Christoph Schiller MOTION MOUNTAIN the adventure of physics – vol.v motion inside matter – pleasure, technology and stars www.motionmountain.net ChristophSchiller Motion Mountain The Adventure of Physics Volume V Motion Inside Matter – Pleasure, Technology and Stars Edition25.40,available asfreepdfat www.motionmountain.net Editiovicesimaquinta. Proprietasscriptoris©ChrestophoriSchiller secundoannoOlympiadistrigesimae. Omniaproprietatisiurareservanturetvindicantur. Imitatioprohibitasineauctorispermissione. Nonlicetpecuniamexpetereproaliqua,quae partemhorumverborumcontinet;liber proomnibussempergratuituseratetmanet. Twenty-fifthedition. Copyright©2012byChristophSchiller, thesecondyearofthe30thOlympiad. ThispdffileislicensedundertheCreativeCommons Attribution-Noncommercial-NoDerivativeWorks3.0Germany Licence,whosefulltextcanbefoundonthewebsite creativecommons.org/licenses/by-nc-nd/3.0/de, withtheadditionalrestrictionthatreproduction,distributionanduse, inwholeorinpart,inanyproductorservice,beit commercialornot,isnotallowedwithoutthewrittenconsentof thecopyrightowner.Thepdffilewasandremainsfreeforeverybody toread,storeandprintforpersonaluse,andtodistribute electronically,butonlyinunmodifiedformandatnocharge. ToBritta,EstherandJustusAaron τῷἐμοὶδαὶμονι DieMenschenstärken,dieSachenklären. PREFACE “Primummovere,deindedocere.* ” Antiquity This book is written for anybody who is curious about nature and motion. Curiosity abouthowbodies,imagesandemptyspacemoveleadstomanyadventures.Thisvolume M presentsthebestadventuresaboutthemotioninsidepeople,insideanimals,andinside otio n anyothertypeofmatter–fromthelargeststarstothesmallestnuclei. M o u Motion inside bodies – dead or alive – is described by quantum theory. Quantum ntain theorydescribesallmotionwiththequantumofactionħ,thesmallestchangeobserved – Th in nature. Building on this basic idea, the text first shows how to describe life, death eA d and pleasure. Then, the text explains the observations of chemistry, materials science, ven tu astrophysicsandparticlephysics.Inthestructureofphysics,thesetopicscorrespondto re o f thethree‘quantum’pointsinFigure1.Thestoryofmotioninsidelivingandnon-living Ph matter,fromthecoldestgasestothehotteststars,istoldhereinawaythatissimple,up ysics p todateandcaptivating. d f fi necIenssoarrdyermtionbimeusimm.plUe,ntdheerstetaxntdfoincgustehseocnocnocnecpetpstos,fwphhyilseickseeispignigvemnapthreecmedateincscetootvheer leavailab le usingformulaeincalculations.Thewholetextiswithinthereachofanundergraduate. free Inordertobeuptodate,thetextisenrichedbythemanygems–boththeoreticaland of ch empirical–thatarescatteredthroughoutthescientificliterature. arg e Inordertobecaptivating,thetexttriestostartlethereaderasmuchaspossible.Read- at w w ing a book on general physics should be like going to a magic show. We watch, we are w .m astonished, we do not believe our eyes, we think, and finally we understand the trick. otio n Whenwelookatnature,weoftenhavethesameexperience.Indeed,everypagepresents m o u atleastonesurpriseorprovocationforthereadertothinkabout.Numerousinteresting ntain challengesareproposed. .net Themottoofthetext,dieMenschenstärken,dieSachenklären,afamousstatementby C o p HartmutvonHentigonpedagogy,translatesas:‘Tofortifypeople,toclarifythings.’Clar- yrig h t ifyingthings–andadheringonlytothetruth–requirescourage,aschangingthehabits © C h of thought producesfear, often hidden by anger. But by overcomingour fears we grow risto instrength.Andweexperienceintenseandbeautifulemotions.Allgreatadventuresin ph S lifeallowthis,andexploringmotionisoneofthem.Enjoyit! chiller Ju n e Munich,18May2013. 1 9 9 0 –M *‘Firstmove,thenteach.’Inmodernlanguages,thementionedtypeofmoving(theheart)iscalledmotivat- ay 2 ing;bothtermsgobacktothesameLatinroot. 01 3 8 preface PHYSICS: Final, unified description of Why does motion Describing motion motion occur? What are with the least action principle. Adventures: understanding space, time and motion, intense joy with quantum particles? thinking, calculating couplings and masses, catching a glimpse of bliss (vol. VI). Quantum General relativity theory with gravity Quantum field theory Adventures: the Adventures: bouncing Adventures: building night sky, measu- neutrons, under- accelerators, under- ring curved space, standing tree standing quarks, stars, exploring black growth (vol. V). bombs and the basis of holes and the life, matter, radiation M universe, space (vol. V). otio n and time (vol. II). How do small M o u How do tWhhinagt sa mreo tvhein?gs? ntain–Th