There are five oceans on the earth. On an average, the five oceans of the world have a salinity of roughly 3.5 percent. However, regions like Mediterranean, the Atlantic, and the Bay of Bengal have higher salinity levels.

The largest ocean in the world - the Pacific Ocean - is ten times bigger than the smallest one - the Arctic Ocean. T.he Pacific Ocean got its name from Fernão de Magalhaes, the Portuguese explorer who organized the first circumnavigation of the Earth.

In 1521, Magalhes - often called Magellan - called it "Mar Pacifico".The Pacific Ocean covers more than 30 percent of the world.
It covers most of the part of the earth's hydrosphere.
Atlantic ocean is the second largest ocean in the world. It's is 'S' in shape. It contains the major sea routes of the world which are used for trading.
The Indian ocean is the third largest ocean in the world. It surrounds most of the Indian suncontinent and the neighbouring arabian countries of the world.
The Arctic and the Southern ocean which is also called the Antarctic ocean are covered by snow and ice throughout the year.