Put salty or colored water in the bowl

Place the cup in the center of the bowl

Stretch clear plastic wrap over the top of the bowl and secure with tape or a rubber band. Make sure the seal is tight and no air can escape.

Place a weight on the center of the plastic wrap above the cup. Press down slightly on the plastic wrap so it stretches and sags down over the cup.

Place the solar still in full sun

Observe what happens.

After some water collects in the cup, taste it. Is the water clear? Does it taste salty? Why does the water taste different that tap water?