Magnetism and Static Electricity Module
The main purpose of this module is to engage students in several science and engineering practices, particularly developing and using models, constructing explanations, and engaging in argument from evidence. The explanatory models students develop are mechanistic, so students get extensive experience with the crosscutting concept of Cause and Effect: Mechanism and Explanation. As students engage in the practices, what emerges is an understanding of magnetic interactions, which is part of the core physical science idea PS2B, Types of Interactions.
The first unit in the module focuses on developing a model of magnetism. Once students have experience with the model development process they then work through the second unit, where developing a model for static electricity is more challenging. Whereas there is only one type of magnetic material, there are basically two types of materials involved in static electric effects: insulators and conductors.
Unit M: Developing a Model for Magnetism
Unit M focuses on helping students develop a model that can successfully explain many different observations involving magnets. This unit provides a nice example of how models are proposed, tested and modified based on evidence. Most students will change their model several times during the unit as they keep obtaining evidence that does not support their current model. By the end of the unit, however, the class will come to consensus on a ‘small-magnet alignment model,’ which can explain a wide range of magnetic phenomena. It has many features in common with the Domain model. In the last activity students apply their ideas about magnetism to an engineering design project involving a prototype maglev train.
Unit SE: Developing a Model for Static Electricity
In Unit SE, students develop a model that can successfully explain many different observations involving static electricity. Unlike Unit M, where their magnetic models usually undergo a paradigm shift, in this unit students often start with a model involving + and – charged entities that has several appropriate features about it. However, they must make refinements to account for the evidence they gather, particularly on the different behaviors of different types of material (conductors and insulators). They then use their model to consider the problem of static discharge during the refueling of a car or plane and design safety procedures to avoid this.