材料科学英语Unit 3 Lecture 3 Physical and chemical properties of materials.ppt

PhysicalandchemicalpropertiesofmaterialsUnit3

ReadingstrategyThereadingofexpositorywritingisessentialforESPstudents.Inordertounderstandthecontentandbasicstructureofthereadingmaterial,itishelpfultomakeanoutline.Itdoeshelpthereaderfollowthewrite’slineofthought,distinguishthemainpointsfromsupportingdetails,andgraspthelogicaldevelopmentofideas.Afollowingstepsarerecommended:1.Skimquicklytogetageneraloverviewofthecontent.2.Dividetheexpositorywritingintosection.Focusontheheadingsandsubheadingsifany.3.Readtheexpositorywritingagain,locateandweritedownthethesisstatement.4.Readparagraphbyparagraph,andfindoutthetopicsentencesofthesupportingparagraphsorsummarizethembyyourself.

5.Listtheexampleordetailsusedtosupportthethesisstatement.6.Makeaconclusion.7.Putwhatyouhavegotintoavisualorganizer.Inthisunit,wewillintroducethreeorganizationalpatterns.Eachofthemhasitsownsignalwordsthathelpdecidewhichorganizationalpatternandvisualorganizershouldbeusedtohelpmakeanoutline.

Inapyramidvisualorganizer,orderisveryimportant.Weusuallyusesignalwordssuchas:first,next,finally,mostimportant,etc.Inafishbonediagram,weusuallyusesignalwordssuchas:asaresultof,because,dueto,since,effects,resultof,inorderto,etc.Inaprocesschart,weusuallyusesignalwordssuchas:then,meanwhile,later,eventually,afterafewdays,etc.NowpleasereadthroughTextBanddecidewhichpartofthetextcanbedrawnintoavisualorganizer.Thendrawthevisualorganizeraccordingtothetext.

Physicalpropertiesarethosethatcanbeobservedwithoutchangingtheidentityofthesubstance.Thegeneralpropertiesofmattersuchascolor,density,hardness,areexamplesofphysicalproperties.Propertiesthatdescribehowasubstancechangesintoacompletelydifferentsubstancearecalledchemicalprope