Objectives After studying this chapter, you will be able to: describe how the five themes geographers use to help explain what a place is like and why.  explain how landforms, waterways, climate, and natural resources have shaped history.  discuss why legends are important to the study of history.  summarize how archaeology helps scientists learn about ancient civilizations. Click the mouse button or press the Space Bar to display the information. Chapter Focus 2

Objective 2 - Land, Water, and Climate Three of the things geographers study: land, water, and climate.  Landforms Land covers about 30 percent of the surface of the earth.  landforms - natural features of the earth’s land surface.  Geographers describe each landform by: elevation - height above sea level  relief - change in height  Section 2-1

Landforms (cont.) elevation - height above sea level relief - change in height  Section 2-3

Landforms (cont.) Four main kinds of landforms:  Mountains are the highest of the world’s landforms and generally have high relief.  Hills are lower than mountains and generally have moderate relief.  Plateaus are raised areas of flat or almost flat land that can vary in elevation. Most of them have low relief.  Plains are large areas of low lying, flat or gently rolling, land with low relief. Section 2-3

Surface Changes From Inside the Earth The land surface of the earth is constantly changing, usually from heat and pressure.  The inside of the earth is made up of three separate layers.  At the center of the earth is the core.  Around the core is the mantle, which is made up mostly of hot, solid rock.  Floating on the melted upper part of the mantle is a thin layer of rock, sand, and soil called the crust. Click the mouse button or press the Space Bar to display the information. Section 2-4

Surface Changes From Inside the Earth (cont.) Heat from the core causes the rock in the mantle to rise, putting pressure on the crust and causing it to move.  In recent years, scientists have come to believe that the crust does not move in one piece but in separate sections called tectonic plates.  The movement of the plates explains what geographers call continental drift.  Plate movement also creates volcanoes. Click the mouse button or press the Space Bar to display the information. Section 2-5

Surface Changes From Inside the Earth (cont.) When tectonic plates slide past one another they can cause earthquakes, or sudden shifts in the earth’s crust.  The tectonic plates are still moving. Click the mouse button or press the Space Bar to display the information. Section 2-6

Surface Changes From Outside the Earth Three main forces from outside the earth that cause changes on its surface are wind, water, and ice.  All three reshape the land by a process called erosion, in which rock and soil are moved from one place on the earth’s surface to another.  Four times in the last 500,000 years, during what are called the Ice Ages, great ice sheets called glaciers spread out from the North and South poles. Click the mouse button or press the Space Bar to display the information. Section 2-7

Landforms in History All through history, landforms have played an important part in helping people decide where to live.  People settled mostly in plains and hilly areas where the soil was rich enough for crops to grow.  Landforms also have made a big difference in the political relationships of people. Click the mouse button or press the Space Bar to display the information. Section 2-8

Waterways About 70 percent of the earth's surface is covered with water.  Oceans - the largest waterways in the world are the four oceans—the Atlantic, the Pacific, the Indian, and the Arctic.  Seas - smaller bodies of salt water, usually partly surrounded by land Lakes - bodies of water that are completely surrounded by land Click the mouse button or press the Space Bar to display the information. Section 2-9

Waterways (cont.) Rivers - waterways that empty into another body of water.  River system – a river and all the streams that flow into it make up a river system. Nile River System – largest in the world Click the mouse button or press the Space Bar to display the information. Section 2-10

Waterways in History Bodies of water - provided travel and trade, drinking water, and irrigation for crops. River valleys - sites for villages and cities. Click the mouse button or press the Space Bar to display the information. Section 2-11

Wind in History Wind - both useful and destructive Can transport great amounts of sediment Loess (les) - in China, winds transported rich soil, from deserts to plains where wheat is grown Dust Bowl - in the U.S in the 1930s wind transported soil away from the plains Click the mouse button or press the Space Bar to display the information. Section 2-11

Climate and the Sun Climate - the pattern of weather of a place over many years.  Sun - provides the earth with heat and light. Earth’s Rotation - spins like a top.  Axis - an imaginary line that runs through the earth’s center from the North Pole to the South Pole. Click the mouse button or press the Space Bar to display the information. Section 2-12

Climate and the Sun (cont.) Orbit - earth moves around the sun in an almost circular path.  Revolution - 365 1/4 days to complete.  Seasons – caused by the combination of earth’s revolution and the tilt of its axis. Section 2-13

Climate Zones Latitude - distance north or south of the equator Determines the amount of heat from the sun a place receives Climate zones – Three zones based on latitude Tropical zone - the area between the Tropic of Cancer and the Tropic of Capricorn. Section 2-14

Climate Zones (cont.) Temperate zone Northern Hemisphere – between the Tropic of Cancer and the Arctic Circle Southern Hemisphere – between the Tropic of Capricorn and the Antarctic Circle Polar zone - north of the Arctic Circle and south of the Antarctic Circle. Click the mouse button or press the Space Bar to display the information. Section 2-15

Climate, Water, and Wind Climate - shaped by large bodies of water. Keeps the temperature of a place from getting too hot or too cold. Ocean current - ocean water that flows in a steady stream. Climate - shaped by the movement of air. Prevailing winds because they blow from a certain direction almost all of the time.  Section 2-16

Books – Page 17

Climate and Altitude Higher the altitude - cooler the climate.  Precipitation–the falling of moisture such as rain or snow.  Adiabatic cooling - As the air rises over mountains, it cools and drops its moisture. Section 2-17

Climate in History Climate helps determine nearly every aspect of a civilization including where people live and what kinds of crops are grown. Give examples of how climate affected history….. Section 2-18

Homework – p. 19, problems 1, 3, 5

Natural Resources Natural resources - materials found in nature. Natural resources help people live better lives. Essential for life - air, water, soil, and sunlight Others - minerals, fossil fuels, forests, and animal life Section 3-1

Kinds of Natural Resources (cont.) Natural resources become valuable only when people learn how to use them. Nonrenewable resources - cannot be replaced as they are used. Renewable resources - replaced as they are used. Minerals - nonliving substances found beneath the earth’s surface.  Click the mouse button or press the Space Bar to display the information. Section 3-3

Natural Resources in History Natural resources affected the location and growth of settlements all through history.  Asians and Europeans came into contact with one another partly because Europeans wanted the silks and spices of Asia that had been cultivated.  Modern industry started in countries that had large amounts of coal and iron ore for making steel. Click the mouse button or press the Space Bar to display the information. Section 3-4

End of Section 3