studying water power.pdf

8/21/2019 Studying Water Power.pdf

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Studying WaterPowerElectricity makes machines run. Coal, gas, and oil areoften used to create electricity. These sources, calledfossil fuels, will eventually run out. There is a limitedsupply of fossil fuels because they are found only insome areas. Fossil fuels can also harm the environment.Water can be used to create electricity. Water power isrenewable and environmentally friendly. Water poweris called hydroelectricity.

Americans use elec tricity to cook, ligh t the ir homes,and power appliances, includ ing th e washer and dryer.


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Water Power FactsWater creates about 20 percent of the world selectricity. There are many more interestingfacts about water power.

Canada is the world's largest producer ofhydroelectricity.The United States ranks second.

About 10 percent of the United States's electric powercomes from hydroe lectricity.

The state of Washington creates more hydroe lectricpower than any other American state.About 87percent o f Washington's elec tricity is producedby hydroelectric facilities.

The world's first hydroelectric power plant openedon September 30,1882. It was located on the FoxRiver nearApp leton,W isconsin.

Water power is the most efficient and least expensivemethod of creating electricity in the United States.


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On the MoveWater is constantly moving. Currents and tides helpmove water around the world. Currents are the pathsalong which bodies of water move. Tides are the regularrise and fall of water level in the ocean. The movementof water is very powerful. It creates energy. Water powerchanges this energy into electricity.

In most places, the tide rises and falls twice each day.


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Water for ElectricityBurning fossil fuels releases harmful gases intothe air. Fossil fuels are expensive and will notlast forever.

The energy created by water falling from a high levelto a low level can be used to create electricity. Largewaterfalls, such as Niagara Falls,create electricity inthis way. Falling water is directed into long pipesconnected to a powerstation.Theforce of the movingwater nnakes waterwheels in the power station spin.The spinn ing waterwheels cause machines calledturbines to turn.These turbines create electricity.


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Water Powerin HistoryPeople have used w ater s energy for tho usan ds ofyears. Ancient Greeks and Romans used waterwheelsto grind wheat into flour and to grind corn. Oceancurrents have brought many explorers to theirdestinations. River currents have pulled heavylogs to sawmills. Water power is still used to sawwood and power mills and factories.

Many early millers relied on river currents to b ring logsto their sawmills.


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The WaterwheelThe waterwheel was the f irst machine created touse w ater power. W aterwhee ls often pow ered millsand factories.

Waterwheels need moving water, so they are buil t onrivers and streams. Flowing water strikes the wheel'sblades in the water.The water pushes the blades,causing the wheel to turn.The spinning wa terwhee lpowers machines.Power fro m a w ate rw he el is no t always rel iable. Du ringw inter, wa ter ofte n freezes. Som etime s a drought leavespeople with no power.


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Steam PowerOver time, people discovered that steam could also beused to create electricity. Water boiled under pressurecreates steam that is full of energy. Inventors createdsteam engines using this energy. Steam engines poweredfactories, farm machinery, locomotive trains, and ships.Steam engines are still used today to create electricity.

In 1801,Richard Trevithick bu ilt the first locomotive.It traveled at 5 miles (8 kilom eters) per hour.


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How a Steam Engine WorksA steam eng ine needs a bo ile r.T he boiler boils waterto produce steam under pressure. hiscreates energy.

The steam in the boiler expands and pushes against apiston or turb ine . A turb ine is a m achine tha t changesth e steam's ene rgy into ele ctr icity, i iSteam engines are not the best way to createelec tr icity. Of the e nergy used to heat the w ater toprod uce steam , only 35 pe rcent becom es e lectr icity.

H James Watt bu ilt the first steam engine.Hefinished the design in 1778. i i


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The WaterCycleWater po wer is a renew able typ e of energybecause the f low of water is part of thew ater cycle. Water recycles i tsel f throughthe water cycle.This diagra m shows howthe water cycle works.


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Sun

louds Evaporation

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Hydroelectric DamsDams are built to stop flooding, to provide water, andto create electricity. Dams are built of concrete that isreinforced with steel. Most dams are built in a curvedshape. This provides a much stronger structure againstthe water currents.As water collects behind a dam, the energy level in thewater builds. When the water is released, the flowingwater gains speed. The flowing water passes throughturbin es that chan ge the water s energy into electricity.

The Hoover Dam blocks the Colorado River.The damcreates electricity.


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Environmental IssuesWater power is clean . It does not release harmful gasesinto the air.Still, using dams to create electricity affectsthe environment.

W hen a dam is built , the land arou nd th e da m is usuallydestroyed.To save the e nv iron m en t, plants and trees needto be rep lanted . Rocks need to be replaced. Co nstruc tionon dams can also cause f lood ing.T he env ironm ent maynever re turn to no rm al . ,, ,i i, i ,, , ;


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Storing PowerReservoirs store water for creating electricity. They arefound beh ind dam s. A reservoir is like an artificiallake. The deeper the water in the reservoir, the morepower can be produced. Water can be directed backinto the reservoir to be reused.Reservoirs also supply drinking water. People can fishin reservoirs. They can even be used for water sportssuch as kayaking.

