CONSERVATION OF MASS AND ATMOSPHERIC CARBON DIOXIDE: IDENTIFYING AND IMPROVING STUDENTS' MISUNDERSTANDINGS OF BUDGETS

It has been hypothesized that some of the complacency about the urgency of climate change and rising atmospheric carbon dioxide concentrations shown by the general public is related to a lack of understanding of stock-flow (or budget) relationships (Sterman and Booth Sweeney, 2007). Several studies have shown fundamental misunderstandings in the balance between inflow and outflow and the resulting stock (reservoir) even in highly educated adults, misunderstandings that violate the law of conservation of mass. We have found similar misunderstandings in 945 undergraduate students enrolled in an introductory geology course, documented by their responses to an extensive survey that describes hypothetical future CO₂ emission scenarios in text and graph form and asked students to identify the time of maximum and minimum CO₂ levels. Students scored particularly low on graphical questions, with the majority of students simply matching highest and lowest emission levels with maximum and minimum atmospheric CO₂ levels, suggesting that pattern matching is probably one of the reasons for the confusion. Overall, gender, major, level of concern about the environment, and parents’ level of education were all significant predictors of students’ score in the survey.

We have developed an assignment rooted in constructivist theory and hosted on the ThinkSpace e-learning, problem-solving environment. In this case study students took on the role of a local snow-cone business owner and completed four budget tasks involving a sink model with faucet and drain, radiation budgets in the atmosphere, a hypothetical bank account, and atmospheric carbon budgets. Preliminary results of a pilot test completed by 64 students enrolled in an introductory geology lab as well as in a lecture show significant learning gains compared to students who only learned about budgets in the lecture.