When negative is not "less than zero": Electric charge as a signed quantity

TL;DR

This paper investigates how students understand electric charge as a signed quantity, highlighting the challenges posed by interpreting positive and negative signs in the context of electromagnetism.

Contribution

It introduces a new perspective on teaching electric charge by analyzing students' conceptual difficulties with signed quantities in electromagnetism.

Findings

Students struggle with interpreting positive and negative signs as electric charge.

Number line intuition can hinder understanding of charge sign conventions.

Addressing sign interpretation improves conceptual grasp of electromagnetism.

Abstract

Electromagnetism (E&M) is often challenging for students enrolled in introductory college-level physics courses. Compared to mechanics, the mathematics of E&M is more sophisticated and the representations are more abstract. Furthermore, students may lack productive intuitions they had with force and motion. In this article, we explore the mathematization of electric charge. Specifically, we explore how difficulties with positive and negative signs can arise for learners who approach integers primarily as positions on a number line.