九年级英语上册unit5lookintosciencelesson26keepthecandleburning教学课件（新版）冀教版

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1、Unit5LookintoScienceLesson26KeeptheCandleBurningThinkaboutit!Doyouthinkscienceisinteresting?Whyorwhynot?2.NameoneortwofamousChinesescientists.Whatdoyouknowaboutthem?Let'sdoanotherexperiment.KeeptheCandleBurning.Whatdoweneed?acandleæ蜡烛abigglassjar玻璃罐子acandleholder烛台ashallowdishwithwaterəʊ浅的æma

2、tches火柴æamatch一根火柴Howdowedotheexperiment?Let'sreadthetextandfillintheblanks.Let’sdotheexperimenttogether!Putthecandleinthecandleholder.Putthecandleholderonthedish.Fillthedishhalffullwithwater.Lightthecandlewithaoralighter.Whatcanyousee?Thecandleisburning.__thecandleburnfortwoorthreeminutes.Th

3、encarefullyputthejar_overituntilthetopofthejarrestsonthedish.Asthecandleburns,ittheoxygenintheair.Whenthecandlestops,ithasusedupalltheoxygenintheair.Thewaterinsidethejarandfillsaboutofthejar.Thisisbecauseaboutonefifthoftheairismadeupofoxygen.matchLetburningrisesWhatishappening?1)分数由分子和分母两部分构成

4、。用英语表达时，分子用基数词，分母用序数词。2)如果分子为1，则分母的序数词是单数形式，如果分子大于1，则分母的序数词用复数形式。½＝one(a)half或onesecond(one-second)¼=one(a)quarter或one-quarterHowtoexpressthefractions:口诀:分子基，分母序。分子﹥1，分母加s。二分之一三分之一四分之一四分之三五分之二十分之九a/onehalf(onesecond)one-thirdonequarterthree-fourthsthreequarterstwo-fifthsnine-tenths1.Practicet

5、hetextingroups.2.Finishtheexerciseonpage69.Dotheexperimentwhatyouwantingroups.Readabouttheexperimentinthislesson.Withagroupofclassmates,practicetheexperiment.Doyourexperimentinfrontoftheclass.Don’tforgetthefollowingthings:First,describeyourexperiment.Second,asktheclasswhattheythinkwillhappen.

6、Third,dotheexperiment.Finally,asktheclassiftheresultiswhattheyexpected.Writetheprogressintheexperiment.1.Listenandread.2.Finishexercisesofthislesson.Homework