Exploring student difficulties with observation location

TL;DR

This paper investigates how students understand the importance of observation location when calculating electric and magnetic fields, revealing common misconceptions and difficulties through analysis of student work.

Contribution

It provides initial insights into student challenges with observation location in E&M, highlighting areas for instructional improvement.

Findings

Students often struggle with the dependence of fields on observation location.

Analysis shows a significant number of incorrect responses regarding observation points.

Preliminary results identify specific misconceptions in vector addition of fields.

Abstract

Throughout introductory physics, students create and interpret free body diagrams in which multiple forces act on an object, typically at a single location (the object's center of mass). The situation increases in difficulty when multiple objects are involved, and further when electric and magnetic fields are present. In the latter, sources of the fields are often identified as a set of electric charges or current-carrying wires, and students are asked to determine the electric or magnetic field at a separate location defined as the observation location. Previous research suggests students struggle with accounting for how a measurement or calculation depends on the observation location. We present preliminary results from a studio-style, algebra-based, introductory electricity and magnetism course showing the prevalence of correct and incorrect responses to questions about observation location by analyzing student written work involving vector addition of fields.