Place a large bowl in an area that receives a lot of sun.
Set a glass in the center of the bowl. The top of the glass must be lower than the edge of the bowl.
Pour sea water (or water to which you have added salt) into the bowl but not into the glass. The level of the water must be lower than the top of the glass.
Cover the bowl with plastic wrap and secure it with tape so the plastic wrap is tight like a drum.
Place a rock in the center of the plastic wrap, directly above the glass, depressing the plastic wrap slightly.
Remove the rock and plastic wrap after a few hours.
Drink the water from the glass.
