CHAPTER 5 Energy And Energy Resources

CHAPTER 5LESSON 3Energy and Energy ResourcesEnergy ResourcesKey Concepts What are nonrenewableenergy resources? What are renewableenergy resources? Why is it important toconserve energy?What do you think? Read the two statements below and decidewhether you agree or disagree with them. Place an A in the Before columnif you agree with the statement or a D if you disagree. After you’ve readthis lesson, reread the statements to see if you have changed your mind.BeforeStatementAfter5. Nuclear power plants release many dangerouspollutants into the air as they transform nuclearenergy into electric energy.6. Thermal energy from within Earth can betransformed into electric energy at a powerplant.3TUDY #OACHReading Check1. Identify Where doesthe energy in plants andfuels come from?88Energy and Energy ResourcesSources of EnergyEvery day, you use many forms of energy in manydifferent ways. According to the law of conservation ofenergy, energy cannot be created or destroyed. Energy canonly change form. Where does the energy that you use comefrom?Most energy you use can be traced back to the Sun. Thechemical energy in the food you eat originally came fromthe Sun. The energy in fuels, such as gasoline, coal, andwood, originally came from the Sun. A small amount ofenergy that reaches Earth’s surface comes from inside Earth.However, the amount of energy that comes from the Suneach day is about 5,000 times greater than the amount ofenergy that comes from inside Earth.Electric Power PlantsMost of the energy you use every day does not comedirectly from the Sun. Much of the energy you use is in theform of electric energy. Many of the appliances in yourhome require electricity. The lights in your classroom arepowered by electricity. Most of the electric energy you usecomes from electric power plants.Reading EssentialsCopyright Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.Organize Your Notes Makea table with two columns tocontrast different types ofenergy resources. Label onecolumn NonrenewableResources and the othercolumn Renewable Resources.Complete the table as youread this lesson.

How Electricity Is merTurbineIntake pipeFuelPower linesSteamCoolingwaterEnergy Sources An electric power plant transforms theenergy in an energy source into electric energy. Power plantsuse three main energy sources. One source of energy comesfrom burning fuels, such as coal. The figure above shows apower plant that uses coal as an energy source. Nuclearpower plants use nuclear energy contained in uranium.Hydroelectric power plants change the kinetic energy infalling water to electric energy.Visual Check2. Specify What form ofenergy changes water intosteam?Copyright Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.Energy Transformation The figure above shows how anelectric power plant transforms the chemical energy storedin coal into electric energy. When coal burns, some of itschemical energy changes to thermal energy. The thermalenergy heats water, producing steam. The steam spins theblades of a turbine, changing thermal energy intomechanical energy. The turbine is connected to a generatorwhich changes mechanical energy into electric energy.The electric energy then travels through power lines.Make a shutter fold toorganize your notes onnonrenewable andrenewable energy resources.NonrenewableEnergy ResourcesRenewableEnergy ResourcesNonrenewable Energy ResourcesThe coal that a power plant burns is an example ofa nonrenewable energy resource. A nonrenewable energyresource is an energy resource that is available in limited amountsor that is used faster than it is replaced in nature.Fossil FuelsFossil fuels are the most commonly used nonrenewableenergy resources. Fossil fuels are the remains of ancient organismsthat can be burned as an energy source. Three types of fossil fuelsare coal, natural gas, and petroleum. Petroleum is also oftenreferred to as oil. Coal is a solid fossil fuel. Fossil fuels takemillions of years to form. They are being used up muchfaster than they form.Reading EssentialsKey Concept Check3. Explain Why are fossilfuels considered anonrenewable energyresource?Energy and Energy Resources89

The Formation of Fossil FuelsThe processes that formed fossil fuels began at Earth’ssurface. Petroleum and natural gas formed from microscopicocean organisms that died and sank to the ocean floor, asshown in the figure below. These organisms were graduallyburied under layers of sediment—sand and mud—and rock.Over millions of years, the weight of the sediment androck layers increased the temperature and pressure on thedead organisms underground. This heat and pressurechanged the dead organisms into petroleum and natural gas.Coal formed on land from plants that died millions ofyears ago. The dead plants were buried under thick layersof sediment and rock.Layer of sedimentcontaining remainsof dead marineorganismsOceanLandOverlying layersof sedimentOiland gasOceanOil and natural gasformed by heat, pressure,and chemical reactionsVisual Check4. Identify What forcesact on the dead organisms insediment, transforming thesematerials into oil and gas?Layer of rockLayer of rockSedimentUsing Fossil FuelsFossil fuels formed from organisms that changed radiantenergy from the Sun to chemical potential energy. Thechemical potential energy stored in fossil fuels changes tothermal energy when the fossil fuels burn.Using Petroleum Gasoline, fuel oil, diesel, and kerosene aremade from petroleum. These fuels are burned mainly topower vehicles and to heat buildings. Petroleum is also usedas a raw material in making plastics and other materials.Using Coal Electric power plants burn about 90 percentReading Check5. Specify Whatpercentage of the coal usedin the United States is burnedin electric power plants?90Energy and Energy Resourcesof the coal used in the United States. Some coal is burnedto heat buildings. Coal is also used to produce steel andconcrete.Burning coal produces more pollution than burning otherfossil fuels. In some places, these pollutants react with watervapor in the air and create acid rain. Acid rain can harmorganisms, such as trees and fish.Reading EssentialsCopyright Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.Old ocean bed

