Sunday, July 17, 2011

Largest Ocean - Pacific Ocean

The pacific ocean is the largest ocean in the world.  It covers nearly 1/3 of the earth's surface.  It is also the deepest ocean on the earth.  The pacific ocean lies between Asia and Australia on the west and North and South America on the East.  Pacific ocean is rich in natural resources and marine life. 
The Pacific's deepest parts are the ocean trenches.  These trenches are long,narrow, steep and very deep holes at the bottom of the ocean.  The deepest trench is the Mariana trench.  The deepth of this trench is more than the hight of Mt.Everest.
There are many islands in the Pacific ocean like Taiwan, Indonesia, Japan and New Zealand.  Other islands have risen from the floor of the ocean.  Some of them were from the volcanoes.  The islands were built over thousands of years by the lava that comes out of the volcanoes.  The Hawaiian islands are from volcanoes.

What are Glaciers?

In high mountains there are places that are packed with ice.  These ice packs are called 'Glaciers' these resemble gaint frozen rivers.  Many thousands of years ago most of the Earth's surface was covered with moving glaciers.
It takes a very long time to make a glacier.  First, snow falls on the mountains.  It collects year after year, until there is a thick layer called a snow field.
During summer months the snow field melts and sinks into the snow below it.  There it freezes and forms a layer of ice.  This happens year after year, until most of the snow field is converted to ice.  The snowfield is now a glacier.
The snow and ice ina glacier can become very thick and heavy.  The glacier then begins to actually move under its own weight and creeps down the mountain valley.  It has now become a valley glacier.
The valley glacier moves slowly but with enormous force.  As it moves, it scrapes the slides of the mountain and tears off pieces of it.  Sometimes it tears off chunks as big as a house.  As the glacier moves down warmer regions, the water melts and becomes source of water for rivers and lakes.