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EnergyProblemsandSolutions2007Macmillan/McGraw-HillIntroductionDuring a space shuttle flight,an astronaut passed some time trying to find his home.As the spacecraft orbited Earth,the astronaut peered through the shuttles windows to the world far below.Finally,he found itthe twinkling lights of the city where he lived.What a thrill!It was comforting to see home when he was so far away.But then a strange thing happened.On the next orbit,he looked out the window again.This time the entire region around the city felt like home.On the orbit after that,he only had to look for his country to feel at home;then only at the continent.Eventually the astronaut saw the entire Earth as home sweet home.Earth is our home in the universe.Are we taking care of it?2Indexacid rain,8Arctic Ocean,1113automobile,45,8,11,1819“building green,”19carbon dioxide,9,11,15climate,1015conservation,2021coral bleaching,12electricity,45,18,20environment,3,78,21Exxon Valdez,7fluorescent light,18,20fossil fuels,56,9,14,21glaciers,1011global warming,1215greenhouse effect,9Grinnell Glacier,10hybrid cars,1819incandescent light,18,20oil spills,7pipeline,6pollution,8power plants,5,8,18recycling,1920smog,8solar energy,14,16,17strip-mining,6wind turbine,1723AB6_U3_W3_Energy.indd 1929/22/05 7:02:25 PMEnergyProblemsandSolutions2007Macmillan/McGraw-HillThe astronaut understood a simple yet important ideaall of Earth is our home.But lately we havent been too kind to our home.In fact you might say our home is in need of repair.Many of the problems facing the planet come down to one thingour quest for energy.This book explores how the use of energy affects the environment.Yes,there are problems.But there are solutions,too.3Glossaryacid rain (AS-id rayn)rain or snow full of poisonous chemicals (page 8)energy (EN-urj-ee)the capacity for doing work (page 3)fossil fuel (FOS-uhl FYEW-uhl)a fuel formed from the remains of prehistoric plants and animals (page 5)generate (JEN-uh-rayt)to bring about or produce (page 5)glacier (GLAY-shuhr)a large mass of ice in very cold regions (page 10)global warming (GLOH-buhl WAWRM-ing)an increase in the average temperature of the atmosphere of the earth (page 12)greenhouse effect (GREEN-hows i-FEKT)the trapping of heat from the sun within the earths atmosphere (page 9)hybrid car (HIGH-brid kahr)a car that can switch from gasoline-powered to battery-powered,using less nonrenewable energy (page 19)nonrenewable (NON-ri-new-uh-bul)relating to a resource that is gone forever once it is used up (page 5)pollution (puh-LEW-shuhn)harmful materials such as certain gases,chemicals,and wastes that pollute the air,water,or soil (page 8)renewable (ri-NEW-uh-bul)relating to a resource that is replaceable (page 5)smog (SMOG)a combination of smoke and fog in the air (page 8)strip-mine (STRIP-mighn)to remove topsoil in order to dig out a mineral that lies close to the surface,especially coal (page 6)22AB6_U3_W3_Energy.indd 1939/22/05 7:02:26 PMEnergyProblemsandSolutions2007Macmillan/McGraw-HillCHAPTER 1The Costs of EnergyClick on the TV.Turn up the heat.Go for a ride in the car.What do all these actions have in common?They all use energy.Energy is an important part of our lives.Try to imagine going through a day without it.First take away everything that uses electricity.No refrigerator,no TV,no light bulbs.Then shut down everything that runs on gasoline or fuel.No cars,trucks,planes,or trains.Next turn off the natural gas or oil that keeps your home warm on bitter cold nights.You get the ideaenergy powers our lives.It may be hard to imagine life with no electricity,but your ancestors got along just fine without it.For example,100 years ago there were no refrigerators that ran on electricity.How did people keep food cold?They used iceboxes.Most iceboxes were wooden boxes lined with metal.A large block of ice placed in one part of the box kept food cool in other parts of the box.A Kitchen Without Electricity4ConclusionThe costs of energy include more than how much money one has to pay to use an energy source.Costs also include the environmental effects of using the energy source and how much of the source we are using up if its nonrenewable.Right now fossil fuels are the cheapest to use,but the costs to the environment and the limited supply may force us to use renewable energy sources more fully.Meanwhile,everyone can help by conserving energy.21AB6_U3_W3_Energy.indd 1949/22/05 7:02:29 PMEnergyProblemsandSolutions2007Macmillan/McGraw-HillThe Problems with Fossil FuelsMost of the energy we use comes from fossil fuelscoal,oil,and natural gas.These energy sources are called fossil fuels because they formed from plants and animals that died millions of years ago.Fossil fuels have many uses.Power plants burn coal and oil to generate electricity.Gasoline and fuel for most cars,planes,trains,and ships come from oil.Oil and natural gas provide heat for homes.In many ways fossil fuels are excellent sources of energy.Whats