GRADE LEVELS: 4-6
SUBJECT AREAS: social studies, science
CONCEPT: Everything we do to our water affects its quality, from washing clothes to siting a new landfill.
OBJECTIVE: To investigate how water is recycled in a small environment and to learn on a small scale how water is cycled on earth.
KEYWORDS: water cycle
BACKGROUND: The amount of water on the earth is the same today as in the days of the dinosaurs. Everything we do to our water affects its quality. In the exercise that follows, we will see how water is recycled. Think about the effects that humans have on this cycle.
1. Cut the 2-liter bottle in two pieces at the top of the hard plastic base.
2. Remove the softer plastic from inside the hard plastic bottom, if possible.
3. Place a layer of stones on the bottom of the clear plastic and add three to four inches of soil.
4. Put the plant in the container, making sure that the soil is firm around the roots.
5. Add one to two tablespoons of water depending on how moist the soil is.
6. Place the top of the bottle securely on the base. Keep the cap on the bottle. Place it in a sunny window.
7. If the water cycle is working, water droplets called condensation will form over time inside the dome. When enough condensation forms, it will rain and water the plants.
Discuss the fact that rain contains more than just water -- it also includes pollutants picked up from the air. Some of these pollutants form acids and cause acid rain, which can stunt tree growth and kill fish and other aquatic organisms.
As an extra experiment, fill another bottle 1/4 full with water colored with food coloring, screw the cover on, and place the water in a sunny window. Ask the students whether they expect the condensation to be colored or clear. (It will be clear, because when water evaporates, any dissolved substances are left behind.)
Back to Solid Waste Activities Grades 4-6
Cornell Waste Management Institute ©1991
Department of Crop and Soil Sciences
Bradfield Hall, Cornell University
Ithaca, NY 14853