There are five main oceans, and each one is special in its own way.
The Pacific, Indian, Arctic, Atlantic, and Southern are the five oceans. Oceans are salty because traces of minerals on land dissolve into rivers, which then feed into the oceans. These minerals are mainly chloride and sodium. Together, they make salt. The saltiest sea is the Dead Sea. It contains over one part salt for every five parts water, making it seven times saltier than the rest of the world’s oceans.
Oceans are known for their huge waves. There are three main parts to a wave: the spilling breaker, the crest, and the spray. The surface of an ocean is never calm, not even when the weather is calm. This is because oceans constantly move in slow circles called gyres.
One especially dangerous type of wave is a tsunami, which is a giant wave caused by earthquakes or volcanic eruptions under the water. When it reaches land, it can build up to 250 feet high. Tsunamis look a lot like regular waves from a distance. This makes them hard to detect and much more dangerous.
Oceans are one of nature’s wonders. They make the world beautiful, and without them, the Earth wouldn’t be the same.
[Source: The Encyclopedia of the Earth: Oceans and Islands]