotHotTemperature

Dry ClimatesTropical Climates

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Mediterranean, Marine West Coast, Humid SubtropicalTypes

In General: A wide variety—forests of deciduous trees, tall shrubs, low bushes, a variety of grassesHumid Subtropical: Has the most heat and precipitation and many types of vegetationMarine West Coast: Mountainous and cooled by ocean currents—supports more forests than grassesMediterranean: Rainy winters and hot, dry summers lead to plants with leathery leaves, which hold in moisture during the dry summers.

Vegetation

Moderate rainMoisture

Seasonal, but almost never below freezingTemperature

Moderate Climates

Moderate Climates

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A Vertical Climate

• A mountain is an example of a vertical climate, where the climate changes according to the mountain’s height.

• A hike up a tall mountain in a moderate climate would go something like this:

– __________________ surround the base, and temperatures are _______________________.

• You soon enter a region with less precipitation than below—there are short grasses, as in a continental climate.

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• Next, you move through deciduous forests where it is cooler and drier.

• Slowly the forests change to coniferous forests.

• Then, you find only scattered, short trees and finally only low shrubs and short grasses.

• Soon it is too cold and dry even for them and you begin to see mosses and lichens of a tundra.

• At the mountaintop is an icecap climate, with _____________________.