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Why aren't lakes salty like the ocean? |
by Mya Kagan (whyzz writer) >> more about the author
Water flow!
To understand the way salty water flows into and out of a lake, try out this experiment!
Get a shallow bowl which will represent your lake and fill it about half way with fresh, clean water. Then, trickle a little bit of salty water into your lake using a cup -- this represents salty groundwater from rain trickling into the lake. Dip a clean finger into the “lake water” -- does it taste salty?
Pour some of the water out of the bowl, and then add more fresh water to it, like rain which comes down from the sky.
Dip a clean finger into the water one more time. Does it taste less salty??
The ocean is salty for several reasons, one of which is the groundwater from rain which trickles down into the ocean and picks up salt from the earth along its way! But this same water trickles down into lakes… so why aren't lakes salty?
The reason lake water usually isn't salty (or at least it's less salty than ocean water) is because the salty groundwater not only runs into the lakes, but also back out of it! Unlike the huge, vast ocean which already covers most of the Earth and therefore can't open up to any larger body of water, most lakes have outlets from which water leaves. This means that the salty groundwater has a chance to filter out and escape! (In the ocean, it has nowhere else to go!)
Some lakes (like the Dead Sea and the Great Salt Lake) don’t have these outlets, so the salt they acquire from groundwater sticks around and keeps the water tasting salty, just like the ocean! But most lakes get a chance to “flush” their salty water out, so they remain fresh and salt-free!
The reason lake water usually isn't salty (or at least it's less salty than ocean water) is because the salty groundwater not only runs into the lakes, but also back out of it! Unlike the huge, vast ocean which already covers most of the Earth and therefore can't open up to any larger body of water, most lakes have outlets from which water leaves. This means that the salty groundwater has a chance to filter out and escape! (In the ocean, it has nowhere else to go!)
Some lakes (like the Dead Sea and the Great Salt Lake) don’t have these outlets, so the salt they acquire from groundwater sticks around and keeps the water tasting salty, just like the ocean! But most lakes get a chance to “flush” their salty water out, so they remain fresh and salt-free!
Water flow!
To understand the way salty water flows into and out of a lake, try out this experiment!
Get a shallow bowl which will represent your lake and fill it about half way with fresh, clean water. Then, trickle a little bit of salty water into your lake using a cup -- this represents salty groundwater from rain trickling into the lake. Dip a clean finger into the “lake water” -- does it taste salty?
Pour some of the water out of the bowl, and then add more fresh water to it, like rain which comes down from the sky.
Dip a clean finger into the water one more time. Does it taste less salty??
