Electromagnetism Unit Plan

by John Bergmann
completed in partial fulfillment of the requirements for
"Teaching High School Physics"
Physics 301
Autumn 1996
Illinois State University
Carl J. Wenning, Instructor

I. UNIT OVERVIEW

A. Unit Plan Summary

This unit plan for Electromagnetism is designed for a first-year, high school course in General Physics. A conceptual, as opposed to historical or thematic, teaching approach has been chosen for the instructional material and activities of the unit, although some historical anecdotes, as well as themes such as motors and electric power, will be included. The unit is targeted toward second-semester, first-year physics students with two years of algebra, but no calculus preparation. It has been assumed that the large majority of the students are college-bound juniors or seniors. The textbook, which will be used primarily as a reference source rather than a curriculum guide, is Modern Physics by Frederick E. Trinklein (1990).

B. Goals

The goals for the unit may be logically grouped into three main categories: content knowledge, process skills, and scientific dispositions.

Content knowledge goals specify, in general terms, what students should know and understand at the conclusion of the unit. National education standards are a good source of broad-based goals that provide focal points for the material we will cover in this unit. Content Standard B of the National Science Education Standards (1996), for example, lists two broad goals that are particularly applicable for our purposes. This standard reads as follows:

As a result of activities in grades 9-12, all students should develop an understanding of: Motions and Forces

Conservation of Energy and the Increase in Disorder (p. 176).

We will examine Motions and Forces when we investigate Oersted's experiment, Ampere's experiment, and the nature of electric/magnetic interactions. Our studies of Lenz's Law and transformers fit nicely under the goal of Conservation of Energy. A concise, yet complete, summary of the goals of this unit is found in Standard 4G in the Physical Setting section of Project 2061: Benchmarks for Scientific Literacy. That standard reads:

By the end of the 12th grade, students should know that...

Magnetic forces are very closely related to electric forces and can be thought of as different aspects of a single electromagnetic force. Moving electric charges produce magnetic forces and moving magnets produce electric forces. The interplay of electric and magnetic forces is the basis for electric motors, generators, and many other modern technologies, including the production of electromagnetic waves (p. 97).

Goals for process skills specify what scientific, procedural skills students should possess at the end of the unit. Learning the requisite skills for experimentally examining a claim or issue is one such goal for this unit. This goal is explicitly stated in the preliminary draft of the Illinois Academic Standards for Science. Illinois Science Standard 11B states that students should be able to apply the steps and methods of scientific inquiry to conduct experiments and investigate research questions (p. 3). Content Standard A of the National Science Education Standards (1996) voices a similar statement (p. 173). At the conclusion of this unit, therefore, students should know the purpose for, and how to use, laboratory equipment relating to electromagnetism. They should be able to explore scientific questions of electromagnetism safely in the laboratory. Finally, they should have sufficient overlap of theoretical and practical knowledge that they could design, set up, and perform a simple laboratory to investigate a certain question or illustrate a specific physical principle.

Goals dealing with students' scientific dispositions are the final group of broad-based goals. While it is much more difficult to teach, and assess the attainment of, disposition goals than content or process goals, this component of a scientific education is no less necessary for American youth of today. Although state and national standards are largely devoid of specifics regarding dispositions, Content Standard A of the NSE Standards (1996) may be thought of as a disposition goal. It reads: "As a result of activities in grades 9-12, all students should develop abilities necessary to do scientific inquiry" (p. 173). Such abilities, presumably, would include: careful observation, objectivity, intellectual honesty, critical thinking skills, logical thought processes, a reliance on conclusive evidence, and effectively working together toward common goals. A final disposition goal for all students will be to lead them to the realization that although science is a meticulous and rigorous discipline, it can be fun and exciting as well. We will attempt to cultivate these dispositions and attitudes throughout our studies here.

C. Rationale

1) Needs of the Student

The content knowledge, process skills, and scientific dispositions learned in this unit are of vital interest to the student. Students will experience the pleasure of knowing the how and the why behind many important aspects of modern civilization, including the essential concept of energy conservation. Other widely-applicable topics which underlie today's technology that will be addressed are motors, generators, and electrical power generation.

Students also will benefit from acquiring the process skills we will cultivate in this unit. With these skills, students will gain confidence in their ability to act, to put thought into practice. The possession of real-life, practical skills will prove to be useful when solving problems and searching out answers to problems far beyond the classroom. Such skills also allow students to be in a position to help others if and when the need arises.

Students can carry the scientific dispositions stressed in this unit into many other areas of their lives. Critical thinking and objectivity are essential in weighing the claims of all sides of any issue, scientific or otherwise. They also allow a student to thoughtfully examine his/her own views and the views of others, to search out and analyze the points of disagreement, and to implement any changes needed for the student to construct a consistent, rational outlook on life - a process that eludes subjective thinkers. Finally, those who can work well with others make effective workers as well as managers, and are in high demand in the workplace.

2) Needs of the Society

Our technology-based society is largely dependent on the application of concepts introduced in this unit. Besides electrical power generation, motors, and generators, our society is finding ever more applications of electromagnetic principles. The USA Today Periodical, for example, reports that nuclear magnetic resonator (NMR) spectrometry allows medical personnel to view both living and non-living materials undisturbed and in their natural states (p. 10). The human brain can be more closely scrutinized today than ever before using functional magnetic resonance imaging (fMRI), a technique that measures the response of the brain to a strong, external, magnetic field (Bower, 1995). The impact of electromagnetism on our society is vast and will continue to grow.

The process skills developed in this unit will benefit society as well as the individual student. If problems in our society are to be addressed, people who can think and act are required. This becomes clear when we acknowledge the fact that thinkers, by themselves, accomplish nothing if people remain passive. The process skills encouraged during this unit will help alleviate passivity by giving students the confidence to act as well as think.

As America enters the twenty-first century, dispositions such as objectivity and practicality become more and more essential to the survival of American industry as well as to the health of our political system. While advocates on both the Left and Right push for sweeping and radical changes, the need for observant, objective, logical thinkers/doers is strong. Although science cannot provide the answers to many of society's ailments, dispositions such as intellectual honesty, objectivity, and a cooperative work ethic will be of use in searching out equitable alternatives for the problems we can address. Truly, society needs the dispositions we will foster in this unit.

3) Needs of the Subject Area

Electricity and magnetism are essential not only to physics, but to all scientific disciplines. Much of the high-technology laboratory equipment of any area of science is largely based on the concepts of this unit. Knowledge of the ideas here will aid the scientist in fully understanding his/her equipment, and will help insure that the resulting data will be interpreted correctly and properly analyzed.

Process skills, too, carry over into any scientific field. Understanding the theory behind one's equipment is of little use if one fails to know how to use the apparatus for investigating research questions.

The dispositions taught in this unit will hopefully serve to continue the tradition previously established by science. Most scientists of the past have endeavored to search for the answers to Nature's mysteries in an "as-objective-as-humanly-possible" fashion. Although science would not be the same discipline without a healthy dose of competition, science has also benefited, and will continue to benefit, from healthy doses of cooperation. We hope that the dispositions acquired by the students during this unit will serve to reinforce these traits of the scientific community.

II. RELATIONSHIP OF UNIT TO COURSE CURRICULUM

A. Explicit Year-Long Curriculum

The curriculum for this course, with accompanying concepts and approximate duration of study, is given below.

Unit	Topic	Concepts Taught	Time (weeks)
1	Kinematics	distance/displacement, speed/velocity, acceleration, linear & projectile motion	4
2	Dynamics	Newton's laws of motion, gravity, friction, center of mass, torque, circular/rotary motion	6
3	Momentum/Energy	work, power, kinetic/potential energy, springs, conservation of energy, elastic/inelastic collisions,conservation of momentum	5
4	Electrostatics	electric charge, charge at rest, conductor/insulator,charge transfer, electric field, electric potential,charge distribution, capacitors	4
5	Electric Circuits	moving charge, dry cells, series/parallel circuits, Ohm's law, internal resistance, introduction to a-c	3
6	Magnetism	magnetic materials, domains, magnetic poles, magnetic fields, Earth's magnetic field	2
7	Electromagnetism	E/M relationships, Faraday's Law, Maxwell's Law, induction, Lenz's Law, generators, motors, transformers, electric power	6
8	Optics	refraction, index of refraction, converging/diverging lenses, the microscope, refracting telescope, dispersion by a prism, color of light	6

Total = 36 weeks

Implicit Year-Long Curriculum

The year-long curriculum also entails plans for teaching process skills and dispositions. General plans for integrating these two types of knowledge follow.

