Unit 5 Lesson 26（冀教）.pptx

,Unit5LookintoScience,Lesson26KeeptheCandleBurning,本课时编写：双辽市第一中学张梅梅老师,Thinkaboutit!Doyouthinkscienceisinteresting?Whyorwhynot?2.NameoneortwofamousChinesescientists.Whatdoyouknowaboutthem?,Letsdoanotherexperiment.,KeeptheCandleBurning.,Whatdoweneed?,acandle,蜡烛,abigglassjar,玻璃罐子,acandleholder,烛台,ashallowdishwithwater,浅的,matches,火柴,amatch,一根火柴,Howdowedotheexperiment?Letsreadthetextandfillintheblanks.,Letsdotheexperimenttogether!Putthecandleinthecandleholder.Putthecandleholderonthedish.Fillthedishhalffullwithwater.Lightthecandlewithaoralighter.Whatcanyousee?Thecandleisburning._thecandleburnfortwoorthreeminutes.Thencarefullyputthejar_overituntilthetopofthejarrestsonthedish.Asthecandleburns,ittheoxygenintheair.Whenthecandlestops,ithasusedupalltheoxygenintheair.Thewaterinsidethejarandfillsaboutofthejar.Thisisbecauseaboutonefifthoftheairismadeupofoxygen.,match,Let,burning,rises,Whatishappening?,1)分数由分子和分母两部分构成。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。one(a)half或onesecond(one-second)=one(a)quarter或one-quarter,Howtoexpressthefractions:,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-tenths,1.Practicethetextingroups.2.Finishtheexerciseonpage69.,Dotheexperimentwhatyouwantingroups.Readabouttheexperimentinthislesson.Withagroupofclassmates,practicetheexperiment.Doyourexperimentinfrontoftheclass.Dontforgetthefollowingthings:First,describeyourexperiment.Second,asktheclasswhattheythinkwillhappen.Third,dotheexperiment.Finally,asktheclassiftheresultiswhattheyexpected.,Writet