What I will learn…

What I will learn…What I will learn…

• (3-1) Describe how technologies help scientists map the ocean floor

• (3-2) Identify the following features on a sea floor map: continental shelf, continental slope, continental rise, trenches, plains, sea mounts, guyots, and mid-ocean ridges.

Think About ItThink About It• At its deepest point, the Puerto Rico

Trench in the Atlantic Ocean is 28,231 feet (more than 5 miles deep). Because of the tremendous pressure, it is not possible for humans to personally explore this deep into the ocean.

Key QuestionKey Question

How do scientists know what the bottom of the ocean floor looks like? How do they know how deep the oceans are?

• I think… because…

Investigating the OceansInvestigating the Oceans

• Earth = Blue Planet– 71% of planet covered with water– 97% of that water is found in oceans

• Oceanography = Study of planet’s oceans

• Ocean Geography– Four major ocean basins

• Atlantic• Pacific – largest and deepest• Indian• Arctic – smallest and most shallow

• Tools for measuring the depth of the ocean floor– Sonar– Satellites– Submersibles

• Sonar = Sound Navigation and Ranging– Sound waves sent to bottom of ocean– Sound waves reflected back to a receiver– Based on time it takes for wave to be

reflected, the distance to ocean floor can be measured

• Satellites– Can measure the differences in the sea-

surface height by bouncing microwaves off the ocean’s surface

– Underwater mountains cause sea surface level to be higher

– Canyons & trenches

cause sea surface

to be lower

• Submersibles– Underwater vessel that can be used for deep

sea research– Can be manned or unmanned (ROV)– Carry scientific instruments to learn about

ocean

• The ocean floor is NOT flat!–3 Major Regions

• Continental Margins

• Ocean Basin Floor

• Mid-Ocean Ridge

A=A=Continental ShelfContinental Shelf= = Gently sloping area that extends from the shoreline

B=B=Continental SlopeContinental Slope= = Steep slope that marks boundary between continental

crust and oceanic crust

C=C=Deep-Ocean TrenchDeep-Ocean Trench= = Deepest part of the ocean; form when one plate moves underneath another plate

D=D=Mid-Ocean RidgeMid-Ocean Ridge= = Underwater mountain system; sea floor spreads

apart; formed new ocean crust

E=E=Volcanic IslandVolcanic Island= = Seamount that reaches the surface of the ocean

F=F=SeamountSeamount= = Underwater volcano

G=G=Abyssal PlainAbyssal Plain= = flat feature on bottom of ocean floor; most level

places on Earth

Cape Roca, Portugal

Cape May, NJ

Investigate Part B:Investigate Part B:Mapping the Ocean FloorMapping the Ocean Floor

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Direction #5Direction #5

• Color the ocean crust (sea floor) brown

• Color the water areas (not the ocean floor) on your graph:– Depth between 0-110 light greenlight green– Depth between 110-1100 light bluelight blue– Depth between 1100 – ocean floor dark bluedark blue

Mapping the Ocean Floor

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Cape May, NJ

Mid Atlantic Ridge

Azores, PortugalCape Roca,

Portugal

Cape May, NJ

Azores, Portugal

Mid Atlantic Ridge

Cape May, NJ

Azores, PortugalCape Roca,

Portugal

Mid Atlantic Ridge

Cape May, NJ

Azores, Portugal

Mapping the Ocean Floor

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Continental ShelfGently sloping area that

extends from the shorelineContinental SlopeSteep slope that marks boundary

between continental crust and oceanic crust

Abyssal PlainDeep extremely flat features

SeamountUnderwater volcanic peaks













Cape Roca, Portugal

Mid Atlantic Ridge

Cape May, NJ

Azores, Portugal



extends from the shoreline

Continental SlopeSteep slope that marks boundary


Documents

What I will learn…