Graphing Henderson Creek: A Case of Relations in Sociomaterial Practice

Introduction Over the past decade, it has almost become a truism to say that the mathematics in school and the mathematics in everyday settings are considerably different, and often incommensurable. However, it is much less evident what the competencies are people bring to (implicit or explicit) mathematical tasks in everyday situations. In the following episode, Nadine, a beginning mathematics and science teacher visits a farm that is part of a movement in the valley to improve the health of a local creek and watershed. (Pseudonyms replace proper names throughout this chapter.) She meets with Karen, a water technician working on the farm and paid to a considerable part by a grant from a governmental agency. Karen is also part of an environmentalist movement that has taken as its goal to improve the watershed and to design the creek, its riparian zones, and the practices of the people living in it (see Lee & Roth, 1999). One of the first things Karen shows Nadine is the water monitoring station, which essentially consists of a pen chart recorder that continuously inscribes water levels on a paper roll. In the following excerpt, Karen reads the graph and provides some explanations. In the process, she points and moves along the graph using deictic and iconic gestures (Figure 1).