Chapter 5: Natural Resources

Big Idea:  Society depends on natural resources for energy and materials.

5.3 Energy comes from other natural resources.

 

I.  Nuclear power is used to produce electricity.

         A.  In the United States, nuclear power plants generate 10% of the total energy used

         B.  In fossil fuel power plants, water is boiled and steam turns the turbine, which drives the generator

         C.  Nuclear power plants

                  1.  The same process happens

                  2.  The source of heat for the water, though, is not burning coal, it is nuclear fission

                  3.  fission vs. fusion

a.  fission- the nucleus of a radioactive atom is split, forming lighter elements and releasing a huge amount of energy

i.  A fission bomb is often called an atom bomb, and is designed to release as much energy as possible as quickly as possible

b.  fusion- nuclei of atoms combine, creating a heavier element and absorbing or releasing energy

i.  When fusion occurs in an uninterrupted chain, a thermonuclear explosion can occur, like that of the hydrogen bomb

                  4.  Nuclear power plants use uranium atoms as fuel

                           a.  When split, they release a large amount of energy as light and heat

                           b.  Control rods inside the reactors limit the reaction to provide a safe amount of energy

c.  The chain reaction caused by the splitting atoms creates enough heat to produce steam in the reactor vessel

                           d.  The steam heats a coiled pipe, which boils water in the heat exchanger

                           e.  Steam from the boiled water turns a turbine that winds the generator

                           f.  Steam condenses into water and is recycled through the system

                  5.  Nuclear power plants need an abundance of water (Beaver Valley Power Station)

D.  Splitting one uranium atom releases 20 million times more energy than burning one molecule of natural gas

         E.  Nuclear fission also produces radioactive waste that remains active for thousands of years

         F.  How do we dispose of this?  Store it, bury it

 

II.  Renewable resources are used to produce electricity and fuel.

         A.  Including:  moving water, wind, Earthís internal heat, sunlight, living matter, and hydrogen

         B.  So far, though, these resources canít produce enough energy to cover their cost

         C.  In the United States, only 6% of energy used comes from these sources

         D.  Hydroelectric Power

                  1.  Hydroelectric energy is energy produced by moving water

                  2.  Generally, these stations are located at dams 

                  3.  How does it work?  (Page 164)

                  4.  But—building dams poses environmental problems

                           a.  Flooding land for reservoirs destroys animal habitats

                           b.  Snake and Columbia rivers (NW US)- interrupts salmon and fish migrating routes

                           c.  Water levels drop near end of river, making it harder for crop-growing

         E.  Solar Energy

1.  Solar cell-  a specially constructed sandwich of silicon and other and other materials that converts light energy to electricity

2.  How does it work? (Page 165)

3.  Current methods of collecting sunlight are expensive and inefficient

4.  As technology improves, sunlight is likely to be an important energy source

         F.  Geothermal Energy

                  1.  Energy produced by heat within Earthís crust

                  2.  How does it work? (Page 166)

                  3.  Problems:  limited to areas with hot water sources

         G.  Wind Energy (windfarms)

                  1.  For thousands of years, people have used wind to sail ships, grind grain, and pump water

                  2.  Wind energy- the force of moving air

                  3.  Modern windmills- made of metal and plastic and can stand 40 stories

                  4.  How does it work? (Page 167)

                  5.  Although clean and renewable, wind power has negatives

                           a.  Need strong, steady wind

                           b.  Take up a lot of land, can be noisy

         H.  Biomass Energy

                  1.  Biomass-  organic matter (plant and animal waste) that can be used as fuel

                  2.  Each year in the United States biomass plants burn 60 million tons of wood/plant material

                  3.  They generate enough electricity to power a whole state for a year

                  4.  How does it work?

                  5.  Some waste can be converted into liquid fuels

                           a.  Ethanol can be mixed with gasoline (gasohol) to fuel small cars, farm machines, and buses

                           b.  Liquid waste used to heat homes in rural areas

6.  Problems:  burning wood releases as much carbon dioxide as burning fossil fuels does, biomass crops take up much space, too expensive to mass produce

         I.  Hydrogen Fuel Cells

                  1.  Hydrogen atoms are simple:  a nucleus and one proton and one electron

                  2.  Scientists have found a way to separate hydrogen from water and fossil fuels

                  3.  Extremely flammable

4.  Hydrogen fuel cell- device that produces electricity by separating hydrogen protons and electrons

                  5.  How does it work?  (Page 168)

                  6.  Problems:  still too expensive for mass production, few fueling stations