The Physics Teacher: Learning Cycles for a Large-Enrollment Class
Citation: Dean Zollman, "Learning cycles for a large-enrollment class," The Physics Teacher 28, 20-25 (1990).
Recent attention to precollege science education has once again emphasized two important conclusions:
Most physicists will accept these conclusions without documentation. Their reactions are frequently to admonish colleges of education with, "Too many methods courses; not enough hard science."
Yet, when we look at the average physics course taken by elementary-education majors and other nonscience majors, we can see our contribution to the problem. Introductory physics courses are generally regarded by students as a collection of facts. While we try to teach reasoning skills and understanding in a survey course, we present such a large quantity of information that most students react by memorizing. They view science as knowledge to be recalled.
We should not be surprised, then, that school teachers frequently feel inadequately prepared to teach science. How can they possibly recall all they need to remember to teach physics, chemistry, biology, earth science, and so on? The answer is that they do not need to recall it. Science is not a collection of facts but a way of observing, collecting data, critically thinking, building models, and comparing with nature. Teachers who understand this concept should be much more comfortable with science.
To address this criticism of typical science courses, several physicists have developed courses for future teachers that emphasize the nature of physics and the reasoning involved in science. See footnote 1 The design of these courses is frequently based on the Piagetian model of intellectual development. See footnote 2 The most common way of teaching these introductory physics courses is with class sizes of 20 to 30 and a large quantity of hands-on materials.
The economics associated with small class size has limited adoption of this method at many universities, including mine. To overcome this difficulty, I have adapted a general learning/teaching model for a class of about 100 students with one faculty member assigned to it. During the past ten years the course has evolved into one with an emphasis on the nature of science and on learning science by doing science.
Although this course has been developed for elementary-education majors, it could be used equally well for other nonscience majors. Because the course is a physics course, its content is not unique to future teachers. More generally, the design of the course could be used to address disenchantments with the introductory course, such as those recently stated by Strassenburg See footnote 3 :
lectures as the principal mechanism for transmitting information
textbook problems as the major student activity and evaluation mechanisms
the laboratory portion of the course
the failure to use computers effectively
the absence of significant amounts of quantum physics
(The course described here addresses all the problems but the last.)
The course is constructed of 15 activity-based units, each of which is one-week long. An activity-based unit is a learning experience that focuses on a series of eight to ten short experiments performed by all of the students in the class. Thus, students perform a large number of experiments and these activities form the backbone of the course.
Each unit involves hands-on activities and is based on the learning cycle format developed by Robert Karplus. See footnote 4 The learning cycle is derived from the intellectual development model of Jean Piaget See footnote 3 and includes three different types of activities. The first activity, exploration, requires the student to explore a concept by performing a series of activities. Students are given a general goal, some equipment, and some general ideas about the concepts involved. They are asked to explore the concept experimentally, in as much detail as they can, and to relate it to other experiences they have had. The second phase of the learning cycle, concept introduction, provides a model or concept to explain observations of the exploration. Frequently, the concept-introduction stage is not an experimental activity but an expository statement of concepts and principles. Following the concept introduction, the students move to concept application. Here, they use the concepts that were introduced and apply them to new situations. This application of the principles and concepts leads to further understanding of the theories and the models. The complete cycle has been used successfully to teach a wide variety of topics to students at all grade levels. See footnote 5 The learning cycle has been used successfully for small-enrollment physics classes at several institutions, including the University of Washington in Seattle, Fairleigh Dickinson University, and the University of Nebraska at Lincoln. See footnote 6 These universities offer courses taught in a laboratory setting to small groups of students, usually 20 to 30 per section. At Kansas State University we are required to teach the physics course for elementary-education majors in one large section. (The enrollment is approximately 100 students per semester.) Thus, the methods of the learning cycle had to be varied to fit the requirements imposed by one large class.
To adapt the learning cycle for a large-enrollment course taught by a single faculty member, we use a combination of activities completed in an open laboratory environment and large class meetings. This adaptation utilizes the KSU Physics Activities Center, See footnote 7 a learning center that is open about 30 hours per week. The format we use is outlined here.
