1. World Geography TodayChapter 4 Landforms, Water, and Natural Resources Preview Section 1: LandformsLandforms Section 2: The HydrosphereThe Hydrosphere Section 3: Natural ResourcesNatural Resources Chapter Wrap-Up

2. World Geography TodayChapter 4 Read to Discover What physical processes inside Earth built up the land? What physical processes on Earth’s surface wear down the land? How do these physical processes interact to create landforms? Section 1: Landforms

3. World Geography TodayChapter 4 Earth’s crust is made up of moving plates, which spread, collide, and slide laterally past one another. Section 1: Landforms Spreading plates form oceanic ridges undersea and rift valleys on land. Colliding plates cause trenches and volcanoes undersea and mountains on land. Plates sliding laterally cause fractures and earthquakes. Plate Tectonics

4. World Geography TodayChapter 4 Question By which processes do weathering and erosion wear down the land? Section 1: Landforms

5. World Geography TodayChapter 4 Weathering and erosion shape the land. Section 1: Landforms Weathering—Slow and hard to detect; includes chemical and physical processes Erosion—Movement of surface material by water, wind, and ice; wears down land Forces on Earth’s Surface

6. World Geography TodayChapter 4 Erosion Chemical Processes Substances in air and water Water Rainfall Rivers Waves Wind Abrasion Move from one place to another Ice Glaciers Weathering Physical Processes Heating and cooling Freezing and thawing Tree roots Section 1: Landforms Weathering and Erosion

7. World Geography TodayChapter 4 Section 1: Landforms Tectonics and Surface Forces Interact Landforms are created through a combination of forces. For example, a mountain range is formed by tectonics and then weathered and eroded to create valleys, alluvial fans, deltas, and other landforms.

8. World Geography TodayChapter 4 Section 2: The Hydrosphere Read to Discover In what forms and where do we find water on Earth? What are the causes and effects of floods?

9. World Geography TodayChapter 4 Section 2: The Hydrosphere Forms of Water Saltwater—97 percent of world’s water Freshwater—most frozen in ice caps; less than 1 percent in vapor and liquid form Where Liquid Freshwater Is Found: Surface Water—in headwaters, tributaries, rivers, lakes, estuaries, wetlands Groundwater—stored in soil and water table

10. World Geography TodayChapter 4 Question What roles do evaporation, condensation, and precipitation play in the hydrologic cycle? Section 2: The Hydrosphere

11. World Geography TodayChapter 4 Evaporation: Energy transforms water into vapor. Condensation: As water vapor rises, it forms droplets. Surface Water Precipitation: Droplets may become heavy enough to fall as rain, snow, or hail. Section 2: The Hydrosphere

12. World Geography TodayChapter 4 Section 2: The Hydrosphere Causes—Rivers carrying more water than the stream channels can hold; heavy rains, sudden snow melts; human activity may contribute Effects—Erosion, loss of vegetation and livestock, death, spread of disease, and property destruction Floods

13. World Geography TodayChapter 4 Section 3: Natural Resources Read to Discover Why are soil and forests important resources? What are the concerns about water quality and air quality? What are some of the ways minerals are used? What are the main energy resources, and how are they used?

14. World Geography TodayChapter 4 Section 3: Natural Resources Importance of Soil and Forests Soil and forests are renewable resources. Natural processes continuously replace them. Soil is crucial for plant life and production of food for humans and for other animals. Forests protect soil from erosion, provide species habitats, and yield useful products, such as wood, paper, food, medicines, oils, and rubber.

15. World Geography TodayChapter 4 Section 3: Natural Resources Air Pollution—Threatens air supply; dangerous to health of humans, animals, and plants; creates acid rain, which can damage trees and kill fish; damages the ozone layer, which absorbs harmful ultraviolet radiation; may contribute to global warming Water Pollution—Threatens clean water supply; contributes to shortages Air and Water Quality

16. World Geography TodayChapter 4 Causes: Factories and automobiles burn chemicals, releasing smoke and fumes into the atmosphere. Effects: Acid rain, which can damage trees and kill fish; ozone layer damage; threat to human health; may contribute to global warming Section 3: Natural Resources AIR POLLUTION

17. World Geography TodayChapter 4 Section 3: Natural Resources Minerals are solid substances that come out of the ground, such as metals, rocks, and salt. Minerals are used in many processes and products, including construction, jewelry, and manufacturing. Items made from minerals include building materials, airplanes, cans, and glass. Examples: Quartz, limestone, aluminum, gold, gemstones Minerals

18. World Geography TodayChapter 4 Section 3: Natural Resources Energy resources are nonrenewable and include fossil fuels — coal, natural gas, and petroleum — and uranium. Uses: Uranium—Energy for nuclear power Coal—Heat source; power for steam engines, mills, electricity generation; dye making Petroleum—Lamp fuel; gasoline; diesel and heating fuel; asphalt; petrochemicals Natural Gas—Home and industrial heating; fuel

19. World Geography TodayChapter 4 Chapter Wrap-Up Understanding the Main Ideas 1.What are the three types of movements possible at plate boundaries? 2.What are the two physical processes that wear down landforms on Earth’s surface? 3.What process makes some inland lakes salty? 4.What are two short-term effects of air pollution? 5.What is a major drawback of using coal as an energy source?