What is the Earth actually?

Continents

                            Geographers have divided the surface of the Earth into seven Continents: Asia, Africa, Oceania (Australasia), the Americas, Europe, and Antarctica (South polar region).

Earth Millions of years ago 

                               Millions of years ago, there was only one huge landmass on Earth, which geologists now call Pangaea (Greek for 'All Earth'). And one greatest Ocean, Panthalassa (Greek for 'All Sea').

How are Continents formed?

                              About 240 million years ago, Pangaea cracked into gigantic pieces (or plates) and began to drift apart on the semi-liquid interior of Earth, rather like icebergs on the sea.

Moving of Plates per year

                                Scientists estimate that the plates moved about 10 centimeters a year. Interestingly, this is about the same rate as human hair grows.

Areas of Continents

                                 Asia                             43,810,000 sq Km
                                 Africa                          30,370,000 sq Km
                                 North America         24,490,000 sq Km
                                 South America         17,840,000 sq Km
                                 Europe                        10,180,000 sq Km
                                 Antarctica                  13,720,000 sq Km
                                 Oceania                       700,500       sq Km

Ocean

                        These great bodies of water make up 71 percent of the Earth's surface. Most geographers say there really are only three oceans: Atlantic, Pacific, and Indian.

Depth of Oceans

                          The average depth of the Oceans is almost 4000 meters, but the Mariana Trench, off the island of Gaum in the pacific, plunges to 11,022 meters.

Without Ocean

                          Without the Oceans, there could be no life on Earth as we know it. The world would be a dry, barren desert with a temperature over 100C.

Importance of Oceans 

                           They are the source of rain on which the world depends for crops and life. They provide transport across much of the world.

Waves

                             Waves are usually caused by the wind blowing along the surface and pushing the water into 'heaps.'

Currents

                             Currents in the Ocean are like giant rivers, sometimes hundreds of kilometers wide, but usually not more than 200 meters deep.

Effects of Currents

                               Currents also act as a spoon-- they stir up the water and mix cold and warm, very salty and less salty water. Currents can also distribute the plants around the world.

Uses of the Oceans

       food
                          The oceans and seas are a major source of food in the shape of fish and shellfish.

      Whaling
                          Whales are not fish but warm-blooded mammals and have been hunted from the earliest times.

    Seaweeds
                           Although very little of the plant life in the sea is eaten, seaweeds are a source of chemicals such as potassium and iodine.

   Minerals 

                           The Oceans are, of course, used as a source of salt in warmer countries.

  Energy in the oceans

There is enough energy in the oceans --tides, waves, and currents to meet all of the world's electricity needs, except that no one has yet found a way of getting this power economically.

Water 

Water is one of the most important causes of weathering and works in several ways.

Wind

Strong winds carry along with tiny particles of rock as sand and wear away the rocks they hit.

Sunshine

The sun heats the rock in the daytime, but at night it cools rapidly. This constant heating and cooling, expansion and contraction, eventually break up the rock.