Exploration. This part of the learning cycle is a series of hands-on activities. In the usual approach, exploration requires a large amount of student-teacher and student-student interaction. In our adaptation, some of the student-teacher interaction is replaced by activity instruction sheets and instructional media. A teaching assistant is always available in the activities center so that a student is able to interact with a teacher. However, the assistant cannot be available to all students. Thus, most of the exploration is performed by students working alone or in small groups.
Concept Introduction. One large class meeting each week is devoted to this phase. Students are asked to describe their exploration observations and any related experiences. Using these observations, the instructor guides the students toward a model or a theory that can be used to explain the observations.
Concept Application. The final phase of the cycle again involves hands-on activities. Using the model developed in the large class (concept-introduction phase), the students make predictions for new situations. Their predictions are tested experimentally in the physics activities center. As in the exploration phase, instruction sheets, instructional media, and teaching assistants are available. Additional applications and summaries are discussed in a large class meeting. This learning cycle is shown schematically in Fig. 1 . The teaching assistants in the activities center are available to help all students in all physics courses. Thus, their availability to students in this course is limited to answering short questions. The assistants act as proctors who help with occasional conceptual or equipment difficulties rather than as instructors in the course.
Operation of the Course
This adaptation of the learning cycle fits nicely into a standard Monday-Wednesday-Friday university schedule (Table I). Each cycle begins on Monday afternoon. At that time, the equipment for the exploration in the unit is available in the physics activities center. Students must complete all exploration activities before class meets on Wednesday. The concepts that were explored are introduced in a lecture discussion format during a 50-min class on Wednesday. Following this class meeting, the application equipment is available until class time on Friday. The class meets on Friday to ask questions about the week's work. In addition, the concepts introduced on Wednesday are applied to situations that, usually, lead to questions not easily answered with present knowledge. These applications introduce the exploration of the next cycle. Monday morning classes are utilized for answering further questions, summarizing the previous week's activities, and giving examinations.
Each exploration and application is composed of six to eight short experiments called activities. The equipment for each activity is placed in the physics activities center at marked stations. The students are told what equipment is located at each station and presented with questions to answer about it. For example, an application activity on electrostatics states: "At station EM-9 is a small Wimshurst Machine. By turning the crank you can charge the two spheres. A small aluminum ball is suspended between the spheres. Describe and explain the motion of the ball as you turn the crank."
The students are guided from station to station until they complete all activities. For each activity they must write answers to all questions on their activity sheets (Fig. 2). When they finish, the students leave the completed activity sheets in the activity center.
To assure that students are adequately motivated to complete the activities, grades are assigned to each exploration and application. Explorations are graded on a Satisfactory/Unsatisfactory basis. To obtain a Satisfactory, a student must try to answer each question on the activities sheet. There are no right or wrong answers--only attempts at exploring new phenomena. Each Satisfactory is translated into five points when course grades are calculated. No points are given for an Unsatisfactory.
The applications are graded on a scale of 0 to 10. In this case, grades are based on the students' abilities to use physics concepts in their explanations and to use those quantitative relationships presented in the class and text. See footnote 8 A student's course grade is computed by utilizing the following components (maximum points possible are indicated in parentheses): exploration (75), application (150), tests (400), and final exam (200).
Sample Learning Cycle
As an example of a week's activity in this class, consider the first of five weeks on the topic of energy. When students start the exploration, they have already studied kinematics, momentum, and forces. Thus, they begin by trying to explain the motion of a pendulum by using either conservation of momentum or Newton's laws. Then they look at several experiments involving motion and change of motion. (At this point the term energy has not been introduced.)
First, a toy car is rolled down an incline into an aluminum can. By releasing the car from several different locations on the incline, the students determine qualitatively the relationship between release location and damage to the can. See footnote 9 The activity sheet then instructs the students to change the angle of the incline and repeat the experiments. (A similar experiment involves driving nails by dropping weights on them. They compare the distance the nail is driven for different release heights and different-sized weights.)
The exploration concludes with a station at which the cart and can are placed on a horizontal surface. The students are asked to make a dent in the can without lifting the cart or can from the table. Once they accomplish that, they are asked to do something to make a bigger dent. Most students decide to move the cart at a higher speed; a few think of adding mass to it.
