高二英语上册全册教案3
StepⅢWhilereading
1.Scanning
Getthestudentstocomprehendthewholescenequicklyandaccuratelyandmeanwhilehelpthemformagoodhabitofreading.Givethestudentssometimetoreadthroughthescenesandthenanswersomequestions
a.HowdidHenryAdamscometoEngland?
b.WheredidHenryworkbefore?Howmuchdidhehave?
c.WhatdidthetwogentlemengiveHenry?
d.WhencanHenryopentheletter.
2.Afterthestudentsdiscussthequestionsandthenchecktheanswerswiththewholeclass.
T:Listentothetapeandtrytofindoutthecharacteristicsofthewholepassage.
Ss:Thisispartofaplay.So,thenarrationiswritteninthepresenttense.
T:OK.Allofyouhavedoneagoodjob.Next,let’sreadthesceneagainanddosomeexercises.
StepⅣPost-reading
Docomprehendingexercisesandexplain:
a.alargeamountof:alargequantityof;agreatdealof
e.g.Theyboughtalargeamountoffurniturebeforetheymovedtheirnewhouse.
b.makeabet:makeanarrangementtoriskmoney,etc.onaneventofwhichtheresultisdoubtful.
e.g.Wemadeabetontheresultofthematch.
c.permitsbtodosomething:allowsomebodytodosomething
e.g.Mymotherdoesn’tpermitmetorideinthestreetafteritrained.
d.byaccident:asaresultofchance
e.g.Ionlyfounditbyaccident.
e.stareat:lookatsomebodyorsomethingwiththeeyeswideopeninafixedgaze(inastonishment,wonder,fear,etc)
f.tobehonest:totellyouthetruth;tobefrank
e.g.Tobehonest,Idon’tthinkwehaveachanceofwinning.
StepⅤHomework
1.Reviewthekeysentencesinthispart
2.Previewthewordsinthesecondperiod.
3.Actouttheplayingroups
Thesecondperiod:Acting
StepIActing
T:Areyoureadytoactouttheplaynowclass?
Ss:Yes.
T:Good.Let’swelcomethefirstgroupandthesecondgrouppleasegetprepared.
…
T:Class,weshouldpayattentiontosomeexamplesofMarkTwain’shumorinthisscene,whichwillhelpusbetterunderstandtheplayandactitoutmoreappropriately.Doyouagreewithme?
Ss:Yes,ofcourse.
StepIIHomework
Reviewwhatwelearnedinthisunit
TheThirdperiodWatchingthemovieTheMillionPoundBanknote
Unit4Astronomy:thescienceofstars
Teachingaims:
1.Talkaboutthescienceofstars
2.Practisegivinginstructions
4.Learntousenounclausesasthesubject
5.Learntowriteanessaytoshowyourproblemsandthewaytoovercomethem.
6.Vocabulary:astronomy,atmosphere,violent,explode,surface,disappointed,gradually,cheer,mass,harmful,presence,intime,prevent…from…dependon,nowthat,getthehangof,breakout
ThefirstperiodIntensivereading
StepⅠPresentation
T:Hello,everyone!TodaywewillcometoUnit4,Astronomy.BeforethatIhaveaquestion:wheredowecomefrom?Orwecansay:Whoareourancestors?
S1:Monkeys!
S2:BeijingRenwholivedmanyyearsago.
S3:dinosaurs
…
T:Verygood!Doyouknowwhatitwaslikebeforelifeappearedonearth?
S4:Fullofwater…
Bs:Idon’tknow.
T:Doyouwanttogetmoreinformation?
Ss:Yes,wedo.
T:Todaywewilllearnsomethingabouthowlifebeganonearth.Turntopage25.Let’scometoWarmingupfirst.
StepⅡWarmingup
5.Readthethreequestions,whilethestudentslistenandfollow.
6.Givethestudentsseveralminutestodiscussthequestions.
7.Collectanswersfromtheclass.
8.Checkanswerswhilediscussing.
StepⅢPre-reading
Getthestudentstodiscussthequestionsonpage25withtheirpartners.Thenaskthestudentstotelltheirstories.Encouragethemtotelldifferentstories,Iftheydon’tknowany,tellthemsome.
T:Nowdiscussthesequestionswithyourpartners.ThenIwillasksomeofyoutotellusyourstories.Areyouclear?
Ss:Yes.
a.Doyouknoweachreligionorculturehasitsownideasaboutthebeginningoftheuniverse?Giveanexampleifyouknow.
b.Doyouknowwhatascientificideais?
Readsomestoriestothestudents.
Panguseparatestheskyfromtheearth;
TheBiblicalAccount;
India;
Japan;
Europe;
StepⅣReading
1.Scanning
Getthestudentstoreadthepassagequicklyandaccuratelyandmeanwhilehelpthestudentstoformagoodhabitofreading.Givethestudentsacoupleofminutestolookthrouththewholepassage.Tellthemtoreadsilentlyandthenasksomedetailedquestionsaboutthetext.Encouragethemtoexpresstheirideas.
T:Wearegoingtolearnapassageabouthowlifebeganontheearth.Nowreadthetextquicklyandthenanswermyquestions.
a.Whatwasthereontheearthbeforelifebegan?
b.Whydoscientistthinktherehasneverbeenlifeonthemoon?
c.Whydoanimalsfirstappearinthesea?
d.Whydogreenplantshelplifetodevelop?
e.Whyweremammalsdifferentfromotheranimals?
Discusstheanswerswiththewholeclass.
2.Skimming
Inthispart,studentswillreadthetextagainandfinishpart1,2,3
T:Nowskimthepassagefasttofinishpart1,2,3,4Thenwewillchecktheanswerstogether.
Keytopart1:DBIGEHACFJ
Discusstherestwiththestudents.
StepⅤListening
Listentothetapeforthestudentstofollowandhavefurtherunderstandingofthepassage.
T:Readafterthetape,thenanswermesomequestionswithyourbookclosed.
a.Howdidwatercomeintobeingontheearth?
b.Whyiswaterimportantonearth?
StepⅥLanguagepoints
T:Turntopage25.Let’slookatthesentences:
a.Itexplodedloudlywithfireandrock,whichwereintimetoproducethewatervapour.
Whichleadsnon-restrictiveattributiveclause.
intime:soonerorlater;eventually
Iwillseehimintime.
Intime(forsth/todosth):notlate
Shewillbebackintimetopreparedinner.
In/outoftime:in/notinthecorrecttime
Theaudienceclappedintimetothemusic.
b.Nobodyknewthatitwasgoingtobedifferentfromotherplanetsgoingaroundthesun.
Bedifferentfrom:notlikesomeoneorsomethingelseinoneormoreways
Citylifeisquitedifferentfromcountrylife.
c.Whetherlifewillcontinueontheearthformillionsofyearstocomewilldependonwhetherthisproblemcanbesolved.
Tocome:servesasattributive
Sheisthelastpersontodosuchathing.
Dependon:somethingmightonlyhappenorbetrueifthecircumstancesarerightforit
Oursuccessdependsonwhethereveryoneworkshardornot.
d.Walkingdoesneedabitofpracticenowthatgravityhaschanged.
Nowthat:becauseofthefactthat
NowthatIamfree,Icanenjoymusicforawhile.
Nowthatyouhavegrownup,youcandecideitbyyourself.
StepⅦHomework
1.Retellthepassage
2.Rememberimportantlanguagepoints
ThesecondperiodLanguagestudy
StepⅠRevision
1.Checkretellingofthepassage
2.Translatethefollowingsentences.
a.你迟早会成功的.
b.我的车与你的不一样.
c.站在门旁边的那个人是谁?
d.他总是第一个来,最后一个走.
e.既然你已经长大了,你自己决定吧.
