Try This At Home

Water Cycle in a Bag

Objective
Identify the components of the water cycle and observe the water cycle by constructing a simple, miniature model.

Materials Needed

• Clear plastic bag (zipper style, sandwich size works best)
• Measuring spoon
• Rubber band or twist-tie
• Masking tape

Vocabulary

water cycle, hydrologic cycle, evaporation, condensation, precipitation, surface water, groundwater, infiltration, recharge (view Groundwater Glossary)

Procedure

1. Pour 2 teaspoons of water into a clear plastic bag.
2. Blow air inside the bag with your mouth and quickly seal the bag closed with a rubber band, twist-tie, or zipper-closure.
3. Place the bag on a sunny window ledge or tape directly to the window pane. Periodically look at the bag throughout the day. What changes do you see?

Variation
For instant results, make two bags. Put cold water in the first bag and hot water in the second bag. Compare the two bags.

Extension
Water Cycle Coloring Sheet

Conclusion
Water molecules are constantly on the move in what is called the water cycle (or hydrologic cycle). Heat from the sun causes the water to evaporate and become a vapor. As the water vapor cools, it condenses, forming tiny droplets which gather to form clouds. As the droplets get larger, they become heavier causing them to fall to the ground as precipitation (like rain, sleet, or snow). Some of this precipitation joins lakes and streams (called surface water), and some of it soaks into the ground where it becomes groundwater. The process of water soaking into the ground is called infiltration, or recharge.

Activity Source
The Groundwater Gazette, published by The Groundwater Foundation.