Unit1GREATSCIENTISTSJOHNSNOWDEFEATS“KINGCHOLERA”JohnSnowwasafamousdoctorinLondon—soexpert,indeed,thatheattendedQueenVictoriaasherpersonalphysician.Buthebecameinspiredwhenhethoughtabouthelpingordinarypeopleexposedtocholera.Thiswasthedeadlydiseaseofitsday.Neitheritscausenoritscurewasunderstood.Somanythousandsofterrifiedpeoplediedeverytimetherewasanoutbreak.JohnSnowwantedtofacethechallengeandsolvethisproblem.Heknewthatcholerawouldneverbecontrolleduntilitscausewasfound.Hebecameinterestedintwotheoriesthatpossiblyexplainedhowcholerakilledpeople.Thefirstsuggestedthatcholeramultipliedintheair,acloudofdangerousgasfloatedarounduntilitfounditsvictims.Fromthestomachthediseasequicklyattackedthebodyandsoontheaffectedpersondied.JohnSnowsuspectedthatthesecondtheorywascorrectbutheneededevidence.SowhenanotheroutbreakhitLondonin1854,hewasreadytobeginhisenquiry.Asthediseasespreadquicklythroughpoorneighbourhoods,hebegantogatherinformation.Intwoparticularstreets,thecholeraoutbreakwassoseverethatmorethan500peoplediedintendays.Hewasdeterminedtofindoutwhy.Firsthemarkedonamaptheexactplaceswhereallthedeadpeoplehavelived.Thisgavehimavaluableclueaboutthecauseofthedisease.ManyofthedeathswerenearthewaterpumpinBroadStreet(especiallynumbers163738and40).Healsonoticedthatsomehouses(suchas20and21BroadStreetand8and9CambridgeStreet)hadhadnodeaths.Hehadnotforeseenthis,sohemadefurtherinvestigations.Hediscoveredthatthesepeopleworkedinthepubat7CambridgeStreet.Theyhadbeengivenfreebeerandsohadnotdrunkthewaterfromthepump.Itseemedthatthewaterwastoblame,Next,JohnSnowlookedintothesourceofthewaterforthesetwostreets.HefoundthatitcamefromtheriverpollutedbythedirtywaterfromLondon.HeimmediatelytoldtheastonishedpeopleinBroadStreettoremovethehandlefromthepumpsothatitcouldnotbeused.Soonafterwardsthediseasesloweddown.Hehadshownthatcholerawasspreadbygermsandnotinacloudofgas.InanotherpartofLondon,hefoundsupportingevidencefromtwootherdeathsthatwerelinkedtotheBroadStreetoutbreak.Awoman,whohadmovedawayfromBroadStreet,likedthewaterfromthepumpsomuchthatshehaditdeliveredtoherhouseeveryday.Bothsheandherdaughterdiedofcholeraafterdrinkingthewater.WiththisextraevidenceJohnSnowwasabletoannouncewithcertaintythatpollutedwatercarriedthevirus.Topreventthisfromhappeningagain,JohnSnowsuggestedthatthesourceofallthewatersuppliesbeexamined.Thewatercompanieswereinstructednottoexposepeopletopollutedwateranymore.Finally“KingCholera”wasdefeated.COPERNICUS’REVOLUTIONAYTHEORYNicolausCopernicuswasfrightenedandhismindwasconfused.Althoughhehadtriedtoignorethem,allhismathematicalcalculationsledtothesameconclusion:thattheearthwasnotthecentreofthesolarsystem.Onlyifyouputthesuntheredidthemovementsoftheotherplanetsintheskymakesense.YethecouldnottellanyoneabouthistheoryasthepowerfulChristianChurchwouldhavepunishedhimforevensuggestingsuchanidea.TheybelievedGodhadmadetheworldandforthatreasontheearthwasspecialandmustbethecentreofthesolarsystem.Theproblemarosebecauseastronomershadnoticedthatsomeplanetsintheskyseemedtostop,movebackwardandthengoforwardinaloop.Othersappearedbrighterattimesandlessbrightatothers.Thiswasverystrangeiftheearthwasthecentreofthesolarsystemandallplanetswentaroundit.Copernicushadthoughtlongandhardabouttheseproblemsandtriedtofindananswer.Hehadcollectedobservationsofthestarsandusedallhismathematicalknowledgetoexplainthem.Butonlynewtheorycoulddothat.Sobetween1510and1514heworkedonit,graduallyimprovinghistheoryuntilhefeltitwascomplete.In1514heshoweditprivatelytohisfriends.Thechangeshemadetotheoldtheorywererevolutionary.Heplacedafixedsunatthecentreofthesolarsystemwiththeplanetsgoingrounditandonlythemoonstillgoingaroundtheearth.Healsosuggestedthattheearthwasspinningasitwentaroundthesunandthisexplainedchangesinthemovementoftheplanetsandinthebrightnessofthestars.Hisfriendswereenthusiasticandencouragedhimtopublishhisideas,butCopernicuswascautious.HedidnotwanttobeattackedbytheChristianChurch,soheonlypublisheditashelaydyingin1543.Certainlyhewasrighttobecareful.TheChristianChurchrejectedhistheory,sayingitwasagainstGod’sideaandpeoplewhosupporteditwouldbeattacked.YetCopernicus’theoryisnowthebasisonwhichallourideasoftheuniversearebuilt.HistheoryreplacedtheChristianideaofgravity,whichsaidthingsfelltoearthbecauseGodcreatedtheearthasthecentreoftheuniverse.Copernicusshowedthiswasobviouslywrong.NowpeoplecanseethatthereisadirectlinkbetweenhistheoryandtheworkofIsaacNewton,AlbertEinsteinandStephenHawking.Unit2TheUnitedKingdomPUZZLESINGEOGRAPHYPeoplemaywonderwhydifferentwordsareusedtodescribethesefourcountries:England,Wales,ScotlandandNorthernIreland.YoucanclarifythisquestionifyoustudyBritishhistory.FirsttherewasEngland.Waleswaslinkedtoitinthethirteenthcentury.NowwhenpeoplerefertoEnglandyoufindWalesincludedaswell.NextEnglandandWaleswerejoinedtoScotlandintheseventeenthcenturyandthenamewaschangedtoGreatBritain.HappilythiswasaccomplishedwithoutconflictwhenKingJamesofScotlandbecameKingofEnglandandWalesaswell.FinallytheEnglishgovernmenttriedintheearlytwentiethcenturytoformtheUnitedKingdombygettingIrelandconnect