1. Chapter 2
Lesson 1: Planet Earth

2. The Solar System
Sun is medium-sized star at edge of the Milky Way galaxy
The solar system includes:
sun and eight planets (Pluto just got voted out.)
comets—icy spheres orbiting the sun
asteroids—large chunks of rocky material orbiting the sun
Earth is third planet in the solar system of the sun

8. Size of Earth Circumference of the earth: about 24,900 miles
Diameter of the earth: about 7,900 miles

9. On and Above the Earth
Atmosphere is the layer of gasses surrounding the earth
contains oxygen
protects Earth from radiation, space debris
Location of all weather and climate
Lithosphere—solid rock portion of Earth’s surface, forms ocean floor
Hydrosphere—water elements on Earth including atmospheric water
Biosphere—atmosphere, lithosphere, hydrosphere combined
Plants and animals live within biosphere

10. Continental Landforms
Relief—difference in landform elevation from lowest to highest point
Four categories of relief—mountains, hills, plains, plateaus
Topography—the configurations and distribution of landforms
Topographic map shows vertical dimensions, relationship of landforms

27. Landforms 1. volcano 2. canyon 3. glacier 4. delta 5. oasis 6. swamp
7. bay/ gulf
8. prarie
9. mesa
10. valley
11. marsh
12. cape/ peninsula
13. straight
14. butte
15. cataract
16. steppe

28. Continental Shelf
the area of seabed around a large landmass where the sea is relatively shallow compared with the open ocean. The continental shelf is geologically part of the continental crust.

29. Lesson 2: Forces of Change
Chapter 2
Lesson 2: Forces of Change

30. Inside the Earth Core Mantle Crust Center of the earth
Made up of iron and nickel
Outer core is liquid
Inner core is solid
Mantle
Surrounds the core
Contains most of Earth’s mass
Made of molten rock called magma
Crust
Thin layer of rock at Earth’s surface

32. Continental Drift Continents—landmasses above water on Earth
Continental Drift—Earth was once one supercontinent (Pangaea)
The seven continents on earth fit together like a jigsaw puzzle
Pangaea split into many plates that slowly drifted apart

34. Plate Tectonics
Tectonic plates are massive, moving pieces of Earth’s lithosphere
Plates ride above circulating, heated rock
Geographers study plate movements to understand:
how the earth is reshaped
how earthquakes and volcanoes are formed

36. Plate Tectonics (continued)
Plates move in one of four ways:
by spreading, or moving apart
subduction, or diving under another plate
collision, or crashing together
sliding past each other in a shearing motion
Movement of plates effects surface of the earth
Saudi Arabia–Egypt’s plates are spreading apart, widening Red Sea
India’s plate is crashing into Asian continent, building up Himalayas

41. Folds and Faults
Two plates meeting can cause folding and cracking of rock
Fault occurs when pressure causes rock to fracture
Fault line is the place where plates move past each other

43. Earthquakes
An earthquake occurs when plates grind or slip at a fault line
A seismograph detects earthquakes and measures the waves they create
Earthquake Locations
Location in the earth where an earthquake begins is called the focus
Epicenter—the point directly above focus on the earth’s surface
Nearly 95% of earthquakes occur at tectonic plate boundaries
Richter Scale—numeric scale showing relative strength of earthquake

44. Earthquake Damage Landslides Land displacement
Fires (broken gas lines)
Collapsed buildings

47. Tsunami Tsunami—a giant ocean wave
begins at epicenter of an earthquake
travels at up to 450 mph
waves of 50–100ft. or higher

50. Volcanoes
Volcano—underground materials pour from crack in the earth’s surface
Most volcanoes occur at tectonic plate boundaries
Eruption—lava, gases, ash, dust, explode from vent in Earth’s crust
Lava—magma that has reached the earth’s surface; may create landform
Ring of Fire—zone around rim of Pacific Ocean where most volcanoes are located

54. Volcanoes (continued)
Hot springs, geysers indicate high temperatures in earth’s crust
Some volcanic action is useful
volcanic ash produces fertile soil for growing plants.
hot springs are tapped for heat, energy

55. Weathering
Weathering—processes that alter rock on or near the earth’s surface
Can change landscapes over time and create soil for plant life
Sediment—mud, sand, silt created by weathering processes

56. Mechanical Weathering
Mechanical weathering—processes that break rock into smaller pieces
Does not change rock’s composition, only size
Examples: frosting, plant roots, road construction, mining

61. Chemical Weathering
Chemical weathering—interaction of elements creates new substance
Example: when iron rusts it reacts to oxygen in air
Warm, moist climates produce more chemical weathering than cool, dry

66. Erosion
Erosion—when weathered material moves by winds, water, ice, gravity
Movement grinds rock into smaller pieces, carries to new location

67. Water Erosion Most streams erode vertically and horizontally
A valley cut by a stream gets deeper, wider; forms v-shaped valley
A river deposits sediment at ocean, creates delta—fan-like landform

71. Wind Erosion Wind transports sediment from one place to another
Loess—wind-blown silt and clay sediment; produces fertile soil

73. Glacial Erosion
Glacier—large, long-lasting mass of ice; forms in mountainous areas
Glaciations—changing of landforms by slowly moving glaciers
Example: cutting u-shaped valleys in land
Moraine—hill or ridge formed by rocks deposited by glacier

75. Soil Formation
Soil—loose mix of weathered rock, organic matter, air, water
Soil supports plant growth; fertility is dependent on three factors:
Texture
Amount of humus, which is organic material in soil
Amount of air and water

76. Soil Factors When geographers study soil, they look at five factors
Parent material—the chemical composition of the original rock
Relief—the steeper the slope, the greater erosion; less soil made
Organisms—plants, worms, ants, bacteria loosen soil; supply nutrients
Climate—hot, cold, wet, dry climates produce different soils
Time—about 2.5 cubic cm. of soil produced each century

77. Chapter 2
Lesson 3: Earth’s Water

78. Hydrosphere The ocean circulates through currents, waves, tides
Currents act like rivers flowing through the ocean
Waves are swells or ridges produced by winds
Tides are the regular rising and falling of the ocean created by gravitational pull of the moon or sun
Motion of ocean helps distribute heat on the planet

80. Hydrosphere
Hydrologic Cycle—cycle of water between atmosphere, oceans, earth
Water covers about three-fourths of the earth’s surface.
Lakes hold more than 95% of the earth’s fresh water
Freshwater lakes, like the Great Lakes, are result of glacial action
Saltwater lakes form when outlet to sea is cut off

81. Hydrosphere
Rivers and streams carry water to and from larger bodies of water
Tributaries are smaller rivers, streams that feed into larger ones
Drainage basin—area drained by river and its tributaries
Ground water—water held in the pores of rock
Water table—level at which the rock is saturated

83. Oceanic Landforms
Landforms are naturally formed features on Earth’s surface
Oceanic Landforms (naturally formed features on Earth’s surface)
Continental shelf—sea floor from continent’s edge to deep ocean
Sea floor has ridges, valleys, canyons, plains, mountain ranges
Islands are formed by volcanoes, sand, or coral deposits