After completing the exploration, the students express in writing any similarities they can see in the various observation activities. These statements will be in their own language since we have not yet introduced the vocabulary of energy-related concepts.
The concept introduction begins with a discussion of the difficulties involved in describing the motion of the pendulum and with the "exchange of something" that causes the pendulum to move fast at the bottom and slow at the top of its swing. The discussion is primarily student centered. The instructor leads off with a question, but the students do most of the talking. The discussion motivates a reason for introducing a new concept.
The general concepts of energy and gravitational potential energy are introduced. Students, by referring to their observations during the exploration, provide a list of variables upon which the potential energy depends. By recalling the nail-driving activities, they can also state the functional dependence of gravitational potential energy on mass and height.
A similar discussion and student-centered introduction occurs for kinetic energy. Most students will state that kinetic energy depends on speed. (However, none of the activities have enabled them to determine the functional dependence.) A few students will have discovered that adding mass to the cart will have an effect. (Two bricks are sitting at the activity station but are not discussed in the instructions.) Thus, with guidance from the instructor and frequent reference to their exploration activities, the students construct the basic ideas of mechanical energy.
To conclude the introduction, we return to the pendulum and develop the idea of conservation of energy. With this material (which closely parallels the textbook See footnote 8 ) the students are ready to begin the concept application.
The beginning of the application is simply a check to determine if the students can plug numbers correctly into the equations. After measuring their masses and walking speeds, they calculate their kinetic energies while walking and their change in gravitational potential energies when they move from the firs to second floor of the physics building. For the next activity, they return to the nail driver, calculate its potential energy at several heights, and use conservation of energy to state its kinetic energy just before it hits the nail. Even though they have "learned" conservation of energy, many students reach a state of disequilibrium here. "How can I determine kinetic energy when I don't know the speed?" is a frequent question. Without the application, the students would not have noticed this problem in their learning until the next test. With this concrete example, they are able to address it at once.
A slot-car racer with a loop-the-loop track is the equipment for the next activity. The students are asked to measure the height of the loop and predict the kinetic energy needed for a car to go through it. Using a photocell timer, the students determine the speed and calculate the kinetic energy at the bottom of the loop. When they compare the actual kinetic energy with their prediction, they find a significant discrepancy. The students are asked to speculate about the reason for differences between these two numbers and told that we will discuss it during Friday's class.
Next, the students drop a feather and a BB from the same height. The two objects have equal mass so they begin with the same potential energy (which the students calculate). Without making any measurements, all students notice that the two objects have different kinetic energies as they reach the floor. Again, they speculate about these differences.
Finally a two-hill "roller coaster" track is used. The students are asked to predict, then experimentally determine, the point on the higher hill from which a steel ball must be released to roll over the lower hill. The experiment is repeated with a cork-covered ball of the same mass. They discuss the differences between these results and the results predicted by conservation of potential and kinetic energy.
After answering questions during Friday's class meeting, we continue looking at situations wherein the sum of kinetic and gravitation potential energies is not conserved. Particular attention is paid to the differences between the BB and the feather and between the bare steel and cork-covered balls. Because the students have studied friction, they speculate that it must be involved. A discussion of work by a frictional force prepares the students for the next activity-exploring thermal energy.
In this example of our adapted learning cycle, students used traditional laboratory equipment to perform all observations and measurements. However, other cycles include activities based on videodiscs, film loops, videotapes, slide sets, and computer simulations. A list of the videodisc-based activities are presented in Table II. In all activities, including the ones based on computer technology, students must answer questions, in writing, about their observations and measurements.
All instructors who use the learning cycle and similar approaches report that they cannot cover as many topics as in a traditional course. See footnote 10 This course is no exception. So we choose to include the topics that could be of greatest value to the elementary-school teacher. The schedule with topics is shown in Table III. These topics appear in most elementary science curricula. (An exception is the second law of thermodynamics, which we believe is important for understanding the world's energy problems.)
We still cannot cover all of the topics included in all elementary curricula. However, we emphasize the nature of learning science and trust that the students will be able to acquire knowledge of additional topics as they need it.
