Making a solar still is a very simple science experiment to try with your kids. We made a solar still with a few common household items.
The great thing about this project is that it would be useful to know how to do in nature if you had no fresh water to drink or in an emergency situation. A solar still is an easy way to distill water, using the heat of the sun to create evaporation from salt water or any impure water and turning it into fresh water, leaving the salt behind.
We made a very simpler version of a solar still with a glass bowl, a small glass jar and plastic wrap.
Fill a bowl with water and mix in a few tablespoons of salt until it dissolves in the water. Put a glass jar in the center of the bowl, and push it down. You do not want to get any of the salt water into the jar, so make sure the water is not too full in the bowl.
Cover it all with plastic wrap and seal it tight. Put a rock in the center to weight it down and allow the water to fall into the jar. Place it outside in the warm sun for a few hours. What happens is the water evaporates and collects on the plastic wrap. Then with the rock in the center it causes the water to run down towards the jar and pool in the jar.
If you let it work for several hours, there will be a small amount of water in the jar. Taste it, and the water will not taste salty, but fresh. My kids thought this was SO cool! But they were a little afraid of tasting it.