Suggestedanswers:
a.Youwillsucceedintime.
b.Mycarisdifferentfromyours.
c.Whoisthepersonstandingbythedoor?
d.Heisalwaysthefirsttocomeandthelasttogo.
e.Nowthatyouhavegrownupyoucandecideityourself.
StepⅡWordstudy
Thispartisaconsolidationofthewordslearntinthisunit.Askthestudentstodotheexercisesindividually.
a.Page27.Firstletstudentsfinishpart1,2
b.Checktheanswerswiththewholeclass.
c.Givestudents3minutestofinishpart3.
d.Letthestudentsreadpart4forawhileandfinishit.
e.Turntopage63.Firstletthestudentsfinish1and2andchecktheanswers.
StepⅢPreparation
Showsomesentencesontheblackboard.
a.Atreehasfallenacrosstheroad.
b.Youareastudent.
c.Tofindyourwaycanbeaproblem.
d.Smokingisbadforyou.
e.“Howdoyoudo?”isagreeting.
f.Whatshesaidisnotyetknown.
g.Thatweshallbelateiscertain.
h.It’scertainthatweshallbelate.
T:Whatpartdoestheunderlinedpartserveasineachsentence?Orfinditssubjectineachsentence.
StepⅣGrammar
1.Givethestudentssometimetofindthesentencesinthepassage.Thecollectanswersfromtheclass.
2.Showtypicalexamplesofhowtomakeasubjectclause.GuidetheSstofindoutwhatchangeswehavetomakewhenwemakeasentenceorcombinetwosentencesusingsubjectclause.TeachershowstheexampleandSswritedownthesentences.
3.Turntopage64.Readthefollowingpassagequicklyandfinishtheeightsentences.
4.Haveadiscussioninpairs.ThetopicisMydream.Onetalksabouttheproblemsinhisstudyorlife,anothergivessomeadvice.Remindthestudentstousethefollowingstructures
a.Myproblemis…
b.Mytroubleis…
c.Thequestionis…
d.Myadviceis…
e.WhatIthinkaboutitis…
f.Thefactis…
g.Mysuggestionis…
StepⅤHomework
1.Finishpart3(P23)
2.Finishpart3(P64)
Addedmaterial:
什么是黑洞?
就是在宇宙中有那么一些点,这些点的体积趋向于零而密度变得无穷大,由于具有强大的吸引力,物体只要进入离这个点一定距离的范围内,就会被这个强大的引力吸收掉,连光线也不例外。因此任何进入这个范围的物体都无法再逃出来,就是说,没有任何信号能够从这个范围内传出,因此这个范围的界限被称作视界,里面的情形人类无法看到。所以科学家给它起了个名字叫黑洞,英文就是blackhole。一颗燃烧尽了的恒星由于自身的重力而不断坍缩,最后就会形成黑洞。
历时30年霍金改观点称黑洞能“吸”能“吐”
从事宇宙黑洞研究近三十年的世界天体物理学泰斗斯蒂芬霍金在前不久承认“黑洞悖论”有误之后,21号,他在爱尔兰都柏林举行的一个学术研讨会上终于就自己的新发现向外界进行了详细阐述。
黑洞是宇宙中引力极强的区域。19世纪70年代,霍金首次提出黑洞能够辐射能量的理论,但是在引入这一理论的同时,霍金也制造了物理学上的一个巨大难题,因为他认为
黑洞辐射不包含以前吸入物质的相关信息,而且随着黑洞的消失,曾经存在的黑洞的相关信息也会消失于无形。这与量子力学中认为物质信息不会完全消失的理论相矛盾。对此,过去近30年来,霍金的解释是:黑洞中的量子运动是一种特殊情况,这种说法受到了许多科学家的质疑。
如今,霍金终于改变了观点,在当天召开的学术研讨会上,霍金说,根据他的最新发现,黑洞并非只是吞噬物质。除了会在星系形成的过程中扮演重要角色外,在经过一段相当漫长的时间后,黑洞也会把一些曾被它吸入的物质信息向外界释放出来。
霍金的最新阐述被不少人称为黑洞理论的一个重要逆转。美国加州理工学院的理论物理学家约翰普雷斯基就是其中之一。20多年前,霍金提出黑洞辐射理论时,普雷斯基就一直坚持物质信息不会完全消失,当时两人还因此打赌。所以,在当天结束演讲后,霍金将一本百科全书赠予普雷斯基,作为打赌输了的代价,而普雷斯基则获得了全场的热烈掌声。
Blackholes
(1)Whatisablackhole?Well,itsdifficulttoanswerthisquestion,sincethetermswewouldnormallyusetodescribeascientificphenomenonareinadequatehere.Astronomersandscientiststhinkthatablackholeisaregionofspace(notathing)intowhichmatterhasfallenandfromwhichnothingcanescape----notevenlight.Sowecantseeablackhole.Ablackholeexpertsastronggravitationalpullandyetithasnomatter.Itisonlyspace----orsowethink.howcanthishappen?
(2)Thetheoryisthatsomestarsexplodewhentheirdensityincreasestoaparticularpoint;theycollapseandsometimesasupernovaoccurs.Formearth,asupernovalookslikeaverybrightlightintheskywhichshineseveninthedaytime.Supernovaewerereportedbyastronomersintheseventeenthandeighteenthcenturies.SomepeoplethinkthattheStarofBethlehemcouldhavebeenasupernova.ThecollapseofastarmayproduceaWhiteDwarforaneutronstar---astar,whosematterissodensethatitcontinuallyshrinksbytheforceofitsowngravity.Butifthestarisverylarge(muchbiggerthanoursun)thisprocessofshrinkingmaybesointensethatablackholeresults.Imaginetheearthreducedtothesizeofamarble,butstillhavingthesamemassandastrongergravitationalpull,andyouhavesomeideaoftheforceofablackhole.Anymatterneartheblackholeissuckedin.Itisimpossibletosaywhathappensinsideablackhole.Scientistshavecalledtheboundaryareaaroundtheholethe"eventhorizon."Weknownothingabouteventswhichhappenonceobjectspassthisboundary.Butintheory,mattermustbehaveverydifferentlyinsidethehole.
(3)Forexample,ifamanfellintoablackhole,hewouldthinkthathereachedthecenterofitveryquickly.Howeveranobserverattheeventhorizonwouldthinkthatthemanneverreachedthecenteratall.Ourspaceandtimelawsdontseemtoapplytoobjectsintheareaofablackhole.Einsteinsrelativitytheoryistheonlyonewhichcanexplainsuchphenomena,sothatthereisno"absolute"timeandspacedependonthepositionoftheobserver.Theyarerelative.Wedonotyetfullyunderstandtheimplicationsoftherelativitytheory;butitisinterestingthatEinsteinstheoryprovidedabasisfortheideaofblackholesbeforeastronomersstartedtofindsomeevidencefortheirexistence.Itisonlyrecentlythatastronomershavebegunspecificresearchintoblackholes.InAugust1977,asatellitewaslaunchedtogatherdataaboutthe10millionblackholeswhicharethoughttbeintheMilkyway.Andastronomersareplanninganewobservatorytostudytheindividualexplodingstarsbelievedtobeblackholes.
(4)Themostconvincingevidenceofblackholescomesfromresearchintobinarystarsystems.Binarystars,astheirnamesuggests,aretwinstarswhosepositioninspaceaffectseachother.Insomebinarysystems,astronomershaveshownthatthereisaninvisiblecompanionstar,a"partner"totheonewhichwecanseeinthesky.Matterfromtheonewecanseeisbeingpulledtowardsthecompanionstar.Couldthisinvisiblestar,whichexertssuchagreatforce,beablackhole?Astronomershaveevidenceofafewotherstarstoo,whichmighthaveblackholesascompanions.