the problem?Fossil fuels are nonrenewable.Once we use them up,they are gone forever.Other energy sources,such as sunshine and wind,are renewable.They cannot be used up.No one knows for sure how long our fossil fuels will last.However,one thing is for sure:sooner or later we will run out of fossil fuels.Oil gathers in rocks undergroundboth on land and beneath the sea.Pumps pull the oil out of the ground.5Conserving energy isnt just for carmakers and housing developers.Everyone can get involved.Here are some things you can do every day to save energy and take better care of our planet at the same time.Use less electricity whenever possible.Turn off lights that you arent using.Dont run any electrical device unnecessarily.Ask a family member about replacing incandescent lights with compact fluorescent lights.Walk or ride a bike instead of asking for a ride.If youre cold,put on a sweatshirt instead of turning up the heat.Keep the curtains closed or shades drawn on hot,sunny days so that it stays cooler indoors without running the air conditioner.Use less hot water by taking showers instead of baths,running dishwashers only with a full load,and doing laundry in cold water.Recycle and reuse things whenever you can.Recycling aluminum cans uses only 5 percent of the energy required to make new cans from raw materials.The more you reuse,the less energy will be spent to make new items.What You Can Do20AB6_U3_W3_Energy.indd 1959/22/05 7:02:33 PMEnergyProblemsandSolutions2007Macmillan/McGraw-HillMining and DrillingSome problems with fossil fuels come from the way we get them.Most coal,for example,is strip-mined.Huge earth-moving machines strip away the top layers of soil and rock to get to the coal beneath.Strip mines become giant scars on the land.Exposed metals and chemicals from the mines often wash into streams and pollute the water.Laws require mining companies to restore strip-mined land close to the way it was before being mined.Some mines have been successfully restored,but it is expensive and time-consuming.Oil and natural gas cause some problems,too.More than half of the oil the United States uses comes from other countries,such as Saudi Arabia and Venezuela.Pipelines carry oil over land.Some of them stretch for thousands of miles across the landscape.What problems might pipelines cause for animals that travel in herds?6 Hybrid cars that can switch from gasoline-powered to cleaner battery-powered are becoming more and more popular.Industries everywhere are looking for ways to use less energy and use it more efficiently.Housing developers are getting involved,too.A trend called“building green”is taking hold.It means building houses that are environmentally friendly.“Green”houses are energy efficient.They are well insulated to keep heat in on cold days and keep heat out on warm days.They use energy-efficient lighting and appliances.Some green houses even use recycled building materials that require less energy to make than new materials.This“green”house is energy efficient.19AB6_U3_W3_Energy.indd 1969/22/05 7:02:35 PMEnergyProblemsandSolutions2007Macmillan/McGraw-HillYou may have heard the saying,“Accidents are bound to happen.”This is true when you are riding a bike.It is also true when ships the size of several football fields are carrying oil on the high seas.Sometimes tankers slowly leak oil into the water.Sometimes a storm or navigation error causes a shipwreck that releases tons of oil into the sea.Either way the oil spill can be devastating to the environment.When the oil washes up on beaches,it harms the animals and plants there.Animals become coated with oil and cannot swim or fly.The oil poisons and kills some animals.It can take years to clean up an oil spill.The worst oil spill in history happened on March 24,1989.The oil tanker Exxon Valdez crashed on rocks near Alaska,dumping 41 million liters(11 million gallons)of oil into the sea.The spill killed 250,000 seabirds,2,800 otters,hundreds of seals,and 22 killer whales in addition to an unknown number of fish.The Exxon Valdez7Using Less and Getting MoreToday everything from light bulbs and windows to kitchen appliances,cooling systems,and entire buildings are being designed for greater energy efficiency.Replacing an incandescent bulb with a fluorescent one would save the buyer up to$50 over the 10-year life of the bulb.Cars are becoming more efficient,too.Carmakers can produce cars that can go farther on the same amount of gasoline.One of the biggest wastes of energy happens in power plants.Generating electricity gives off a lot of waste heat.But this heat can be recovered and put to use.Some power plants redirect the waste energy to heat buildings and water.Other power plants use the waste heat to operate machines at the plant such as scrubbers,which remove harmful gases from the smokestacks.18AB6_U3_W3_Energy.indd 1979/22/05 7:02:38 PMEnergyProblemsandSolutions2007Macmillan/McGraw-HillThe Costs of Using Fossil FuelsMining,drilling,and transporting fossil fuels