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1、八上科学作业本答案(Eight,sciencehomework,answer)Eight,sciencehomework,refertotheanswerThefirstchapter:waterinlifeFirstwhereiswatersaving?1.(1)ofoceanwaterglaciersandpermanentsnowwater(2)wateroceanwater(3)glaciersandpermanentsnowwater(4)isnotcorrect・Thewaterweuseeverydayismainlyriversandfres
2、hwater,whilethefreshwaterintheearth，swaterbodiesisverysmal1.2.C3.,water,water4.(1)C(2)thisviewisnotcorrect,becausepollutionwillbetransferredthroughthewatercycletootherwaterbodies・5.(1)precipitation,evaporation,watervaportransport,planttranspiration(2),watercycle,6.biologicalactivit
3、iescannotlivewithoutwater,inthewatershortageenvironment,someorganismscanautomaticallyadjusttoadapttothewatershortageenvironment・Second,water-savingcomposition1.solidliquidgasliquefiedoxygenmeltingsublimation2.rightbluehydrogenandoxygenwaterhydrogenandoxygen3C0C0C4.physicalchemistry
4、5.D6.B7.,willbringMarsintothewoodinthejar,thewoodisoxygenagain.Thirddensityofwaterconservation(a)1.(1)1.51.5(2)22(3)slightly(4)ratioofmassandvolume(5)of2.differentdensityisproportionaltothequalityofacertainvolumeof3.to1meters3copperfor8.9x103kg5.A6.C7.B8.C8.94.C9.(1)homogeneousmate
5、rial,qualityandvolumeratioisaconstant(2)1and4(or2and5,3and6)(3)thesameliquidmassandvolumeratio,differentliquid,ratioofmassandvolumearegenerallydifferent(two)1.small2.massvolumedensity3.47434.B5.C6.C7.gasoline8.(1)solution:Answer:thedensityofpetroleumis0.82*103kg/M3(2)solution:Answe
6、r:thequalityoftheoilinstalledis2.46*104kg9.V二9mx6m*3.5m=189M・3Answer:thequalityoftheairintheclassroomisabout243.8kilograms10.(1),10grams(2),11.25grams(3)choosetitaniumalloy,thequalityisrelativelysmall,31.25grams(three)1.massvolume2.can3.77.4g30cm32.58*103kg/M34.C5.0.7x1036.(1)BACD(
7、2)1882.57.(1)200(2)1200kg8.doesnotmeetrequirementshouldbeaddedwater9.(1)75.6(2)ironFourthwaterpressure(a)Thesizeof1.verticalsurface2002・pressureforceareapressureperunitareapressureforceareapressureof3.nm2PascalPaPa4.reducedstressareaincreasespressureof5.4.C7.C8.flatverticalpressure
8、(1)stressarea,thegreaterth