(5)Thestoryofblackholesisjustbeginning.Speculationsaboutthemareendless.Theremightbeamassiveblackholeatthecenteronourgalaxyswallowingupstarsataveryrapidrate.Mankindmayonedaymeetthisfate.Ontheotherhand,scientistshavesuggestedthatveryadvancedtechnologycouldonedaymakeuseoftheenergyofblackholesformankind.Thesespeculationssoundlikesciencefiction.Butthetheoryofblackholesinspaceisacceptedbymanyseriousscientistsandastronomers.theyshowusaworldwhichoperatesinatotallydifferentwayfromourownandtheyquestionourmostbasicexperienceofspaceandtime.
Readthepassagecarefullyandchoosethebestanswerforthefollowingquestions
1)Blackholesarerelatedto____
A.geographyB.astronomyC.physicsD.economic
2)Ablackholeis____
A.adarkstarB.alargeheavenlybody
C.aregionofspaceD.agreatmassofmatter
3)whatcausessomestarstoexplode,theoreticallyspeaking?
A.theirdensityB.theirgravity.C.theirmovementD.theirlight
4)Scientistscalltheareaaroundtheblackhole____.
A.aWhiteDwarfB.asupernova
C.theeventhorizonD.thestarofBethlehem
5)accordingtoEinsteinsrelativitytheory,thereisno"absolute"timeandspace.Isittrueorfalse?
A.trueB.false
6)whichofthefollowingstatementsisnottrue?Thestoryofblackholesinspace____
A.isacceptedbymanyseriousscientistsandastronomers
B.hastosomeextentbeenprovedbyresearchintobinarystarsystem
C.isquestioningourbasicideaofspaceandtime
D.Soundslikesciencefiction
7)accordingtothepassage,ourearthmaybeswallowingbytheblackholeoneday,isittrueorfalse?
A.trueB.false
8)accordingtothepassage,thehumanbeingonedaymaymakeuseoftheenergyofblackholebyadvancedtechnology.Isittrueorfalse?
A.trueB.false
Unit5Canada---Thetruenorth
Teachingaims:
1.TalkaboutthebasicinformationaboutCanada.
2.Learnhowtoreadatravelingreportandusemaps.
3.Learntoexpresslocationsanddirections.
4.Masterthenounclauses---appositiveclause
5.Vocabulary:minister,continent,surround,dawn,booth,slightly,settledown,haveagiftfor,figureout,asfaras,alltheway,ratherthan
Thefirstperiod
StepⅠRevision
1.Checkthestudents’homework
2.Checktheassignment.
StepⅡLead-inandwarmingup
Showthestudentsthemapleflagandaskthemsomequestions.
T:Doyouknowwhichcountryusesthisnationalflag?
Ss:Canada.
T:WhatcontinentisCanadain?
Ss:InNorthAmerica.
T:Howlargeisit?
Ss:Itisthesecondlargestcountryintheworld.
T:Yes.Itoccupiesanareaof9,984,670squarekilometers.ItisabitbiggerthanChina.Whichcountryisitsneighbor?
Ss:TheUnitedStates.
(ShowamapofCanadatothestudents)
T.Right.TheUnitedStatesis.Canadaisabeautifulcountry.Firstlet’shaveaquizandseehowmuchdoyouknowaboutCanada.
(GivetheSsoneminutetofinishthequiz.)
T:OK.Timeisup.Let’schecktheanswers.
1.C2.D3.A4.B5.A
StepⅢPre-reading
T:NowIwanttoaskyouaquestion:Doyouliketravelling?
Ss:Yes.
T:Iknowmostofyoudo.Sohaveyoueverbeenabroad?
Ss:Yes/No.
T:What’sthelongesttripyouhaveevertaken?
…
T:Verygood.Ifwewanttomakeourmotherlandmorebeautifulandmoredeveloped,weshouldknowmoreaboutothercountries.Herearetwoquestions,youmayaskyourpartnerforanswersandgiveyouranswerstohim/her.
a.IfyoutakeatriptoCanada,whatdoyouexpecttosee?
b.WhatthreewordswouldyouusetodescribeCanada?
(Asksomepairstotelltheirideastotheirclassmates.)
StepⅣFastreading
Getthestudentstoreadthepassagequicklyandaccuratelyandmeanwhilehelpthestudentstoformagoodhabitofreading.
T:Doyoufeelpuzzledwhenyoureadthetitle?Whatisthetruenorth?Nowreadthepassageandgetthegeneralideaofthepassage.Underlinethemainplacesmentionedinthetext.
GivetheSs5minutesforreading.
a.Whatthepassageismainlyabout?
b.Whatarethemainplacesmentionedinthetext?
c.Drawthetravelingrouteofthetwogirlsonthemap.
T:Doyouhaveanydifficultyinreading?Nowlet’sdiscusssomedifficultpointstogether.
StepⅤHomework
1.Remembertheunderlinedsentence.
2.WriteashortpassagetoreportwhatLiDaiyuandLiuQiansawinCanada.
Thesecondperiod
StepⅠRevision
1.Haveadictation.
2.Asktwostudentstowriteontheblackboard.
3.Askonestudenttomakeashortreport.
StepⅡLead-in
T:LiDaiyuandLiuQianwereonthetrainyesterday.ThetrainrushedacrossthetopoftheLakeSuperior.Whichisthenextcityitrunstowards?
Ss:Toronto.
T:Torontoisanimportantcity.ItisthefinancecenterofCanada.Ithasrichpopularartsandculture.HowmuchdoyouknowaboutToronto?
Ss:ThereareChinatownswhereyoucanbuyChinesemedicine.
T:Quiteright.DoyouwanttoknowmoreaboutToronto?
Ss:Yes.
StepⅢReading
T:Readthepassageon38.Inthispassage,youcanlearnalotaboutToronto,andMontreal,whichisCanada’ssecondlargestcity.Iwillgiveyoufourminutestoreadthepassage,thenanswerthequestionson37—38.
Fourminuteslater,checktheanswerswiththeclass.
StepⅣIntensivereading(readingtask)
T:Readthepassageandfillinthechartusingtheinformationofthetext.
PointsinthepassageWhatBeththoughtInformationinpassage
Thetemperature
Howtotravel
Holidays
Howpeoplelive
WhattheInuitdo
Daylighthours
T:Youcanhaveadiscussionwithyourpartner.
StepⅤDiscussion
T:WehaveknownalotaboutCanada.Nowlet’scompareChinawithCanada.
SameasChinaDifferentfromChina
LargelandSixtimearea
Weatherisdifferentfromareatoarea,longandhardwinterNoplacesashotassouthchina
DifferentpeoplespeakdifferentlanguagesCanadahastwoofficiallanguages,smallerpopulation
ManyriversandlakesWorldfamousriversandlakes
Muchcoal,oilgasandothernaturalresourcesMuchfreshwater,alotofforest
StepⅥHomework
2.ReadthetwopassagesagainandfindthemaincharactersofToronto,MontrealandIqaluit.
3.Readfunreadingbyyourself.
Unit1Festivalsaroundtheworld
1.Teachingaimsofthisunit
Talkaboutfestivalsandcelebrations
Talkaboutthewaystoexpressrequestandthanks
LearntouseModalverbs
Writeasimilarstorywithadifferentending
2.Sentencepatterns:
Request:
Could/Wouldyouplease…?
CouldIhave…?
Couldwelookat…?
Ilookforwardto…
MayIsee…?
Thanks:
It’sverykindofyou…
Thankyouverymuch/Thanksalot.
I’dloveto.
Itwasapleasure…
Don’tmentionit.
Youaremostwelcome.
3.Modalverbs:
Maymight,cancouldwillwouldshallshouldmustcan
ThefirstperiodSpeaking
1.Teachingaims:
Vocabulary:takeplace,lunar,festival,ArmyDay,Christmas,dressup
Phrases:Wouldyoulike…CouldIhave…?