1) Process Skills

The skills to be developed throughout the year include how to use a wide range of physics laboratory equipment, how to work in the lab safety, and how to conduct independent studies on scientific questions.

I plan to integrate these skills into the curriculum by having students perform a copious amount of hands-on lab work. Most of the hands-on work will be done in "little labs" that entail the students working with equipment for perhaps 20 minutes at a time for the purpose of learning about the equipment or getting a few bits of data. With "little labs," students will get repeated exposure to the equipment to facilitate process learning, rather than seeing a particular piece of equipment a single time the whole year. "Little labs" may be thought of as student-performed demonstrations." "Big labs" will be done as well. Formal lab reports will be submitted for all "big labs."

Details regarding the safety procedures to be followed throughout the school year are included in Section IX of this unit plan, entitled Safety Considerations. The reader is referred to that section for safety information.

Students will also have the opportunity to conduct several student-designed laboratories throughout the year. Students will be assigned a general goal or task and will work together in teacher-chosen groups. Students will be required to complete the task, submit individual lab reports, and give a group presentation on their efforts and results. Student involvement in all phases of the experimental process is the goal.

There are several reasons why the above skills and methods have been incorporated into the curriculum. First of all, it is my contention that knowing "what" is not enough - one must also know "how." Labs, by helping to illustrate "how", are therefore crucial to the learning process. Safety has been included, not because teachers fear lawsuits, but because life and health are valued by teachers. Repeated practices of safety and conscientious action by the teacher are required. Finally, student-developed labs have been included in the curriculum because they involve completely different cognitive processes than those normally called for in the secondary classroom. Such labs entail a holistic approach to the subject and would require: evaluation of physics theory, determination of an approach and the apparatus that will result in the desired experimental set-up, measurement and data-taking, data manipulation, report writing, and oral presentation. Student-designed labs are the best way to cultivate "big picture" thought processes in an over-analyzed subject.

2) Dispositions

Desired dispositions include careful observation, objectivity, logic, a reliance on evidence, peer cooperation, and an appreciation for the excitement of science.

There are several ways these dispositions will be encouraged. The simplest way is for the teacher to demonstrate and embody these traits himself, which I will make every effort to do. Also, teaching methods such as concept change and constructivism will be used regularly to address student preconceptions and reinforce scientifically-accepted explanations for physical phenomena. These two methods are targeted at all the desired dispositions except that of peer cooperation, which will be addressed with the lab work.

Concept change/constructivism has been chosen with the goal that students will be forced to acknowledge ignorance regarding many concepts in physics. While the destruction of faith in one's own common sense is not the goal, the understanding that gut instinct cannot always be counted on most assuredly is. Inquiry methods, which pose a problem and give students the responsibility of finding a solution, will also be incorporated into the curriculum. In this way, students will come to learn that observation, careful consideration, logic, and persistence are powerful tools when properly used by the scientist.

Peer cooperation will be facilitated through cooperative laboratory work. Cooperative lab work will be structured on the following criteria: all group members achieving the learning goal, individual accountability for learning, and equal opportunity for success. Traditional group work, in which interdependence is absent or minimized, will be de-emphasized. Cooperative labs, as supervised by the teacher, will also encourage social skill development and, since "practice makes perfect," the more lab work, the better. It is hoped that students also understand that they can, potentially, learn more and be more efficient when working as a team than when working alone.

III. UNIT CONTENT OUTLINE

The following is a detailed outline of the explicit curriculum in the Electromagnetism unit.

Electricity and Magnetism Relationships

electrostatic charges, stationary magnets (brief review)

Oersted's experiment, 1820

forces between electric currents and moving magnets

magnetic field

current direction determines magnetic field direction

Ampere's experiment

forces between parallel, current-conducting wires

Ampere's rule for magnetic flux

magnetic flux density and total magnetic flux

solenoids

Ampere's rule for solenoids

affect of core materials - permeability

the galvanometer

how a galvanometer works

adapt to make a d-c voltmeter

adapt to make a d-c ammeter

Electromagnetic Induction

Michael Faraday and Joseph Henry, 1832

E and M fields, not V and I, are induced

occurs regardless of medium

due to changing magnetic flux

relative motion (perpendicular) of conductor and magnet

Faraday's Law

Maxwell's Law

factors affecting induction

speed of relative motion

direction of motion

strength of magnetic field

Lenz's Law

closed circuits

conservation of energy

Generators

converts mechanical energy to electrical energy

elements

armature

slip rings and brushes

field magnet

commutator for d-c circuits

alternating current and emf

stator and rotor

increasing generator output

increase armature turns

increase magnetic field strength

Motors

Michael Faraday, 1821

converts electrical energy into mechanical energy

current is supplied to conductor

wire moves due to magnetic force

commutator to keep armature spinning the same way

groups of coils

Transformers

Joseph Henry, 1838

elements

primary and secondary coils

iron core

a-c current

varying numbers of windings

C. step-up/step-down transformers

Lenz's Law

energy losses

Electric Power

3-phase generators

armature connected to steam-powered turbine

nuclear or fossil fuel

water

power transmission

heat losses in wires

step-up transformers outside generating plant

step-down transformers in the city

step-down transformers in the neighborhood

60 Hz a-c for residential use

power plant efficiency

IV. MAJOR OBJECTIVES

By the end of this instructional unit, the student will be able to demonstrate the following objectives in writing, and under test conditions, unless otherwise specified.

Content Knowledge Objectives

Given the direction of the current and the shape of a current-carrying conductor such as a straight wire or a solenoid, sketch the configuration and direction of the induced magnetic field around the conductor.

Given the direction of the current in a conductor and the location and direction of the magnetic field, explain the induced magnetic force in terms of the direction of the force and what materials are affected by the force.

List two factors that affect the magnitude of a current induced by moving a conductor through a magnetic field.

Explain how a galvanometer works using terms such as permanent magnet, pointer, pivot, coil, control spring, induced magnetic field, and magnitude of allowable current.

Explain Lenz's Law in terms of the types of circuits to which it applies, the direction of the induced current and the resulting force from that current, and how the Law is related to the idea of conservation of energy.

Describe an electric generator using terms such as mechanical energy, electrical energy, armature, slip ring, and field magnet.

Describe an electric motor using terms such as mechanical energy, electrical energy, armature, slip ring, and field magnet.

Explain how a transformer conforms to the idea of the conservation of energy.

List three fuel sources commonly used to produce electric power today.

Explain why the long-distance transmission of electric power is done using very high voltages by using the terms transformer, current, heat loss, and efficiency.

Process Skill Objectives

Demonstrate electrical safety in the laboratory by performing the following behaviors during a laboratory test: check for damp hands or a wet floor, turning off and unplugging electrical/magnetic equipment when adjusting apparatus, and keeping one hand behind back at all times.

Given an input a-c current or voltage, sufficient wire, and a magnetic iron core, produce a transformer that will theoretically provide a given output current or voltage.

Initiate and carry out one experiment using the scientific method by identifying a problem, determining an approach and appropriate apparatus, proposing an hypothesis, setting up the apparatus, measuring and recording the observed data, and drawing a logical conclusion from the gathered data.

Disposition Objectives

Given a complete description of an occurrence, analyze the situation, distinguishing clearly between observation and inference, and write an hypothesis as a possible explanation for the occurrence.

Under anonymous conditions, write a one-page essay on what you liked/disliked in this instructional unit, what changes could be incorporated that would better serve your needs, and how the studies in this unit changed or did not change your appreciation and knowledge of science and E/M technology.

V. ALTERNATIVE CONCEPTIONS

No alternative conceptions dealing with electromagnetism have been documented to date in Dorothy Gabel's Handbook of Research on Science Teaching and Learning (1994). Although its contents do not apply specifically to this plan, the title page from the Handbook and the section on alternative conceptions in physics has been photocopied and included in the hard copy of this report. Gabel's compilation has also been cited in Section XIV, References. The reader is referred to Gabel's work for additional information on preconceptions in the area of physics.

Although Gabel's work does not list any preconceptions regarding electromagnetism, preconceptions in this content area are almost certainly prevalent among high school students and the general public. While it is probably true that perhaps 25% of American adults have the vague notion that electricity and magnetism are related, it is almost certainly equally true that less than 1% are aware of the most basic concepts relating E and M. One place to start addressing "E/M ignorance" is the high school physics classroom, and we intend to do so during this unit.

CLASSROOM METHODS

A. See the appendix of this unit plan for a copy of the title page from the following work on physics teaching:

Arons, A. B. (1990). A Guide to Introductory Physics Teaching. New York, NY: John Wiley & Sons.

This text was used in the preparation of this plan, as demonstrated in the following section.