certainly can have some adverse effects on the environment.But the biggest problems with these fuels come from actually using them.If you have ever gotten stuck behind a car or truck belching exhaust into the air,you know how unhealthy air pollution can be.Burning gasoline in an engine releases gases into the air,including nitrogen oxides.These gases form a yellowish-brown haze called photochemical smog.Motor vehicles are the single largest source of air pollution in the United States.But they are not the only one.Electric power plants and factories burn coal and oil,releasing nitrogen oxides and sulfur oxides into the air.These gases can cause acid rain that damages plants,kills fish,and even damages stone and metal statues.Smog is most common in cities where many vehicles are burning gasoline.8Solar energy has some big advantages over fossil fuels.Sunlight is a renewable energy sourceit wont run out.It is a clean source of energyit doesnt pollute.But solar energy has some disadvantages,too.It is difficult to store solar energy at night and on cloudy days.There are other renewable energy sources that are clean.But each has some disadvantages.Wind turbines can generate electricity.But not all places on Earth have strong,steady winds.Flowing water at a dam or waterfall also turns a turbine to make electricity.But dams cause problems,too.When a river is dammed and the area behind the dam floods,it forces people to move,changes wildlife habitats,and interrupts the natural flow of water.Scientists and engineers are working on ways to make renewable energy sources more affordable as well as more practical.Wind farms in California produce one percent of the states electricity.17AB6_U3_W3_Energy.indd 1989/22/05 7:02:44 PMEnergyProblemsandSolutions2007Macmillan/McGraw-HillFossil Fuels and the Greenhouse EffectHave you ever been in a greenhouse?A greenhouse is made almost entirely of glass.Sunlight shines through the glass and warms up the inside.The heat cannot escape back through the glass so the greenhouse stays warm.In our atmosphere carbon dioxide,water vapor,and other gases act like the glass on a greenhouse.These gases let sunlight pass through but prevent most of the heat from escaping back into space.This trapping of heat is called the greenhouse effect.It causes Earth to stay warm enough to support life.There is evidence that the greenhouse effect is getting stronger.Many scientists say it is because of fossil fuels.Burning the fuels adds enough carbon dioxide to the air to trap more heat,making the planet warmer.Sunlight changes to heat when it strikes Earths surface.Certain gases in the atmosphere prevent most of the heat from escaping into space.9CHAPTER 3Energy SmartsOne solution to the energy problem is to find ways to use other forms of energy.Using solar energy is as simple as raising the window blinds and letting the sun shine in.The sunshine warms the inside so that on a chilly day,you can use less oil or natural gas to run the furnace.Some buildings are designed to take advantage of solar energy.For example,sections of the roof might hang over the sides of a house.The overhang shades the windows in the summer when the sun is highest in the sky and you want to keep the house cooler.The overhang lets more light enter in winter,when the sun is lower in the sky and you welcome the warmth.Solar panels heat water used for cooking,washing,and heating.16AB6_U3_W3_Energy.indd 1999/22/05 7:03:05 PMEnergyProblemsandSolutions2007Macmillan/McGraw-HillCHAPTER 2Is Our Climate Changing?Glaciers carved the landscape of Glacier National Park in northern Montana.During the last Ice Age,these tongues of ice slowly crept down the mountainsides,gouging out deep valleys.Today 26 glaciers remain in the park.But maybe not for long.The glaciers are melting away.Grinnell Glacier,for example,covered 440 acres in 1910.Today its less than 180 acres.As the glacier melts,the meltwater feeds a growing lake nearby.1932198810Scientists also disagree about the future effects of global warming.Many factors affect climates:Carbon dioxide dissolves in ocean water.It is unclear whether more or less carbon dioxide will dissolve in the oceans as the water temperatures rise.Trees and other plants absorb carbon dioxide.If Earth gets warmer,more plants might grow.The extra plants will absorb more carbon dioxide from the air.But if more trees are cut down,more carbon dioxide will stay in the air.A warmer Earth will cause more water to evaporate.More water vapor in the air increases the greenhouse effect.But more water vapor also causes more clouds,which reflect more sunlight away from Earths surface.Its hard to say which effect will be greater.People voice their opinions about global warming.Whats yours?15AB6_U3_W3_Energy.indd 2009/22/05 7:03:10 PMEnergyProblemsandSolutions2007Macmillan/McGraw-Hill?Warmer temperatures are causing Grinnell Glacier to melt.Glaciers arent the only things melting.Large slabs of sea ice in the Arctic Ocean have been noticeably shrin