1. The Importance of Natural Resources
Earth’s Land - Chapter 2
The Importance of Natural Resources

2. Key Concepts natural resources come from the land
soil is the most important resource -- plants grow =
food source
important to conserve soil

3. Gully! It’s Soil Erosion
Geologist – scientists who study Earth materials
soil – loose rock material covering the Earth’s land surface
soil erodes more quickly from bare soil than with sod
plants grown to anchor soil

4. Soil – A Limited Resource
natural resource – any useful material from Earth (ex: coal, trees, air, water, soil)
soil most important – plants grow in it (food source for all living things)

5. Using Soil Wisely greatest cause of soil erosion = running water
gullies – miniature river valleys formed
conservation – wise use of natural resources
To conserve soil: leave plants growing
contour plowing – plowing hilly land following shape of land
strip cropping – planting cover crop between rows
dam building – helps slow or stop formation of gullies
terracing – building step-like ridges to prevent or slow down water runoff

6. Soil Profile
topsoil – weathered rock & humus (decayed plant & animal matter – provides nutrients)
subsoil – clay particles
weathered rock

7. From Rocks to Riches
thinnest layer of Earth – crust (thickest parts are the continents & ocean floors)

8. An Inside Look at Rocks
rock – solid material made up of one or more minerals
mineral – natural solid that has a definite chemical makeup, found in Earth’s crust

9. Uses of Rocks & Minerals
rock use depends on its properties
- granite – hard rock
- marble – beautiful rock
- graphite – lead pencils
- calcite – chalk
- halite - salt

10. Minerals in Ore
ore – rock that can be mined for the minerals it contains
metals are most valuable substances that come from ore (ex: iron, copper, gold, aluminum, tin)
obtaining metals in ore  long & costly

11. Resources Worth Saving
renewable resource – resource that can be replaced
- ex: trees – can plant more
nonrenewable resource – resource that cannot be replaced
- ex: water, air,
- must be conserved or people will need to
do without them in the future

12. Fuels Around the World
How does the use of fossil fuels in the United States compare with that of other nations?
U.S uses MORE or LESS

13. Fuel From Living Things
Wood – comes from trees / stores energy from sun
Solid Animal Waste (dung) – energy stored in plants eaten by animals (CA – power plant)

14. Fossil Fuels
Fossil Fuels – fuels made from the remains of once living things
-NONRENEWABLE RESOURCE
Ex: natural gas, coal, petroleum (crude oil)
Ex: peat – made from remains of ancient swamp plants / can change into coal

15. Supply & Demand World’s fossil fuels not shared equally.
U.S. uses about 47 times more petroleum per person than someone in India.
U.S. uses 3 times as much coal as per person in China.
Fossil fuels are nonrenewable resources.

16. They will eventually run out!
Coal, Gas, and Black Gold
What are the major drawbacks of using fossil fuels as the main source of energy?
They will eventually run out!

17. Energy From Ancient Sunlight
All fossil fuels contain energy that was once stored in the cells of living things.
Plants & animals got their energy from the SUN.

18. Fuel From Fossils
Millions of years ago plants & animals were covered by mud & sand (ocean floor & swampy areas).
Heat & pressure slowly changed the once-living things into petroleum and natural gas.
Eventually became peat and can change to coal if given enough time.

19. Bad News About Fossil Fuels
Fossil fuels cannot be replaced in our lifetime.
Natural gas & petroleum take millions of years to form.
Coal is more plentiful than oil or natural gas.
Mining coal destroys huge areas of land, is costly, & takes a long time.
Burning fossil fuels adds carbon dioxide and other harmful gases to the air.
Carbon dioxide traps & holds heat close to the Earth’s surface = GREENHOUSE EFFECT = CLIMATE CHANGE

20. Good News About Fossil Fuels
It is possible to estimate when supplies will run out.
We can remove fossil fuels only as needed.
Fossil fuels used to warm rooms, heat water, & power machines.

21. New Energy Sources solar energy – energy from the Sun
wind energy – energy from the wind (windmills)
sea water, energy from inside the Earth