WHY IS SEA WATER SALTY ??

The vast expanse of water in the sea that covers most of the space on earth is salty.This is because most of the rivers and streams empty in themselves into it.The rivers are strewn with rock and plant debris.The rocks contain many minerals and salts [especially sodium chloride] which dissolve in the water.As the rivers train into the sea a considerable amount of salt gets dissolved in the sea water.

When these waters evaporate due to the heat of the sun they leave the salt behind.The evaporated water is brought back to the land in the form of rain and the rivers carry the water again to the sea.As this cycle is repeated,the amount of salt increase but the water content does not.May be,the too would have lost their salt if they had outlets to let out the salt.