Title: Science Teachers' Conceptual Understanding of a Critical Rationalist Stance in Science and a Proposed Learning Module to Enhance Their Professional Knowledge
Description: The history of science is rich in examples of the importance of theories and hypotheses. Among the various disciplines of science, theories and hypotheses have been important in guiding research, including such large ideas as the atomic theory, theory of evolution, laws of motion in physics, and plate tectonics. One of the major ways science progresses is to gather evidence in relation to theories and hypotheses and to refine our explanations of how natural events occur both at very small scales of space and time or at the level of the universe. This dissertation research focused on understanding science teachers' conceptual models about theories, and the use of corroborating evidence based on a critical rationalist stance in science. The study explored a sample of science teachers' level of understanding of critical rationalism, and issues in modeling science within a `critical rationalist', post-positivist framework. During the initial phase of the research, a pilot study was done to gather contextual evidence obtained from a sample of teachers' views on the nature of science (NOS) who responded to an online questionnaire.

Subsequently, a more comprehensive study based on the findings from this initial pilot study was done. In the subsequent more comprehensive study, an online learning module on NOS, containing core concepts within a critical rational stance, was presented to a second sample of pre- and in-service teachers. This module specifically focused on how theories are initiated and rigorously tested under the highest risk conditions within a critical rationalist model. It also explained why this is a more productive approach than an exclusively verificationist cognitive framework underlying some logical positivist approaches. The results of a pretest, and post-test assessment, following the completion of the online learning module, provided robust evidence that the teachers who initially demonstrated significantly weak understandings of a critical rational stance improved to a level where they reached a preset benchmark level of accomplishment established by the researcher prior to the online intervention.

The pretest results of the comprehensive study also aligned well with the results of the pilot study. That is, science teachers' pre-learning views on scientific theories and experimentation fall mostly within inductive verification-based models, more closely aligned with a positivistic worldview, outside of a contemporary critical rationalist view of a hypothetico-deductive or falsification approach. In this study, a convenient and reliable method of online learning and associated assessment instruments regarding critical rationalist understanding of NOS is presented and evaluated. The evaluation of the pre- and post-learning assessments, and analyses of questionnaire responses by the participants, showed that the use of the online learning module significantly improved science teachers' cognitive understandings of the nature of science, and that the learners generally reported favorable responses about the learning experiences based on quantitative and qualitative evidence. Based on this initial evidence, the online learning module and related assessment instruments appear to be a valuable resource for assessing teacher understanding of a modern critical rational view of science, and as a potentially productive way to introduce pre-service and in-service teachers to these modern views of NOS through application of the online learning module.