WORLD GEOGRAPHY
CHAPTER 4
“LANDFORMS, WATER, AND NATURAL RESOURCES”

SOLs
WG.2b, WG.2c, WG.4, WG.7b

I. FORCES THAT SHAPE THE LAND
A. Theory of plate tectonics
1. Earth’s crust is divided into more than a dozen rigid, slow-moving plates
2. Plates move slowly across Earth’s upper mantle (continental drift)
B. Volcanoes
1. Signal that a plate boundary is nearby
2. Opening in Earth’s surface from which lava comes or the surface feature created by the lava
3. Lava is melted liquid rock from within Earth that spills out on Earth’s surface
C. Earthquakes
1. Sudden shakings of Earth’s crust
2. Occur when tectonic forces cause masses of rock inside the crust to break
3. Common near plate boundaries
D. Weathering
1. Process in which rocks break and decay over time
2. Causes include chemicals, daytime heating and nighttime
cooling, repeating freezing and thawing, and roots of trees
E. Erosion
1. Movement of surface material from one location to another
2. Causes
a. Water: most important force of erosion
b. Waves
c. Wind
d. Glaciers (thick masses of ice)
c. Build dams across rivers
II. SHAPES ON THE LAND (worksheet)
III. THE HYDROSPHERE (worksheet)
IV. NATURAL RESOURCES
A. Any physical material that makes up part of Earth and that people need
and value
B. Two kinds: renewable and nonrenewable





V. RENEWABLE RESOURCES
A. Those that natural processes continually replace
B. Soil
1. Profile varies according to climate and major vegetation types and
on local environmental conditions
2. Necessary to produce food so it must be preserved, how?
a. Contour plowing
b. Prevent soil exhaustion, how?
1. Use of fertilizers
2. Crop rotation
3. Don’t overuse irrigation as it leads to soil salinization
C. Forests
1. Protect soil from erosion, provide habitats for different species, and yield useful products
2. Must stop deforestation (destruction or loss of forests); main causes include logging for wood, clearing for farmland and ranch land, and cutting wood for fuel
3. Reforestation (replanting of trees)
D. Air
1. Threatened by pollution
2. Polluted air can be harmful to human health
E. Water
1. For centuries, people have moved water through dams, canals, reservoirs and aqueducts
2. Must be protected from pollution
F. Energy Resources
1. Hydroelectric power: electricity produced by moving water
2. Wind power
3. Geothermal energy: heat of Earth’s interior
4. Solar energy
VI. NONRENEWABLE RESOURCES
A. Those that cannot be replaced naturally after they have been used
B. Metals: gold, iron, copper and bauxite
C. Energy Resources
1. Have become more useful and valuable as people develop new technologies that need them for power
2. Uranium
a. Radioactive
b. Provides energy for nuclear power plants
1. Do not pollute the air
2. Creates waste material that remains dangerous for thousands of years
3. Problem of disposing of nuclear waste has limited the use of nuclear power


3. Fossil fuels: formed from the remains of ancient plants & animals
a. Coal
1. Long used for heat
2. Powered early steam engines and steel mills
3. Remains an important fuel for electric power
generation
4. Disadvantage is that it pollutes the air when it is burned and can lead to acid rain
5. Advantage is that its supply is plentiful
b. Petroleum (oil)
1. First used as fuel for lamps
2. Automobile expanded market for oil
3. As it became for useful, became more valuable
4. Supplies are limited
c. Natural Gas
1. Important for home and industrial heating
2. Along with oil, used to produce electricity as they both burn more cleanly than coal
3. Growing in importance as it is abundant
4. Prices are rising