Water Cycle in a Bag

This activity models the water cycle using a sealed plastic bag, water, and sunlight. Evaporation, condensation, and precipitation can be observed as water droplets form and move inside the bag.

1. Gather materials: a clear plastic zip-lock bag, permanent marker, water, blue food coloring, and clear tape.
2. Use the permanent marker to draw a sun and clouds on the upper part of the bag.
3. Fill a cup with water, add a few drops of blue food coloring, and stir until mixed.
4. Carefully pour the colored water into the plastic bag and seal it tightly.
5. Tape the bag to a sunny window so that sunlight warms the water.
6. Check the bag after several hours to observe evaporation (water vapor rising), condensation (droplets forming on the bag), and precipitation (droplets sliding back down).

Making a Water Cycle in a Baggie! - Clayton’s Exploration Station:

Water Cycle in a Bag - funsciencedemos:

📄 How to Make a Water Cycle in a Bag - Mobile ed: https://www.mobileedproductions.com/blog/how-to-make-a-water-cycle-in-a-bag

• Try using different amounts of water to see how it affects droplet formation.
• Place one bag on a sunny window and another on a shaded window to compare results.
• Use warm water at the start to speed up the process.

• Ensure the bag is sealed tightly to prevent spills near windows.
• Use permanent markers carefully to avoid staining surfaces or skin.
• Do not drink the colored water.

• Why does condensation appear on the sides of the bag? (Water vapor cools against the bag surface and changes back into liquid droplets.)
• How does this model represent rain? (Droplets run down the bag, similar to precipitation falling from clouds.)
• Why is sunlight important for the experiment? (It provides energy for evaporation, just like the sun drives the real water cycle.)
• How is this model similar to and different from the real water cycle? (It shows evaporation, condensation, and precipitation, but does not include processes like runoff or groundwater movement.)