Science Common Sense

138 - Why are oceans salty?

The oceans are salty because of a thing called 'dissolved salts'. These salts come from rocks on the land. When it rains, the water washes over the rocks and picks up tiny bits of salt from the rocks. The salt then flows through rivers and eventually into the oceans.

Imagine you have a cup of water and you add a little bit of salt to it. The salt dissolves in the water, making it taste salty. That's what happened with the oceans over millions and millions of years. The salt gets into the oceans and doesn't leave because the oceans are so big and the water keeps moving around.