Abstract
Generating a concept inventory for a specific student sample is a task that, if completed successfully, could help the instructor have a better approach to what students think at the time they are taking a test. This allows the instructor to observe which concepts the students are struggling with the most, and make the necessary adjustments for that current group, or for future ones. This investigation aims to analyze and classify the electrostatic items of the Conceptual Survey of Electricity and Magnetism (CSEM) in order to decide which items are useful and which ought to be modified. By performing a psychometric analysis on each of these items, mostly based on the Item Response Curve's (IRC) graphs' evaluation, this study will target and determine the items that fit the best for the students enrolled in the Electricity and Magnetism undergraduate course at a private university in the north of Mexico.
TopLiterature Review
Alternate Conceptions and Misconceptions in Physics
It is precise to clarify that an alternate conception is any concept that is not consistent with the consensus of the scientific community (Mulford & Robinson, 2002). The next subsections covers some of the specific misconceptions found in students reasoning, which will be taken as the starting point for the development of this research. For this work, misconception and alternate conception will be taken as undifferentiated concepts.
Specific Alternate Conceptions
Newton’s Movement Laws
The conceptual understanding of Newton’s Laws is among the most common conflicts students encounter when it comes to electromagnetism (Terry & Jones, 1986). The main reason of this could lie in the fact that these concepts, frequently used in classic mechanics courses, seem unrelated to the new subject, therefore causing trouble once it is time to apply them in the area. According to several studies, Newton’s Second and Third Laws seem to be the most problematic (Terry & Jones, 1986).
An important misconception in electromagnetism is directly related to Newton’s Third Law. This alternate conception could be summarized as follows: “The bigger the charge, the stronger the force.” This demonstrates that the majority of students fail to visualize the Symmetry of Coulombs’ Law between unequal charges (Bohigas & Periago, 2010). There is an analogy, presented in classical mechanics; Galili (1995) assesses that this alternate concept is just a particular case of the same alternate concept presented with the Cause-and-Effect Law, “the bigger the mass, the stronger the contact force will be” (Brown & Clement, 1987). In this same study, the authors suggest that students underestimate Newton’s Third Law.
Superposition Principle in Electrostatics
Just as with Newton’s Third Law, previous work has found that the superposition principle is one of the biggest barriers students must deal with in order to understand the concepts in electromagnetism (Vercellati, 2012). In fact, it has been proven that many students are capable of solving problems that involve simple vector additions, but they would not be able to solve other problems of higher complexity (Maloney, O’Kuma, Hieggelke, & Van Heuvelen, 2001). Most of the students’ issues arise whenever they are trying to define the direction of the electric field when charges are added to a problem with specific characteristics given at the beginning (Maloney et al., 2001).
Key Terms in this Chapter
Dichotomous Item: Multiple-choice item that only presents one alternative model, or distractor, among the possible answers, besides the correct answer.
Item Difficulty: Item trait given by the amount of students who are capable of answering the item correctly, and relates to the complexity of the question.
Item Discrimination Capability: Item trait that shows its ability to distinguish good performing students from low performing ones, in terms of their likelihood of answering it correctly.
IRC Graphic: Visual tool that allows the deep evaluation of a multiple-choice item on its difficulty, discrimination capacity and randomness level.
Test Reliability: Test trait that represents how trustworthy are the results, and how feasible would it be to have similar results when application is repeated to a different sample with similar characteristics.
Misconception: Naïve or mistaken idea used by students to explain phenomena, normally acquired by every-day experience, and unaccepted by the scientific community.
Randomness Level: Amount of students classified under a low performance category that answer correctly any given item.