• Question: how do you extrach salty water from the sea?

    Asked by haseebatahir786 to Tim, Sarah, Derek, Dalya on 13 Jun 2011.
    • Photo: Tim Millar

      Tim Millar answered on 13 Jun 2011:

      Pick it up in a bucket?

      Or you may be trying to extract salt from the sea. For this you have to seperate the salt and the water. Heating the water to make it evaporate will seperate them with the salt staying behind and the water drifting off in to the clouds (or you can condense it and collect the fresh water for drinking.

      Some countries use desalination plants to remove salt from sea water so in can be used for drinking.

      Of course there is lots of gold in sea water… I wonder how I could collect that and become rich?

    • Photo: Derek McKay-Bukowski

      Derek McKay-Bukowski answered on 13 Jun 2011:

      To get salt water out of the sea, you can use a pump, bucket, cup or anything.

      To get the actual salt out of the water, the best way is to evaporate the water, leaving the salt behind. You can then cool the steam down somewhere else and when it condenses it will be just fresh water.

      This process is used on some ships and submarines to ensure that there is always fresh water on long sea voyages.

    • Photo: Dalya Soond

      Dalya Soond answered on 13 Jun 2011:

      Do you mean get rid of salt from sea water?

      This can be done by a process called desalination. Essentially, the water is boiled and turns to steam. Salt will fall to the bottom of a container since it is solid and heavy, but steam rises, as you probably know if you look at the steamy mirrors when you take a shower. The steam can be pushed into another container, and when it cools off it will become a liquid again without most of the salt in it.

      It would take a long time to boil so much water, so the pressure in the container is lowered, which lowers the boiling temperature. Have you learned this equation yet in chemistry of physics? PV=nRT Desalination is an example of when such an equation might be needed to calculate the pressure (P) needed to get the boiling point to a lower level.

    • Photo: Sarah Thomas

      Sarah Thomas answered on 13 Jun 2011:

      Yes I agree with Derek, I would just put the sea water in a bowl and place it on the window sill and let the water evaporate and after a couple of days all that would be left behind would be the salt crystals.

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