Initial Publication Date: November 22, 2010

Lab 5: Air, Water, Land, & Life: A Global Perspective

Part B: The Water Cycle

water droplet
Image source: NASA
The abundance of water on Earth makes our home planet a uniquely livable world. Water sustains life and is an important link between each of the four "spheres" of the Earth system (hydrosphere, atmosphere, pedosphere, biosphere). The water cycle, which describes the continuous movement of water on, above and below the surface of the Earth, includes all water processes: precipitation, evaporation, freezing, melting, and condensation. Earth's climate and climate variability are largely driven by the cycling of water and energy exchanges among the ocean, atmosphere, and land.


Play the NOAA Water Cycle Game

This role-playing game will help you gain a better understanding of the complex journey a water molecule takes as it moves through the water cycle. Each player will simulate the movement of water within the water cycle. Your teacher will set up stations representing nine different compartments of the water cycle. On each turn, you will roll dice to determine where to move next. Colored trackers record each person's unique journey through the water cycle so you can compare your journey to those of others after you are done playing. During the game, you will identify the states of water and when water changes states as it moves through the water cycle. You will also learn where pollutants can enter the water cycle, be transported, or get left behind.

Stop and Think

1: After playing the Water Cycle Game, think about the pathways that water takes through the Earth system. Tell the story of a drop of water, and describe what happens to it. Through which components does it travel, and how does it get there? Describe the water drop's path as a series of steps.

For example:
Step 1. It rains, and the water drop falls near my house.
Step 2. The water is absorbed by the soil.
You can add any details that you imagine. Remember to include the various forms that water takes (solid, liquid, and gas).

Turn your water drop into a world traveler, and take it across the globe. Don't leave it in your neighborhood!


2: Go back through your steps. After each one, write the name of the system components that were involved. For example, if you wrote, "It rains, and the water drop falls near my house," after that, you would write "atmosphere." If you wrote, "The water is absorbed by the soil," after that, you would write, "Soil," or "Pedosphere." Which of the four major components of the Earth system are involved in the water cycle?


Diagram the Water Cycle

  1. Get a clean sheet of paper. Write the names of the four major components of the Earth system, far apart from each other on the page. (It doesn't matter in what order you write them.)
  2. Draw a circle around each name. For each step in the water pathway during which water moved from one major Earth system component to another, draw an arrow between the two components. For example, if you described water being evaporated from the ocean, draw an arrow from the ocean to the atmosphere.
  3. Along the shaft of each arrow, write a short phrase describing how the water moved from one component to the other. For example, on the shaft of the arrow from the ocean to the atmosphere, you would write, "Water evaporates from the ocean."
  4. Do this for all your water pathway steps that involve water moving from one system component to the other.