Page 137 - Getting the Picture Modeling and Simulation in Secondary Computer Science Education

Students’ Understanding and Difficulties
up some of the data. Group G1 researched how many tubers a potato plant yields, what are the costs of fertilizer and spray, and other relevant data for potato farming. However, when asked how come their results suggested not to use fertilizer and spray, S1 responded that it was difficult to find out how much money a potato earns, and how much does it cost to fertilize and spray a single potato plant. Similarly, group G3 who modeled sustainability of human colony on Mars, investigated how much electricity does a solar panel produce, how much oxygen and tubers a potato plant produces, how much energy, oxygen and water a person needs to survive, how photosynthesis works, and many other relevant details. Student S6 comments, “we simply looked up many things the way they would resemble reality.” On the other hand, group G5 did look up the categorization of cheese depending on age (young, mature, etc.) but did not investigate specific economic aspects of cheese production and sales. Rather, they relied on what they learned in the economy class about market forces in general.
Abstraction
All students pay careful attention to build their models upon correct theoretical
assumptions and thus engage in the process of abstraction (Grgurina et al., 2016) 6 where they decide which aspects of the phenomenon under scrutiny to take
into account and in what form, and which ones to leave out. When employing a
proper perspective, students use sound judgement and make appropriate choices
concerning the theoretical assumptions underlying their models. This paves the
road to building a model that is sufficiently fit for its purpose. For example, in
the process of abstraction, group G1 chose to unite all possible potato diseases,
infestations etc. into one phenomenon and call it pests. This decision simplifies
the design of their model by disposing of the unnecessary details while retaining
the essence of infectious and transferable diseases and infestations.
Among the six groups observed, we see three erroneous perspectives when performing abstraction.
1. Oversimplification occurs when the students go too far in their quest for feasible assumptions, leading to a very specialized model of limited usefulness. This is a conscious course of action caused by inability to design or implement a model that would be based
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