PhotoDiscElectricityandMagnetismIronfilingsclusteraroundthenorthandsouthpolesofabarmagnetbecauseofmagneticforce.Magneticforceisexertedthroughamagneticfield,whichisoutlinedbytheironfilings.Thisfieldiscausedbynegativelychargedelectronsspinningintheatoms.Sendallinquiriesto:Glencoe/McGraw-Hill8787OrionPlaceColumbus,OH43240-4027ISBN:0-07-861773-1PrintedintheUnitedStatesofAmerica.2345678910027/111090807060504Copyright©2005byTheMcGraw-HillCompanies,Inc.Allrightsreserved.ExceptaspermittedundertheUnitedStatesCopyrightAct,nopartofthispublicationmaybereproducedordistributedinanyformorbyanymeans,orstoredinadatabaseorretrievalsystem,withoutpriorwrittenpermissionofthepublisher.TheNationalGeographicfeaturesweredesignedanddevelopedbytheNationalGeographicSociety’sEducationDivision.Copyright©NationalGeographicSociety.Thename“NationalGeographicSociety”andtheYellowBorderRectanglearetrademarksoftheSociety,andtheiruse,withoutpriorwrittenpermission,isstrictlyprohibited.The“ScienceandSociety”andthe“ScienceandHistory”featuresthatappearinthisbookweredesignedanddevelopedbyTIMESchoolPublishing,adivisionofTIMEMagazine.TIMEandtheredborderaretrademarksofTimeInc.Allrightsreserved.PhotoDiscCONTENTJackCooperEnnisHighSchoolEnnis,TXCarlZorn,PhDStaffScientistJeffersonLaboratoryNewportNews,VAMATHMichaelHopper,DEngManagerofAircraftCertificationL-3CommunicationsGreenville,TXREADINGBarryBartoSpecialEducationTeacherJohnF.KennedyElementaryManistee,MIRachelSwaters-KissingerScienceTeacherJohnBoiseMiddleSchoolWarsaw,MOSAFETYSandraWest,PhDDepartmentofBiologyTexasStateUniversity-SanMarcosSanMarcos,TXACTIVITYTESTERSNermaCoatsHendersonPickeringtonLakeviewJr.HighSchoolPickerington,OHMaryHelenMariscal-CholkaWilliamD.SliderMiddleSchoolElPaso,TXScienceKitandBorealLaboratoriesTonawanda,NYN◆iiiAuthorsSeriesConsultantsDeidreAdamsWestVigoMiddleSchoolWestTerreHaute,INKarenCurryEastWakeMiddleSchoolRaleigh,NCAnthonyJ.DiSipio,Jr.8thGradeScienceOctoranaMiddleSchoolAtglen,PAGeorgeGabbGreatBridgeMiddleSchoolChesapeak...
