Warm Up 2/4
• Name the Earth’s four major ocean basins.
• Pacific, Atlantic, Indian, and Arctic
• Sediments that cover the ocean floor
come from which of the following
a. Life forms
b. Land
c. Water
d. All of the above
• What size of sediment will be found closer
to the shore?
• Large
The Vast World Ocean
Chapter 14, Section 1
The Blue Planet
• Nearly 71% of Earth’s surface is covered
by the global ocean
• It has only been since the late 1800s that
the ocean became an important focus of
scientific studies
• Oceanography – a science that draws
on the methods of geology, chemistry,
physics and biology to study all aspects of
the world ocean
The Blue Planet
Geography of the Oceans
• The world ocean can be divided into four main
•
•
•
•
ocean basins – the Pacific Ocean, the Atlantic
Ocean, the Indian Ocean, and the Arctic Ocean
The Pacific Ocean is the largest ocean and the
largest geographic feature on Earth (deepest at
an average depth ~ 3940 m)
The Atlantic Ocean is about half the size of the
Pacific, and much more narrow
The Indian Ocean is slightly smaller than the
Atlantic, but has about the same average depth
The Arctic Ocean is only about 7% the size of
the Pacific and about ¼ as deep as the rest of
the oceans
Geography of the Oceans
Concept Check
• What are the four main ocean basins?
• Pacific Ocean, Atlantic Ocean, Indian
Ocean, and Arctic Ocean
Mapping the Ocean Floor
• If all the water were drained from the oceans,
•
•
•
we would see everything from chains of
volcanoes, tall mountain ranges, trenches, and
large submarine plateaus
The topography of the ocean floor is as diverse
as that of continents
Bathymetry – the measurement of ocean depths
and the charting of the shape or topography of
the ocean floor
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
Mapping the Seafloor
Sonar
• Sonar is an acronym for sound navigation and
•
•
•
•
ranging
It works by transmitting sound waves toward
the ocean bottom
A sensitive receiver intercepts the echo reflected
from the bottom
Then a clock precisely measures the time
interval to fractions of a second
Depth can be calculated from the speed of
sound in water and the time required for the
energy pulse to reach the ocean floor and return
Sonar
Satellites
• We can now measure the shape of the ocean
•
•
•
•
floor from space with satellites orbiting Earth
Gravity attracts water towards regions where
massive ocean floor features occur
This produces relative elevated areas on the
ocean surface by mountains and ridges and
depressions at canyons and trenches
Devices on satellites can measure variations in
sea-surface height as small as 3-6 cm
Using this data and sonar data, scientists are
creating detailed maps of the ocean floor
Satellites
Concept Check
• How do satellites help us learn about the
shape of the seafloor?
• Satellites bounce microwaves off the
ocean surface. Outgoing radar pulses are
reflected back to the satellite and can be
used to detect differences in sea surface
height that can be correlated to seafloor
features.
Submersibles
• Submersible – a small underwater craft
used for deep-sea research
• They are used to collect data about areas
of the ocean that were previously
unreachable by humans
• Most submersibles are unmanned and
operated by computers
Submersibles
Cool Down
1. How does the area of Earth’s surface covered
•
2.
•
3.
by the oceans compare with the area covered
by land?
Nearly 71% of Earth’s surface is covered by
oceans, 29% is covered by land
Why is deep-sea exploration and data
collection difficult?
The deep ocean is a harsh environment for
humans—cold, dark, and under high pressure.
It is difficult to supply submersibles with power
for continuous use.
What is one thing that you learned today that
you never knew? Explain this new knowledge.
Assignment (Due 2/9)
• Read Chapter 14 (pg. 394-413)
• Do Chapter 14 Assessment #1-33 (pg. 417-418)