B. The chapter of Arons' book that relates to this unit plan is Chapter 8: Electromagnetism. A brief summary of each section of that chapter follows.

Chapter 8: Electromagnetism

Introduction

When teaching electromagnetism, Arons emphasizes that physics teachers distinguish clearly between electric and magnetic phenomena, since students often confuse the two. Without a basic understanding of the differences, electromagnetism makes little sense to the average high school student. Once the basics are addressed, Arons suggests that students will gain a lasting impression of electromagnetism only by a large number of visual and hands-on experiences. These experiences take time to become embedded in the memory of a student, and the teacher should not expect immediate comprehension of the concepts.

Oersted's Experiment

Oersted's experiment has to do with the magnetic effect of a current-carrying wire. Arons suggests that this experiment is very worthwhile for students, who should be allowed to observe what happens to a compass needle at various positions around the wire and for different currents and resistances. Arons says that the teacher should stress the idea that the force on the compass acts perpendicular to a radial line from the current-carrying wire, unlike other forces encountered up to this point, which have been co-linear.

Forces Between Magnets and Current-Carrying Conductors

In this section, Arons suggests that students should be made aware that not only are forces exerted on the compass in Oersted's experiment, but that forces are exerted on the wire as well. In demonstrations of the interaction between magnets and current-carrying conductors, the observations should clearly be linked to the Oersted effect, with which students are already familiar. Arons also proposes that students be allowed to feel the tug on the wire, instead of to merely see it. A final useful idea would be for the teacher to give a demonstration of the interaction of a magnet with a current-carrying electrolyte such as copper sulfate solution, and using wood filings to allow visual understanding of the phenomenon.

Ampere's Experiment

Ampere's experiment deals with the interaction between two parallel current-carrying conductors. As we know, if the currents are traveling in the same direction, the wires are attracted, and the wires are repelled if the currents are traveling in opposite directions. Arons notes that it is important for teachers to identify this effect as an electromagnetic one instead of merely an electrostatic one. Some points for making this argument are as follows: 1) the effect is dynamic because the effect is gone as soon as the circuit is broken, 2) when similarly charged ends are adjacent, the result is attraction, unlike with electrostatics, 3) if the two wires make contact, they remain in contact, unlike electrostatic charges which eventually wear off, and 4) if 3 wires are used, they all attract, which could never happen if the effect was an electrostatic one.

Mnemonics and the Computer

Arons advocates a certain amount of drill work in order that students master rules such as the right-hand rule for the Oersted effect and the left-hand rule for Faraday's law of electromagnetic induction. Arons sees the computer as an excellent tool in this regard. He also states that students should be required to draw pictures to represent their answers because having to put something down on paper is much different than simply saying aloud the words that sound right.

Faraday's Law in a Multiply Connected Region

This demonstration involves a long solenoid with two light bulbs. When one bulb is short-circuited, students expect both bulbs to go out, but only the one goes out, while the other burns more brightly. Students must think through what happens to the change in flux through the various connections of the loop system. This would make a fine demonstration for either a concept change/constructivist lesson or an inquiry lesson.

Faraday's Criticism of Action at a Distance

In this section, Arons discusses a bit of scientific history. Michael Faraday, an English scientist, laid the basis for the concept of a "field", and this concept was elaborated upon mathematically by James Clerk Maxwell. Although he was a brilliant scientist, Faraday lacked formal training in the abstract language of analysis (i.e., the calculus), and preferred to interpret his observations and formulate concepts in geometrical and physical terms. Faraday also wrestled with the crucial question of whether finite time intervals were required for the propagation of electric and magnetic effects, which was settled conclusively in the positive by Heinrich Hertz in 1887. Arons continues this brief history of scientific endeavor in the next section.

Infancy of the "Field" Concept

Here, Arons discusses briefly the contributions of Faraday, Thomsen, and Maxwell to our understanding of the "field" concept, in general, and to electromagnetic "fields", in particular. It outlines the gradual shift in paradigm from the "action at a distance" idea to the present era of field theories, which was essentially complete by the end of the nineteenth century. Although a history of Faraday and other outstanding physicists is not necessarily correlated to increases in content knowledge, a little history in the physics classroom can serve to show students "where this stuff comes from" as well as be a welcome break from the normal routine of the classroom.

Laboratory Measurement of a Value of B

Arons suggests that students engage in this activity for the sake of the measurement itself. This is most easily done by making a direct measurement of the force on a current-carrying wire in a magnetic field and calculating B from F/(IL). Arons justifies his suggestion by stating that students have no feel for the magnitude of B, and goes so far as to say that some students doubt the reality of B numbers. Arons also recommends that the set-up for such a measurement should be simple and variable such that the angle between the field and the wire can be altered. Arons claims that students have a much better feeling for the meaning of B once this investigation has been performed.

C. Lesson Plans

Three, 30-minute, idealized lesson plans that may be used during the course of this unit plan are presented below.

---

1) Concept Change / Constructivist Lesson (5E version)

Department: Science Course: Physics I

Unit: Electromagnetism Concept: Relatedness of E & M

OBJECTIVE: Show that electricity and magnetism are related by citing and describing: 1) at least one example in which an electric current influences a magnet, and 2) at least one example in which a magnet influences an electric current.

CONTENT

Knowledge

an electric current produces a magnetic field

deviation of a compass in or near solenoid

iron filings on a glass sheet

the greater the current, the greater the strength of magnetic field

the direction of the current determines the direction of the field

a changing magnetic field induces an electric current

putting magnet into solenoid

the faster the change, the greater the induced current

the direction of the change determines the direction of the current

Process Skills

hypothesizing: "What would happen if we...?"

experimentation

trying out hypotheses

trying out variations on a hypothesis

observation

objectively determining "what happened"

honesty

recording

recording experimental conditions

systematic records of experimental successes and failures

conclusions

drawing logical conclusion, if any, from recorded data

honesty if no conclusion can be stated

INSTRUCTIONAL ACTIVITIES

(0) 1. Have all materials set out on table before lesson begins.

(5) 2. Begin by introducing new unit, Electricity and Magnetism. Ask students what kind of experiences they have had with electricity. Ask for examples. Ask students what kind of experiences they have had with magnetism. Ask for examples.

(5) 3. Continue questioning. Do the overhead electrical wires ever stick to, say, the garbage truck? Have you ever received an electric shock from a refrigerator magnet? Have you personally witnessed any demonstrable relationship between E and M? So why are electricity and magnetism lumped together in this unit? Are they both equally unimportant and so we lump them together to finish faster and get on to more important topics in physics? Suggest that there may be no relationship between E and M.

(2) 4. Have students come up to table where equipment is located. Tell them that this electrical and magnetic equipment is to be used to determine if any relationship exists between electricity and magnetism.

(16) 5. Observe students closely as they work with equipment. Stress safety. Cue students with hints, if needed. Teacher's activities will depend largely on procedures of students. Make sure that trials get recorded in some way.

(0) 6. If time is left, query students about rate of change of magnetic field and its direction, magnitude and direction of current, number of coils in solenoid, shape of magnetic field.

(2) 7. With 2 minutes left, state that there is, indeed, a relationship between E and M. The interaction of the two will be examined in the next couple of weeks. Practical examples of E/M interaction are motors, generators, and transformers. We will look at these topics in detail as the unit progresses.

(30)

MATERIALS: 2 refrigerator magnets, 3 bar magnets, 2 compasses, 2 solenoids, 6V/20A power supply and wires, galvanometer, iron filings, bent wires in wood frames.

STUDENTS WITH SPECIAL NEEDS: None.

SOURCES:

Trinklein, Frederick E. Modern Physics. (Austin, TX: Holt, Rinehart and Winston, Inc.). 1990.

---

2) Inquiry-based Learning Lesson

Department: Science Course: Physics I

Unit: Electromagnetism Concept: Magnetic Force

OBJECTIVE: Describe the magnetic force by explaining, given the direction of two of the following (F, I, B), how to predict the direction of the third vector using the right-hand rule.

CONTENT

Knowledge

an electric current through a straight conductor produces a magnetic field

shape is concentric cylinders around conductor

direction follows right-hand rule, with thumb in direction of current

parallel conductors carrying parallel currents attract

not due to electrostatics

magnetic force

mutually perpendicular to both I and B

direction follows right hand rule, with thumb in direction of force

parallel conductors carrying anti-parallel currents repel

Process Skills

1. observation

What happened in parallel-conductor apparatus?

What were the conditions under which it happened?

experimentation

investigation of shape of B field around a straight conductor

investigation of direction of B field around a straight conductor

How can we figure these out?

