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Geography

The Oceans

Scientists have reason to believe that at an early time in our planet's history, there was only one continent, Pangea, and one ocean, which covered the rest of the planet. Over time, the plates under the one continent floated away from each other, and the plates under the one ocean also floated away, some moving around the moving continents so that there was water between most of the continents.

The oceans of the world contain lots of plant and animal life. The oceans are all salty, but some are saltier than others. Most of the Arctic Ocean is covered by ice, but submarines have traveled across the Arctic Ocean under the ice. The floor of the oceans is not smooth, but contains mountains, plains and low spots just like land does. If the mountains are tall enough, they may form islands on the surface of the Oceans. The low spots are called trenches, and form the very deep areas of the oceans.

The Arctic Ocean is at the northern top of the planet. It surrounds the North Pole. The Arctic Oceans is usually covered with ice. But, when the planet has a change in climate, the ice may get larger and cover the continents along the Arctic Ocean, or the ice may get smaller and allow ships to travel in areas that are usually under ice.

The Atlantic Ocean lies between the American continents and the continents of Europe and Africa. The Atlantic Oceans stretches from the Arctic Ocean at the north, to the Southern Ocean in the south. Below South America, it meets the Pacific Ocean, and below Africa, it meets the Indian Ocean. The Prime Meridian passes through the Atlantic Ocean. The Prime Meridian is the longitude line number zero, in mapping the planet.

The Indian Ocean is located mostly in the southern hemisphere. The Indian Ocean edges the western side of Africa, the Southern side of Asia, and the Eastern part of Australia. Some of the islands between Asia and Australia are located in the Indian Ocean. The Indian Oceans meets the Atlantic Ocean below Africa and meets the Pacific Ocean under Australia. To the south, it is bound by the Southern Ocean surrounding Antarctica.

The Southern Ocean surrounds the continent of Antarctica. It's current flows in one direction around the continent in the southern summer, and reverses direction in the southern winter. The Southern Ocean meets all the other oceans of the world except the Arctic Ocean.

The Pacific Oceans is the largest ocean on the planet. It stretches from the Arctic Ocean at the north, to the Southern Ocean to the sounth. It edges North and South America on the east, and Asia and Australia on the west. The International Date line runs north to south is about the middle of the Pacific Ocean. This is longitude line 180 degress. After crossing this line, the longitude lines begin to decrease. Crossing this line will also change the date on your calendar.

EARTH'S OCEANS

Oceans cover about 70% of the Earth's surface. The oceans contain roughly 97% of the Earth's water supply. The oceans of Earth are unique in our Solar System. No other planet in our Solar System has liquid water (although recent finds on Mars indicate that Mars may have had some liquid water in the recent past). Life on Earth originated in the seas, and the oceans continue to be home to an incredibly diverse web of life.

The oceans of Earth serve many functions, especially affecting the weather and temperature. They moderate the Earth's temperature by absorbing incoming solar radiation (stored as heat energy). The always-moving ocean currents distribute this heat energy around the globe. This heats the land and air during winter and cools it during summer.

THE OCEANS

The Earth's oceans are all connected to one another. Until the year 2000, there were four recognized oceans: the Pacific, Atlantic, Indian, and Arctic . In the Spring of 2000, the International Hydrographic Organization delimited a new ocean, the Southern Ocean (it surrounds Antarctica and extends to 60 degrees latitude).

There are also many seas (smaller branches of an ocean); seas are often partly enclosed by land. The largest seas are the South China Sea, the Caribbean Sea, and the Mediterranean Sea .

Find the deepest points of each ocean in an atlas. Mark the deepest point in each ocean with an X.