chapter 14 the ocean floor. section 14.1 the vast world ocean

Chapter 14

The Ocean Floor

Section 14.1

The Vast World Ocean


• The “Blue Planet” or “Water Planet”– Nearly 71% of Earth’s surface is covered by the

global ocean. – Oceanography – is a science that draws on the

methods and knowledge of geology, chemistry, physics and biology to study all aspects of the world ocean.

The Vast World Ocean• Geography of the Oceans– Of the 510 million square km of Earth’s surface

360 million square km is covered in water– The world ocean can be divided into four main

ocean basins:1. Pacific Ocean – largest and has the greatest depth2. Atlantic Ocean – half the size of the Pacific and not

quite as deep3. Indian Ocean – slightly smaller than the Atlantic and

is mainly in the southern hemisphere4. Artic Ocean – 7% of the size of the Pacific

What percentage of Earth’s surface is covered by water?

A. 45 percentB. 51 percentC. 71 percentD. 85 percent

Oceanography is the

A. science that draws on the methods and knowledge of geology, chemistry, physics and biology to study all aspects of the world ocean.

B. study of all the living organisms in the oceans.C. study of ocean water chemistry.D. study of the ocean floor and its topography.

Which of the world’s oceans is the largest and deepest?

A. Arctic OceanB. Atlantic OceanC. Indian OceanD. Pacific Ocean


• Mapping the Ocean Floor– The topography of the ocean floor is as diverse as

that of the continents.– Bathymetry – is the measurement of ocean

depths and the charting of the shape or topography of the ocean floor. (bathos = depth, metry = measurement)

– Challenger expedition – Dec. 1872-May 1876• First understanding of the ocean floors topography• 127,500 km trip (every ocean except Artic)


• Today’s technology – particularly sonar, satellites, and submersibles – allows scientists to study the ocean floor in a more efficient and precise manner than ever before.

The Vast World Ocean• Sonar – an acronym for sound navigation and ranging. It is also referred to as echo sounding. – Developed in the 1920’s. – Sonar works by transmitting sound waves toward

the ocean bottom and timing how long it takes for the echo to come back.

– Used to map the ocean floor– “Mowing the lawn” – method of sonar where a

multibeam sonar is used in a back and forth motion to map the ocean floor


• Satellites – Satellites are able to measure small differences by

bouncing microwaves off the ocean surface.– Using this new technology, scientists have

discovered that the ocean surface is not perfectly flat.

– Differences in the height of the ocean surface are caused by ocean-floor features.

Bathymetry is

A. the measurement of ocean currents, tides and waves.

B. the measurement of ocean depths and the charting of the shape or topography of the ocean floor.

C. the study of the various sediments on the ocean floor.

D. the study of seismic activity on the ocean floor.

What does sonar equipment measure?

A. The density of the ocean’s waterB. The depth of the ocean floorC. The sound produced by bottom-

dwelling ocean creaturesD. The shape of the ocean surface

Scientists use satellites to measure the

A. Ocean floor depth.B. Size of underwater features.C. Sea-surface height.D. Ocean’s salinity.

The Vast World Ocean• Submersibles – small underwater crafts used for

deep-sea research. – First submersible used in 1934 by William Beebe

• Dove 923 meters deep off of Bermuda• Steel sphere that was tethered to the ship

– 1960 – Jacques Piccard descended 10,912 meters into the Mariana Trench• Untethered submersible named Trieste

– Manned submersibles• Alvin – can reach 4000 meters• Sea Cliff II – can reach 6000 meters

– Today, many submersibles are unmanned and operated remotely by computers. These remotely operated vehicles (ROVs) can remain underwater for long periods.

Submersibles

Which of the following is NOT an example of a submersible?

A. AlvinB. TriesteC. Sea Cliff IID. Red October

chapter 14 the ocean floor. section 14.1 the vast world ocean

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