It's a worksheet about ocean information and has the following topics:What are Earth’s five main oceans?How is the ocean floor studied? What are the two main regions of the ocean floor? What are the features of the ocean floor?including activities to develop in the science class

1. What are Earth’s five mainoceans?
Almostthree-fourthsof Earthiscoveredbyoceanwater.On a map, the continentsappearas
huge islandssurroundedbyavastglobal ocean.Earth’sglobal oceanisdividedintofive main
oceans.Indecreasingorderof size,theyare the PacificOcean,AtlanticOcean,IndianOcean,
SouthernOcean,andArctic Ocean.
The chemical characteristicsof oceanwaterinclude salinity,orthe amountand type of
dissolvedsalts.Chemical characteristicsalsoinclude the amountandtype of gasesinthe
seawater.The physical characteristicsof oceanwaterinclude temperature anddensity.
The overall salinityof seawaterisabout3.5 percent.Dissolvedsaltscome fromwaterflowing
on or underEarth’ssurface,and fromunderwatervolcanoesandvents.The salinityof seawater
has remainedrelativelysteady,butitvariesfromplace toplace dependingonthe entryof
freshwaterstreams,precipitation,andrate of evaporation.
The ocean has three temperature layersbydepth.The toplayer,or surface zone,isthe
warmestlayer.Inthe nextlayer,the thermocline,watertemperature dropswithincreased
depthfasterthanit doesinotherlayers.The deepzone isthe deepestlayerandthe coldest.
By latitude,surface wateriswarmestnearthe equator andcoldestnearthe poles.Byseason,
surface wateriswarmestin summerandcoldestinWinter.
Densityis a measure of the mass of a substance dividedbyitsvolume.The densityof ocean
waterdependsontemperature andsalinity.Saltwaterisdenserthan freshwaterbecause salt
watercontainsa largeramount of dissolvedsolids.Temperature affectsthe densityof ocean
watermore than salinitydoes.Coldwaterisdenserthanwarmwater.
How isthe ocean floorstudied?
To learnaboutthe oceanfloor,scientistsuse technologysuchassonar,drills,underwater
explorationvessels,andsatellites.
1.Sonar, whichstandsfor soundnavigationandranging,usessoundwavestomeasure
distances. Sonardatacan be usedto make mapsof the oceanfloor.
2.Satellitescan measure variationsinthe heightof the ocean’ssurface.The oceanfloor’s
featurescanaffectthe heightof the waterabove them.
To explore the oceans,scientistsuse 3.underwatervessels,some of whichhave pilots and
researchers. With 4.Deep-Seadrilling scientistscandrill andcollectcores,or longtubesof
rock and sediment,fromthe seafloor.
What are the two main regionsof the ocean floor?
The two mainregionsof the oceanfloor are the continental marginandthe deep-oceanbasin.
The continental margin isthe edge of the continentthatiscoveredbythe ocean. The
continental marginisdividedintothe continental shelf,the continental slope,andthe
continental rise.

2. The deep-oceanbasinbeginsatthe endof the continental marginandextendsunderthe
deepestpartsof the ocean.The deep-oceanbasinincludesnarrow depressionsandflat,
smoothplains.
Whatare the featuresof the ocean floor?
A long,underseamountainchainthatformsalongthe floorof the oceanis calleda mid-ocean
ridge.Mid-oceanridgesoccurat the boundariesof Earth’stectonicplates,whereplatesmove
apart fromeach other.Thismotioncreatesacrack in the oceanfloorcalledarift,allowinghot
magma to move upwardthroughthe riftand cool to form new rock.
The large,flat,almostlevel areaof the deep- oceanbasiniscalled the abyssal plain.Thisarea
iscoveredwithlayersof fine sediment.
A long,narrow depressioninthe deep-oceanbasiniscalledan oceantrench.It formswhere
one tectonicplate subductsanotherplate.
Volcanoesandearthquakesare commoninandalongsubductionzones.
Submergedvolcanicmountainsonthe oceanfloorare called seamounts.
Theymay format tectonicplate boundariesandalsofarfromplate boundariesoverplaces
calledhotspots ( magma). If a seamountgrowsabove sealevel,itbecomes avolcanic island.
Workshop5
1.Write the definitionsofthe followingwords: salinity,deepoceanbasin,mid-ocean
ridge,Oceantrench,Thermocline,continental margin
2.)What’sare the three characteristics of ocean water?
b) How is the oceanfllor studied?Define the four ways to do it .
c)What are the two main regions of the ocean floor?
Workshop6
1.Match the featuresofthe ocean floor with theirdefinitions.

3. Term/feature of the ocean floor Definition
a) Mid-oceanridge_________ 1) The large,flat,almostlevelareaof the
deep- oceanbasin
b) the abyssal plain.____________ 2) A long,narrow depressioninthe deep-
oceanbasin
C) Ocean trench________________ 3) A long,underseamountainchainthat
formsalongthe floorof the ocean
d) seamounts_________________- 4) A seamount that growsabove sealevel,
e) Volcanic island_________________- 5) Submergedvolcanicmountainsonthe
oceanfloor
2.Fill the blanks with the right words from the box.
hot magma crack Tectonic plates rift move apart
A.Dad, howcan Mid-oceanridgesform?
B. At the boundaries of the Earth’s__________________, where plates _______________-
___________________-from eachother.Thismotioncreatesa_______________in the ocean
floorcalleda____________, allowing __________________ to move upwardthroughthe rift
and cool to formnewrock.
A.Thanksdad,you’re sowise!