Why is the Ocean Salty?

Ask your favorite uncle why the ocean is salty and, if he is one of those uncles that wants to have a bit of fun he will say that the ocean is salty because there is a lot of salt in it. While this might get a laugh from you and your siblings it won’t help you understand the difference between salt water and “fresh” water.

A simple explanation for the salt content in the ocean would include such items as rain, rocks and minerals, rivers and finally, the ocean itself. Rain washes across the land, carrying with it some of the minerals in rocks. This mixture enters small streams, then rivers and eventually gets to the ocean. The sea is a collector of whatever the rains and rivers carry.

Not All is Salt

According to scientific research the most common elements collected in seawater from this process are chlorides and sodium. Salt is a compound made up of sodium and chloride (NaCl). Thus, the combination of these two common elements makes the ocean water salty. About 3 percent to 4 percent of the weight of sea water is salt.

Fresh-water streams and rivers don’t collect the elements at the same level as sea water, primarily because of movement. All water has some salt content. The taste and feel is different in the ocean because of the high level of salt content. In fact, the ocean’s water is so salty that we cannot drink it. It is hazardous to our health. Drinking sea water is often fatal.

So, rain and the water running over the Earth carry chemicals to the ocean. The most prominent among these are chloride and sodium, the two basic components of common salt. As the rain and the streams dissolve rocks, wear away hills and mountains and wash soil into the sea, the ocean’s water becomes salty.

Fresh water isn’t salty to our taste because the water is constantly moving its chemicals to the sea. But there is another factor that contributes to the salt content of the ocean. Salts collect in the sea, which has such a large surfaced that sunlight and wind vaporize much of the pure water, leaving behind a salty liquid. Over a period of millions of years, the oceans have become saltier, thanks to the repeating process of rain, flow of water to the sea and evaporation from the surface of the ocean.

One of the interesting facts about ocean water is that it supports floating objects much more readily than fresh water. The salt content has a lot to do with this.