How can potable water be produced from salt water

The process in which salt is removed from salt water to produce drinkable water is called desalination. There are two major mechanisms that humans use to achieve this: thermal desalination, or distillation, and reverse osmosis. During thermal desalination, salt water is boiled which causes evaporation to occur. The water vapour that is produced can then be collected and condensed. The water that is collected is pure water as the salt has been left behind in the boiling process. Reverse osmosis relies on the fact that the water potential of a liquid is a sum of the water potential due to dissolved solutes and the water potential due to the pressure of the liquid. A salt water solution and a pure water solution are separated by a partially permeable membrane that is not permeable to salt. Pressure is applied to the salt water solution so that it now has a higher water potential than the pure water solution. The water from the salt water solution then moves down the water potential gradient, across the partially permeable membrane, and increases the volume of the pure water solution.