surface tens

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1、SURFACETENSIONSURFACETENSIONWhat’sgoingonatthesurfaceofaliquid?What’sgoingonatthesurfaceofaliquid?Let’stakealook!Particlesthatmakeupaliquidareinconstantrandommotion;theyarerandomlyarranged.Youmightexpecttheparticlesatthesurface,atthemicrolevel,toformarandomsurface

2、,asshownbelow.Youmightexpecttheparticlesatthesurface,atthemicrolevel,toformarandomsurface,asshownbelow.=intermolecularattractionsButhowdointermolecularforcesinfluencethesurface?Underthesurface,intermolecularattractionspullonindividualmoleculesinalldirections=inter

3、molecularattractions=intermolecularattractions=intermolecularattractionsAtthesurface,pullonthemoleculesislaterallyanddownward;thereisnegligibleintermolecularattractionsabovethemolecules(fromthemediumabove,suchasair).SO,thenetforceonsurfacemoleculesisdownward.There

4、sultofthisdownwardforceisthatsurfaceparticlesarepulleddownuntilcounter-balancedbythecompressionresistanceoftheliquid:Surfacemoleculesarecompressedmoretightlytogether,formingasortofskinonthesurface,withlessdistancebetweenthemcomparedtothemoleculesbelow.Surfacemolec

5、ulesalsoformamuchsmoothersurfacethanonewouldexpectfromrandomlymovingmolecules.Thisexplainsthecharacteristicroundedshapethatliquidsformwhendroppingthroughtheair:Themoleculesareallbeingpulledtowardthecenter.Thisexplainsthecharacteristicroundedshapethatliquidsformwhe

6、ndroppingthroughtheair:Themoleculesareallbeingpulledtowardthecenter.Waterinparticularhasaveryhighsurfacetension.Whatpropertydoeswaterhavethatwouldgiveitsuchastrongsurfacetension?Thisisthewaterstriderinsect.Haveyouseenone?Howisthispossible?