Daisyworld: Stella Mac or PC
This material is replicated on a number of sites
as part of the
SERC Pedagogic Service Project
Summary
Daisyworld is a very simple planet that has only two species of life on its surface - white and black daisies, and bare ground. Daisyworld is a good example of homeostasis and was first proposed by James Lovelock as a plausible example of his Gaia hypothesis. With guidance, students build a Stella model of Daisyworld from scratch. After constructing the model they perform guided experiments to explore the behavior of Daisyworld to changes in model parameters and assumptions.
Learning Goals
Students explore:
- Concepts and terms such as:
- Stefan-Boltzman's radiation law
- albedo, emissivity, blackbody
- Basics of Stella and Model construction in the Stella environment
- The concept of homeostasis
- Learn how surface albedo changes can influence local and global temperature
- Use a plausible plant growth factor as a function of local temperature
Context for Use
Appropriate for introductory geoscience courses with an Earth Systems approach.
Teaching Materials
The complete activity is located at Dave Bice's Daisyworld using Stella II.
Teaching Notes and Tips
This activity will likely take about 3 to 4 hours for students to work through assuming some introduction and discussion about Daisy world and the Stella environment in lecture. If you do not have Stella at your school you can download a free demo version of Stella from High Performance Systems, Inc. (more info)
Assessment
Grading completed activity is a good measure of assessment. Also a follow-up in class discussion can help assess student understanding of key concepts.
References and Resources
A slide show discussion of Daisy World (more info) by Mike Barnsley of the Department of Geography, University of Wales Swansea, Singleton Park, Swansea, SA2 8PP.
PDF file of The University of Wales, Swansea Daisy World activity. This activity is for fairly advanced students with familiarity in GAWK programming. It does provide a lot of detail regarding the Daisy World model and algorithms.
Here is a link to Daisy World Model (more info) written by R.M. MacKay.
More on Daisy World: a feedback perspective.
