Buildingaphysicalmodel
Physicsisadisciplinethatstudiesthelawsofmattermovement,andtheactualphysicalphenomenaandlawsaregenerallyverycomplicatedandinvolvemanyfactors.Abandonthesecondaryfactors,graspthemainfactors,soastohighlighttheessentialcharacteristicsofobjectivethings,thisiscalledbuildingaphysicalmodel.
Buildingaphysicalmodelisascientificthinkingmethodforstudyingphysicalproblems.
Middleschoolphysicsmodel
Physicsmodelsatthemiddleschoolstagecangenerallybedividedintothreecategories:materialmodels,statemodels,andprocessmodels.
Mattermodel
Materialscanbedividedintophysicalmatterandfieldmatter.(Ofcourse,inmodernphysics,thereareotherformsofmattersuchasdarkmatteranddarkenergy).
Physicalmaterialmodels,suchas:masspointsinmechanics,lightsprings,elasticballs,etc.,pointchargesinelectromagnetics,parallelplatecapacitors,close-woundsolenoids,etc.,idealsingaspropertiesGas,thinlensinoptics,homogeneousmedium,etc.
Fieldmattermodels,suchasuniformelectricfield,uniformmagneticfield,gravitationalfield,etc.areallmodelsofspacefieldmatter.
Statemodel
Inthestudyoffluidmechanics,thesteadyflow(state)ofthefluid;inthestudyofidealgas,theequilibriumstateofthegas;inthestudyofatomicphysics,thegroundstateoftheatomAndexcitedstates,etc.,belongtothestatemodel.
Processmodel
Inthestudyofparticlemotion,suchasuniformlinearmotion,uniformlyvariablelinearmotion,uniformcircularmotion,horizontalthrowingmotion,simpleharmonicmotion,etc.;inthestudyofidealgasstateWhenchanging,suchasisothermalchange,equalpressurechange,isovolumechange,adiabaticchange,etc.;therearealsosomeuniformchangesofphysicalquantities,suchastheuniformdecreaseanduniformincreaseofthemagneticinductionintensityofauniformmagneticfield;theprocessofnon-uniformchange,Suchasasuddenstopofacarisanidealprocessmodel.
Usingphysicalmodels
Modelsareanabstractionofpracticalproblems.Theestablishmentofeachmodelhascertainconditionsandscopeofapplication.Whenstudentslearnandapplythemodeltosolveproblems,theymustunderstandtheconditionsofuseofthemodelanduseitaccordingtotheactualsituation.Forexample,whethertheoperationofatraincanberegardedasamasspointdependsontheconceptofmasspointandthemovementofthetraintobestudied.Whenstudyingthetimerequiredforatraintocrossthebridge,thelengthofthetrainisgenerallynotnegligiblerelativetothelengthofthebridge,soitcannotberegardedasamasspoint;whenstudyingthetimerequiredforthetraintotravelfromBeijingtoShanghai,thelengthofthetrainismuchshorterthanthatofBeijingThedistancetoShanghaiisnegligible,atthistimethetraincanberegardedasamasspoint.