MightIofferhelp…?MayIsee…?
Youshouldtry…Couldwelikeat…?
Canyousuggest…?Wemighttake…
TeachingProcedures
StepILeadingin
T:Hello,everybody!Welcomebacktoschool!Didyouhaveagoodtimeinyourwinterholidays?
Ss.Yes.Ofcourse!
T:Whendidyoufeelmosthappyandexcited?
Ss:AttheSpringFestival.
T:Whocantelluswhy?Anyvolunteers?
S1:Becauseitisthemostimportantfestivalinourcountry.
S2:BecauseIgotalotofluckymoneyfrommyparents.
S3:BecauseIneedn’tstudyatfestivalsandtherewasalotofdeliciousfoodtoeat.Howgreat.
S4:BecauseImetmycousinsandfriendswhoIhadn’tseenforalongtime.
T.Veryfood!Iamgladtohearthat.Todaywewilltalkaboutfestivals,whicharemeanttocelebrateimportantevents.Pleasethinkaboutsomeotherfestivals.Canyounamejustafew?
Ss:Newyear,Yuanxiaofestival…
:T:Quiteright.That’scalledtheLantern’sFestival.Howaboutsomeotherfestivals?
Ss:TheArmyDay,InternationalLabour’sDay,NationalDay,TombSweepingFestival,DragonBoatFestival,Mid-autumnDay…
T:Youhavedoneagoodjob,boysandgirls!.
StepⅡWarming–up
Festivalsaremeanttocelebrateimportantevents.Differentcountrieshavedifferentfestivals.WorkingroupsandlostfiveChinesefestivalsthatyouknow.Discusswhentheytakeplace,whattheycelebrateandonethingthatpeopledoatthattime.Thefirstoneisgiventoyouasanexample.
FestivalsTimeofyear/dateWhatdoesitcelebrateWhatdopeopledo
Mid-AutumnFestivalAutumn/FallThebeautyofthefullmoon,harvest,timewithfamilyandfriendsGive/Eatmooncakesandwatchthefullmoonwithfamilyandfriends
StepⅢPre-reading
Discussingroupsoffour
1.What’syourfavouriteholidayoftheyear?Why?
2.Whatfestivalsorcelebrationsdoyouenjoyinyourcityortown?Doyoulikespendingfestivalswithyourfamilyorwithfriends?Whatpartofafestivaldoyoulikebest---themusic,thethingstosee,thevisitsorthefood?
StepⅣAssignment
1.Consolidation
2.Listeningtothematerialagainafterclasstobefamiliarwithit.
3.Homework:Collectasmuchinformationaboutfestivalsaspossible.
ThesecondperiodReading
TeachingAims
1.Vocabulary:starve,starvation,plenty,satisfyancestorlampsleadfeastboneorigininmemoryofdressuptrickpoetarrivalnationalgainindependencegatheragriculturalEuropeancustomawardswatermelonhandsomeroosteradmirelookforwardtoreligiousasthoughhavefunwithdaily
2.Toenablethestudentstoknowtheearliestfestivalswithreasonsforthemandfour
differentkindsoffestivalsthatoccurinmostpartsoftheworld
3.ToenablethestudentstomastersomeEnglishexpressionsandphrasesaboutfestivals.
4.Teachthebasicreadingskills:skimmingandscanning.
5.Trytocompareandmakeconclusionsofdifferentfestivals.
StepⅠRevision
1.Greetings.
2.Reviewthenewwordsofthispart.
3.Checkthestudents’homework---festivals
StepⅡReading
1.Scanning
T:Openyourbooksandturntopageone.I’dlikeyoutodothescanning.Readthetextquicklyandaccuratelytogetthemainideaandanswerthe6questionsonPage3.
(Askthestudenttolookthroughthequestionsandthenreadthetextsilently.)
(Fourminuteslater,checktheanswerswiththewholeclass.Showthesuggestedanswersonthescreen.)
2.Intensivereading
(Allowthestudentstoreadaloudandcarefullythistimetounderstandthemainideasofeachparagraphandtheimportantdetails)
T:ReadthetextloudlyforasecondtimeandthemtrytotellifthesesentencesareTrueorFalse.
1.Theancientpeopleneedn’tworryabouttheirfood.(F)
2.Halloweenusedtobeafestivalintendedtohonorthedead.(T)
3.QuYuanwasagreatpoetwhopeoplehonoralotinChina.(T)
4.Mid-autumnFestivalisheldtocelebratetheendotautumn(F)
5.EastercelebratesthebirthofJesus.(F)
3.Readinganddiscussion
T:ReadthetextathirdtimeandthenworkimpairstodoExercise2onPage3.
(Letthestudentshaveenoughtimetoreadthepassagecarefullyanddiscussthechartwiththeirpartners.Encouragethemtoexpandtheiranswersaccordingtotheirownexperiences.)
4.Explanation
(Inthisparttrytohelpthestudentsanalysethedifficult,longandcomplexsentencesandguessthemeaningofthenewwords;askthemtodealwiththelanguagepointsinthecontext.)
T:NowIwilldiscusssomeimportantsentencesandphrasesinthepassage.
a.Somefestivalsareheldtohonorthedead,orsatisfyandpleasetheancestors,whocouldreturneithertohelportodoharm.
b.Inmemoryof
c.InIndiathereisanationalfestivalonOctober2tohonorMahatmaGandhi,theleaderwhohelpedgainIndia’sindependencefromBritain.
d.Peoplearegratefulbecausetheirfoodisgatheredforthewinter,andbecauseaseasonofagriculturalworkisover.
e.Themostenergeticandimportantfestivalsaretheonesthatlookforwardtotheendofwinterandtothecomingofspring.
f.Thecountryiscoveredwithcherryflowerssothatitlooksasthoughitmightbecoveredwithpinksnow.
Thesuggestedexplanation:
a.Anattributiveclause.
Thesentencemeanspeopleholdsomefestivalseithertoshowrespecttothedeadortomaketheirancestorshappyincasetheymightcomebacktodoharm.
b.inmemoryof…servingtorecallsb,tokeephimfreshinpeople’minds.
Hewroteapoeminmemoryofhisdearestwife,whodiedinanaccident.
inhonorof(showinggreatrespectorhighpublicregard)
inhopes/thehopeof(hoping)
indefenceof(defending)
c.anounphrasefollowedbyanattributiveclauseastheappositive
d.twoclausesforreason
e.energy→energeticadj.(fullofordonewithenergy)
lookforwardto(toisaprepositionhere.)
devoteto,be/getusedto,getdownto,stickto
e.g.I’mlookingforwardtohearingfromyou.
StepⅢListening
T:NowIwillplaythetapeforyou.Youcanjustlistenwithyourbooksclosedorlookatyourbooksorreadinalowvoicetogetherwiththetape.It’suptoyou.Afterlistening,pleasewritedownthreethingsthatmostfestivalsseemtohaveincommon.(ComprehendingEx.3onPage3).
ThethirdperiodLearningaboutlanguage
Teachingaims:
1.Letthestudentsknowtheusageofmodalverbs.
2.Enablethestudentstorecognizethewordsandexpressionsinthereadingpassageaccordingtowhatmeanthesameasthem.
StepⅠGreetingandRevision
(Asksomestudentstoretellthetextwelearned.)
StepⅡ.Practicingtheusefulwordsandexpressions
T:Asweknow,therearetwoimportantkindsofverbs---transitiveverbsandintransitiveverbs.Butmanyintransitiveverbshavethestructure“verb+preposition+objects”Canyougivemesomeexamples?
Ss:Sure.Suchaslookatthepicture,hearfrommyfriends,listentotheradioandsoon.
T:Ok.Nowturntopage4,Ex.4.Youaretomakesomesentencesofyourown,usingthewordsgiven.