Classical gravity everyday, Special relativity Quantum theory eA d Adventures: fast and large Adventures: light, Adventures: death, ve n climbing, skiing, things move? magnetism, length reproduction, biology, ture space travel, contraction, time chemistry, evolution, of P tahster ownoonmdey rasn odf dEil=at miocn2 a (nvodl . II). earntj,o aylli nhgig cho-ltoeucrhs and hysics 0 geology (vol. I). business, medicine pd f G c h, e, k (vol. IV and V). file availab le Galilean physics, heat and electricity free Adventures: sport, music, sailing, cooking, of ch describing beauty and understanding its origin arg (vol. I), using electricity, light and computers, eat understanding the brain and people (vol. III). ww w .m FIGURE 1 Acompletemapofphysics:theconnectionsaredefinedbythespeedoflightc,the otio n gravitationalconstantG,thePlanckconstanth,theBoltzmannconstantkandtheelementarychargee. m o u n tain .n Advice for learners et C o p Learningshouldbefastandfun.Themostinefficientandmosttediouslearningmethod yrigh t © istouseamarkertounderlinetext:itwastestime,providesfalsecomfortandmakesthe C h textunreadable.Nobodymarkingtextislearningefficientlyorisenjoyingit. risto p h Inmyexperienceasastudentandteacher,onelearningmethodneverfailedtotrans- S ch form unsuccessful pupilsintosuccessful ones: if you readabook for study, summarize iller Ju every section you read, in your own words and images, aloud. If you are unable to do n e 1 so, read the section again. Repeat this until you can clearly summarize what you read 99 0 inyourownwordsandimages,aloud.Youcandothisaloneorwithfriends,inaroom –May 2 orwhilewalking.Ifyoudothiswitheverythingyouread,youwillreduceyourlearning 01 3 preface 9 andreadingtimesignificantly,enjoylearningfromgoodtextsmuchmoreandhatebad textsmuchless.Mastersofthemethodcan use itevenwhilelisteningtoalecture,ina lowvoice,thusavoidingtoevertakenotes. Advice for teachers Ateacherlikespupilsandlikestoleadthemintoexploringthefieldhechose.Hisorher enthusiasmforthejobisthekeytojobsatisfaction.Ifyouareateacher,beforethestart ofalesson,picture,feelandtellyourselfyourhowyouenjoythetopicofthelesson;then picture, feel and tell yourself how you will lead each of your pupils into enjoying that topic as much as you do. Do this exercise consciously, every time. You will minimize troubleinyourclassandmaximizeyoursuccess. This bookis not writtenwithexams in mind; it is writtentomake teachersand stu- dentsunderstandandenjoyphysics,thescienceofmotion. M o tio n Using this book Mo u n tain Textingreen,asfoundinmanymarginalnotes,marksalinkthatcanbeclickedinapdf – Th e reader. Such green links are either bibliographic references, footnotes, cross references A d tootherpages,challengesolutions,orpointerstowebsites. ven tu Solutionsandhintsforchallengesaregivenintheappendix.Challengesareclassified re o f asresearchlevel(r),difficult(d), standardstudentlevel(s)andeasy(e).Challengesfor Ph whichnosolutionhasyetbeenincludedinthebookaremarked(ny). ysics p d f fi le Feedback and support availab le Thistextisandwillremainfreetodownloadfromtheinternet.Iwouldbedelightedto free o [email protected],especiallyonthefollowingissues: fch arg e Challenge1s — Whatwasunclearandshouldbeimproved? at w — Whatstory,topic,riddle,pictureormoviedidyoumiss? ww .m — Whatshouldbecorrected? otio n m Inordertosimplifyannotations,thepdffileallowsaddingyellowstickernotesinAdobe ou n Reader. Help on the specific points listed on the www.motionmountain.net/help.html tain .n webpagewouldbeparticularlywelcome.Allfeedbackwillbeusedtoimprovethenext et C edition.Onbehalfofallreaders,thankyouinadvanceforyourinput.Foraparticularly op useful contribution you will be mentioned – if you want – in the acknowledgements, yrigh t © receiveareward,orboth. C h Your donation to the charitable, tax-exempt non-profit organisation that produces, risto p h translatesandpublishesthisbookseriesiswelcome!Fordetails,seethewebpagewww. S ch motionmountain.net/donation.html. If you want, your name will be included in the iller Ju sponsorlist.Thankyouinadvanceforyourhelp,onbehalfofallreadersacrosstheworld. n e 1 Thepapereditionofthisbook,printedondemand and deliveredby mailtoany ad- 99 0 dress of your choice, can be ordered at www.lulu.com/spotlight/motionmountain. But –May 2 aboveall,enjoythereading! 01 3 10 preface M o tio n M o u n tain – Th e A d ve n tu re o f P h ysics p d f fi le availab le free o f ch arg e at w w w .m o tio n m o u n tain .n et C o p yrig h t © C h risto p h S ch iller Ju n e 1 9 9 0 –M ay 2 0 1 3