Developing second level students’ understanding of the inverse square law and electric fields

Abstract

There are specific mathematical tools involved in building an accurate model of introductory electric field theory. Algebra operations, vectors, field lines, proportional reasoning and the inverse square law are all integral parts of gaining a complete understanding of an electric field. In this paper we present a small body of research, taken from a case study with a group of 14 upper second level students, in which they developed their understanding of the inverse square law, using a pre-test-tutorial-post-test tutorial lesson model. Students struggle to understand the inverse square law unless they are repeatedly exposed to it. Using the context of intensity, our students develop their understanding of the inverse square law using a variety of representational forms, such as diagrammatic, tabular / graphical and calculations using formulae. Using our pre-test and post-test results, our students showed gains in their reasoning used to explain the variation of intensity when an object is moved various distances from a source, which we attribute to their reasoning developed in the tutorial lessons. Additionally, students completed quantitative problems involving the inverse square law in the context of Newton’s gravitational law. Six weeks after the completion of the inverse square tutorial, our students completed a tutorial lesson, in which they applied their understanding of the inverse square law to Coulomb’s law and the electric field. Our results show that our students could apply the inverse square law to these contexts when guided, but some difficulties still remained, such as proportional reduction / increase based on variation of the distance, and transfer between representations, such as algebraic to graphical.

The impact of using PhET simulation on conceptual understanding of electrostatics within selected secondary schools of Muhanga District, Rwanda

“…According to Moynihan and Hons' (2018) study, students are unable to distinguish between electric force and field intensity. Due to their inadequate conceptual understanding of static electricity and atomic structure, some students assume that charged objects only have one type of charge (Moynihan et al, 2016). Nevertheless, students view atoms as charges and use a north-south charge model (Moynihan et al, 2016).…”

“…Due to their inadequate conceptual understanding of static electricity and atomic structure, some students assume that charged objects only have one type of charge (Moynihan et al, 2016). Nevertheless, students view atoms as charges and use a north-south charge model (Moynihan et al, 2016). Ndeleni (2017) added some of the difficulties that students run into when learning electrostatics: Students are unable to distinguish between magnetic and electric attraction when asserting positive electric charges are drawn to the north magnetic poles.…”

“…However, Batuyong and Antonio (2018) investigated how learners can learn at their own pace and relate/associate concepts with real-life situations almost immediately when they participate in the video. Furthermore, guided inquiry materials can help students adjust their mental models to consider information that modifies their initial conceptual understanding of electrostatics (Moynihan et al, 2016).…”