The Kuroyon Dam in Kurobe, Ja pa njs one of the world'slargest dam s. It is 610 feet (186 meters) h igh and 1,614 feet(492 m) long.


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Good or Bad?The chart below lists some of the advantages anddisadvantages of water power. Can you think ofother points to add? Do you thin k using water tocreate electricity is a good idea or a bad idea? Why?

Advantages Hy drop ow er is cheaper tocreate than power from

fossil fuels. Water power does not

cause pol lut ion. The electric energy

created by water powercan be used immediately.

Disadvantages Dams are expensive

to bui ld . Building dams destroys

the envi ronment and cancause f loo din g. Turbines can hurt animals

in the water.


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Tidal PowerThe energy in tides can be used to create electricity.Tidal power is created using a huge dam built acrossa river estuary The tidal waters flow through tunnelsin the dam. The water then passes through turbines tocreate electricity. Tidal power stations can only createpower when the tide is flowing in or out. This happensfor about 10 hours per day. Only about twenty sites inthe world can be used to create energy from tides.

Tidal water bu ilds up in estuaries. When water is releasedfrom the estuary, the turbines move,crea ting elec tricity.


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A Life of ScienceLester Allan Pelton

Lester Allan Pelton lived in Caiifornia in 1849.Goldhad been discovered in California, and many peoplehad moved the re. Pelton w orked as a carpenter andmillwright.The gold mining industry was growingfast, so there was great dem and for new ways to powermachinery andmills.Waterwheels did no t work well innriountain creeks; While w atching a waterwheel, LeSter Peltori sawabarcalled a shaft s lip. He saw that the wheel spun fasterwhen water hit the edge of the wheel than when it hitthe center. Lester Peiton created a new, more efficientdesign for a water tu rb ine after seeing thisJ


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Surfing WaterScienceHow can I f ind m ore information

about water power? Libraries have many interesting

books about wa ter power. Science centers and museums

are great places to learn aboutwater power.

The In terne t offers some great Websites ded icated to w ater power.

W here can I find a good reference Website to learn m ore abou t water power?Encarta Homepagewww.encarta.com

Type any water power-related te rm into th e search engine.Some terms to try include "hydroe lectricity"and"dam."

How can I f ind ou t mo re abou t water powerand hydroelectricity?Water Science for Schoolshttp://ga.water.usgs.gov/edu

This Un ited States Geological Survey Web site offerspictures,data,and maps. It even has an interactive centerwhere you can test your water knowled ge.


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Science in ActionBuild a WaterwheelYou can bu ild your ow n waterwhee l to see the power of waterin action.You will need: a long skewer or stick

about twice the lengthof the ball

a foam ball plastic spoons a large cup water a sink or large bowl1. Poke the skewer throu gh the center of the ball.2. W iggle the skewer un til the ball easily spins around it.3. Place the plastic spoons evenly in a row around the ball.

Make sure the scoops all face up.4. Fill the cup w ith water.5. Ho ld the ball by the skewer over the sink or bow l.6. Raise the cup of wa ter as high as you can. Pour the water

over your wa terwheel.What happens? Try pouring the water from higher and lowerlevels. Does the level change how th e waterwheel spins?


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hat HaveYouLearned?twoameways in wh ichwater moves.

What causesa waterwheelto move?

What is ano ther namefor water power?

What storeswater behinda dam?

What isthemost e ff icientway to create elec tricity'nthe United States?


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Which countryis the numberone producerof water power?What machinescreate elec tricityfrom water energy?

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Earthof water?


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Worartificial:som ething made by

people, not natureboiler:alarge tank th at heats w ater

and turns it into steamdams:wa lls bu ilt across streams

or rivers to hold back andcontrol water

drought:a long period w ith no rainestuary:the m outh ofariver w here

the river meets the sea and isaffected by the tides

millwright:a person w ho sets upma chinery in a m il l

pollution:harmful materials suchas gases, chem icals, and wastetha t d irty air, water, and soil

recycles:returns to an origina lco nd ition so a process canbegin again

renewable:can be m ade likenew again

Ap pleto n, Wisconsin 5 Hoover Dam 14currents 6,8,14dams 14,15,16,17,

18,20energy 6 ,7 ,8 ,10 ,11 ,

12,14,17,18environment 4,15,17factories 8,9,10fossil fuels 4,7 ,17

Kuroyon Dam 16lakes 12,16Niagara Falls 7oceans 6,8,13Pelton,Lester Allan 19rivers 5,8,9,13,14,18

steam 10,11tides 6,18turbines 7,11,14,17,

18,19Washington 5water cycle 12-13waterwheel 7,8,9,

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