INSTRUCTIONAL ACTIVITIES

(0) 1. Have all materials set out on table before lesson begins.

(1) 2. Begin by stating that last time we found out that there does exist a relationship between E and M, and that today we are going to continue our discussion of that topic.

(4) 3. Demonstrate the parallel-currents apparatus. Ask students what happened? What were conditions? Why did this happen? Does electrostatics have anything to do with it? From last time, does the current through each wire set up a B field around that conductor? Cue until students answer yes.

(5) 4. Ask students what B field around a straight conductor looks like. Have students investigate configuration and direction of B field around straight conductor using "transparency" conductors, iron filings, and compass.

(5) 5. Go back to parallel-current apparatus. Ask students if there was a force between those wires and how they know. Ask students in what direction the force was acting. What direction was the current going? What direction is the B field directed around a given wire? Ask students to identify the relative directions of F, I, and B. Cue, if necessary, until students say mutually perpendicular.

(5) 6. Introduce right-hand rule for finding direction of F. Introduce the relation F = qv x B and show how it relates to right-hand rule. Demonstrate on chalkboard how right-hand rule can be used to predict movement of wires in parallel-conductor apparatus.

(4) 7. Using transformer and hanging wire, show how currents in opposite directions result in forces that repel. Ask student to explain this phenomenon using right-hand rule.

(4) 8. Evaluate students using the C-magnet and swinging conductor apparatus. Ask them examine apparatus and then predict which way the conductor will swing. Turn on current to show students correct answer. Conduct another explanation, if necessary.

(2) 9. Close by stating that today we learned about the directional relationship between F, I, and B and state that this information will prove useful in our future studies of generators and motors.

(30)

MATERIALS: transformer, parallel-current apparatus, "transparency" conductors and iron filings, compass, C-magnet and swinging conductor apparatus, necessary wires

STUDENTS WITH SPECIAL NEEDS: None.

SOURCES:

Trinklein, Frederick E. Modern Physics. (Austin, TX: Holt, Rinehart and Winston, Inc.). 1990.

---

3) Cooperative Learning Lesson (Learning Together model)

Department: Science Course: Physics I

Unit: Electromagnetism Concept: Electric Power

OBJECTIVE: Gain an understanding of how electromagnetism can be applied to a practical situation and develop an elementary awareness of how various disciplines relate to one another in a "real" world context.

CONTENT

PIGS-Face Cooperative Learning model (Johnson & Johnson)

positive interdependence - ensure that all group members learn the material

students individually quizzed over their team's project

average score of group is small component of each student's individual grade

individual accountability - everyone must participate

quiz (see above)

log form to record each individual's actions on a daily basis

teacher observations

group members evaluate themselves at the conclusion of the project

group processing - reflect upon what was done

what worked, what didn't

social skills - one person cannot complete the project in four weeks

must rely on team members to pull their portions of the load

teacher observation - if any conflict is detected, we will work it out immediately

face-to-face interaction - we will work in our groups during class off and on

see also Part 4 above

Project

types of power plants - find advantages and disadvantages

petroleum-fired, coal-powered, hydroelectric, nuclear

large-scale electric generator: terms

turbine, steam, stator, rotor, exciter

electric power transmission

transformers, power losses due to heat, land availability, natural obstacles/weather hazards

significant issues related to various groups

power company, local residents, facility designers, electric consumers, state governments, environmentalists

other disciplines involved

accounting, agriculture, biology, carpentry, civics/government, economics, English, foreign language, geology, history, psychology, speech communication, welding

INSTRUCTIONAL ACTIVITIES

(0) 1. Have all materials set out on table before lesson begins.

(1) 2. Begin by stating that we have talking extensively about the theories of electricity and magnetism. Today, we are going to begin investigating a practical application of electricity and magnetism, as well as begin to gain an understanding of how the various educational disciplines interrelate in the "real" world.

(4) 3. Explain that this class project will be completed by cooperative groups. Give brief lecture on the PIGS-Face Cooperative Learning model and how each facet of that model will apply to this project.

(2) 4. Hand out the project sheets and go over the sheet with the students. State that although each group will submit its own project, today we will work as one large cooperative group in order to get all groups off on the right foot.

(1) 5. Hand out the group task sheets, state that textbooks are available at the front to aid the students.

(12) 6. Have students work on group tasks. Monitor class closely and answer questions as needed. Be sure all group members are participating and staying on task.

(3) 7. Have each group find interdisciplinary relationships for the project.

(6) 8. Discuss briefly the results the groups came up with. Write results on the board as the students state them. Remind groups that these ideas may be ones that they wish in incorporate in their projects.

(1) 9. Close by stating that this project will allow us to study a practical application of E/M and to touch briefly on the interrelationship of all types of knowledge.

(30)

MATERIALS: project sheet handouts, group work handouts, assorted physics textbooks for reference

STUDENTS WITH SPECIAL NEEDS: None.

SOURCES:

Trinklein, Frederick E. Modern Physics. (Austin, TX: Holt, Rinehart and Winston, Inc.). 1990.

---

PROJECT SHEET HANDOUT

Problem: In light of current electrical energy needs and projected industrial growth, it has been determined that within the next 15 years a large, new power plant will be needed to provide electric power to both the St. Louis and Memphis metropolitan areas.

Task: The tasks involved in this project are as follows:

identify the pros and cons of various types of power plants, choose one type of plant for the project, and justify your choice in a 3-page paper

explain, in a 3-page paper (not including diagrams) how a large-scale electric generator works

explain, in a 2-page paper, how electromagnetism is involved in the transmission of electric power from the power plant to the consumer

cite and explain significant issues related to this project that are of interest to: the power company, local residents, the facility designers, electric consumers, the state governments of the affected locales, and environmentalists

list at least one example of how each of the following areas will affect or be affected by the planning, design, construction, and/or operation of this power facility: accounting, agriculture, biology, carpentry, civics/government, economics, English, foreign language, geology, history, psychology, speech communication, and welding.

Purpose: The purpose of this cooperative project is to relate the concepts we have learned in physics to practical, real-world applications. We will also gain a basic understanding of how the various educational disciplines come into play when we address a true-to-life situation.

GROUP 1 TASKS

Describe each of the following types of power plants as completely as you can in the time allotted: petroleum-powered plant, coal-fired plant, hydroelectric plant, nuclear power plant. You may want to consider such factors as initial vs. maintenance costs, pollution, availability of fuel resource, public perception, and anything else you can think of.

Define the following terms and explain their purpose in a large-scale electric generator: turbine, steam, stator, rotor, exciter.

GROUP 2 TASKS

List factors that need to be considered in the long-distance transmission of electric power. Include in your list such items as transformers, efficiency of transmission, land availability, natural obstacles/weather hazards.

List factors that need to be considered as electric power is carried to individual consumers. Include in your list such items as transformers, customer service considerations, line repair/maintenance, and customer billing.

VII. DEMONSTRATIONS

Most of the demonstrations in this electromagnetism unit have to do with electrical current. Precautions taken to minimize the possibility of injury due to electrical shock have been listed above, and the reader is referred to those measures. Demonstrations for which electrical hazard is the sole safety consideration are assumed to be demonstrations C-P and R, and no further comment on safety is made here for those demos. There are several demonstrations, however, which require some attention to safety other than electrical safety.

Demonstrations A and Q involve the use of iron filings. Filings could be hazardous if they managed to find their way into a student's eye. As such, the teacher will be the only person handling the iron filings.

Demonstration B involves the use of a nail, which could cause problems if the point touched a student's clothing or body. The teacher will be sure to cut the sharp point off the nail before using this demonstration.

Demonstration S involves a motor, which will be somewhat heavy. The teacher will ensure that the motor is placed on a strong table and is not moved during the course of the class period. The rule about keeping fingers away from strong magnets to avoid smashing or pinching applies here as well.

The demonstrations to be included during the course of this unit are as follows:

MAJOR DEMONSTRATIONS

A. 3-D views of magnetic effects

Purpose: to show the 3-D shape of magnetic field

Procedure: a magnet is covered with several layers of glass; iron filings are sprinkled on the various layers to create a 3-D magnetic field effect

Source: Miller, Phillip E. A Potpourri of Physics Teaching Ideas. College Park, MD: American Association of Physics Teachers. 163.

B. magnetic field strength as affected by permeability of core

Purpose: to show how permeability of core affects magnetic field strength

Procedure: make a current-carrying solenoid; observe effect on compass at a given distance with nothing in solenoid core; repeat after inserting large nail into core

Source: Physics Handbook. Albany, NY: The University of the State of New York/The State Education Department Bureau of Secondary Curriculum Development. 1970. 127.