S1.I’mlookingforwardtohearingformmyfriend
S2:Wearetalkingaboutverbs.
S3:Wouldyouliketotalkwithme?
S4:Whocanthinkofaneffectivesolutiontotheproblem?
S5:Pleasethinkaboutmyproposal.
StepⅢUsefulStructures
T:Let’scometothenextpart.Thispartisaboutmodalverbs.YouaretoreadthesentencesinEx.1andthentofindoutandwritedowndifferentsentenceswithmodalverbsformthereadingpassageandtrytoexplaintheirmeanings.IfyouhaveanydifficultyinunderstandingthemyoucanrefertoGrammarinPages92---94
StepⅣSummingupandhomework
T:Boysandgirls,todaywehavepracticedusefulwordsandphrasesofthisunitandtheusageofmodalverbs.Ithinkitisnoteasyforyoutomasterthem,afterclassyoushouldreviewthem.
Homework
1.PracticeofWBP42EX.1,2,3.
2.Pleasefindout10sentenceswithmodalverbs,andtrytogettheirmeanings.
ThefourthperiodListening
Teachingaims:
1.Vocabulary:gowith,thebigbands,musicians,overandoveragain,forsale,getusedto,thewinnersofthisyear’sawardsforthebestcostumes
2.Enablethestudentstoknowhowtogetthekeywordstounderstandtheconversationaboutthecarnivalparade,totalkaboutsthhappenedandexpressrequestandthanks.
StepⅠRevision
AftercheckingtheWBEx.1,2,3theteacheraskthestudentstogiveexamplesaboutmodalverbsandtrytoexplainthem.
StepⅡWarmingup
T:Bytheway,what’sthetopicofthisunit?
Ss:Festivalsaroundtheworld.
T:Wouldyouliketoknowsomethingmoreaboutfestivalsaroundtheworld?
Ss:Ofcourse.
T:NowIwillshowyouseveralpictures.What’sthefestivalcalled?
Ss:Carnival.
T:Yes.Thisclasswewilllistentoadialogueaboutcarnivals.Firstlookthroughthefourquestionsinlisteningparttofindoutthelisteningpoints.
StepⅢListening
T:Iwillplaythetapeforyoutwice.Pleaselistencarefullyandpaymuchattentiontotheimportantpoints.Forthefirsttimeyouaretomakenotesbesidethequestions.Forthesecondtime,youshouldwritedowntheanswersandthencheckthemwithyourpartners.
(It’simportanttoencouragethestudentstoadapttheirpresentknowledgeany
skilltoavarietyofsituationswherevertheycan.Makesuretoallowvarious
expressionsoftheanswers.Donotdemandthesamewordsformallstudents.)
StepⅣSpeaking
Thispartisintendedtogivethestudentstheopportunitytopracticeatelephoneconversationusingthefunctionalitemsforrequestsandthanks.ThepoliteformofEnglishareimportantandshouldbepracticedinavarietyofsituations.
StepⅤListeningtask
T:Thereareabout10minutesleft.Let’scometolisteningtask.Turntopage43
andlookatthepictures.Theyhavesomethingincommon.Canyoufinditout?
Ss:Theyareallaboutfestivalsboutthedead.
T:That’sright.Iwillplaythetapeforyou.Forthefirsttimeyoushouldtryto
writedownthenameofthecountrywherethefestivalareheld.ForthenexttwotimesyoushoulddoEx2.Youcanmakeabriefnotefirstandthencompletethechart,accordingtowhichyoucanmakeareport.
ThefifthperiodExtensivereading
Teachingaims:
1.Vocabulary:heart-broken,turnup,keepone’sword,holdone’sbreath,drownone’ssadnessincoffee,setofffor,remindsomebodyofsomething,
2.LearntocomparethefestivalsinChinaandinwesterncountries.
StepⅠRevision
Checkhomework
StepⅡReading(1)
T:Asweknow,thereareallkindsoffestivalsaroundtheworld.WehavetalkedabouttwoChinesefestivalsforthedead.Todaywearegoingtireadasadstory,whichistointroduceacrossculturalviewoflovers’festival—QiQiaoandValentine’sDay.Nowpleasereaditquicklyandfindoutthesentencebelowaretrueorfalse.
ThegirlLiFanglovedandwaitedbutshedidn’tturnup.Buthedidn’tloseheart.(F….)
Becausehermostlovelydaughtergotmarriedtoahumansecretly,theGoddessgotveryangry..(…T.)
ZhinvwasmadetoreturntoHeavenwithoutherhusband.Theywereallowedtomeetonceayearontheseventhdayofthetenthlunarmonth,.(F….)
HuJinhadbeenwaitingforLiFangforalongtimewithagiftforhim..(…T.)
T:Ithinkyouhavegotthegeneralideaofthepassage.NowpleasereadthepassageoncemoreandanswerthequestionsonPage8.
Somelanguagepoints:
1.turnup:appear
2.keepherword:keepherpromise
3.holdhisbreath:waitwithoutmuchhope
4.drownone’ssadness/sorrowincoffee:drinkcoffeeinordertoforgetthesadness/sorrow
5.remindsbofsth:makesbthinkofsth
StepⅢDiscussionandwriting
T:That’sforthereadingpartofthepassage.Pleasethinkabouttheendingofthestory.Areyousatisfiedwiththeending?Differentpeoplehavedifferentopinionstoamatter.Nowanyoneofyouhaveanopportunitytomakeupanendingtothestory.Pleaseengageimaginativelyinthestoryanduseyourownideas.Trytousethevocabularyandstructuresyouhavelearnedofyoulike.
StepⅣReading(2)
T:Let’scometoanotherpassageaboutcarnivalinQuebec.PleaseturntoPage44,readitquicklyandanswerthequestionsinPage45.Fiveminutesforyou.
Addedmaterial:
ThanksgivingDay
FourthThursdayinNovemberiscelebratedas‘ThanksgivingDay’PeoplethankGodforhisblessings.Peoplecan‘Thank’friends,foesandanyonefortheexperiences,happinessandsunshinetheybringintotheirlives.PilgrimscelebratedthefirstThanksgivingDayinAmericaduringthesecondwinterinthenewworld.Thefirstwinterhadbeenbadasnearlyhalfofthepeoplehadperishedduetolackoffoodandbadweather.Butthefollowingyear,withthehelpofIndianswhoshowedthemhowtoplantIndiancorn,thepilgrimshadsuccessfulharvest.GovernorWilliamBradforddecidedthatDecember13,1621besetasideforfeastingandprayer.TheIndianswereinvitedtosharethefestival.Sincethan,ThanksgivingDayisbeencelebratedinAmerica.However,itwasonlyin1941,theCongressinajointresolutionnamedthefourthSundayinNovemberastheofficialThanksgivingDay.
Datingback,itisknownthattheCouncilthoughttoappointandsetapartthe29thdayofJune,asadayofSolemnThanksgivingandpraisetoGodforhisGoodnessandFavour.TheFirstThanksgivingProclamationwashoweveronJune20,1676.ThegoverningcouncilofCharlestown,Massachusetts,heldameetingtodeterminehowbesttoexpressthanksforthegoodfortunethathadseentheircommunitysecurelyestablished.ByunanimousvotetheyinstructedEdwardRawson,theclerk,toproclaimJune29asadayofthanksgiving,ItisalsoknownthatthePilgrimssetgroundatPlymouthRockonDecember11,1620.Theirfirstwinterwasdevastating.Atthebeginningofthefollowingfall,theyhadlost46oftheoriginal102whosailedontheMayflower.Buttheharvestof1621wasabountifulone.Andtheremainingcolonistsdecidedtocelebratewithafeast--including91IndianswhohadhelpedthePilgrimssurvivetheirfirstyear.ItisbelievedthatthePilgrimswouldnothavemadeitthroughtheyearwithoutthehelpofthenativesThefeastwasmoreofatraditionalEnglishharvestfestivalthanatrue"thanksgiving"observance.Itlastedthreedays.
