Secondary school students' evaluation of evidence from investigations of force and motion

Abstract

This research examined secondary students’ evaluation of the sufficiency of evidence to evaluate a scientific claim. It aimed to describe how students evaluated the evidence that concerns data including variability under misconceptions of a particular domain and to explore the factors that accounted for those evaluations.

This study investigated students’ evaluations of evidence from an investigation of force and motion in physics. Two studies were conducted. Study One aimed to describe how students evaluated the sufficiency of the evidence to evaluate a scientific claim. Fifty-seven students from Grades 6 and 7 were asked to evaluate the sufficiency of evidence from an investigation to evaluate the scientific prediction of an object’s movement. The results revealed that participants used three practices to evaluate the evidence: 1) making or evaluating predictions, 2) assessing the quality of the data collection method and 3) examining the consistency of the data with the prediction. Moreover, the participants whose initial prediction of the object’s movement was confirmed by the evidence were more likely to consider the evidence sufficient to evaluate the scientific prediction than those whose initial prediction was disconfirmed.

Study Two aimed to test whether an intervention incorporating three factors changed students’ reasoning during their evaluations of evidence. These factors included an epistemic understanding of scientific knowledge, content knowledge of the domain and knowledge about variability in scientific data. This study also aimed to explore other potential factors that could affect the development of strategies of evaluating evidence. In the intervention, 36 students from Grade 7 who made a particular misconception in their predictions of an object’s movement were shown three inappropriate responses to reasoning about evidence and three informational texts that conveyed the key ideas associated with the factors; they were then asked to evaluate the responses against the informational texts. The results show that the participants were more likely to believe in the sufficiency of evidence and to disagree with the inappropriate responses after the intervention. The results also identify three factors that influenced strategy development: the students 1) kept the conflict between the competing claims of the domain unresolved, 2) doubted the validity of the inference from the thought experiment and 3) mistakenly assessed the plausibility of the competing claims.

Theoretically, this thesis should help to clarify how students evaluate evidence in physics by revealing the practices they adopt to evaluate the sufficiency of evidence that concerns data including variability. It helps to explain students’ reasoning during the evaluation of evidence by demonstrating the roles of epistemic understanding, scientific explanations for evidence and knowledge about variability in scientific data in developing this reasoning. Pedagogically, its findings suggest that focusing explicitly on each particular practice when evaluating evidence can be helpful for students. Engaging students in evaluating the epistemic and conceptual aspects of their reasoning about evidence is a fruitful approach to promoting this reasoning.