C. strength of an electromagnet

Purpose: to show how electromagnetic strength is affected by number of coils, magnitude of current, and length of wire used in coils

Procedure: make various solenoids: one with 25 turns, one with 50 turns using 2X the length of wire, one of smaller diameter with 25 turns, one of smaller diameter with 50 turns; see how the number of paper clips picked up by magnet is affected by different solenoids and different currents

Source: Physics Handbook. Albany, NY: The University of the State of New York/The State Education Department Bureau of Secondary Curriculum Development. 1970. 128.

D. magnetic field around a coil of wire

Purpose: to show the magnetic field pattern created around a short solenoid

Procedure: make 2 solenoids using Dixie cups as "templates": one with 20 turns, other with 100 turns; using a magnetized paper clip, map the lines of the magnetic field, noting the differences between the 20- and 100-turn coils; see if the lines of force form complete loops

Source: Edge, R. D. String & Sticky Tape Experiments. College Park, MD: American Association of Physics Teachers. 1987. 12.01.

E. force on a stiff wire in a magnetic field

Purpose: to show the presence and direction of force on current-carrying conductor in a magnetic field

Procedure: attach C-magnet to ring stand such that B field is oriented vertically; have conductor running horizontally through B field; show that a force exists when current is flowing; show the direction of the force using the right-hand rule

Source: Physics Handbook. Albany, NY: The University of the State of New York/The State Education Department Bureau of Secondary Curriculum Development. 1970. 130.

F. force on current-carrying aluminum foil

Purpose: to show direction of force on current-carrying Al foil in magnetic field

Procedure: set up three horseshoe magnets on table such that magnets are straddling a long, thin strip of Al foil and so poles of magnets are equidistant from strip; run current through foil and see how foil responds to magnetic force

Source: Siddons, J. C. A Potpourri of Physics Teaching Ideas. College Park, MD: American Association of Physics Teachers. 156.

G. forces between parallel conductors

Purpose: to show the direction of the magnetic force that exists between two parallel conductors

Procedure: use battery as power source; connect strip of Al foil to terminals and hang Al over table such that the strip of foil acts as two parallel conductors close together; repeat, but attach another strip of foil so that parallel conductors contain current in same direction; show how direction of current for each case determines the direction of the magnetic force

Source: Edge, R. D. String & Sticky Tape Experiments. College Park, MD: American Association of Physics Teachers. 1987. 12.07.

H. induced voltages using simple compass

Purpose: to show how relative motion of a magnet and a conductor will generate a current in the conductor

Procedure: make 2 coils of 50 turns each, connected in series; place a compass inside one of the coils and insert strong magnet into other, then remove

Source: Physics Handbook. Albany, NY: The University of the State of New York/The State Education Department Bureau of Secondary Curriculum Development. 1970. 136.

I. induction and motion of current-carrying conductor in magnetic field

Purpose: to show how relative motion between magnet and conductor produce a current which, in the presence of a magnet produces motion; Lenz's Law

Procedure: using one thin wire, make a complete circuit containing two coils; support circuit on ring stand with one pole of horseshoe magnet through each coil (two magnets needed); start one coil swinging - other coil will begin swinging and first one will stop

Source: Physics Handbook. Albany, NY: The University of the State of New York/The State Education Department Bureau of Secondary Curriculum Development. 1970. 136-137.

J. mutual inductance

Purpose: to show how a changing current induces a current in an adjacent conductor

Procedure: make two coils of wire, attach one to d-c power supply and other to galvanometer; place coils face to face, as close as possible; switch power supply on and off while observing galvanometer

Source: Edge, R. D. String & Sticky Tape Experiments. College Park, MD: American Association of Physics Teachers. 1987. 12.05.

K. eddy currents and Lenz's Law

Purpose: to illustrate Lenz's Law

Procedure: support an aluminum pie tin using a vertical nail at the tin's center; hang a strong horseshoe magnet so that it clears the tin by º"; wind up magnet on string and release; tin will spin in same direction as magnet

Source: Physics Handbook. Albany, NY: The University of the State of New York/The State Education Department Bureau of Secondary Curriculum Development. 1970. 138.

L. eddy currents and magnetic brake

Purpose: another example of Lenz's Law

Procedure: support a strip of sheet aluminum at one end so it can swing like a pendulum; as it swings, place a strong alnico magnet so that B field is cut by Al; Al will slow very quickly and stop

Source: Physics Handbook. Albany, NY: The University of the State of New York/The State Education Department Bureau of Secondary Curriculum Development. 1970. 139.

M. generators and Lenz's Law

Purpose: to show the relationship between generators and motors; to show the energy losses in the generator/motor system

Procedure: couple two small motors together using a rubber band; can have one motor run the other as a generator; generator can support flashlight lamp; use ammeter and voltmeter to measure power input and output; emphasize energy transformations and losses

Source: Physics Handbook. Albany, NY: The University of the State of New York/The State Education Department Bureau of Secondary Curriculum Development. 1970. 139.

N. transformer demonstration

Purpose: to illustrate principles of a transformer

Procedure: connect primary coil of transformer to a-c source; have second wire with small bulb attached; wind second wire around core so that it becomes secondary coil; bulb will get brighter with each turn of secondary coil

Source: Siddons, J. C. A Potpourri of Physics Teaching Ideas. College Park, MD: American Association of Physics Teachers. 151.

MINOR DEMONSTRATIONS

O. Oersted effect on the overhead

Purpose: to show how compass needle is deflected when placed near a current-carrying conductor

Procedure: mount straight conductor and compass on clear, insulated base; place apparatus on overhead; observe compass needle as current is turned on

Source: Siddons, J. C. A Potpourri of Physics Teaching Ideas. College Park, MD: American Association of Physics Teachers. 140.

P. forces between parallel currents on the overhead

Purpose: to show how currents in parallel conductors affect direction of magnetic force

Procedure: mount parallel conductors on clear, insulated base; place apparatus on overhead; observe conductors as direction and magnitude of current is altered

Source: Siddons, J. C. A Potpourri of Physics Teaching Ideas. College Park, MD: American Association of Physics Teachers. 144.

Q. magnetic field around current-carrying conductor (using compass, using Fe filings)

Purpose: to show the geometry of the magnetic field around a current-carrying conductor

Procedure: hang wire vertically through small hole in a card; move compass around conductor; sprinkle iron filings on card to see field geometry; can tie in to Ampere's rule for direction of magnetic flux

Source: Physics Handbook. Albany, NY: The University of the State of New York/The State Education Department Bureau of Secondary Curriculum Development. 1970. 127.

R. magnetic induction

Purpose: to show how relative motion of a magnet and a conductor will generate a current in the conductor

Procedure: make a solenoid out of copper wire, hook up to galvanometer, and alternately insert and remove bar magnet

Source: Edge, R. D. String & Sticky Tape Experiments. College Park, MD: American Association of Physics Teachers. 1987. 12.04.

S. d-c generator

Purpose: to illustrate the important features of generators

Procedure: obtain an old "St. Louis"-type motor that can be dissected; can connect galvanometer to brushes and spin armature with fingers; point out slip rings, commutator; explain how generator works, nature of current

Source: Physics Handbook. Albany, NY: The University of the State of New York/The State Education Department Bureau of Secondary Curriculum Development. 1970. 139.

T. motors and generators

Purpose: to show the relationship between generators and motors

Procedure: connect two identical galvanometers together with a long length of wire; jiggle one galvanometer and other reads a current; explain mechanical and electrical energy transformations

Source: Siddons, J. C. A Potpourri of Physics Teaching Ideas. College Park, MD: American Association of Physics Teachers. 144.

VIII. LABORATORY ACTIVITIES

Three significant laboratory activities are listed below. Activities A and B have been taken from Cunningham, 1994 (see Section XIV, References), while Activity C is student-directed lab created by this author.

A Simple DC Motor

Purpose: for students to learn about the DC motor by building a simple one from common materials

Procedures: The materials needed for each setup of this lab include a wooden base (roughly 8" x 2" x "), four long nails, two short nails, a test tube, a 6-volt emf source, speaker wire, copper foil, and a blob of clay (roughly 1 in3). Each lab group should be supplied with the above materials and should construct a simple DC motor, as shown below. The following is taken from Cunningham (1994), page 629.

image to be inserted

This lab will serve not only to give students some practical experience in working with motors, but can serve as an excellent way to learn about components of a DC motor, such as the field magnet, commutator, brushes, current source, armature, and rotor. One idea for helping to ensure that students obtain benefit from the lab is to have the students make the motors during one class period, store the motors, and have students bring them out several times over the next week to illustrate points made it lecture or to gain a visual understanding of what is happening in a problem that students are working on.