Thanksgiving,asweknowittoday,hascomealongwayfromthePilgrimsharvestfestivalin1621.Itisaneventthatseems,aseachyeargoesby,toreinventitselfandtoexpanditsmeaningtolargervistas.Maybethisistherealsignificanceoftheoccasion;foraswecontinuetochangeandgrowasapeople,thereareanincreasingnumberofthingsforwhichwecanbethankful.
一名优秀的教师就要对每一课堂负责,教师要准备好教案,这是每个教师都不可缺少的。教案可以让学生更好的吸收课堂上所讲的知识点,帮助教师提前熟悉所教学的内容。那么如何写好我们的教案呢?为满足您的需求,小编特地编辑了“高二数学必修二全册教案”,大家不妨来参考。希望您能喜欢!
一、教学目标
1.知识与技能
(1)通过实物操作,增强学生的直观感知。
(2)能根据几何结构特征对空间物体进行分类。
(3)会用语言概述棱柱、棱锥、圆柱、圆锥、棱台、圆台、球的结构特征。
(4)会表示有关于几何体以及柱、锥、台的分类。
2.过程与方法
(1)让学生通过直观感受空间物体,从实物中概括出柱、锥、台、球的几何结构特征。
(2)让学生观察、讨论、归纳、概括所学的知识。
3.情感态度与价值观
(1)使学生感受空间几何体存在于现实生活周围,增强学生学习的积极性,同时提高学生的观察能力。
(2)培养学生的空间想象能力和抽象括能力。
二、教学重点、难点
重点:让学生感受大量空间实物及模型、概括出柱、锥、台、球的结构特征。
难点:柱、锥、台、球的结构特征的概括。
三、教学用具
(1)学法:观察、思考、交流、讨论、概括。
(2)实物模型、投影仪
四、教学思路
(一)创设情景,揭示课题
1.教师提出问题:在我们生活周围中有不少有特色的建筑物,你能举出一些例子吗?这些建筑的几何结构特征如何?引导学生回忆,举例和相互交流。教师对学生的活动及时给予评价。
2.所举的建筑物基本上都是由这些几何体组合而成的,(展示具有柱、锥、台、球结构特征的空间物体),你能通过观察。根据某种标准对这些空间物体进行分类吗?这是我们所要学习的内容。
(二)、研探新知
1.引导学生观察物体、思考、交流、讨论,对物体进行分类,分辩棱柱、圆柱、棱锥。
2.观察棱柱的几何物件以及投影出棱柱的图片,它们各自的特点是什么?它们的共同特点是什么?
3.组织学生分组讨论,每小组选出一名同学发表本组讨论结果。在此基础上得出棱柱的主要结构特征。(1)有两个面互相平行;(2)其余各面都是平行四边形;(3)每相邻两上四边形的公共边互相平行。概括出棱柱的概念。
4.教师与学生结合图形共同得出棱柱相关概念以及棱柱的表示。
5.提出问题:各种这样的棱柱,主要有什么不同?可不可以根据不同对棱柱分类?
请列举身边具有已学过的几何结构特征的物体,并说出组成这些物体的几何结构特征?它们由哪些基本几何体组成的?
6.以类似的方法,让学生思考、讨论、概括出棱锥、棱台的结构特征,并得出相关的概念,分类以及表示。
7.让学生观察圆柱,并实物模型演示,如何得到圆柱,从而概括出圆标的概念以及相关的概念及圆柱的表示。
8.引导学生以类似的方法思考圆锥、圆台、球的结构特征,以及相关概念和表示,借助实物模型演示引导学生思考、讨论、概括。
9.教师指出圆柱和棱柱统称为柱体,棱台与圆台统称为台体,圆锥与棱锥统称为锥体。
10.现实世界中,我们看到的物体大多由具有柱、锥、台、球等几何结构特征的物体组合而成。请列举身边具有已学过的几何结构特征的物体,并说出组成这些物体的几何结构特征?它们由哪些基本几何体组成的?
(三)质疑答辩,排难解惑,发展思维,教师提出问题,让学生思考。
1.有两个面互相平行,其余后面都是平行四边形的几何体是不是棱柱(举反例说明,如图)
2.棱柱的何两个平面都可以作为棱柱的底面吗?
3.课本P8,习题1.1A组第1题。
4.圆柱可以由矩形旋转得到,圆锥可以由直角三角形旋转得到,圆台可以由什么图形旋转得到?如何旋转?
5.棱台与棱柱、棱锥有什么关系?圆台与圆柱、圆锥呢?
四、巩固深化
练习:课本P7练习1、2(1)(2)
课本P8习题1.1第2、3、4题
五、归纳整理
由学生整理学习了哪些内容
六、布置作业
课本P8练习题1.1B组第1题
课外练习课本P8习题1.1B组第2题
[讲述]由蛋白质变性引起的蛋白质凝结是不可逆的。蛋白质变性凝结后丧失可溶性,还失去生理活性。
[回答](1)医疗上高温消毒杀菌,就是利用加热使蛋白质凝固,从而使细菌死亡。
(2)误服重金属盐,可以服用大量牛乳、蛋清或豆浆,以吸收重金属盐解毒,免使人体蛋白质变性中毒。
(3)用卫生酒精擦洗皮肤,能使皮肤表面附着的细菌(体内的蛋白质)凝固变性而死亡,达到消毒杀菌,避免感染的目的。
(4)甲醛使蛋白质凝固变性,使标本透明而不浑浊,说明甲醛溶液能长期保存标本,不影响展示效果。
3.颜色反应
[实验1—4]
[讲解]蛋白质可以跟许多试剂发生颜色反应。这种反应能用于蛋白质的检验。
[板书]三、人体必需的氨基酸
[阅读]相关内容说出人体必需的8种氨基酸及搭配食物的营养作用。
[讲解]人体必需的8种氨基酸
口诀:甲携来一本亮色书。注:甲(甲硫氨酸)、携(缬氨酸)、来(赖氨酸)、一(异亮氨酸)、本(苯丙氨酸)、亮(亮氨酸)、色(色氨酸)、书(苏氨酸)
[阅读]资料卡片——酶,总结酶的特性。
[总结]酶是有生物活性(生物催化作用)的蛋白质。它有条件温和、高效、专一的催化活性。
[课外作业]P18、P19两个实践活动。
[课堂练习]
1.下列物质中,不能使蛋白质变性的是
A、硫酸铜B、苯酚C、乙醇D、硫酸铵
2.下图表示蛋白质分子的一部分,图中(A)、(B)、(C)、(D)标出分子中不同的键,当蛋白质发生水解反应时,断裂的键是
3、关于氨基酸的叙述中不正确的是
A.氨基酸的组成上只有碳、氢、氮三种元素
B.氨基酸既能和强酸反应又能和强碱反应C.蛋白质水解得到α-氨基酸
D.氨基酸分子结构中有酸性的羧基和碱性的氨基,但氨基酸溶液不一定是中性的
4.属于物理变化的是
A.麦芽糖和稀硫酸共热B.蛋白质溶液中加入饱和NaCl溶液有固体析出
C.蛋白质溶液中加入浓NaOH溶液D.氨基酸加入盐酸
5.重金属盐能使人体中毒,这是由于它使人体内的蛋白质
A.发生了水解作用;B.发生了盐析作用;C.发生了变性作用;D.发生了分解作用。
6.在热、酸、碱、重金属盐、紫外光线的作用下,蛋白质会发生变性凝聚_。它是不可逆的,所以用高温和紫外线消毒,就是使细菌的菌体蛋白质变性。
7.脂肪、淀粉、蛋白质被称为人类的三大营养物质,它们的共同性质是都与水发生水解反应。我们从食物中摄取的蛋白质,在胃液中的胃蛋白酶和胰蛋白酶的作用下水解反应,生成氨基酸,它被人体吸收后,重新合成人体所需要的各种蛋白质,人体内各组织的蛋白质不断分解,最后主要生成尿素排出体外。
8.缬氨酸是一种中性的α-氨基酸,分子量117,经分析测得含氮12%,每一个缬氨酸分子中碳原子数是氮原子数的5倍,氢原子数是碳原子数的2倍再多一个,已知缬氨酸的碳链上有支链,且氨基与支链在不同碳原子上,写出缬氨酸分子式______,其结构简式为______,井用系统命名法加以命名______。
α-氨基-β-甲基-丁酸
[板书计划]
二、蛋白质性质
1.盐析
蛋白质在浓无机盐溶液中因胶体凝聚而析出,叫做盐析。盐析是可逆的,
2.变性
3.颜色反应
蛋白质可以跟许多试剂发生颜色反应。这种反应能用于蛋白质的检验。
三、人体必需的氨基酸
教学反思:
课题:第四节维生素和微量元素
知识与技能:
1.通过实例了解人体必需的维生素的主要来源及其摄入途径。了解维生素在人体中的作用。
2.认识微量元素对人体健康的重要作用。
3.了解合理摄入营养物质的重要性,认识营养均衡与人体健康的关系。
4.通过实例了解某些药物的主要成分和疗效。
过程与方法:实验探究、调查、查阅资料并讨论。
情感、态度、价值观:通过人体常量与微量的关系,让学生明白物质的辩证唯物主义理念。
教学重点、难点:通过实例了解人体必需的维生素的主要来源及其摄入途径。认识微量元素对人体健康的重要作用。
课时划分:两课时
教学过程:(第一课时)
[导课]在20世纪,科学家发现只用糖类、脂肪、蛋白质和水的饲料喂养,实验动物不能存活。但如果在饲料中加入极微量的牛奶后,动物正常生长。科学家反复实验后认为,动物膳食中除含糖类、脂肪、蛋白质和水外,还必须含有微量维生素、矿物质等。
[板书]第四节维生素和微量元素
[阅读]资料卡片---维生素的发现
[交流]你知道的维生素有那几种?它们各有什么性质?
