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Daisyworld: Interactive On-line PC and Mac

Activity and Starting Point page by R.M. MacKay. Clark College, Physics and Meteorology.
This material was originally created for Starting Point:Introductory Geology
and is replicated here as part of the SERC Pedagogic Service.

Summary

Students use a JAVA interface design by R.M. MacKay to explore the Daisy World model described by Mike Barnsley of the Department of Geography, University of Wales Swansea, Singleton Park, Swansea, SA2 8PP (see resources) . The JAVA interface comes with a link to a student activity page in PDF format.

The following is a direct excerpt from University of Wales model description. "The Daisy World model is intended to illustrate a mechanism through which - according to the Gaian hypothesis - biota might optimize their abiotic environment by means of negative feedback. The model does not attempt to describe all of the possible mechanisms and feedbacks which might influence the ways in which the plants and climate develop. Instead, it is an heuristic model - one that seeks to describe the ways in which this mechanism might work. The original model was developed by Watson and Lovelock (1983)."

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Learning Goals

Students:
  • Explore the concept of homeostasis in Daisy World;
  • Use Excel to graph and analyze results from Daisy World simulations
    • Global temperature vs Solar luminosity for Daisy World;
    • Area of Black and White daisies vs. Solar Luminosity
    • Area of Black and White daisies vs. average planetary temperature
    • Planetary Albedo on the Y axis vs. Solar Luminosity L on the X- axis
  • In their own words describe how Daisy growth on Daisy World results in homeostasis;
  • Compare and contrast Daisy World to a dead planet (no daisies);

Context for Use

This activity is designed for introductory geoscience courses with an Earth Systems approach and is appropriate for course with minimal mathematics or science prerequisites. Students should have some experience with either Excel, another graphing program, or making graphs by hand. Since the graphical analysis is introductory and fairly qualitative, the activity is appropriate as a beginning graphing exercise.

Description and Teaching Materials

Here is a link to Daisy World Model (more info)

More on Daisy World: a feedback perspective.

See also the resources below.

Teaching Notes and Tips

The activity will take students about 4 hours to complete and, since Model and Activity are available on-line, it can be given as a home work assignment. One approach could be to start students out in a lab setting for a hour or so and then let them finish as a homework assignment.


This JAVA activity works best on a PC but it has also worked on Macs (OS 10.2) and Mozilla Browser. Sometimes the reload button had to be used on the Mac.


Assessment

Grading the activity is a good assessment of student performance and understanding. A follow-up classroom discussion can also be useful to get a sense of student comprehension.

References and Resources

The Daisy World JAVA Model and PDF Activity (more info)

More on Daisy World: a feedback perspective.

Sea Floor Spreading I or World Population Activity I are good introductory lessons on how to use Excel and how to make graphs with Excel.

Another good reference for students is: Resources Graphing Tutorial: Graphing with Excel (more info) . Basics: Data input into cells, Creating a scatter plot and line graph. Advanced: Bar graphs and histograms, Importing text files, Final formatting, Regression lines, Superimposing graphs, Descriptive statistics, Selecting data for display.

A slide show discussion of Daisy World by Mike Barnsley (more info) of the Department of Geography, University of Wales Swansea, Singleton Park, Swansea, SA2 8PP.

JAVA Daisy World by Ginger Booth (more info) This is a great Flash application which gives students huge flexibility in manipulating input and output. JAVA simulations are also available from the web page. Questions and homework come with this activity.

Andrew Ford's Daisy World Flight Simulator (more info) This is a Stella Model flight simulator based on chapter 21 of Fords Modeling the Environment book

Dave Bice's Daisy World Using Stella. ( This site may be offline. ) Dave has developed a great Stella modeling activity here. Students build the Stella model by following clear instructions and then use it to perform experiments on the behavior of Daisyworld. The Basic equations are identical to those used in the JAVA Daisy World Model (which are also the equations described at the University of Wales Swansea site).