Source: Cunningham, James and Norman Herr. (1994). Hands-On Physics Activities with Real-Life Applications. West Nyack, NY: Center for Applied Research in Education. Pp. 628-629.

Mutual Inductance and Transformers

Purpose: for students to learn about the transformer by: 1) building a simple one from common materials, and 2) by taking quantitative measurements

Procedures: The materials required for each lab setup include a 6 volt emf source, large nail, insulated copper wire, voltmeter, galvanometer or milliammeter, and a strong bar magnet. Wrap one wire of 50 turns around nail and wrap the other wire of 10 turns around the same nail. Attach voltmeter to leads of one wire and emf source to leads of other wire. The figure below was taken from Cunningham (1994), page 631.

image to be inserted

Replace voltmeter with milliammeter. Swap the leads to the emf source and the measuring device. Observe under what conditions voltage/current is induced and what arrangement of equipment and wires leads to maximum and minimum values. Additionally, students can simulate an a-c transformer by constructing a solenoid which is attached to the leads of one of the wires on the nail and moving a bar magnet in and out of the coils. The voltmeter and milliammeter can be used to investigate this situation as well.

Source: Cunningham, James and Norman Herr. (1994). Hands-On Physics Activities with Real-Life Applications. West Nyack, NY: Center for Applied Research in Education. Pp. 630-631.

Energy Transformations

Purpose: to illustrate that, although total energy is always conserved, there exist energy losses in any energy transformation

Procedures: Groups of 3-4 students will be given general goals and will be allowed to formulate plans, approved by the teacher, for achieving the goals. One goal will be to determine whether usable energy is conserved by a transformer. Another goal, which could be given to other groups, will be to determine whether usable energy is conserved by generators or motors. The teacher will be available for consultation, but will be stingy in "giving out answers." The students will instead be counter-questioned by the teacher and then will be directed to possible sources for obtaining their own answers. The teacher will ensure that all groups have formulated a plan, are making progress, and are conducting activities in a safe manner. A formal laboratory report and a group presentation will be required at the conclusion of the activity.

Source: none.

IX. SAFETY CONSIDERATIONS

The following works were consulted in the construction of this portion of the unit plan:

Safety in the Secondary Science Classroom. (1978). Washington, D. C.: National Science Teachers Association.

Peterson, Richard W. (1978). Teaching Physics Safely. College Park, MD: American Association of Physics Teachers.

The reader is referred to the above documents for additional information.

A. General Safety Responsibilities of Various School Officials

1) Principal

The safety responsibilities of the principal center around the facilities of the school building, classroom, and laboratory. The principal is charged with ensuring that all utilities such as electricity, water, and natural gas are available and that the equipment for each, including a master shut-off, is working properly. The physical layout of the facilities is another responsibility of the principal. Physical layout includes such things as providing the required amount of work space, sufficient and well-labeled exits, and enough space for storage of laboratory equipment. The final duty of the principal deals with major items of lab safety, such as a functioning hood, fire extinguishers, and eye and body showers in properly working order.

2) Science Department Chairperson

The science department chairperson has responsibilities in the science lab as well. The chair's "people" duties include holding quarterly meetings with science staff to stress lab safety and encourage teachers to rehearse labs beforehand to identify any safety hazards, as well as to ensure that no non-science instructors are teaching science. The chairperson is also responsible for informing the principal, in writing, about any defective laboratory equipment or furniture. Finally, the chairperson is directly involved with lab safety. Responsibilities falling under this heading include locking up all dangerous materials; keeping a stocked first aid kit in every lab; inspecting hardware and equipment and recording dates of inspection and observations; and ensuring that metal or ceramic waste containers are present in labs and in classrooms in which scientific demonstrations are performed.

3) Science Teacher

The first responsibility of the science teacher with regard to lab safety is to instruct students about general and specific lab safety procedures. The teacher should give students a set of lab safety rules and should post them at several locations in the lab. Rules listed should include instructions for: eye and face protection, fire hazards, use of fire extinguishers and blankets, the fume hood, handling of lab animals, and handling of radioactive materials. The teacher must also remind students of the applicable safety rules before all class periods which may entail danger to the students.

B. Safety During the Electromagnetism Unit

During this unit, safety will be stressed at all times. Students will be required to sign an unofficial contract at the outset of the year. The contract will list safety rules as well as regulations and consequences for safety violations. Safety rules will be posted in the classroom and in the laboratory. Safety issues will be explicitly stated before all lab work. In addition, safety concerns will briefly be mentioned before teacher-conducted demonstrations, even though students are not involved. Consistent mention of safety should serve to inculcate an awareness of safety.

Potential sources of danger in this unit center around the possibility of electric shock and the chance of injury due to mechanical means. Electric hazards will be minimized by informing the students of electrical safety issues such as the effect of electrical current on the human body; broken or damp skin; and wet floor. In addition, students will be instructed to turn off and unplug equipment before adjusting, to approach all circuits with the back of the hand and have the other hand behind the back, and to immediately cease activity and inform the teacher if equipment appears to be damaged or a cord is frayed. Finally, students will be repeatedly instructed to never walk away from a current-carrying electrical circuit for any reason. Although we will not use magnets that are large enough to pose a genuine threat to safety, large magnets can result in pinched skin or smashed fingers. Students will be instructed to handle magnets with care and to keep fingers away from poles of magnets. A final safety tip that will be stressed throughout the unit is that students should be sure to not leave any E/M apparatus "on", or any current running, for sustained time periods. Neglect of this rule could result in overheating of conductors and/or equipment, with the possible result of bodily injury or damage to laboratory equipment.

C. Dangers Associated with Classroom Demonstrations and Laboratory Activities (see Sections VII and VIII above)

General safety precautions, other than precautions taken to maximize electrical safety, include precautions to prevent mechanical injury. Such precautions include ensuring that desks and tables are sufficiently sturdy and insulated, and being careful not to drop any object which could cause bodily harm.

The same safety considerations mentioned above regarding electricity apply to the laboratory activities. Although the activities require only low-voltage/low-amperage circuits, the teacher will work to ensure that the safety rules are strictly adhered to by the students. Laboratory A also poses the threat of using nails, hammers, and the fine threads of speaker wire, which are potentially dangerous. Students will be warned against the possible dangers of these materials and will be closely supervised throughout the activity. The teacher will make no attempt, however, to construct the items in Labs A or B for the students because construction of the devices by the students themselves is integral to the learning process. The teacher will, however, do everything possible to ensure safe handling of these common, but theoretically dangerous, materials.

Laboratory C will have varying safety considerations, depending upon how the students opt to achieve the goals. Let it be said that the principles previously stated about electricity, magnetism, and heavy and sharp objects apply to this activity as well. Besides closely supervising the activities of the students, the teacher will have the chance to nip any safety hazards in the bud by requiring that students get a plan of action approved before beginning their work.

X. SPECIAL STUDENT NEEDS

A. Student with Disability: Cerebral Palsy (see Woolfolk, 1995)

Cerebral palsy is a ""condition involving a range of motor or coordination difficulties due to brain damage" (p. 131). The condition is caused when the brain is damaged before or during birth, and can result in a great diversity of results. Mild cases may result in a student simply appearing somewhat clumsy, whereas severe cases may cause a student to have almost no control over voluntary movement. While some students with cerebral palsy experience secondary handicaps such as mild mental retardation or hearing impairments, we will consider here primarily the actions required for a student with motor coordination difficulty.

B. Potential Handicaps in the Physics Classroom

Several handicaps that a student with cerebral palsy might experience in the physics classroom are difficulty taking notes, completing written assignments, manipulating laboratory equipment, seeing teacher-performed demonstrations, participating in discussions and student presentations, and reading the textbook.

A student with cerebral palsy may have difficulty taking notes and completing written assignments if his/her fine motor skills are underdeveloped. If accommodation is not made for this potential handicap, the student will be unable to learn the lecture material and will receive few, if any, points for written homework assignments. In short, the failure to accommodate such a student will probably result in the student failing the course.

Because the laboratory work in this unit involves fine motor skills, a student with cerebral palsy may have difficulty being an active participant in lab activities. Failure to accommodate this handicap would result in the student being denied the real-world, kinesthetic, hands-on portion of the unit. As a result, the student would fail to understand fully the physical meaning of electromagnetism, which is of primary importance.

Because students with cerebral palsy are sometimes confined to wheelchairs, they may have difficulty viewing some demonstrations. Along with labs, demonstrations are a focal point of this unit, and the inability to view demonstrations would severely stifle the student's interest and excitement for the subject.

