How to Make a Water Cycle in a Plastic Bag?

You can create a mini water cycle in a plastic bag to observe the processes of evaporation, condensation, and precipitation in action.

Steps to Build Your Water Cycle Bag

Here's how to make your own water cycle model using a plastic bag, based on the provided information from KiwiCo:

Prepare the Bag:
- Pour about ⅓ cup of water into a plastic bag. Avoid filling the bag more than halfway.
- Add one or two drops of blue food coloring to the water. This makes the water easier to see.
Seal and Place the Bag:
- Seal the bag tightly to prevent leaks.
- Find a sunny window and tape the bag to the window. The sun's heat will power the water cycle.
Observe the Water Cycle:
- Check the bag at different times over the next few days.
- You should see the water evaporating, condensing on the sides of the bag, and then precipitating (forming droplets and running down).

The sun acts as the energy source in your mini water cycle. The water inside the bag:

Evaporates: The sun's heat turns the liquid water into water vapor.
Condenses: The water vapor rises and cools, turning back into tiny water droplets on the sides of the bag.
Precipitates: When enough water droplets gather, they become heavy and fall back down to the bottom of the bag, simulating rain.