Modeling Daisyworld

Dave Bice
Penn State Geosciences
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This activity describes the Daisyworld model in conceptual terms and then describes how to construct a STELLA model of the system. Following this, a series of experiments are outlined, along with questions for students to answer.

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This model is used in Earth 202: Modeling the Earth System, an intermediate level course that is a required course for one of our majors.

Skills and concepts that students must have mastered

They need to understand some very basic things about energy flow in the climate system, especially concepts of albedo, insolation, emitted energy and the Stefan-Boltzman law, and feedback mechanisms.

How the activity is situated in the course

This is one of the first models we work with in this class and the exercise is their first assignment involving the use of STELLA.


Content/concepts goals for this activity

The conceptual goals are to advance their understanding of albedo, energy balance in climate models, and feedback mechanisms. On another level, the goal is to appreciate how organisms can influence the climate system and achieve homeostasis within a certain range of conditions.

Higher order thinking skills goals for this activity

The higher order skills involve development and modification of a computer model, experimentation, and making predictions about how changes will effect the system's behavior.

Other skills goals for this activity

Description of the activity/assignment

Daisyworld is a classic model of complex feedbacks in a simple climate system; this activity guides students through the construction of a STELLA model that can be used to experiment with the system, exploring the somewhat surprising dynamics that arise from the interplay of positive and negative feedbacks between daisies and the temperature of their environment.

Determining whether students have met the goals

Students are evaluated based on their written answers to questions associated with the various experiments.

More information about assessment tools and techniques.

Teaching materials and tips

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Supporting references/URLs

Watson, A.J. and J.E. Lovelock , 1983, Biological homeostasis of the global environment: the parable of Daisyworld: Tellus B , 35 (4), p. 286–289.