Page 133 - Getting the Picture Modeling and Simulation in Secondary Computer Science Education

Students’ Understanding and Difficulties
• G2 (S3 and S4): Fire evacuation. In case of fire, it is important that people are alarmed quickly in order to leave the building on time. What are the optimal numbers of alarm bells and emergency exits on the ground floor of your school to achieve this goal?
• G3 (S5 and S6): Life on Mars. After the initial supplies and shelter are delivered to Mars, would it be possible to produce sufficient water, air and food to survive? In other words, would be possible to found a sustainable human colony on Mars?
• G4 (S7 and S8): Ohm’s Law. Check the Ohm’s law for series circuit and parallel circuit.
• G5 (S9 and S10): Cheese barn: A cheese farmer produces cheese and stores it in a warehouse with limited capacity. The older the cheese, the high the price it fetches. The farmer can sell the cheese to supermarkets with guaranteed purchase and fixed price, or at the farmers market for higher price but uncertain sales volume. What are the optimal production and selling strategies?
• G6 (S11): Bank counters. Investigate the optimal number and task division of bank counters as to minimize the waiting time of the customers with various needs.
The purpose of the most of these models was to find an optimal solution for
a problem through experimentation. Only one of the models — Ohm’s Law — 6 had a different purpose, namely, to seek explanation for Ohm’s Law as a result of
behavior of electrons.
6.3.3 Data Collection
After the project were graded, these eleven students were interviewed. We performed individual semi-structured interviews with them using the protocol cited below. While we were primarily interested in verification and validation, for the sake of a naturally flowing conversation and completeness, we enquired about the entire modeling process and emphasized the part concerning verification and validation. To help recollection during interviews, we ran students’ models on a computer and presented their documentation.
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