UC Berkeley

Recently, there have been many calls for an increase in instruction on the nature of science (NOS) in schools (i.e. NRC, 1996; NGSS Lead States, 2013). These calls recognize the importance of this topic at all levels of science education, but there is little guidance in terms of how to address it effectively in curricula. Similarly, there have been calls for reforms to chemistry laboratory courses (Hofstein & Lunetta, 2004). These reforms include an increase in the level of authenticity in laboratory activities along with a need to help students find a connection to these types of courses. This dissertation describes a project that attempts to address each of these issues with the creation of a general chemistry laboratory curriculum designed to include explicit instruction on topics from the nature of science.

The overall hypothesis for this dissertation is that including NOS topics (which fall into the categories of the nature of scientific knowledge, scientific practice, and the social and cultural aspects of science) in a laboratory curriculum could provide positive outcomes for students. For example, explicitly teaching students about the nature of scientific practice and how it impacts scientific knowledge, in the context of a practical laboratory course, could help them connect their own work in the course to larger scientific principles. This would enable them to apply this learning to future science courses or even outside of school in the real world, thus providing a path to meaningful learning and making the laboratory course a more positive experience for students. Additionally, explicit discussion of the nature of scientific practice in a laboratory course, where authenticity can be constrained by resources, time, and students’ lack of scientific experience, could alleviate some of these difficulties by allowing students to see how their activities, whatever they may be, relate to different aspects of authentic practice. Perhaps it could also help students undertaking high-level inquiry activities, such as experimental design, in an introductory course by providing a level of scaffolding for them to see how their actions in the lab are reflective of authentic scientific practice.

This dissertation describes and assesses a general chemistry laboratory curriculum that includes explicit instruction on the nature of science embedded in the context of the laboratory activities. The design process involved examining the already-established laboratory activities to determine what elements of NOS were implicitly present and then changing the curriculum and its implementation to explicitly address those topics. This was done iteratively, and data was collected from two different semesters in an attempt to determine the most effective presentation of NOS in the materials, along with the best instructional methods for impacting students’ understanding and application of these topics. While NOS topics of all kinds were included over the course of the semester, only the topics of scientific models and model building were specifically examined in the studies presented here. These topics were covered in the most depth during the course, and they represent the goals of the curricular redesign well: addressing topics of scientific practice as they relate to scientific knowledge in the context of practical scientific activities. Analyzing this subset of data still yields important determinations of the effectiveness of this curriculum.

It was determined from the three studies presented here that students did indeed make gains in their understanding of scientific models. They were also able to apply that understanding in writing their own models during laboratory activities. However, students were able to write the best models when they had an instructor who explicitly addressed these issues during lecture and directed the graduate student instructors (GSIs), who taught individual lab sections, to do the same. That semester also included a more streamlined set of materials concerning scientific models, more directly addressing the chemistry content of those labs in terms of developing models and designing experiments to test those models.

Finally, students were able to design more thoughtful and logical experiments to test their models when they encountered the curriculum with more direct prompts for considering the relationship between experiments and models along with an instructor who better articulated the role of experiments in model building. Thus, explicit instruction on scientific models, coupled with an adequate curriculum and engaged instructors, led to changes in students’ practices in the lab. Students were very receptive of NOS topics in the course, as well, as indicated by their responses on course evaluation questions on a class-wide survey. They found the labs enjoyable and pointed to NOS topics as some of the most valuable takeaways from the semester. Overall, then, it appears an established curriculum that has been updated to include explicit instruction on models and model building can lead to positive gains and positive experiences for students in a general chemistry laboratory course.