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1、Energy1IntroductionEnergyisoneofthemostfundamentalpartsofouruniverse.Weuseenergytodowork.Energylightsourcities.Energypowersourvehicles,trains,planesandrockets.Energywarmsourhomes,cooksourfood,playsourmusic,givesuspicturesontelevision.Energypowersmachineryinfactoriesandtractorsonafarm.Energyfromthes
2、ungivesuslightduringtheday.Itdriesourclotheswhenthey'rehangingoutsideonaclothesline.Ithelpsplantsgrow.Energystoredinplantsiseatenbyanimals,givingthemenergy.Andpredatoranimalseattheirprey,whichgivesthepredatoranimalenergy.Everythingwedoisconnectedtoenergyinoneformoranother.Energyisdefinedas:"theabil
3、itytodowork."Whenweeat,ourbodiestransformtheenergystoredinthefoodintoenergytodowork.Whenwerunorwalk,we"burn"foodenergyinourbodies.Whenwethinkorreadorwrite,wearealsodoingwork.Manytimesit'sreallyhardwork!Cars,planes,lightbulbs,boatsandmachineryalsotransformenergyintowork.Workmeansmovingsomething,lift
4、ingsomething,warmingsomething,lightingsomething.Alltheseareafewofthevarioustypesofwork.Butwhataretheformsofenergy?Themainformsofenergywewilllookatinclude:·BiomassEnergy-energyfromplants·GeothermalEnergy·FossilFuels-Coal,OilandNaturalGas·HydroPowerandOceanEnergy·NuclearEnergy·SolarEnergy·WindEnergy2
5、FossilFuels-Coal,OilandNaturalGasTherearethreemajorformsoffossilfuels:coal,oilandnaturalgas.Allthreewereformedmanyhundredsofmillionsofyearsagobeforethetimeofthedinosaurs-hencethenamefossilfuels.Asthetreesandplantsdied,theysanktothebottomoftheswampsofoceans.Theyformedlayersofaspongymaterialcallpeat.
6、Overmanyhundredsofyears,thepeatwascoveredbysandandclayandotherminerals,whichturnedintoatypeofrockcalledsedimentary.Moreandmorerockpiledontopofmorerock,anditweighedmoreandmore.Itbegantopressdownonthepeat.Thepeatwassqueezedandsqueezeduntilthewatercameoutofitanditeventually,overmillionsofyears,itturne
7、dintocoal,oilorpetroleum,andnaturalgas.Coalisahard,blackcoloredrock-likesubstance.Itismadeupofcarbon,hydrogen,oxygen,nitrogenandvaryingamountsofsulphur.Therearethreemaintypesofcoal-anthracite,bituminousandl