Because a student with cerebral palsy may have difficulty speaking, class discussions and student presentations are a concern. The student may speak slowly, haltingly, or with nonstandard pronunciation. Insensitive students may want to laugh. If accommodations are not made for the student to participate in these activities, the student may come to believe that he/she has nothing worthwhile to say, or may feel alienated from the rest of the student body to a greater degree than he/she already is. Self-esteem is of particular concern here.

If the student has visual problems, reading the textbook or other materials may be a problem. Such a handicap will result in the student being exposed to less content than the other students, and could cause the student to perform poorly in the course. Such problems should be minimized, if at all possible.

C. Accommodations to be Made

The first step in accommodating a student with cerebral palsy will be to have a private meeting with the student to get specific information about the student's needs directly from the student. The student may, in fact, be quite able to function adequately in the classroom with little assistance from the teacher. On the other hand, there may be specific needs that the teacher had not previously considered or that apply specifically to this one student.

In terms of difficulty taking notes or completing written homework assignments, I could do several things to accommodate a student with cerebral palsy. Firstly, although I have no intention of copying and distributing my personal lecture notes to students in general (note-taking is an essential part of the learning process, I believe), I would certainly be willing to do so in a case such as this. As far as written assignments and exams, I would first be sure that the student had available someone who could take dictation and write for him/her. If such a person is not available, I would be willing to accept homework on a cassette tape. The student could essentially read (or have someone else read if speech is impaired) his/her solution aloud and record it on the tape. Although the student could not pass the course without fulfilling the minimum requirements, I am certainly willing to alter the standard framework as needed to accommodate a student with special needs.

Accommodations to be made for the laboratory include having the equipment at an elevation such that the student can clearly see what is happening. I will also speak privately with the other members of the student's lab group and instruct them to be sure to allow the student to manipulate whatever equipment he/she can and to involve him/her in the lab activities. I will, of course, closely monitor the group to be sure that the student with cerebral palsy is participating as much as his/her condition allows.

The main concern for demonstrations is to be sure that a student with cerebral palsy can see the demonstrations clearly, and does not end up confined in his/her wheelchair behind another student who is standing.

There are several factors to consider for accommodating a student with cerebral palsy in class discussions and student presentations. Firstly, I will expect the student to voice his/her opinion and ask questions just as often as the other students. I will ensure that the student is given adequate time to say his/her piece, and that the other students are as attentive and respectful as they are with their other peers. Unless the student is severely speech-impaired, I will also expect him/her to participate, at least partially, in student presentations.

If vision is a problem, there are several things I can do to help the student with cerebral palsy. I would be willing to record, on tape, the material from the textbook for the student to listen to at home. I would also be willing to allow lectures to be recorded so that the student could re-listen to them later. In such a case, I would make up alternative forms of exams and homework assignments.

I should note here that I will also consult guidance counselors and other school officials to ensure that my plans are appropriate for a student with any disability, not just cerebral palsy.

D. Gifted Student Enrichment Activity

Because I believe that being able to clearly express one's ideas in writing is a crucial skill for today's students, I would have my gifted students create a research paper of perhaps five pages in length, citing no fewer than five different sources. I would have a list of possible topics from which students could choose, although any topic of their choice that I approve would be acceptable. Because I myself am interested in history and because I think that the outstanding thinkers of the past deserve our recognition of their trials and successes, most of the topics on my list would deal with the history of science. Historical topics, which would not be limited to physics, could include scientific personalities such as Marie Curie, Joseph Henry, or Michael Faraday; or technological developments, such as the history of the incandescent light bulb, the development of the steam engine, or Darwin's voyage on the Beagle. Additionally, if a student has a specific project in mind, such as designing and conducting a research study, I would be willing to allow a student to get some "hands-on" experience with such a topic.

XI. RESOURCES

A. Textbook Resources

R. R. Bowker's El-hi Textbooks & Serials in Print was consulted to determine appropriate resources for this unit plan. The reader is referred to Section XIV, References, for a complete bibliographic entry of this work. Photocopies of the title page and of the section on physics textbooks have been included in an appendix of this report. Any text that was thought to be of value as a reference source for electromagnetism has been highlighted in green.

The Bowker's work can be of significant value to the physics teacher primarily because it lists all of the elementary and secondary physics textbooks that are currently in print and available from a publisher. It lists not only general textbooks that deal with many different physics concepts, but it also includes "specialty" books that address one main theme, such as electromagnetism or optics. The novice physics teacher would do well to be familiar with this resource, and should consider building a respectable reference library for personal or classroom use from the texts available.

As mentioned at the outset of this unit plan, the chosen text is Frederick E. Trinklein's Modern Physics. This text, while quite advanced for a first-year physics course, has been chosen for several reasons. The first reason is that I would rather have a text that challenges the reader through higher-level concepts coupled with math than a low-level text that omits math. Secondly, I want a text that goes even deeper into the material than we will go in class for those motivated students who wish to push themselves. Finally, this rather difficult text can be defended by the fact that it simply will not be used much in my class. I intend to do the teaching myself, and plan to rely as little as possible on a single textbook. In addition, if students are overly concerned about reading a simpler textbook, I will have other general physics books available for students to check out overnight.

B. List of Ideal Materials

The implementation of this unit plan will require equipment and other materials. What follows is a list of materials that would be required to "ideally" implement this unit plan, including demonstrations and laboratories, as outlined in this report. The source of each item is listed on the right, and the complete bibliographic entries for those sources are listed in Section XIV, References.

Price Total

Item Quantity Per Item ($) Price ($) Source

bar magnets, strong alnico 10 sets of 2 9.25 92.50 CENCO, p. 118

glass plates, 1' x 1' x 1/8" 3 2.55 7.65 Frey, p. 753

compass 20 2.40 48.00 Fisher, p. F82

nails, large 4 sets of 25 0.95 3.80 CENCO, p. 939

nails, small 1 set of 75 2.50 2.50 CENCO, p. 939

dry cell, 6 V 10 4.95 49.50 CENCO, p. 818

copper wire, insulated, 26 gauge 327 ft. 4.10 4.10 Frey, p. 640

HO model train power supply 1

ring stand 8 18.85 150.80 Frey, p. 765

C-magnet 5 3.95 19.75 Frey, p. 619

d-c power supply, 12 V 5 109.00 545.00 Fisher, p. F150

resistor, 10 ohm 1 set of 8 2.50 2.50 Frey, p. 646

copper wire, thin, 18 gauge 203 ft. 11.35 11.35 Frey, p. 640

galvanometer 2 95.65 191.30 CENCO, p. 176

motor, small 2 96.15 192.30 Fisher, p. F85

flashlight bulb 1 pkg. of 10 7.50 7.50 CENCO, p. 139

ammeter/voltmeter 5 49.95 249.75 CENCO, p. 177

Elihu Thompson Apparatus 1

plexiglass sheet, 1' x 6" x " 2

iron filings 1-500 g jar 3.95 3.95 CENCO, p. 153

wooden base, 8" x 2" x " 10

test tube 1 pkg. of 100 34.95 34.95 Fisher, p. D173

copper foil 1-100 g pkg. 12.25 12.25 Frey, p. 489

clay 2-1 lb. pkgs. 1.75 3.50 Frey, p. 785

TOTAL $1632.95

Thankfully, many of these items could be re-used many times, thereby bringing the cost per use down to more palatable levels. The above table merely shows what we would have to pay if we purchased all of these items at one time.

XII. STUDENT ASSESSMENT

A. Process Skill Assessment

Students will be given, on paper, a situation describing a C-magnet and a current-carrying conductor. The orientation of the poles of the magnet and the direction of the current in the conductor will be given. The task is for the student to hypothesize the direction of the resulting magnetic force and, using appropriate laboratory equipment, safely construct a model of the situation to investigate the hypothesis.

B. Scientific Disposition Assessment

Students will be given the following task, which will not count against any student's grade but, depending on how a student supports or documents his/her position, may count toward extra credit.

"Under anonymous conditions, write a one-page essay on how the studies in this unit changed or did not change your appreciation and knowledge E/M technology. Cite examples of your initial and current points of view, as well as specific concepts we addressed in this unit which significantly contributed to your change of state."

XIII. CONGRUENCE WITH STATE AND NATIONAL GOALS

It would be wise for new teachers to construct their unit plans and lesson plans so that they are closely aligned with both state and national goals in science. This unit plan includes content and processes that address both sets of goals. Details are included below.

