2007-02-06 08:44:48 · 5 answers · asked by Anonymous in Science & Mathematics ➔ Earth Sciences & Geology
Salt water is slightly more dense than freshwater. The two types will readily mix over a short period of time (eg. in estuaries where rivers run out into the sea) where the freshwater over-runs the heavier salt-water. However, turbulent flow and tidal processes ensure that the waters soon churn up and mix together.
If the water is perfectly still and clean, freshwater can sit atop the denser saltwater without mixing. I saw some spectacular pictures of this taken by cave divers, who found a pocket of salt water trapped at the bottom of a cave system largely full of freshwater. The contact ("hypnocline"?) was sharp and reflected light. Spooky!
Lake Balkhash (in Kazakhstan) is freshwater at one end, and saline at the other. I believe this is unique. I suspect the boundary is enhanced by some sort of geological constriction on the lake bed. It's a pretty huge lake, and the climate is very arid. The salinity varies, I think, because of the different rates of river runoff from mountain meltwaters at each end, offset by differing rates of evaporation of the lake water.
2007-02-06 21:00:32 · answer #1 · answered by grpr1964 4 · 0⤊ 0⤋
Salt water is denser due to all the "salts" (a lot of minerals) dissolved in it. Fresh water is less dense.
In consequence,salt water is heavier than fresh water.
Pressure and temperature,can influence the issue too.
If you go diving where rivers flow into the sea,you will be able to see this kind of effect , as,after big periods of rain,while diving you could find a first layer of fresh water(close to surface) and the salt water deeper. You can recognize the passing through the two layers for differences in visibility,and temperature,too.
2007-02-06 22:14:39 · answer #2 · answered by scubanino 3 · 0⤊ 0⤋
They have different densities and tend to mix only slowly.
this is why big rivers remain fresh right out into the sea
2007-02-06 17:26:45 · answer #3 · answered by rosie recipe 7 · 0⤊ 0⤋
The other answers are perfectly good, but there's a lake in Central Asia (possibly in Tazekstan) which has fresh water in one half, and salt-water in the other!
It doesn't come any more side-by-side.
How weird is that?
2007-02-06 19:19:19 · answer #4 · answered by musonic 4 · 0⤊ 1⤋
It's a density thing but they will mix. Fresh water does contain dissolved salts.
2007-02-06 16:51:09 · answer #5 · answered by Anonymous · 0⤊ 1⤋