0708_static_electricity.pptxVIP专享VIP免费原创优质

StaticElectricityWhatIsStaticElectricity?•AstationaryelectricalchargethatisbuiltuponthesurfaceofamaterialTwokindsofcharges•Afterbeingrubbed,aplasticrulercanattractpaperscraps.Rulercarrieselectriccharge.Itexertselectricforceonpaper.Theinteractionbetweenstaticelectricchargesiscalledelectrostatics.Thischargingmethodiscalledchargingbyfriction.Wheredochargescomefrom?Matterismadeupofatoms.+++–––+–Proton(positivecharge)neutron(neutral)electron(negativecharge)atomnucleusIfelectrons=protonsneutralWheredochargescomefrom?Ifelectrons>protonsgainingelectrons,negativechargeIfelectronsrepulsion+++++metalcan------------buttomofthecan:negativeinducedchargesattractionrepulsionAttractionofunchargedobjectsSimilarly,whenchargedrodisclosetopaperscrap...-------moleculesofpaperalign.attractionbetweentherodand+charge>repulsionbetweentherodand-charge.paper+–+–+–+–+–+–+–+–attractionrepulsionStaticDischargeHumanbodycannotfeellessthan2,000voltsofstaticdischargeStaticchargebuiltupbyscuffingshoesonacarpetcanexceed20,000volts?GasStationFires•Carolsaidastaticgaspumpfireisblamedforburningherdaughtersobadlysheneededskingraftsonherlegs.•Carolhadputthegaspumpnozzleonautomaticandre-enteredhercartowriteacheck.Whenherthen-12-year-olddaughter,wearingasweaterandjacketthatmayhavecreatedstaticelectricity,reachedforthenozzle,flamessuddenlyignitedherclothing.1Iftheballooncanattractsomepaperscraps,whichofthefollowingcannotbethechargeofpaperscraps?ANeutralBPositiveCNegativeAballoonhasanegativechargewhenrubbedbyawoollencloth.2Duringrubbing,whathavebeentransferredbetweenthewoollenclothandtheballoon?AElectronsBProtonsCNeutronsAballoonhasanegativechargewhenrubbedbywoollencloth.Whena+chargedrodisputnearneutralobject,______________isinducedonthesideoftheobjectneartherodand_____________isinducedonthesideawayfromtherod.Therodcanattracttheneturalobjectbecause_________betweenrodand–inducedcharge>the________betweenrodand+inducedcharge.Howdoesapositivelychargedrodattractaneutralobject?negativechargepositivechargeattractionrepulsionGroundingAnobjectisgroundedwhenitisconnectedtotheearththroughaconnectingwire.Whatisgrounding?Ifachargedconductorisgrounded,itwillbecomeneutral.GroundingbHowdoesgroundingoccur?+++++Whenwetouchametalballofpositivecharge...electronsflowfromtheearthtothemetalballtoneutralizethemetalball.–Metalballbecomesneutral.Similarly,ifthemetalballisofnegativecharge...GroundingHowdoesgroundingoccur?––––––extraelectronsflowfromthemetalballtotheearthandtheballbecomesneutral.Whydogasolinetankersusuallyhavemetalchainsattheback?Whencarsrun,theirtiresandbodiesareusuallychargedby_______.Forgasolinetankers,iftheaccumulatedchargeislargeenough,_______canbeproducedand_________willoccurifgasolinevaporisignited.Thosemetalchainsconductthechargeonthebodiesoftankerstothe_______andavoidthedanger.frictionsparksexplosiongroundLightning•killsmorethan60peopleand•injuresmorethan400peopleayearintheUS•onemileeveryfiveseconds•about20,000C•Voltageofupto1.2x108volts•LimitExposureDoNowWriteaparagraphaboutthecartoon.Tellwhatheistryingtodo.Willitworkandwhy?Whatdoyouthinkwillhappen?Usethefollowingwords,staticelectricity,lightning,electrons,positiveandnegativecharges.TheEnd