You probably like going to the beach for a walk or a swim. But did you know that two thirds of the world’s surface is coverd by oceans and seas.
The world has four oceans : the Pacific, the Atlantic, the Indian and the Arctic.
The Pacific covers half our planet and is the largest and deepest ocean. There are mountains under the ocean just like on the land. And these are bigger than the ones you find on land. In fact the world’s longest mountain range is under the sea.
The sea level rises and falls twice a day along the word’s coasts. These changes in level are called tides. The moon’s gravity causes the tides to happen. Sometimes there are very big waves called tidal waves or tsunamis.
U.S. Navy ships are in the Atlantic Ocean. (Photo credit: Official U.S. Navy Imagery)
The water in the sea is not like tap water it is like a salty soup full of millions of tiny animals. It gives food to many of the animals that live in the sea. There are over 21,000 different types of fish. The biggest fish are sharks. The world’s biggest warm-blooded animals also live in the sea.
When you go down 100 metres under the sea surface it is very cold, and if you go down 900 metres it is black. Scientists are still discovering the strange animals living in this dark world.