Ask Tappity: Science Questions for Kids > Why is the Ocean Salty?
Why is the Ocean Salty?
Everyone who’s tasted a mouthful of seawater knows the ocean is salty. But where did all that salt come from? Watch this video to find out, or read our explanation below!
The Ocean’s Salt Comes From the Earth
Most of the salt in the ocean originally came from the Earth. The Earth is made up of lots of different rocks and minerals, including salty ones. Rivers slowly erode their riverbeds, bringing small amounts of salt to the ocean. Ocean water also gets trapped underneath the Earth’s crust when it flows through gaps in tectonic plates. It moves around underneath the surface of the Earth, mixing in with salts and other compounds, before bursting out in a hydrothermal vent.
Is the Ocean Getting Saltier?
If the ocean is getting salt from the Earth all the time, does that mean it's getting saltier? The answer is no - because the ocean is also LOSING salt all the time. One big way the ocean loses salt is by evaporation of ocean water in some hot parts of the world. All of the water evaporates, leaving large salt deposits behind. This takes a long time - salt deposited in the ocean stays there for about 100 million years before it is removed!
Ocean Facts for Kids
Got ocean questions? We’ve got ocean answers!
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Fish drink water, just like us. Saltwater fish are able to drink the salty water around them because they have special cells that do nothing but pump extra salt out of their bodies.
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A salt molecule is made up of a sodium atom and a chlorine atom stuck together. When you eat salt, your saliva dissolves the salt, meaning it breaks up the molecule into individual atoms. So when you’re tasting something salty, your taste buds are actually interacting with sodium and chlorine atoms individually.
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If you took all the salt in the ocean and spread it out on land, it would make a blanket 500 feet tall. That’s a lot of salt!
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The Gaet’ale Pond in Ethiopia is 43% salt - 14 times as salty as the sea! - making it the saltiest body of water on Earth. The water comes out of a spring from under the Earth’s crust, bringing lots of salt with it.
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The total amount of salt in our oceans is roughly equal to the mass of the Moon!
More Answers to Ocean Questions from Kids
Why can’t you drink saltwater? How do fish breathe? The Tappity Oceanography Library has interactive lessons with answers to those questions and more!
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