Effectiveness of the Course
To determine the effectiveness of this course, the office of planning and evaluation at Kansas State University performed an independent evaluation of student learning and attitudes. Attitudes were assessed through a student feedback on instruction form. Student learning was examined by administering essentially identical final examinations to two classes. Both classes were taught by the same instructor - one by standard lecture procedures; the other by the learning cycle described above. Students' ratings of the instructor were essentially equal for both courses. No differences in attitudes were detected.
To investigate student learning, the final examination was analyzed in two ways. First, the exam score was divided into four partial scores representing the major topics - space and time, forces, energy, and electricity and magnetism. Second, the exam questions were analyzed in terms of the type of "effort" needed to answer the questions. Three types - calculation, conceptual explanation, and recall - were identified. In all analyses the students' cumulative grade-point averages were used as covariate to control for different learning capacities.
For all topic categories, the learning-cycle group scored higher than the lecture group. The differences in the score for forces and energy were statistically significant. When analyzed for type of effort, the scores showed that the learning-cycle group scored higher on conceptual explanations and calculations but lower on recall questions. However, none of the differences were statistically significant. Thus, the evaluation of the course concluded that the learning-cycle course contributed positively to student understanding of forces and energy.
The most obvious difference between this course and a lecture course is the immediate feedback received by the students. By the time they come to class on Friday, students have been forced to use the material presented on Wednesday. If they had difficulties, they ask questions. Frequently, students will seek help from fellow students; thus, interaction among students is much greater than in a lecture class.
The interaction during the large class sessions is also much greater than that occurring in most classes of 100 or more students. The activity format seems to establish a less formal atmosphere in the lecture hall. Students respond to questions from the instructor. Because they know that they must use the concepts immediately, the students frequently interrupt the discussion to ask for clarifications. Student/teacher interaction is much greater than in most large classes.
Most students see almost immediately the value of the application activities. However, early in the semester the explorations are considered less valuable. Many students complain that the goals of the exploration are not specific. They do not know what they are supposed to do. (Of course, specific statements of goals would defeat the purpose of the explorations.) As with most instruction, a concrete example is the best teacher. By the time they complete a few learning cycles, most students see that the explorations are preparing them to learn new concepts. When they see that grades of Satisfactory are given for what they do, not for meeting an unstated objective, they feel free to explore phenomena in a variety of ways. Thus, the explorations, which seem confusing and sometimes frustrating at the beginning of the semester, become enjoyable learning experiences.
The activities become the vehicle for learning physics. Many students have stated that they do not know how physics could be learned any other way. I, for one, certainly would not return to teaching it by the lecture method.
The author was aided in the development of some activities by James Langford and Dean Stramel. The evaluation was completed by William Pallet. The course began in 1978 with support from the Local Course Improvement Program of the National Science Foundation under grant number SER 79-00507. Continued development has been supported by Kansas State University.
A.B. Arons, "Cultivating the capacity for formal reasoning: Objectives in an introductory physical science course," Am. J. Phys.44, 834 (1976), and R. G. Fuller et al., Multidisciplinary Piagetian-Based Programs for College Freshman, (ADAPT-University of Nebraska, Lincoln, NE, 1980).
BĒrbel Inhelder and Jean Piaget, The Growth of Logical Thinking from Childhood to Adolescence (Basic Books, New York, 1958).
A.A. Strassenburg, "Problems of beginning physics courses," AAPT Announcer 17 (4) 55 (1987).
The learning cycle and its dependence on the intellectual model of Jean Piaget has been described frequently. See Robert Karplus, J. Res. Sci.Teach. 14, 169 (1977) or F. Collea et al., Physics Teaching and the Development of Reasoning (American Association of Physics Teachers, College Park, MD, 1976).
See Chet Meyers, Teaching Students to Think Critically (Jossey-Bass, San Francisco, 1986).
See Ref. 1.
Dean Zollman, "The physics activities center--a mini-exploratorium," Phys. Teach. 12 213 (1974).
Jacqueline D. Spears and Dean Zollman, The Fascination of Physics (Addison-Wesley, Reading, MA, 1985).
Dean Zollman, "The car, the beer can, and the brick wall," Phys. Teach. 13, 173 (1975).
See Ref. 5.