You can try this simple experiment to change salt water into freshwater. This is a process called "desalination." The water evaporates and leaves the salt behind, so the water you collect in your collection glass is clean drinking water. Make sure it is a sunny day before you begin this experiment.
Fill the bowl about halfway with water. Add a few spoonfuls of salt to the water. Make the water as salty as you like. Stir the salt into the water to make sure it is mixed.
Place the drinking glass inside the bowl. If the salt water flows into the cup, remove some of the water.
Stretch plastic cling wrap over the top of the bowl. Make sure it is tightly wrapped all the way around the bowl.
Place a small weight in the center of the plastic wrap, over the cup. Use a small rock or any small, heavy object. This will weigh down the plastic wrap just enough to allow the water to drip into the glass.
Place the bowl somewhere sunny. Leave it there for a few hours. After a few hours, you should have clean water in the drinking glass, and a layer of salt on the inside of the bowl.
If the water doesn't end up in the cup, try wrapping the plastic wrap a little more loosely, or using a slightly heavier weight.
Do not drink the salt water.