Different "Discovery"ary L. Sneider

With the introduction of new “discovery” type courses into manyschool curricula, I expected that many students who were previouslybored by traditional classes would now be stimulated and excited bythe new, more involving’approaches to classroom work. However, whenI began working with students in an Upward Bound program (andacting as counselor and confidante to others), I was surprised to learnthat many of the students who had been exposed to these new,progressive science classes found them as dull and boring as the moretraditional classes they were supposed to replace.

Last year, as I prepared for my first regular teaching position as a highschool physics teacher, I began asking myself questions about my owneducational experience. I hoped to find some clues to use in planningmy physics classes that would make them more than just another dullschool experience.

As I looked back on my high school and college science classes, Iremembered how unexcited I was about the required lab experiments-now I laboriously would follow, step by step, the directions to anexperiment; how relieved I was when it “came out right” so that Icould then forget about it. Although some of the lab courses I tookwere supposedly “discovery” type courses, the procedures were sostrictly laid out that there was no opportunity for real experimentationor innovation. As I was interested in learning about science (andphysics in particular), and feeling frustrated by my regular class, Irequested permission to use the lab after class hours to carry out someminor research projects in which I had a special interest.

Needless to say, I became very involved in these projects of my owninitiation, and though I occasionally ended up with results similar tothose required in class, the freedom to set up my own experiments inmy own way, making mistakes and learning from them, progressing inany manner I wished, made all the difference to me. I was vitallyinvolved and interested in what I was doing, for I was my own boss.

It was with these thoughts in mind that I began structuring classesfrmy students. For the moment, I would follow a more traditional

approach in our lecture-discussion sections and use the Harvard ProjectPhysics materials to generate discussions, demonstrations and providea coherent flow of topics. It was in the lab periods (which constitutedmost of the class time) where I decided to try something moreinnovative. Rather than adhere to any text, in various ways I wouldtry to encourage as much freedom and choice as possible.

We began with a unit on kinematics. At our first lab session I told thestudents we would be studying moving objects for the purpose ofdescribing their motion. I then defined speed and showed the class howto use instruments that measure speed, demonstrating a stroboscope,a polaroid camera and a PSSC paper tape timer. Then I told the classthey could pick any moving object they wished for study, and pointedout that they could choose unusual as well as usual subjects, such"How does the human body move?" "What are the different parts ofthe body doing when a person walks?" Or, “How does a fist aboutto hi t something move?”

I divided the class into small groups and asked each group to choosea subject for study and then design an experiment to study it. Onegroup of three high school seniors became interested in comparing themovements of a wind-up baby doll with the movements of a person.

SEPTEMBER 1972

Cary Sneider taught mathematics and scienceat Harvard University’s Upward Bound and thenbecame a physical science teacher and banddirector at Biddeford High School, Biddeford,Maine, where he developed the approach de-scribed in this article. Since then, he has beenan associate of Interaction Associates, Inc.,of Berkeley, California, where he helped todevelop a teacher training program. He isa t p r esen t a phys i ca l s c i ence t eache r a tCoalinga High School, Coalinga, California.Mr. Sneider holds a B.A. degree in astronomyfrom Harvard College (1969) and a Californiateaching credential from the University ofCalifornia at Berkeley (1971). (178 BuchananStreet, Coalinga, California 93210.)

327

Using the paper tape timer, they described their experimentas follows: (The account and illustration are taken directly

Another 12th grade student wrote this description ofherself skating while three classmates studied her motion

from their lab report.) in detail:

"A Study in Motion-In this experiment a wind-upcrawling baby was set into motion while having itsspeed and pattern of speed measured with a“clicking” apparatus. This apparatus is composedof a metal “clicker” which indented the paper tapebeing pulled through and under it every 1/60th of asecond. By measuring the space between the indenteddots on the tape, not/only could the rate of speed beestablished, but also how constant and inconstant itwas. A human crawl was also used, and each of therepresentative crawls were compared by a graph."

"... Perhaps I should give a physical picture of whatis going on. The little block of wood on wheels isunder one foot while the other foot is acting like apusher or pumper. Starting at a time and distancezero, the ‘pusher’ takes a step and then distributesthe weight to the cart foot. The wheels roll, thenagain, the weight goes back to the ‘pusher,’ andagain back to the cart foot. The wheels go a littlefurther and a little faster. This goes on frantically inscooter style for maybe two intervals since the cartand foot are rather awkward and the wheels arerather independent... ."

"...The doll seems to slow, jump, slow, and jump,etc. Again, as best we can determine, this rapidacceleration occurs when the weight of the object istransferred from the forward hand to forward the foot"

Other groups took for their subject of study variousfalling and rolling bodies, the acceleration of a rubber-banddriven airplane, the speed of an oscilloscope trace ,a spark from a Van de Graaff electric generator.

"...In taking this profile (a tape showing the speed ofa person crawling) I attempted to follow thesequence of movement of the doll. Thus, the doll’smechanism is designed to copy that of a person..."

