Splash Screen Intro 1 Section 1-3 Click the mouse button or press the Space Bar to display the information. Antarctica Europe Asia North America

Click the mouse button or press the Space Bar to display the information.Click the mouse button or press the Space Bar to display the information.

• Antarctica • Europe • Asia • North America

• South America • Africa • Mount Everest • Dead Sea

• Mariana Trench

• Australia

Places to LocatePlanet Earth

Click the Speaker button to listen to the audio again.


Earth has one moon, which revolves around the planet about once a month; in fact, the words moon and month come from the same Latin word. The relative positions of the earth, moon, and sun make the moon appear to be a different shape every night, from a barely visible curve to a crescent, a half-circle, an ellipse, and finally a full circle. The side of the moon that seems brightly lit is the side facing the sun

Our Solar SystemThe sun is at the center of our solar system. It exerts a strong force of gravity that keeps Earth and all the other objects in the solar system revolving around it.

(pages 33–35)(pages 33–35)


• At least eight planets orbit our sun.

• Some of the planets have one or more moons.


Our Solar System (cont.)

• Farther from the sun are the gas giant planets–Jupiter, Saturn, Uranus, and Neptune.

• Mercury, Venus, Earth, and Mars are terrestrial planets because they have solid rocky crusts.

(pages 33–35)(pages 33–35)


Our Solar System (cont.)

• Asteroids are small, irregularly shaped, planetlike objects.

• Comets are made of icy dust particles and frozen gases. Meteoroids are pieces of space debris–chunks of rock and iron.

• Asteroids, Comets, and Meteoroids Smaller objects in the solar system include asteroids, comets, and meteoroids.

(pages 33–35)(pages 33–35)


Getting to Know Earth

(pages 35–36)(pages 35–36)

• Water, Land, and Air The surface of the earth is about 30 percent land and about 70 percent water.

• The atmosphere is about 78 percent nitrogen, about 21 percent oxygen, and about 1 percent other gases, such as argon.



Getting to Know Earth (cont.)

(pages 35–36)(pages 35–36)


• The part of a continent that extends underwater is called a continental shelf.

(pages 35–36)(pages 35–36)

Getting to Know Earth (cont.)

Earth’s Heights and Depths


• Earth’s lowest point of dry land is on the shore of the Dead Sea at 1,349 feet (411 m) below sea level.

• The deepest known level of the ocean floor is the Mariana Trench at 35,827 feet (10,923 m) below sea level.

• The highest point on Earth is the summit of Mount Everest at 29,035 feet (8,852 m) above sea level.

(page 36)(page 36)

In what ways do you think heights and depths of lands affect the way that people live?

Possible answers: Heights and depths affect the way people live because altitudes affect temperatures, forms of transportation, clothing, activities, occupations, and access to shopping, medical facilities, and schools.

Earth’s Heights and Depths (cont.)

Click the mouse button or press the Space Bar to display the answer.


(page 36)(page 36)

Critical Thinking

Drawing Conclusions Recently NASA has launched space probes to explore Mars. Why might Mars have been chosen for these explorations?

Mars might have been chosen because it is close to Earth, is a terrestrial planet like Earth, and is cooler than other nearby planets.



Analyzing Diagrams

Location Study the diagram below. How is the size of a planet’s orbit influenced by its distance from the sun?





In 1906 the booming city of San Francisco was destroyed by an earthquake that measured 8.6 on the Richter scale. Over 400 people were killed, and 28,000 buildings were reduced to rubble. Another slightly less forceful earthquake struck the city in 1989, doing far less damage and claiming 67 lives. Most people remember it because it interrupted the World Series for 12 days while damages were repaired in Oakland and San Francisco.


• Plates move gradually. As they move, they come together and pull apart.

• This movement pushes up mountains, creates volcanoes, and produces earthquakes.

• These activities are called plate tectonics.

• Plate Movement Many scientists believe that all the continents once were joined and have broken apart and drifted. This theory is called continental drift.

(pages 37–39)(pages 37–39)

Earth’s Structure (cont.)

Internal Forces of Change (cont.)

• The Ring of Fire is a zone of earthquake and volcanic activity surrounding the Pacific Ocean.

• Cities in this area, like San Francisco and Los Angeles, are prone to severe earthquakes.

• Earthquakes Sudden, violent movements along the fault lines are called earthquakes.


(pages 39–41)(pages 39–41)

External Forces of Change


• Wind Erosion The movement of dust, sand, and soil from one place to another is called wind erosion.

(pages 42–43)(pages 42–43)

• Water erosion often forms valleys and canyons.

• Water Erosion Rain, rivers, streams, and oceans wear away soil and rock in a phenomenon called water erosion.


External Forces of Change (cont.)

(pages 42–43)(pages 42–43)

Analyzing Maps

Region Study the map of plates and plate movement below. Which plates are responsible for the earthquakes that have occurred in California in the United States?





The Water Cycle

• Most of the hydrosphere is salt water, found in the oceans, seas, and some lakes.

• The rest of the hydrosphere is the freshwater of lakes, rivers, and springs.

• The part of the earth that is covered by water is called the hydrosphere.


(pages 46–47)(pages 46–47)

Bodies of Salt Water• Oceans About 97 percent of the

hydrosphere is a huge body of salt water divided into four oceans: the Atlantic, the Pacific, the Indian, and the Arctic Oceans.

(pages 47–48)(pages 47–48)


Bodies of Salt Water (cont.)

• Ocean Water to Drinking Water Because of the great demand for drinking water, people are experimenting with desalination–the removal of salt from ocean water.

• Seas, Gulfs, and Bays Large bodies of salt water partially enclosed by land comprise seas, gulfs, and bays.

(pages 47–48)(pages 47–48)



Bodies of Salt Water (cont.)

(pages 47–48)(pages 47–48)

• Most people and animals live near sources of freshwater.

• Groundwater Groundwater is freshwater lying beneath the planet’s surface.

• Because rivers and streams flow through land, they carry freshwater to people and animals.


Bodies of Freshwater (cont.)

(pages 48–49)(pages 48–49)



Bodies of Freshwater (cont.)

(pages 47–48)(pages 47–48)

Analyzing Diagrams

Physical Geography Look at the diagram of the water cycle below. What source of water supplies wells and springs?



Click the mouse button or press the Space Bar to display the answers.

Click the mouse button or press the Space Bar to display the answers.

Locating PlacesMatch the letters on the map with the physical features of Earth.

__1. Rocky Mountains __6. Ural Mountain__2. Isthmus of Panama __7. Arctic Ocean__3. Gulf of Mexico __8. Mediterranean

Sea__4. Andes __9. Bay of Bengal__5. Himalaya __10. Europe

BEGCH

DIJFA







Documents

Splash Screen Intro 1 Section 1-3 Click the mouse button or press the Space Bar to display the information. Antarctica Europe Asia North America