To explain the water cycle to kids, find age-appropriate books that engage a child's imagination but describe the process well. Next, help kids create a physical model that represents the water cycle.
Provide kids with a paper plate and construction paper, and draw the sun, some clouds, raindrops, a puddle of water and arrows. Allow the kids to cut out the shapes with child-safe scissors. Use school glue or a glue stick and glue, and have the kids glue the shapes to the paper plate in the proper order of the cycle.
Another way to explain the cycle is to produce rain in a jar. Using a mason jar, fill it 1/3 full with very hot tap water. Cover the top of the jar with a plate, and in about two minutes, ask the kids to add some ice cubes to the plate. Approximately 15 minutes later, the hot water that rises as steam collects on the bottom of the plate while the ice turns the steam back into water, causing it to "rain" inside of the jar.
Another illustration involves collecting rainwater into a large, shallow bowl. The kids place the bowl outside before it rains and then measure and mark down the water level once the rain stops. The kids then place the bowl outside in the sun and check the water level every 8 to 12 hours. Explain to them that the water slowly evaporates back into the air and the clouds, eventually causing it to rain again.