Better than two-thirds of the total class time was spentin the laboratory. At the beginning of each two- orthree-day lab period, I spent five to ten minutesdescribing the equipment or instructions for laboratory

328 THE PHYSICS TEACHER

reports. For the remainder of the lab time, I went fromgroup to group answering questions, making suggestions

and being generally helpful where needed.

I think the essential difference between my approach andthe more usual science classes stems from my belief thata student would learn more from attempting to structurea simple experiment on his own, than from an elaborateexperiment that was set up for him. Let me explain.

The “discovery” method of many new physical sciencecurricula is a method whereby the student is expected to“discover” some known scientific principle such as theexistence of atoms or the relationship between force andacceleration In designing the laboratory activity for thenew curricula, those activities which could be influencedby variables other than the one being tested are oftenreejected as being simply confusing; and simpler labactivities are continuously being sought. The result maybe a set of nearly “perfect” labs in which the major taskfor the student becomes understanding the directions.furthermore, it seems that if students are expected to"discover" fundamental principles of science throughexperiments, they must be led very carefully and surelythrough the two or three centuries of research relevantto that topic. The very sureness of each step often destroysthe sense of discovery. And, the “discovery” is really notthe student’s at all, but the scientist’s whose work he isstudying.

My goal is for students to truly discover how phenomena"work," in their everyday environment, and while this maybe a less ambitious goal than having a student “discover”convervation of momentum through a planned experiment,believe a student actually learns more about how ascientist works by this method.

For, in allowing students the freedom of choice in thesubjects they choose to study and, at times, freedom instructuring their course, this opens up a whole new realmof problems that the students must deal with. Not onlydo they have to figure out what the teacher wants, theymust also decide what is important or simply interestingto themselves. Then, as they go about designing anexperiment, say, to study the motion of a lame hamsteror the physical properties of cornstarch mixed withwater, they have very few instructions to tell themwhat to do. They must invent models, isolate variables,predict results and draw conclusions. In short, thestudents have to exercise the same mental processesthat any scientist would, albeit the problems a scientistdeals with are more complex.

I felt it would be a mistake to immediately makeunlimited possibilities available to my students, for it isa rare student who knows where to begin. I decided tostart with a structure that allowed for some measure offreedom and choice, and as time went on (and, I hopedas interest increased), leave more and more of the decisionson how to spend lab time up to the students themselves.For those few students who were unable to make freechoices, I did allow them to use standard labs from theHarvard Project course. This textbook was alwaysavailable if students chose to use it, and although manystudents followed the standard lab instructions for someof their projects, by the end of the year nearly everystudent had completed at least two or three originalexperiments.

Though the students who followed lab instructions hadthe opportunity to deal with some experimental difficulties,they gained a great deal more experience with the problemsof research and experimental design when they worked onmore original projects.

Near the end of the year one student, who previously hadonly rarely become involved in any class activity,mentioned that he had noticed that bright stars appearto move around in the sky, even though he knew that itwas impossible. This led to an experiment which he and aanother student designed to measure their classmates’perception of the motion (or non-motion) of a tiny brightlight in a blackened room. The students learned aboutrecording data, how to use pilot studies to design anexperimental procedure, as well as a lot of factual“by-products” such as the variation of dark adaptationtime for different people and about the very low lightlevels that people need to “anchor” the light bulbvisually in the room.

Another self-motivated project was that of three seniorgirls who became very involved in building a polygraph(the “lie detector” featured in hundreds of TV shows).Though the girls were not interested in the areas ofscience and engineering, their interest in what a liedetector could do and how it worked motivated themto learn something about practical electric circuitry andthe concept of electrical resistance. They also learnedabout how to interpret results at the fringe ofdetectability. (To increase the magnitude of the effectthey were looking for, they designed some mischievouslycreative experiments to evoke strong emotional reactionsin their classmates.)

Another important learning experience in our labs camefrom my practice of assigning students to laboratorygroups of from two to five people. I find this encouragestutorial-type relationships to occur within the lab groups.As students worked together in lab groups they wouldoften divide the labor. A particularly gifted artist woulddraw diagrams for the lab report while the “engineertype” student planned the experiment or drewconclusions. Although this separation of functions mightimply that some students avoided being involved orthinking through the problems, I in fact observed a greatdeal of discussion and peer teaching going on as thestudents set up and manipulated the lab equipment andprepared reports. Just seeing how different people thinkand solve problems in a small group setting was in itself animportant learning experience.

Towards the end of the year, the class was spending mostof its time in the lab. In addition, many functions which Ihad retained at the beginning of the year were now beingdecided by the class, such as what kinds of exams theywanted and when, what kind of reading schedules shouldbe set up, etc. Some students indicated they had becomeinvolved in science labs for the very first time in theirschool experience, and general interest in the class hadincreased considerably. I do believe that by allowingstudents choice whenever possible, their motivation andinterest were substantially increased.

Ed. Note. Mr. Sneider is interested in hearing from readersabout other possible discovery approaches they have used.

SEPTEMBER 1972 329