Oceanography

Intro to Earth

• Video introduction to the formation of the solar system.

Oceanography

• Interesting general stuff:1. Oceans cover 70.8% of the earths surface.2. Oceans contain 97% of earth’s life.3. Oceans contain 97% of earth’s water.

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4. Oceans greatly affect earth’s weather.5. Oceans release between 50-85% of earth’s oxygen6. Ocean’s absorb around 50% of atmospheric carbon dioxide.

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7. Ocean’s produce a huge percentage (difficult to calculate) of human food sources.8. Approximately 80% of the human population live on or within one hour’s drive of the ocean.

Oceanography

Oceanography

“We should explore and take care of the ocean as if our very lives depended on it. Because they do.”

Dr. Sylvia A. Earle

Oceanography

I. How many oceans on earth – 4 principal oceans plus one.A. Pacific Ocean - My personal favorite Ocean

1. Largest ocean in size (Over 50% of the worlds total ocean surface area).

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2. Covers about 1/3 of the earth’s surface.3. Worlds deepest

ocean.4. Has killer surfing.

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B. Atlantic Ocean1. Lies between the East coast

of the American continent and

the West coast of the “Old world” continent.

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2. The Atlantic Ocean is about ½ the size of the Pacific.3. Named after Atlas (Greek Titan).

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C. Indian Ocean 1. Slightly

smaller than the Atlantic.

2. Mostly in Southern hemisphere.

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D. Arctic Ocean1. Only 7% of the size of the Pacific.2. Has permanent layer of Sea-Ice.

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3. Named after Ursa Major (big dipper)-Arktos = bear

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E. Southern Ocean (Antarctic Ocean)

1. Near Antarctica2. Defined by currents3. S. of 50 degrees south latitude.

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F. Comparing Oceans to Continents.Changing oceans video1. Oceans

a. Average depth of the ocean is 12,000 ft.b. The Mariana Trench logs as the deepest point in the Ocean (36,000 ft below sea level).c. Contains the tallest mountain in the world (Mauna Kea) at 31,601 ft.

Oceanography

d. The magnetic pattern on the seafloor is symmetrical about, and parallel to mid- oceanic ridges.

- Due to new rock formation at ridge.

Oceanography

e. New seafloor forms at the mid-Atlantic ridge.** This means the seafloor increases in age from the ridge outward.

Oceanography

2. Continentsa. Average

height above sea level = 2756 ft.

b. Tallest land mountain (Mt. Everest) is 29,035 ft in height.

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c. The continents are slowly moving away from one another = Continental Drift.- Alfred Wegener theorized that aprox. 200 million years ago there was one supercontinent called Pangea.

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II. History of Ocean explorationA. Early history

1. Pacific Navigators did not leave a clear written account.

-Earliest proposed sea migration (New Guinea to New Ireland) about 4000BC.

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-Evidence (Pottery) of further migration at about 1100BC.- Ancestral Hawaiians probably reached Hawaii around 300AD.-Polynesians then reached Easter Island around 1200AD.

Oceanography

2. European Navigators- Did a little boating as well.a. Phoenicians – From the Fertile Crescent.

-Explored Indian ocean around 2000BC- Also circumnavigated Africa in 590BC.

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B. Middle Ages – Vikings-Leif Eriksson was the first to land in the Americas in 995 AD (Newfoundland

Canada).-Due to bad luck and bad weather Viking colonies in Newfoundland died out by

1490.

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C. The Age of Discovery- 1492 – 1522 – Europe – fueled by the need for a new Eastern Trade Route (Money).

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1. Christopher Columbus – 1492 Financed by Spain to find a new route to East Indies.

• - When he landed in the Bahamas he thought they had made it to Asia.

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2. Ferdinand Magellan – 1519 – Spain-Initiated the first circumnavigation of the globe.

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-Sadly, he was killed in a fight with Philippine natives on March 15, 1521.-Began with 5 ships and 280 Sailors-3 years later (1522) 1 ship and 18 men completed the voyage.

D. Beginning of Scientific Voyaging– 1. James Cook (England) made 3 scientific voyages between 1768 & 1779.

a. Mapped a great deal of the ocean.b. Determined the outline of the Pacific.c. Discovered Sauerkraut prevents scurvy. d. Killed in Hawaii by Natives.

Tides

Tides

• What are tides?• How does a tide

differ from most waves?

• What is the simple explanation for the forces that cause tides?

• What is the center of mass of the Earth-moon system called? So, does the moon really revolve around the earth?

• What is a Centripetal Force? If this force, relating to the earth and sun, were to stop, in which direction would the earth move in relation to its current orbit?

• When the moon is directly overhead and therefore at 90° from your horizon, it is at its Z point. What does Z stand for? Is the gravitational pull of the moon stronger at the Z point or Nadir point? Why?

• Which is longer, a day on the moon (lunar day) or a day on earth?

• What is the term for the difference between low and high tide in vertical height?

• What is the difference between a neap and a spring tide?

• How often do neap and spring tides occur?

• What causes a neap tide?• What causes a spring tide?

• Considering the distance from the moon, during which period will changes in tides (from low to high) be the most dramatic? Why?

• What is the difference between a diurnal and a semidiurnal tidal pattern?

• What is a mixed tide pattern and where in the US would one experience such a pattern?