WhatYou’llLearn•Youwillunderstandthatlightbehaveslikeparticleshavingmomentumandenergy.•Youwilllearnthatsmallparticlesofmatterbehavelikewavesandaresubjecttodiffractionandinterference.WhyIt’sImportantQuantumtheoryprovidesthebasisforanamazingdevicecalledascanningtunnelingmicroscope(STM).TheSTMisvitaltoresearchersstudyingDNAandchemicalreactionmechanisms.Italsoisusedinthedevelopmentofsmallerandfastercomputers.Atomic-ScaleImagesTwotypesofsiliconatoms,appearinginredandblue,areseeninthisSTMimageofsilicon.ThinkAboutThis�AnSTMwasusedbyTheColoradoSchoolofMinestoproducethisimageofthesurfaceofsilicon.TheSTMusestheabilityofelectronstojumpacrossabarrier.Howdoesthisjump,whichisimpossibleaccordingtothelawofconservationofenergy,occur?722physicspp.comphotocourtseyofPeterSutter/ColoradoSchoolofMinesWhatdoesthespectrumofaglowinglightbulblooklike?QuestionWhatcolorsofvisiblelightareemittedbyaglowing,incandescentlightbulb?Procedure1.Screwaclear,incandescentlightbulbintoalampsocket.2.Plugthelampintoanelectricaloutletthatiscontrolledbyadimmerswitch.Turnthelamponanddimitsothatitglowsweakly.CAUTION:Donottouchtheglowingbulb,asitisveryhotandcancauseburns.3.Dimorturnofftheotherlightsintheclassroom.4.Standingabout1-2mawayfromthelightbulb,holdaholographicdiffractiongratingclosetoyoureye.Observethelightbulbthroughthediffractiongrating.CAUTION:Donotdirectlyviewtheglowinglightbulbwithoutusingthediffractiongrating,asdamagetoyourvisionmayresult.5.MakeandUseScientificIllustrationsUsecoloredpencilstosketchadiagramofwhatyouobserve.6.Turnupthedimmercontroltoincreasethelightbulbtoitsmaximumbrightness.7.MakeandUseScientificIllustrationsUsecoloredpencilstosketchadiagramofwhatyouobserve.AnalysisDescribethespectrumemittedbythelightbulb.Isitcontinuousoraseriesofdistinctcoloredlines?Describehowtheobservedspectrumchangedwhenthelightbulbglowedbrighter.CriticalThinkingWhatisthesourceofthelightemittedbythebulb?Whathappenstothetemperatureofthelightbulb’sfilamentwhenthebulbglowsbrighter?27.1AParticleModelofWave...
