NetLogo User Community Models
by Edmund Hazzard (Submitted: 09/08/2008)
WHAT IS IT?
This model of the water cycle was developed for grades 3-6. It shows the major paths that water takes when traveling around the earth.
This model is used by the Concord Consortium in the UDL (Universal Design for Learning) project. To see the model in the context of an activity, go to http://udl.concord.org. Find the Intermediate Clouds Unit (Grades 56) and go to the activity called "Water cycle model".
HOW IT WORKS
Five areas of the earth's surface are represented by different colors: ocean, forest, lake, earth, and ice. Water molecules are represented by small circles. There is a fixed number of water molecules in the model.
Water (blue) can evaporate (move upward) from the ocean and the lake. When it reaches a certain height, the water changes to cloud droplets (white). The "wind" pushes it to the left or the right.
The droplets can turn into rain (gray), which falls straight down. If it lands on white, it turns to ice. If it lands on land or forest, it migrates to the right as groundwater (gray) until it reaches a body of water.
The sliders control wind speed and the temperatures of various areas -- ocean, lake, ice, and cloud.
HOW TO USE IT
Run the model and watch what the water molecules do and where they go.
You can watch a single water molecule with the "watch one water" button.
THINGS TO TRY
Try each of the sliders, starting with wind-speed, and see what effect they have on the water cycle.
Try to accumulate a lot of snow.
Try to get rid of the snow. (There will always be one white layer left.)
Try to make it rain more a lot over the mountain, or over the ocean.
Try to imitate a dry season vs. a monsoon season.
EXTENDING THE MODEL
Add a cyclical feature to wind-speed, to imitate day-night conditions or dry/monsoon season.
Add a desert.
Make a graph of rainfall or snowfall.
Have the lake level rise or fall according to how much water evaporates of returns to the lake.
Include rules for transpiration from the forest.
Add rules that make plants grow or die according to how much rain they have.
Change the level of the lake according to the amount of rain, evaporation, and runoff.
The background image "cl_56_nl_background2.png" was created especially for this model. It won't look right if the graphics window size is changed! The lower half of the image is transparent so that the patches are visible.
CREDITS AND REFERENCES
This model was written by Edmund Hazzard as part of the Universal Design for Learning Project (UDL) at the Concord Consortium (http://www.concord.org) in March of 2008. The image was also produced by the Concord Consortium.
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