Thefourgreatinventions 　　Paper:paperisanimportantchemicalprocesses,theinventionofpaperisChineseinthespreadofhumancultureanddevelopmentmakeavaluablecontribution,isChina'schemicalhistoryofamajorachievement. 　　Thepaperalsobefore,oraclebones,bambooslipsandsilksilkisusedforwriting,theancientrecordedmaterial.Butduetotherapiddevelopmentoftheeconomy,culture,bonesandbamboocannotmeetthedemandofdevelopment,thuscontributingtotheimprovementofwritingtools.Atthattimepeoplebeganusingsmallsilkmadeofpaper,astheancientChinesewhenpaperbyhempthreadandsilk,andpreparationmethodofroughpaper,sothequalityisnotsogood.Butthehempthreadandsilkhasitsownrole,tousethemasarawmaterialforpaper-making,wouldbegreatlyrestricted,anddifficulttogetrapiddevelopment,tomeettheculturallifeoftherequirementtopaper. 　　Inthenewsituationrequest,CaiLunofEasternHanDynastyfortheemergenceofpapermakingtobringnewbreakthroughintheEasternHanDynasty,"viewson"2records:"CaiLun,talented,dedicatedtocautious,everyvacation,closedtotheguest,aerationbodyfield.Codeforthesale,madewithbarkandspaciouscloth,nettomakepaper.XingYuanfirstyearplaying,theemperorcan,sinceisnotused,thesaltycalledCaiHoupaper".Fromabove,CaiLunisusingbark,rags,netofpapermaking.AlthoughbeforeCaiLunalsohasapaper,butrawmaterialitselfisverylimited,andCaiLunonthenewrawmaterials,tosolvethisproblem.Becausetherag,brokenfishnethadalreadyfinishedtheirtask,awasteandusedasarawmaterialforpapermakingindustry,whichplaysanimportantrole. 　　Printing:istheworkingpeopleinancientChinathroughlong-termpracticeandresearchbeforetheinventionof.Abouttheyearbeforeandafter600yearsofSuiDynasty,peoplefromtheengravedsealinspired,inthehistoryofmankind'searliestinventionofwoodblockprinting. 　　Woodblockprintingisinacertainthicknessofthesmoothwood,pastecopyneatmanuscript,thinandalmosttransparentpaperfrontandwoodpaste,thewordbecamethebody,strokesclear.Engravingworkersgraverinthesuiteshavewritingsectioniscutaway,isaconvexembossedfont,andfontrecessedbeneaththedifferentsteles.Whenprinting,onaraisedfontswithink,andthenthepapercoveringontopofit,gentlywipeawaythepaperback,writingremainonthepaper.BytheSongDynasty,woodblockprintingcareerdevelopmenttotheheyday.Woodblockprintingonthespreadofcultureplayanimportantrole,butalsohasobviousdisadvantages.Thefirstversion,time-consumingmaterialcosts,second,alargenumberofbooksstoredinconveniently,third,isnoteasytocorrectmistakes. 　　TheNorthernSongDynastycivilianinventorBiShenginventedmovable-typeprinting,woodblockprintingthesedrawbacksimprovement.BiSheng'sDynastyofanordinarycivilianintellectuals,thepersonwho.Hesummeduptheblockprintingofrichexperienceinpractice,afterrepeatedtests,theemperorRenzongofevolutionyears(AD10411048)madethemoveable,executetypesettingprinting,completedtheprintinghistoryofamajorrevolution,about200yearslater,thistechnologyspreadtoothercountries,thedevelopmentofworldcivilizationprocesstopromotetheroleof. 　　Gunpowder:isoneofthefourgreatinventionsofchina.Gunpowder,asthenamesugges