|MadSci Network: Earth Sciences|
Hi Mollie! My wife's from Centerville, so I'm especially happy to answer your question. First, all water in the environment has some salt in it. "Fresh" water just doesn't have as much salt as "salt" water. In most lakes, the salt comes in with the water from a stream and goes out with the water into another stream. Oceans are salty because no water flows out of them. The water can evaporate and fall again somewhere else as rain, but the salts stay behind when this happens. Over time the salts build up and eventually are left at the bottom of the ocean. Some lakes are salty for the same reason. Salt lakes are also called "terminal lakes" because they're at the end of the water flow; no water flows out of them. So, just like the ocean, the water can leave by evaporation, but when it does it leaves the salts behind in the lake. If you want to learn more, the US Geological Survey has a good web page about Great Salt Lake in Utah. Eli Hestermann
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