Transcript Ch. 20 The Ocean Basins

Ch. 20 The Ocean Basins
Journal Question 1: Why do Earth’s oceans
matter????
Ch. 20 The Ocean Basins
Journal Question 1: Why do Earth’s oceans
matter????
What do you know about “El Nino”? (as it
pertains to Global Science)
Journal: Why do Earth’s oceans
matter????
70 % of Earth’s surface
Oceans interact with atmosphere  influence
climate and weather patterns
Part of natural processes (ecosystems,
biogeochemical cycles, plate tectonics)
Habitat for many organisms
Food source
Journal Questions
2. What do you think the bottom of the ocean
looks like? Do you think it looks the same in all
places around the world? Why or why not?
3. How do you think scientists explore regions of
the ocean floor too deep for scuba gear?
Video Clip
• Monitoring the World’s Oceans
20.1 The Water Planet
Divisions of the Global Oceans
3 Major Oceans
Atlantic
Pacific
Indian
Seas: smaller areas of a particular ocean that are
surrounded by land.
Exploration of the Ocean
• What is oceanography????
• What does an oceanographer do???
• Oceanography: The study of the physical
characteristics, chemical composition, and life
forms in the ocean.
• Submersibles: Underwater research vessels
– Piloted by people
– Robotic (remote controlled)
Bathysphere
Bathyscaph
SONAR
Review from reading……
What does sonar stand for?
SONAR
Sound Navigation and Ranging
Its all in the name ….. Observing what this acronym
stands for, what might the name have to do
with how sonar works?
SONAR
Sound Navigation and Ranging
• Active sonar sends out a pulse of sound
• The pulse reflects when it hits an object
• The reflected sound waves are received by the
investigators receivers.
What might be the uses
of SONAR?
• Mapping Ocean Floor Topography
• Measuring the Depth of Ocean
20.2 Features of the Ocean Floor
• Two Major Areas:
– Continental Margins
– Deep Ocean Basins
Features of the Continental Margins:
• Continental Shelf
• Continental Slope
– Submarine canyons
– Continental rise
• Trenches
Deep Ocean Basins
– Caused by converging plate boundaries, oceanic
crust is subducted
• Abyssal Plains
• Mid-Ocean Ridges
– Created by diverging oceanic plates
• Seamounts
– Submerged volcanic mountains associated with hot
spots.
Article
“Rocket Plunge to Deep End of the Planet”
First Read: What is the purpose of the article?
• Underline major points
• Circle Key words or phrases
Journal:
According to Mr. Broad, “The deep sea is much
harder to explore than outer space.”
Does this surprise you? Why or Why not?
What are some factors that make deep-sea
exploration so difficult?
Using evidence from the article,
discuss in your group….
• What is unusual about the way Mr. Cameron’s
submersible travels?
• When was the last time people descended to
the Challenger Deep? What is the significance
of this?
• What are three innovative factors in the
submersible’s design?
20.3 Ocean Floor Sediments
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How are ocean sediments formed????
River Run off
Shore line erosion
Glacier Erosion
Remains of organisms that sink
• The sediments in the ocean are sorted by size…..
• What does this statement mean???
Sources of Deep Ocean Sediment
• Inorganic Sediments: Rock Particles
– How do these rocks get to the ocean floor???
• Organic Sediments: Produced by living
organisms
– What are 2 examples of organic sediments???
• Chemical Deposits
– During some chemical reactions, solids are
formed: precipitates
– Ex. Nodules
Classification of Sediments
• Muds
– Very fine silt and clay sized particles
– Red clay
• Ooze
– Soft organic sediment
– Calcareous ooze: composed of calcium carbonate
– Siliceous ooze: composed of silicon dioxide
In class: Density Review/Preview
• When have we discussed density this year???
• What do you remember about density?
• We have two cubes at each of our table
groups…..
– Which is more dense?
– How do you know? (Justify your answer)
– Design a procedure to test your assumption