[板书]一、维生素
1、维生素的作用
[讲述]维生素是参与生物生长发育和代谢所必需的一类微量有机物质.这类物质由于体内不能合成或者合成量不足,所以虽然需要量很少,每日仅以毫克或微克计算,但必须由食物供给。绝大多数维生素作为酶的辅酶或辅基的组成成分,在物质代谢中起重要作用。
维生素都是小分子有机化合物,在结构上无同性,通常根据其溶解性质分为脂溶性和水溶性两大类。
名称来源缺乏症
水溶性维生素
维生素B1豆,瘦肉,谷类外皮脚气病,多发性神经炎
维生素B2蛋黄,绿叶疏菜等口角炎,舌炎,皮炎等
维生素C新鲜水果,蔬菜坏血病
脂溶性维生素
维生素A肝,蛋黄,鱼肝油,奶汁,胡罗卜等夜盲症,皮肤干燥
维生素D鱼肝油,肝,蛋黄,日光照射佝偻病,软骨病
[板书]脂溶性:维生素A、维生素D、维生素E、维生素K;水溶性:维生素B族(维生素B1、维生素B2等)、维生素C。
[演讲故事]著名探险家雅克卡蒂尔的历险故事。
卡蒂尔在1534年11月至1535年4月间率一队船员在考察圣劳伦斯的加拿大湾。当时有数周的时间,他们被坚冰困在海湾里出不去,渐渐的他们都出现了以下症状:牙龈出血、皮肤反应性青紫、身体虚弱、易怒、肌肉隐隐作痛、关节痛。幸运的是他们遇到了一位魁北克印弟安人,印弟安人让他们喝一种由当地生长的一颗大松树的叶子和皮制成的茶,这种茶竟然神奇的治好了他们的病。马斯魁勒(Masquelier)博士受此启发,开始研究该树种的树皮于1951年提取OPC成功,并应用于心脑血管疾病的治疗中,19年后,即1970年,他成功的从葡萄籽中提取了纯正的OPC,含量高达95%以上,而且无论浓度还是抗氧化作用都优于松树皮提取物,患者服用后都感觉更有效。OPC即维生素C。
[板书]2、维生素C
[讲解]维生素C,其化学名称为:L-抗坏血酸。其结构式为:分子式:C6H8O6,是水溶性维生素,溶液显酸性,有可口的酸味。维生素C广泛存在于水果、蔬菜中,水果中又以柑桔类含量较多,蔬菜中青色者含维生素C较多。人工不能合成维生素C,必须从食物中获得。又叫抗坏血酸,是人体中新陈代谢不可缺少的物质,它维持牙齿、骨胳、血管肌肉的正常功能、具有解毒作用。能增强人体对疾病的抵抗力,促进伤口愈合,并能预防肿瘤。在新鲜蔬菜和水果中含量丰富,尤其是绿叶蔬菜,西红柿等酸性水果和豆芽中含量较高,缺乏时使人得坏血病表现为骨胳脆弱等症状。中学生每天需要补充60mg维生素C。
[板书]维生素C,其化学名称为:L-抗坏血酸。分子式:C6H8O6。
[结构]
[查询]根据维生素C结构推断它具有那些性质?
[回答]加成、氧化、水解等。
[例析]研究性试题:维生素C是一种水溶性维生素(其水溶液显酸性),它的化学式是C6H8O6,人体缺乏这种维生素可能得坏血病,所以维生素C又称抗坏性血酸。维生素C易被空气中的氧气氧化。在新鲜的水果、蔬菜、乳制品中都含量较高,如维生素C在新鲜的橙汁中含量500mg/L左右。学校课外活动小组测定了某中品牌的软包装橙汁中的维生素C的含量。下面是测定实验的分析报告。
I、测定目的:测定某中品牌的软包装橙汁中的维生素C的含量。
II、测定原理:C6H8O6+I2=C6H6O6+2H++2I-
III、实验用品及试剂
①仪器和用品(自选)
②试剂:指示剂。维生素C溶液(浓度7.50×10-3molL-1)标准碘溶液、蒸馏水等。
IV、实验过程:
⑴洗涤仪器,检查滴定管是否漏水,润洗后装好标准碘溶液。
⑵打开:软包装,目测:颜色——橙黄色。澄清度——好。用仪器向锥形瓶移入20.00ml待测橙汁,滴入2滴指示剂。
V、数据记录与处理:
滴定次数待测溶液体积
(ml)标准碘溶液体积
滴定前刻度滴定后刻度体积(ml)
第一次20.000.2415.22
第二次20.000.1015.11
根据以上数据,计算此橙汁中维生素C的含量
VI、问题讨论
⑴橙汁和碘溶液分别盛放在何种滴定管中?
⑵滴定时能否剧烈摇动锥形瓶?为什么?
