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What Is the Water Cycle?

Author(s): Nancy P. Moreno, PhD, Barbara Z. Tharp, MS, and Judith Dresden, MS.

Let’s Talk About It

This activity enables students to learn about the water cycle, and to begin to understand the states of matter involved in this cycle. For example, they will learn that without the continuous cycling of water, our freshwater supplies would run out. Also, they will discover that heat from the sun is the major source of energy driving the water cycle. When conducting a class discussion, expect a variety of answers and observations, and pose questions that encourage students to think. 

Students will notice that the ice cubes melted, turning from a solid to a liquid. Some of the liquid will pool on the opposite end of the sandy slope, and some water will be absorbed by the sand. Students also should be able to see tiny drops of water forming on the underside of the lid or plastic wrap. Explain that the drops formed when water, in the form of a gas (water vapor), came into contact with the plastic lid. 

Since the shoe box with the lid creates a closed system, as the sun shines through the lid, heat is trapped inside, creating a warmer environment. When the vapor touches the cooler surface of the box, it condenses back into a liquid. And as more and more vapor touches the plastic cover, the water that condenses there collects into larger drops, which eventually will fall back onto the bottom of the shoebox. These drops are like raindrops falling from a cloud. 

The sand also will change because it will absorb some of the water from the melted ice. Challenge students to think about what would happen if other substances, such as motor oil or chemicals, were present in the sand.

Give each student a copy of the student page, use a class transparency, or use this PowerPoint® slide. Encourage students to identify the parts of the experiment that model different phases of the water cycle. Have them identify the forms of water shown in the diagram. For example, the snow on the mountaintop is a solid form of water; water evaporating from the ocean is a gas. With very young students, direct each child to place a sticker everywhere on the page where he or she can find some form of water.


Funded by the following grant(s)

National Institute of Environmental Health Sciences, NIH

National Institute of Environmental Health Sciences, NIH

The Environment as a Context for Opportunities in Schools
Grant Numbers: 5R25ES010698, R25ES06932


Houston Endowment Inc.

Houston Endowment Inc.

Foundations for the Future: Capitalizing on Technology to Promote Equity, Access and Quality in Elementary Science Education