Mrs. Lascano's Science Chapter 16 Notes
Chapter 16 Notes
Lesson 1: Composition and Structure of Earth's Oceans
Water covers 70 percent of Earth's surface.
The five main bodies of water are:
The Pacific Ocean is the largest and deepest ocean. It is larger than all of Earth’s combined land area.
The Atlantic Ocean is half the size of the Pacific. It occupies about 20 percent of Earth’s surface.
The Indian Ocean is between Africa, India, and the Indonesian Islands. It is the third largest ocean.
The Southern Ocean surrounds Antarctica. It is Earth’s fourth largest ocean. Ice covers some of its surface all year.
The Arctic Ocean is near the North Pole. It is the smallest and shallowest ocean. Ice covers some of its surface all year.
Evidence indicates that Earth’s oceans began to form as early as 4.2 billion years ago (bya).
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Ocean formation theories:
Volcanoes: Many volcanoes covered its surface. These ancient volcanoes erupted huge amounts of gas. Much of the gas was made of water vapor, with small amounts of carbon dioxide and other gases.
Condensation: As water moves through the water cycle, water vapor in the atmosphere cools and condenses into a liquid. Tiny droplets of liquid combine and form clouds. As early Earth cooled, the water vapor in its atmosphere condensed and precipitated. Rain fell for tens of thousands of years, collecting on Earth’s surface in low-lying basins. Eventually, these basins became the oceans.
Asteroids and Comets: Evidence suggests a second source of water for Earth’s oceans. During the time when oceans formed, many icy comets and asteroids from space collided with Earth. The melted ice from these objects added to the water filling Earth’s ocean basins.
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Tectonic Changes: Earth’s oceans change over time. As tec- tonic plates move, new oceans form and old oceans disappear. However,
Lesson 1: Composition and Structure of Earth's Oceans
Water covers 70 percent of Earth's surface.
The five main bodies of water are:
The Pacific Ocean is the largest and deepest ocean. It is larger than all of Earth’s combined land area.
The Atlantic Ocean is half the size of the Pacific. It occupies about 20 percent of Earth’s surface.
The Indian Ocean is between Africa, India, and the Indonesian Islands. It is the third largest ocean.
The Southern Ocean surrounds Antarctica. It is Earth’s fourth largest ocean. Ice covers some of its surface all year.
The Arctic Ocean is near the North Pole. It is the smallest and shallowest ocean. Ice covers some of its surface all year.
Evidence indicates that Earth’s oceans began to form as early as 4.2 billion years ago (bya).
------------------------------------------------------------------------------
Ocean formation theories:
Volcanoes: Many volcanoes covered its surface. These ancient volcanoes erupted huge amounts of gas. Much of the gas was made of water vapor, with small amounts of carbon dioxide and other gases.
Condensation: As water moves through the water cycle, water vapor in the atmosphere cools and condenses into a liquid. Tiny droplets of liquid combine and form clouds. As early Earth cooled, the water vapor in its atmosphere condensed and precipitated. Rain fell for tens of thousands of years, collecting on Earth’s surface in low-lying basins. Eventually, these basins became the oceans.
Asteroids and Comets: Evidence suggests a second source of water for Earth’s oceans. During the time when oceans formed, many icy comets and asteroids from space collided with Earth. The melted ice from these objects added to the water filling Earth’s ocean basins.
------------------------------------------------------------------------------
Tectonic Changes: Earth’s oceans change over time. As tec- tonic plates move, new oceans form and old oceans disappear. However,