The purpose of The Line of Resistance educational module is to provide teachers with creative, inexpensive, hands-on/minds-on ideas that illustrate electrical properties of materials and circuits. The ideas include activities, as well as creative drama exercises, intended to supplement regular curriculum materials. There are detailed teacher instructions for learning and performing the activities and dramas, as well as mathematical explanations.
The publication is for high school and college science teachers. Some aspects of the publication are also appropriate for middle school (after Ohm's Law has been introduced), but the mathematics and explanations may be beyond the conceptual level of most middle school students. The student instructions are somewhat open-ended, allowing ample opportunity for students to construct their own knowledge of electrical properties with, of course, help from the teacher.
Along with teacher activities and student handouts are suggestions for teaching "The Line of Resistance". There are ideas for classroom organization, introductory exercises, assessments and creative dramas.
Many aspects of "The Line of Resistance" relate to students' everyday lives, and making connections between the two can further learning. Graphite pencils are familiar to students. Drawing resistors and circuits with pencils allows the student freedom to explore and discover relationships for themselves.
Teachers can use this kit to teach their students how to measure the electrical properties of materials and circuits using a graphite pencil, a piece of paper and an ohmmeter.

The Line of Resistance is Copyright Board of Regents of the University of Wisconsin System - CC BY-NC

• Activities
• The electrical resistivity of graphite
• The dependence of resistance on dimensions - intrinsic and extrinsic properties of materials
• Resistance of series circuits
• Resistance of parallel circuits
• Open and short circuits
• The electrical resistivity of silver ink
• A precise measurement of the electrical resistivity of a metal
• The resistance of a banded carbon resistor
• The electrical breakdown field of air
• The path of least resistance - lightning rod demonstration
• Teaching Strategies
• Creative Dramas
• Conductor vs semiconductor vs insulator
• Length and width dependence of resistance
• Summary and assessment ideas
• Summary of Scientific Principles

Addenda to the Line of Resistance 
The addenda contain additional experiments and creative dramas that complement the original unit. There are a new series of experiments and problems on lightning safety that also use a graphite pencil and a piezoelectric sparker. In a new section on superconductors, students measure electrical losses in "superconducting" and normal magnets that they make using copper wire and the graphite pencil. They also fabricate a superconducting magnet with a "persistent switch." A creative drama and assessment about electrical conduction by electrons and holes extends the creative dramas described in the original module.