The purpose of "The Line of Resistance" 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 directed to 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.
The exploratory activities in this booklet correspond with recommendations
of National Science Education Standards.
This unit addresses the following National Science Education
Standards (NSES) for grades 5-8:
Properties and Changes in the Properties of Matter
This unit addresses the following National Science Education Standards
for grades 9-12:
Transfer of Energy
- "A substance has characteristic properties, such
as density, a boiling point and solubility, all of which are independent
of the amount of the
- "Energy is a property of many substances and is
associated with heat, light, electricity, mechanical motion, sound,
nuclei and the nature of
a chemical. Energy is transferred in many ways."
- "Electrical circuits provide a means of transferring
electrical energy when heat, light, sound and chemical changes are
Interaction of Energy and Matter
This unit also addresses the NSES standards that call for more emphasis on:
- "In some materials, such as metals, electrons flow
easily, whereas in insulating materials such as glass they can hardly
flow at all. Semiconducting
materials have intermediate behavior. At low temperatures some materials
become superconductors and offer no resistance to the flow of electrons."
- "Learning subject matter disciplines in the context
of inquiry ..."
- "Investigations over extended periods of time."
- "Using multiple process skills - manipulation, cognitive,
- "Doing more investigations in order to develop understanding,
ability, values of inquiry and knowledge of science content."
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.
are familiar to students. Drawing resistors and circuits with pencils allows
the student freedom to explore and discover relationships for themselves.
Developed by Dr. Lawrence Woolf, a physicist
at General Atomics, in collaboration with the Institute
for Chemical Education, the Line
of Resistance kit is available for purchase through the Institute for Chemical Education.
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 contents are outlined below:
- 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 now sold by the Institute for Chemical
Education at the University of Wisconsin . 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.
THIS ADDENDA IS FREE! DOWNLOAD USING THE LINK ABOVE