Start a Garden
Nothing teaches the water as a life lesson better than a garden. Take a year-old seed that's been sitting in an envelope, add some water, and you have a pretty spectacular lesson about the power of H2O. Planting a garden may not teach your kids to count the seconds they run the tap when they brush their teeth, but it still has value. After growing their own sunflowers, they'll value moisture more -- and differently. The concept of water won't be limited to its function as a means of getting clean or, say, making ice cubes.
There's another garden lesson you can show them, too. It's about the way nature protects water resources when they're scarce. Plant a cactus garden to illustrate how plants fight to survive by defending water reserves. Show them the needles and spines on those chubby water hoarders -- desert survivors. Cactus plants are a dramatic symbol of the value and power of water in nature.