Water Cycle Demonstrations

See also: Weather and Climate, Water and Solubility

Water cycle activities illustrate how water moves through evaporation, condensation, precipitation, and collection. They provide a clear, visual way to understand a process that is both everyday and global.

Demonstration	Materials	Difficulty	Safety	Summary
Rainfall Simulator	★★★	★☆☆	★☆☆	This demonstration uses a rainfall simulator to show how different types of land use - such as natural vegetation, agricultural land, and urban surfaces - affect water runoff and water quality. By comparing runoff and infiltration between surfaces, students learn how human activities influence water pollution and watershed health.
Cloud in a Bottle	★★☆	★★☆	★★☆	This demonstration shows how changes in pressure and temperature can create visible clouds. When air inside a sealed bottle containing rubbing alcohol is compressed and then suddenly released, the vapor condenses into tiny suspended droplets, forming a cloud.
Distribution of Earth’s Water	★☆☆	★☆☆	★☆☆	Cups and measured amounts of water are used to visually represent how much of Earth’s water is salt water compared to fresh water, and how the fresh water is further divided among glaciers, groundwater, and surface water.
Ecosystem in a Bottle	★☆☆	★☆☆	★☆☆	Students create a self-contained bottle ecosystem using soil, rocks, seeds, and water. This hands-on activity models how living and nonliving components interact in ecosystems and illustrates the role of plants and the water cycle in maintaining balance.
Evaporating Seawater	★☆☆	★★☆	★☆☆	Dissolve table salt in warm water to make a saturated solution, then leave the solution in a shallow container for days. As water evaporates, the remaining liquid becomes supersaturated and salt recrystallizes on the dish and along the waterline.
Homemade Water Purifier Model	★☆☆	★☆☆	★☆☆	Students build a simple water filter using a cut plastic bottle and layers of materials like sand, gravel, cotton, and activated charcoal. The experiment shows how filters remove impurities from dirty water, though the filtered water is not safe to drink.
Hot Water Condensation	★☆☆	★☆☆	★★☆	This experiment demonstrates condensation, a key stage in the water cycle. By placing an upside-down cup with an ice cube over a cup of hot water, students can observe how water vapor cools and condenses into liquid droplets, similar to how clouds form in the atmosphere.
Observing Plant Transpiration	★☆☆	★☆☆	★☆☆	This demonstration shows how plants release water vapor through their leaves in a process called transpiration. By sealing leaves inside a plastic bag and comparing it with a control bag, students can observe condensation forming as water vapor escapes from stomata and condenses on the bag’s surface.
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.
Water Salinity and Density	★☆☆	★★☆	★☆☆	Salt water and fresh water can form distinct layers due to differences in density. By testing with an egg and layering colored water, students can observe how salinity affects whether water sinks, floats, or mixes.

Materials
★☆☆ Easy to get from supermarket or hardware store
★★☆ Available in most school laboratories or specialist stores
★★★ Requires materials not commonly found in school laboratories

Difficulty
★☆☆ Can be easily done by most teenagers
★★☆ Available in most school laboratories or specialist stores
★★★ Requires a more experienced teacher

Safety
★☆☆ Minimal safety procedures required
★★☆ Some safety precautions required to perform safely
★★★ Only to be attempted with adequate safety procedures and trained staff