Science Fair Projects
earth scienceeasy elementary 7 days

The Water Cycle in a Bag

Create a mini water cycle using a plastic bag and observe evaporation, condensation, and precipitation over a week.

The Water Cycle in a Bag

Hypothesis

If a sealed bag with water is placed in sunlight, then the water cycle processes will be visible within the bag.

Materials Needed

Plastic ziplock bag — 1Buy
Water — 1Buy
Blue food coloring — 1Buy
Permanent marker — 1Buy
Tape — 1Buy
Sunny window — 1Buy

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Step-by-Step Procedure

  1. 1

    Fill the plastic bag with a small amount of water.

  2. 2

    Add a few drops of blue food coloring.

  3. 3

    Seal the bag tightly.

  4. 4

    Tape the bag to a sunny window.

  5. 5

    Observe the bag daily for a week.

  6. 6

    Note changes in water level and condensation.

  7. 7

    Record temperature and sunlight conditions.

  8. 8

    Discuss the stages of the water cycle observed.

Expected Results

Water will evaporate and condense, forming droplets at the top of the bag, mimicking the natural water cycle.

Variables

Independent Variable

Amount of sunlight

Dependent Variable

Rate of water cycle processes

Controlled Variables

Amount of water, Bag size, Food coloring

Safety Notes

Ensure the bag is sealed to prevent spills.

Presentation Tips

  • Show daily photos of the bag changes.

  • Explain each stage of the water cycle clearly.

  • Relate the experiment to natural weather cycles.

Frequently Asked Questions

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