Recent releases

Monday January 30, 2012 Elizabeth Cowan (Collège de Valleyfield) Julie Hamel (Collège de Valleyfield) Sara Fernandez (Collège de Valleyfield) Teaching Without Books in 101 The authors decided to replace the traditional student books and grammar books used in their classes with material from the Net. All in all it was a wonderful experience in creativity, but because they ended up doing both the teaching and writing, time became an issue. Whether they repeat the experience depends on the publication du jour.
Monday January 16, 2012 Suzanne Roy (Collège Jean-de-Brébeuf) Marie-Stéfanie Taschereau (Collège Jean-de-Brébeuf) An Easy Step-by-Step Guide to Creating a Weebly Site Suzanne Roy and Marie-Stéfanie Taschereau, teachers at Collège Jean-de-Brébeuf, suggest creating a pedagogical website to colleagues. They explain its advantages as well its value for students using the example of their experiences with the Weebly web editor.
Monday December 19, 2011 Karen Tee (Vanier College) PowerPoint Redux
PowerPoint allows Karen Tee to do some things that help students learn, and it’s so much more interesting, for both her and the students! Although doing PowerPoint slides right requires a lot of preparation, the results make all the work worthwhile.

Stories

Monday December 14, 2009 | Biology 101

Challenging Students with Probabilistic Models

Silvia d'Apollonia Teacher, Dawson College

Several years ago I attended a talk on complex systems where the proposition was made that we were entering a new stage in science - the Computational Stage, in which the prevalent methodology was the use of simulations and models rather than traditional experimentation. Kaput, Bar-Yam, Jacobson, Jakobsson, Lemke, and Wilensky (2001) argue that science education should include exposure to complex systems thinking and not only to, what Resnick and Wilensky (1993) call, the traditional Deterministic Centralized Mindset.

Swiss watch mechanism from

http://www.freepatentsonline.com/7184369-0-large.jpg

The double pendulum model is used to explain diurnal sleep-wakefulness cycles from

thebrain.mcgill.ca/flash/capsules/images/outil_bleu24_img03.jpg

The Swiss watch is a highly predictable, linear system (although complicated) and thus a simple system. The double pendulum is a complex system behaving in highly chaotic and nonlinear ways.

There is abundant evidence that students have major difficulties understanding phenomena exhibiting the characteristics of complex systems - phenomena such as evolution, population dynamics and gas laws. However, features of complex systems, such strange attractors, self-organization, scale-free networks, deterministic chaos, etc. can and are appreciated by even young children when they "play" with probabilistic models such as those provided by NetLogo and Star Logo.

Properties of Simple Systems Versus Complex Systems

single causes with predictable effects, versus multiple causes with random effects
centralized control versus decentralized control
linear reactions versus non-linear reactions
deterministic processes versus emergent processes

As part of a research funded by PAREA, I began using NetLogo simulations with students in my General Biology classes. My objective was to encourage them to see that many biological phenomena were best understood as complex systems rather than as simple systems - that consistent patterns emerged at one level as a result of random events at a lower level.

: Click on the image to link to the Daisyworld Information Sheet

Net Logo is a programmable modeling environment authored by Uri Wilensky from the Center for Connected Learning and Computer Based Modeling. Netlogo can be obtained free of charge from ccl.northwestern.edu/netlogo/ It provides a stimulating environment where students (and teachers) can explore the characteristics of complex systems. That is, they can explore the influence of random micro-level behaviours (gas molecules, termites, birds) on macro-level patterns (volume, colony, flock). Students can also easily change the parameters of the provided models and build their own models.

Of the many models that I have used, one of my favourites is Daisyworld. Daisyworld is a micro-world with white daisies (with a high albedo, thus cooling global temperatures) and black daisies (with a low albedo, thus raising global temperatures). In turn, the daisies respond to environmental conditions by increasing or decreasing in population size (boom or bust). Students can run the model, and try to predict the reciprocal influences of climate change, solar output, reflection of solar energy, population size and distribution of white and black daisies, etc. To see a student activity, click here or on the image of a Daisyworld screen shot at right.

: A Probabilistic Model for Daisyworld on NetLogo

Students, quickly observe that the cycles of low and high population densities of black daisies are associated with changes in global temperatures and, given enough time, these cycles "damp out". They become intrigued by the observation that if they begin with an equal number of white and black daisies (20% each), the white daisies die off (sooner or later) and the black daisies regulate global temperature. However, if the environment is covered with the same amount of daisies, but they are all white, all the daisies die off and the system cannot regulate global temperature. On the other hand, if all the daisies are black, the population reaches equilibrium and global temperature is regulated. They become animated and begin experimenting with increasing the heat trapped by the earth (simulating the greenhouse effect) and discussing such concepts as entropy, causes of glaciation, effect of urbanization, etc.

However, the greatest effect of using these models in class is that students begin to appreciate that there are different ways of exploring scientific phenomena. They begin to understand how to model such phenomena as climate, disease transmission, and evolution. They begin to become more comfortable with explanations that are expressed in probabilistic rather than deterministic terms. They become more flexible thinkers.

For some references on either Complex Systems in Education or using NetLogo models link here to see the attached file.

Use the Reader Response Feature below to discuss the concept of complex versus simple systems and the potential of using NetLogo in your courses.