⑶从分析数据看,此软包装橙汁是否是纯天然橙汁?[]
A、是B、可能是C、不是
⑷制造商可能采取的的做法是[]
A、加水稀释天然橙汁B、橙汁已被浓缩C、将维生素C作为添加剂
⑸你是否同意这种做法[]
A、同意B、不同意C、调查后再作结论
分析:①根据题意信息维生素C水溶液显酸性,所以把它放在酸式滴定管中,碘溶液具有氧化性同样应放在酸式滴定管中。
②反应原理是用碘氧化维生素C,维生素C溶液中滴入淀粉溶液,当维生素C被碘氧化后继续滴入碘溶液使淀粉溶液变蓝。
③由于维生素C易被空气氧化,所以滴定时不能剧烈摇动锥形瓶。④维生素C溶液的体积为20.00ml,与之反应的贷内溶液的体积为两次滴定的平均值15.00ml。
由反应原理:C6H8O6+I2=C6H6O6+2H++2I-维生素C的浓度C=5.6×10-3molL-1,即每升溶液中含有C6H8O6质量为985.6mg/L。⑤信息中新鲜橙汁维生素C的含量500mg/L左右,计算结果远大于此数据,说明此橙汁
肯定不为天然橙汁。对于制造商而言需要作调查后才能下结论。
[作业]P251、5、6
[板书计划]
第四节维生素和微量元素
一、维生素
1、维生素的作用
脂溶性:维生素A、维生素D、维生素E、维生素K;水溶性:维生素B族(维生素B1、维生素B2等)、维生素C。
2、维生素C
维生素C,其化学名称为:L-抗坏血酸。分子式:C6H8O6。
例析:
[教学反思]
第二课时
[讨论]“是药三份毒”谚语。
[查阅]兴奋剂、毒品。
[交流]兴奋剂:
兴奋剂作为一种短期提高体育成绩但对身体造成极度危害的药物,已经像幽灵一样附着在人类体育运动的许多领域,玷污着人类崇高的体育精神。那么什么是兴奋剂呢?
兴奋剂实际是禁用药物的统称,即凡是能提高运动成绩并对人体有害的药物都是兴奋剂。目前人们还没有发现仅能提高成绩而不损害身体的兴奋剂。
由于兴奋剂的主要功能是用强加的方法来改变身体的机能,而这种改变必将导致身体的平衡遭到破坏,造成自身原有的功能受到抑制,进而形成人体对药物的长期依赖及这种依赖的不可恢复性,甚至导致猝死的发生。
不同种类的兴奋剂对人肌体的作用是不同的。像刺激剂就对增加反应,提高竞争意识有作用。蛋白同化制剂则增加人体肌肉,增强体能。阻断剂能增加动作稳定性。利尿剂能够减轻体重,还可以利用它的强排泄作用掩饰其它的兴奋药物。
[交流]毒品:根据《中华人民共和国刑法》第357条规定:毒品是指鸦片、海洛因、甲基苯丙胺(冰毒)、吗啡、大麻、可卡因以及国家规定管制的其他能够使人形成瘾癖的麻醉药品和精神药品。目前,我国吸毒者常用的毒品是:海洛因、鸦片、大麻、冰毒、摇头丸等。
鸦片,又称阿片,包括生鸦片和精制鸦片。将未成熟的罂粟果割出一道道的刀口,果中浆汁渗出,并凝结成为一种棕色或黑褐色的粘稠物,这就是生鸦片。精制鸦片亦称"禅杜",即经加工便于吸食的鸦片。另外还有鸦片渣、鸦片叶、鸦片酊、鸦片粉都是鸦片加工产品,均可供吸食之用。长期吸食鸦片可使人先天免疫力丧失,引起体质严重衰弱及精神颓废,寿命也会缩短,过量吸食可引起急性中毒,可因呼吸抑制而死亡。
吗啡(Morphine)是鸦片中的主要生物碱,在医学上,吗啡为麻醉性镇痛药,但久用可产生严重的依赖性,一旦失去供给,将会产生流汗、颤抖、发热、血压升高、肌肉疼痛和痉挛等明显的戒断症状。长期使用吗啡,会引发精神失常,大剂量吸食吗啡,会导致呼吸停止而死亡。
海洛因(Herion)通常是指二乙酰吗啡,它是由吗啡和醋酸酐反应而制成的。海洛因被称为世界毒品之王,是我国目前监控、查禁的最重要的毒品之一。海洛因品种较多,其中较为流行的有西南亚海洛因、中东海洛因、东南亚海洛因。
冰毒,即兴奋剂甲基苯丙胺,因其原料外观为纯白结晶体,晶莹剔透,故被吸毒、贩毒者称为“冰”(Ice)。由于它的毒性剧烈,人们便称之为“冰毒”。该药小剂量时有短暂的兴奋抗疲劳作用,故其丸剂又有“大力丸”之称。又因苯丙胺(Amphetamine)有其译音名安非他明或安非它命之称,故甲基苯丙胺也有甲基安非他明之称。此外,甲基苯丙胺是在麻黄素化学结构基础上改造而来,故又有去氧麻黄素之称。
[特殊班会]“拒绝毒品、关爱生命”(班主任等共同组织)。
[课堂例题]
例题1:鸦片是一种容易上瘾的毒品,其毒性主要是来自下列哪一个化合物
(A)海洛因 (B)安非他命 (C)吗啡 (D)尼古丁
解析:(A)海洛因:化学结构类似吗啡,属白色晶体纯度较吗啡高,比吗啡更易上瘾,属于植物碱。(B)安非他命:白色,无臭有苦味晶体,沸点为320℃;化学式为:C9H13N。(C)鸦片中含有20多种植物碱,其毒性主要由吗啡所造成。(D)尼古丁的分子式为:C10H14N2,尼古丁是一种兴奋剂,刺激肾上腺素,使心跳加速血压上升。答案(C)。
例题3:吗啡和海洛因都是严格查禁的毒品。吗啡分子中C、N、H的质量分数依次为:
71.58%、4.91%、6.67%,其余是氧。
(1)通过计算得出吗啡的相对分子质量(不超过300)根据已知数据,可计算氧的质量分数为:l-71.58%-4.9l%-6.67%=16.84%,则吗啡中C、H、N、O原于数最简整数比为C:H:N:O=17:19:1:3,则最简式为:C17H19NO3式量为12×17+1×19+14×1+16×3=285。因吗啡的相对分子质量不超过300,故吗啡的相对分子质量为最简式式量即285。;吗啡的分子式是就是最简式C17H19N03。
(2)已知海洛因是吗啡的二乙酸醋。则海洛因的相对分予质量是因为海洛因是吗啡的二乙酸酯,据酯化反应的过程:CH3COOH+R-OH→CH3COOR+H2O则每1分子CH3COOH参加酯化反应所生成的酯比原来的醇的相对分子质量增加60-18=42。由于海洛因是吗啡的二乙酸酯,则海洛因的相对分子质量比吗啡增加42×2=84,所以海洛因的相对分子质量为285+84=369。;分子式是C17H19NO3+C4H4O2=C21H23NO3。
例题4:大麻是一种毒品,我国政府严禁生产、销售和吸食。大麻中的主要成分为大麻酚,已知其分子式为C21H26O2。大麻酚在空气中焚烧,可生成CO2和H2O,这个反应的化学方程式是
2C21H26O2+53O2燃烧42CO2+26H2O。
例题6:"虎门销烟"是禁烟运动的伟大胜利。1839年6月,收缴到的110万千克鸦片被集中运到虎门海滩,和数以万担生石灰十起投入挖好的销烟池中。-随着大网拉起,海水灌进池中,顿时地中热浪翻滚,通过各种化学和物理作用;鸦片被全部销毁。鸦片是黑色青状物,它含有二十多种成分,吗啡和罂粟碱是其中有效成分中较主要的两种
在吗啡和罂粟碱的分子中,都含有相同的基团是(“-CH3”、“-CH2-”等键烃基除外)_____________,所以它们都可以看作是芳香族化合物;其中,能与NaOH溶液发生中和的是(填物质名称)____________,lmol这种物质能被____________molNaOH中和。
较强的碱性和较高的温度是鸦片在池中被销毁的原因之一。海水灌进池后;产生较强碱性的原因是(用化学方程式表示)________________________,由于这是一个____________反应,所以产生较高的温度。
答案:苯环(或苯基)、吗啡、2、CaO+H20=Ca(OH)2、放热。
[小结]略
[作业]P434、5
教学反思:
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