Using Natural Gas About half of all homes in the United Statesuse natural gas for heating. Electric power plants burn about30 percent of the natural gas used in the United States.Burning natural gas produces less pollution than burningother fossil fuels.Fossil Fuels and Global WarmingBurning fossil fuels releases carbon dioxide gas intoEarth’s atmosphere. Carbon dioxide is one of the gases thathelps keep Earth’s surface warm. However, over the past100 years, Earth’s surface has warmed by about 0.7oC. Someof this warming is a result of the increasing amount ofcarbon dioxide produced by burning fossil fuels.Nuclear EnergyPeople can transform nuclear energy into thermal energy.Nuclear energy is energy that is released when the nuclei ofuranium atoms break apart. Certain minerals containuranium, but significant amounts of uranium are no longerbeing formed inside Earth. As a result, nuclear energy fromuranium is a nonrenewable energy resource.Copyright Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.Nuclear Power Plants The figure below shows the energychanges that occur inside a nuclear power plant. Breakingapart uranium nuclei transforms nuclear energy into thermalenergy. This thermal energy changes water into steam. Thesteam spins a turbine, changing thermal energy intomechanical energy. The turbine spins a generator, changingmechanical energy into electric energy.Math SkillsElectric energy is oftenmeasured in units calledkilowatt-hours (kWh). Tocalculate the electric energyused by an appliance in kWh,use this equation:wattskWh ( hours1,000 )Appliances typically have apower rating measured inwatts.6. Solve a One-StepEquation A hair dryer israted at 1,200 watts. If youuse the dryer for 0.25 hours,how much electric energy doyou use?Reading Check7. Explain Why is nuclearenergy released fromuranium nuclei considereda nonrenewable energyresource?Unlike a fossil fuel power plant, a nuclear power plantdoes not release pollutants into the air. However, a nuclearpower plant produces harmful nuclear waste.Electrical Energy from Nuclear Energy1. Nuclear energyof atoms2. Thermal energyof water3. Kinetic energyof steam5. Electrical energyout of generator4. Kinetic energyof turbineGeneratorVisual Check8. Sequence Describe theenergy changes that takeplace to make electricityfrom nuclear energy.Reading EssentialsEnergy and Energy Resources91

Storing Nuclear Waste Nuclear waste contains radioactivematerials that can harm living organisms. Some of thesematerials can remain radioactive for thousands of years.Almost all nuclear waste in the United States is currentlystored at the nuclear power plants that produce the waste.Renewable Energy ResourcesKey Concept Check9. Contrast renewable andnonrenewable energyresources.hydroelectric power?(Circle the correct answer.)a. energy from windb. energy from falling waterc. energy from the SunHydroelectric Power PlantsThe most widely used renewable energy resource is fallingwater. The figure below shows a hydroelectric power plant.The power plant changes the kinetic energy in falling waterinto electric energy. First, a dam is built across a river. Thisforms a large pool of water called a reservoir (REH zuh vwor)behind the dam. The water stored behind the dam haspotential energy. As this water falls through tunnels in thedam, the water’s potential energy changes into kineticenergy. The kinetic energy of the flowing water spins aturbine. The turbine spins a generator, changing kineticenergy into electric energy.Hydroelectric power plants do not produce pollutants.However, in some places, the dams can disturb the life cycleof some wildlife, such as fish.1. Potential energy ofwater in reservoir2. Kinetic energyof water3. Kinetic energyof turbineLong-distance4. Electrical energy power linesout of generatorVisual Check11. Infer what wouldhappen to the turbine if theriver stopped flowing.92Energy and Energy ResourcesReading EssentialsCopyright Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.10. Define What isFossil fuels and uranium are being used up faster thanthey are being replaced. However, other energy resources arenot being used up. These energy resources are called renewableresources. A renewable energy resource is an energy resource thatis replaced as fast as, or faster than, it is used. Renewable energyresources include water, sunlight, geothermal energy, wind,and biomass.