Working in groups, students build simple solar stills filled with salt water and observe what happens when the stills are placed in the sun. The students then taste the water they have collected and discuss what has happened in their stills.

Handout included, bowl (one per group), plastic cup, 2-3" shorter than sides of bowl or cut to size (one per group), clear plastic food wrap, tape or rubber band large enough to go around bowl (one per group), small rock or weight (one per group), and salty water.

National Standards: K-4

• PRI-A: 1.b. Plan and conduct a simple investigation.
• PRI-B: 1.c. Materials can exist in different states-solid, liquid, and gas. Some common materials, such as water, can be changed from one state to another by heating or cooling.