A. Illinois State Goals for Learning

One focus of the Illinois State Goals for Learning (nos. 11-13) is to ensure that students are introduced to the concepts and vocabulary of physical science and how those concepts are applied in society. This unit plan is very much in line with the above concern. We introduce many new concepts involving electromagnetism, such as the laws of Maxwell, Faraday, and Lenz. New vocabulary includes rotor, stator, commutator, and armature. Finally, we will spend considerable lecture and lab time on the practical applications of electromagnetism, including motors, generators, transformers, and electric power generation.

Another concern of the State Goals deals with the social and environmental implications and limitations of technological development. Although this issue is not of primary concern in this unit, we will touch briefly on ideas that relate to this issue. For instance, we will discuss briefly the incredible effect cheap electrical energy had on the development of modern society in the U.S. and throughout the world. Also, the cooperative project on electric power deals with many "Science and Society" issues which are of concern here.

Understanding the principles of scientific research and their application in research projects will become necessary when students tackle Laboratory Activity C, which involves energy transformations. All the elements of the scientific process are necessary for the successful completion of that student-directed lab. The principles of scientific research will, of course, have been stressed throughout the school year prior to this unit and will be re-emphasized here before Lab C is assigned.

A final focus of the State Goals is the extent to which students become familiar with the processes, techniques, methods, equipment, and available technology of science. We have addressed this concern quite well in this unit plan. Plenty of worthwhile demonstrations have been included to illustrate the equipment used in science. As mentioned in Section II.B, both "little" labs and "big" labs will be employed to give students sufficient experience in practicing with the techniques, methods, and equipment used in scientific studies. The student-directed laboratory will be an appropriate activity that should give students the opportunity to fine-tune their scientific skills in a true-to-life problem of energy transformations and efficiency.

B. National Science Education Standards

Inquiry-based instruction is an integral part of the NSE Standards, and elements of such instruction have been included in this unit plan. For instance, a sample inquiry-based lesson has been provided in Section VI.C above. Although not explicitly stated, many of the major and minor demonstrations could also be employed in an inquiry-based learning lesson. Such a demonstration coupled with an inquiry lesson would provide sufficient "mental discomfort" to seize the attention of the class, as well as allow the students the opportunity for formulating possible explanations for each phenomenon. By using inquiry techniques, it is hoped that the students would retain the concepts better than if expository approaches alone were used.

All students are important, and all students should be provided an equal opportunity to learn. I have endeavored to provide enough diversity in instructional methods to achieve this desired end. For example, provisions have been made for expository, concept change, inquiry, and cooperative learning methods. These various methods allow for both individual initiative as well as group learning. Demonstrations and laboratories have been included to facilitate hands-on experience with electromagnetism. Several practical applications of electromagnetism are discussed in depth. I have included historical anecdotes in my content outline to allow interested students to catch a glimpse of the human side of science. Finally, I plan to have a variety of physics textbooks in my classroom which will be available for reference by any of the students. I hope that each and every student will be able to find something in this class which he/she finds interesting and which induces him/her to choose to put forth the effort required to learn.

Teachers should also take care to periodically assess their teaching as well as student learning. Although no explicit plans are set forth in this document, I do plan to be a reflective teacher. I consider myself a good observer, and feel that I will be able to ascertain which aspects of my instructional methods are in need of work. Furthermore, I am unafraid to ask for student input and alter my teaching where necessary. Finally, I am flexible enough to change my plans within the unit itself, if necessary, if I discover that the students are simply not "getting it." If student learning is faltering, it is up to the teacher to try something else, as long as he/she always remembers that a small percentage of students will refuse to learn no matter how the teaching is done.

This unit plan allows for adequate time, space, and resources needed for learning science. Given the six weeks I have allotted to this unit (see Section II.A) and the ideal list of materials (see Section XI.B), I feel that this unit would result in a successful learning experience for students, not only with regard to electromagnetism, but with regard to science in general. This unit incorporates principles which exist throughout all of science, such as hypothesizing, experimentation, problem-solving, and practicality, along with the more-specific concepts of electricity and magnetism. In addition, the general principles of science will be a part of the rest of the physics curriculum throughout the school year in my classroom.

The final aspect of the NSE Standards that should be mentioned here deals with the creation of learning communities. While this topic is difficult to address in this unit plan, several statements can be put forth. I intend that my classroom will be a place in which everyone who is inclined to learn can learn. The asking of questions will be encouraged, and I myself will ask many questions of my students; I am one who takes the dictum, "Everyone is my superior at something", seriously. I will never pretend that I know all the answers, and I will expect my students to admit when they do not know or are unsure. Finally, I hope to foster a sense of community in my classroom via cooperative learning and by stressing the idea that every individual in the room, including me, has a great deal to learn ñ and what better way to learn than to learn together?

C. Project 2061: Benchmarks for Scientific Literacy

With regard to Project 2061, Standard 4G Forces of Nature of The Physical Setting is most appropriate to this unit plan. Although the standard is quoted in Section I.B, it is worth a second look:

By the end of the 12th grade, students should know that...

Magnetic forces are very closely related to electric forces and can be thought of as different aspects of a single electromagnetic force. Moving electric charges produce magnetic forces and moving magnets produce electric forces. The interplay of electric and magnetic forces is the basis for electric motors, generators, and many other modern technologies, including the production of electromagnetic waves (p. 97).

This unit plan introduces and fully develops the ideas put forth in the above quote. We examine the nature of electrical and magnetic interaction, as well as analyze the practical applications of those interactions. Although the content and activities of this plan were not based on the above quote (they were from my own research and personal preferences), a more accurate and concise description of this plan would be difficult to find or construct. I take comfort in the fact that what I arrived at largely on my own is in substantial agreement with nationally-recognized learning goals. Had my plans been grossly at odds with national and state goals, however, I probably would have altered my plan of action somewhat and worked to incorporate some of those goals. A "loose cannon" first-year teacher is probably not welcome in most public schools today and, unless he/she alters his tactics, would soon be looking elsewhere for employment.

XIV. REFERENCES

American Association for the Advancement of Science. (1993). Project 2061: Benchmarks for Scientific Literacy. New York, NY: Oxford University Press.

Arons, A. B. (1990). A Guide to Introductory Physics Teaching. New York, NY: John B. Wiley & Sons.

Berry, D. A., editor. A Potpourri of Physics Teaching Ideas. College Park, MD: American Association of Physics Teachers.

Bower, B. (1995). Map unfolds for brain vision areas. Science News, 147, 295.

CENCO - Central Scientific Company. 1996 Catalog. 3300 Cenco Parkway, Franklin Park, IL 60131. Ph. 800-262-3626.

Cunningham, James and Norman Herr. (1994). Hands-On Physics Activities with Real-Life Applications. West Nyack, NY: Center for Applied Research in Education.

Edge, R. D. (1987). String and Sticky Tape Experiments. College Park, MD: American Association of Physics Teachers.

El-Hi Textbooks & Serials in Print. (1994). New Providence, NJ: Pub. by R. R. Bowker.

Gabel, Dorothy L., editor. (1994). The Handbook of Research on Science Teaching and Learning. New York, NY: MacMillan Publishing Company.

Fisher Science Education. 1996-1997 Catalog. Fisher Scientific Company. Ph. 800-955-1177.

Frey Scientific. 1994-1995 Catalog. FSC Educational, Inc. 905 Hickory Lane, P.O. Box 8101, Mansfield, OH, 44901-8101.

Haber-Schaim, Uri and John H. Dodge and James A. Walter. (1981). PSSC Physics. Lexington, MA: D. C. Heath and Company.

Hewitt, Paul G. (1987). Conceptual Physics. Menlo Park, CA: Addison-Wesley Publishing Company, Inc.

Holton, Gerald and F. James Rutherford and Fletcher G. Watson. (1981). Project Physics.

Illinois State Board of Education. Preliminary Draft: Illinois Academic Standards. Volume Two: State Goals 11-18. Science, Social Science. (1996).

National Research Council. (1996). National Science Education Standards. Washington, D. C.: National Academy Press.

Peterson, Richard W. (1978). Teaching Physics Safely. College Park, MD: American Association of Physics Teachers.

Physics Handbook. (1970). Albany, NY: University of the State of New York/The State Education Department Bureau of Secondary Curriculum Development.

Safety in the Secondary Science Classroom. (1978). Washington, D. C.: National Science Teachers Association.

Solving molecular and biological problems. (1995). USA Today Periodical, 123, 10.

Trinklein, Frederick E. (1990). Modern Physics. Austin, TX: Holt, Rinehart, and Winston.

Woolfolk, Anita E. (1995). Educational Psychology, 6th Edition. Needham Heights, MA: Allyn & Bacon.

Return to Unit Plans Overview