Abstract

This paper characterizes the way three preservice mathematics teachers (PSTs) understand and quantify the rate of change as they model the link between carbon dioxide (CO2) pollution and global warming. I also discuss what PSTs learned about the concept of forcing by CO2, a key metric of global warming. The PSTs completed a mathematical task during an individual, task-based interview. The study revealed three levels of understanding of the rate of change in relation to quantitative operations (comparison versus coordination), graphing activity (pointwise versus smooth and continuous), and concavity (discovering versus anticipating). Depending on their level of understanding, PSTs could imagine the rate of change changing discretely or continuously with respect to an independent variable. PSTs also learn four central ideas regarding the forcing by CO2 as a result of working on the task.