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NetLogo User Community Models

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.

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.
- Greater temperature in the ocean or lake increases the chance that a given water molecule will evaporate.
- Lower temperature in the cloud increases the chance that a cloud water droplet will form rain.
- Greater temperature on the mountain increases the chance that an ice molecule will change to groundwater (i.e. melt) and flow to the lake or ocean.

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.

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.

NETLOGO FEATURES

This section could point out any especially interesting or unusual features of NetLogo that the model makes use of, particularly in the Procedures tab. It might also point out places where workarounds were needed because of missing features.

RELATED MODELS

This section could give the names of models in the NetLogo Models Library or elsewhere which are of related interest.

CREDITS AND REFERENCES

This section could contain a reference to the model's URL on the web if it has one, as well as any other necessary credits or references.