My daughter needs to know why the sea is salty for her homework, any ideas?

Answer 1

It is extracted from the rocks and from the sea bed. Many tiny fragments continue to break off into the sea, and after thousands of years of weathering from these rocks the build-up of salt brings it to noticeable levels.

The reason the amount is so low in freshwater rivers that we cannot notice it is because it is constantly moving, so the salt never gets the chance to build up. The sea its its journeys end, the only way out of the sea is through evaporation. The traces of salts carried through to the sea cannot evaporate with the water, so they build up. They continue to do this all the time, and so the sea will continue to get saltier.

Answer 2

Loads of people have said already - it is because of the minerals washed out of the land by rivers and carried to the sea. An interesting point though is that this was one of the ways the first people to question the biblical idea that the world is 6000 years old estimated the true age of the earth: they knew how much salt is in the sea, they knew how much salt rivers carry into the sea each year, so they could work out how many years it would take for the rivers to carry that much salt into the sea. Of course, it isn't very accurate (they didn't know what the river systems all those millenia ago were like), but it was a brave attempt.

Answer 3

I hope your daughter is a Geology graduate looking at some of the earlier answers, however to keep it simple - Wherever water comes into contact with the rocks of Earth’s crust, either on land by rainfall or in the ocean or within the oceanic crust, some of the minerals/salts in the rock dissolve and are carried by the water/rivers to the ocean. The salt content of seawater does not change because new minerals are forming on the sea floor at the same rate as salt is added. Thus, the salt content of the sea is at steady state.

Answer 4

Over millions of years water has poured of the land into the sea bringing with it all sorts of chemicals. Salt does not degrade because it is very stable. the salt gradually built up water condensation not taking the salt with it so consequently it has been left behind. The sea tastes salty.
Experiment boil some very salty water until it is dry. Use a container with a very small bottom. When it has cooled down wipe your finger along the bottom and taste. Salt?

Answer 5

The ocean—the seas—are made up of 96.5 percent pure water. The remaining 3.5 percent is made up of 75 other elements. Six elements are responsible for 99 percent of the sea's saltiness. They are: chloride, sodium, sulfur, magnesium, calcium, and potassium. Most of the saltiness comes from the compound sodium chloride (ordinary table salt).
Where do the elements come from? The wearing away of rocks on land. As rock erodes, rivers carry the salts and other minerals to the ocean. Volcanoes and undersea springs also release salts to the ocean.
I HOPE YOUR DAUGHTER WILL BE HAPPY FOR THIS ANSWER

Answer 6

The seas are made up of 96.5 percent pure water. The remaining 3.5 percent is made up of 75 other elements. Six elements are responsible for 99 percent of the sea's saltiness. They are: chloride, sodium, sulfur, magnesium, calcium, and potassium. Most of the saltiness comes from the compound sodium chloride (ordinary table salt).

Where do the elements come from? The wearing away of rocks on land. As rock erodes, rivers carry the salts and other minerals to the ocean. Volcanoes and undersea springs also release salts to the ocean.

Answer 7

The sea is salty because all the rainwater that falls on the earth gathers various chemicals etc on its way to the sea.
The water cycle then sucks up water from the sea, pure water, no chemicals which are filtered, falls on the earth, gathers more chemicals, flows to the sea.
In time the sea gets heavily contaminated with these chemicals and tastes `salty.`
To drink that water means certain death if enough is drunk because the salts enter the bloodstream and natural causes draws pure water from the blood to dilute the chemicals, thereby thickening the blood which cannot flow freely.
Too long and complicated to go into here, but that should satisfy you.

Answer 8

Ocean water is a complex solution of mineral salts and of decayed biologic matter that results from the teeming life in the seas. Most of the ocean's salts were derived from gradual processes such the breaking up of the cooled igneous rocks of the Earth's crust by weathering and erosion, the wearing down of mountains, and the dissolving action of rains and streams which transported their mineral washings to the sea.

Answer 9

the sea is salty because the rivers that flow into it wash salts and other minerals out of the ground

John Connoly is a brainy guy
Asking questions and wondering why
The sea is salty which is such fun
When splashing in the waves and sun
Is not freshwaer from the tap
Or from a bottle with a cap;
So he ill learn that salt and sea
Mix just like sugar into tea
And that many other kinds of salt
Dissolve into this briny malt,
Sodium Chloride, the salt of table
Has other friends within it's stable
Potassium Ch, magnesium Ch and Iodide
All flow solvent with the tide.
So now dear John, you clever lad
Off you go - Tell Mum and Dad!!

Answer 10

Because there is salt in it. :)

But seriously, the ocean is the ultimate destination for all water in the world. All bodies of water carry minerals, whether it be from dissolved materials (ie, mtns, rocks, etc.) or from decayed organisms. All of this material is dumped into the ocean.
Some of the salt comes from the ocean dissolving rocks at the sea floor as well.
Yet more salt comes from the volcanic vents at the ocean floor and from any dissolved material in rain.
Hope this helps your daughter out!