DESIGNING A PER-BASED INTRODUCTORY PHYSICS LAB

By

Nicholas Karl Corak

A paper submitted in partial fulfillment of the requirements of the Honors Program in the Department of Physics and Physical Oceanography.

Approved By:

Examining Committee: ______ Russell L. Herman, Ph.D.

Faculty Supervisor ______

______

______

________ Department Chair

Honors Council Representative

Director of the Honors Scholars Program

University of North Carolina Wilmington

Wilmington, North Carolina

December 2010

Table of Contents

Abstract 3

Acknowledgements 4

Introduction 5

Motivation 6

What is PER? 8

Research Methods and Tools 13

Students Use Mental Models 16

Epistemology 19

Implications from a Traditional Laboratory—Observations 23 Lab I 23 Lab II 25

The PER-based Laboratory Exercise: A modified design 26

How to Run the Laboratory Exercise 27

Conclusion

Appendix A 33

Appendix B 33

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Abstract

Physics Education Research (PER) faculty investigate how students develop their

understanding of physics concepts and phenomena. They have found that students do not

walk away from introductory physics courses with a coherent knowledge of physics

principles even if they make a good grade in the course. When asked to explain their

reasoning or describe their solution, students do not make correct conjectures about the

physics. Through a modified laboratory exercise, designed from an analysis of research

from introductory physics courses, we look for more effective ways to achieve student

understanding. The exercises are designed to increase student involvement in class

through hands-on activities with a focus on increasing students’ communication with the

instructor, lab group, and the class.

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Acknowledgements

I would like to express my thanks to the Edward Redish and the University of Maryland’s

Physics Education Research Group (PERG) for their extensive commitment to fostering

research in the field of physics education. Without the research conducted there and at

other institutions across the nation at universities such as the University of Colorado-

Boulder, the University of Washington, North Carolina State University, and others, I

would not have found the inspiration for this thesis. My gratitude extends to Dr. Shelby

Morge, Dr. Kate Bruce and the entire Honors Scholars Program at the University of

North Carolina Wilmington. My time completing the Honors Scholars Program could

not have been done with out the extensive support from the honors faculty, staff, and

students. I would also like to thank my parents, Patty and Eli Corak, for their lifelong

encouragement to follow my dreams, keeping me focused on what is important. I would

like to thank my sister, Rachel, for her young words of wisdom. To my friends and

classmates for their ears whenever I have needed to talk, I appreciate all that you continue

to do. Special thanks are needed for Dr. Timothy Black, Dr. Brian Davis, and Dr. Dennis

Kubasko for their dedication as committee members for my honors thesis. You have all

been influential and inspiring teachers to me. Lastly, Dr. Russell Herman deserves my

upmost appreciation for his patience, wisdom, and loyalty. I could not ask for a better

faculty supervisor to help me begin my quest as a physics researcher.

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Introduction

Over the last twenty years, physics education research (PER) has become a growing field

in physics departments. Faculty members in physics departments are reshaping

instructional methods based on results from research conducted on how students come to

develop their understanding of physics concepts and phenomena. They have found that

students often have a disconnection among physics principles. They come to class with a

set of knowledge already engrained and often fail to correctly adapt their prior knowledge

when presented with new physics topics (Sabella, 1999).

As instructors of physics, we have a skewed view of how students learn physics (Redish,

1994). We think that our students see and understand physical concepts as we do. This

is not the case. Students learn physics based on their own interpretations of physical

principles presented to them. Students rarely have an opportunity to express their

interpretations of the physics they are learning. It is our duty as instructors to serve

students by asking them to explain themselves so they begin articulating physics in their

own words. When students are asked to explain themselves and their reasoning, they

begin to think about how they think about physics (McCaskey, 2009).

It was not until recently that physicists began to collect data on how their students learn

and process information. They notice that as physics teachers we fail to make a strong

impact on how our students view the world (Redish, 1994). In this essay, I seek to show

how to design a laboratory exercise based on research from physics faculty across the

nation. Research groups in large physics departments across the nation are implementing

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modified methods of instruction which focus on the learner. Instructors often focus too

much on the physics content covered in class rather than how their students are

interpreting and learning. If we want to see success from more students, we must pay

closer attention to what the students are asking and doing when in physics courses

(Redish 1994).

In this paper, I seek to show how to design a lab which engages students in their own

learning processes. The lab design moves away from the traditional procedural based lab

and towards an inquiry based lab. In the inquiry-based lab, the students undergo

empirical investigations in order to discover or validate a physical principle guided by

their own intuition and discussion among class (Russ, 2006). People, in general, learn

better by actively engaging in activities rather than passively watching the activities

(Redish 1994). I have focused on how to actively engage physics students through a lab

design which requires students to think, discuss, question, and articulate their ideas and

views on physics. My goal is to provide an environment in which students develop their

own ideas about physical phenomena and articulate the principles in their own words. I

believe that once this is done, the physical principle will lie in the mind of the student.

Motivation: Why study how students learn?

Researchers have been studying how students learn physics for years yet students are still

struggling with the basics (Redish, 1994). Understanding the learning process of students

will help instructors better meet the needs of their students in the classroom. Instructors

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should probe the students with thoughtful questions about the physical concepts at hand

(Driscoll, 1999). The students should analyze their own thought processes. When

students communicate their thoughts with their classmates and the class works together to

give one another feedback, the students will have a greater understanding of the thought

process that led to the development of physical principles.

When faced with solving a problem, researchers have found that students use a set of

strongly related pieces of knowledge called a schema. This may consist of memorizing a

formula or fact and applying it to the context of the problem (Sabella, 1999). However,

when students are faced with more difficult problems, the schemata may not suffice.

Students must look for new ways to solve the problem. The goal of PER is to develop

effective methods for teaching students a useful set of problem solving skills.

In this thesis, we review research topics including student coherence and deep conceptual

understanding of physical phenomenon. As an application, we will see how the research

can be applied through laboratory exercises, namely using springs to teach concepts

about forces and equilibrium. We show how students apply schemata and how

instructors can design labs in order to increase student knowledge of the schemata. By

analyzing their own thought processes, students compare their common sense and instinct

with the principles and concepts set forth through the lab.

The lab design shows how previous research can be applied to a traditional lab. We

compare a traditional, procedural lab with a modified lab based on PER. The adaptations

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and modifications will enhance students’ conceptual understanding coupled with a hands-

on experience. Students will be able to observe and describe what they see in physical

terms. By increasing student communication throughout the lab, students will enhance

their physics vocabulary and have a better sense for the true meaning of words like

displacement, force, and equilibrium (Aarons, 1997).

The students will numerically and conceptually evaluate data in small groups.

Intermittently and at the end of the lab, the students have a chance to communicate their

findings with the class. The instructor will then lead a class discussion. Critiques and

questions regarding the lab and any discrepancies again give the students an opportunity

to verbally conceptualize their understanding. Some of the probing questions require that

students predict what will happen and support their claims (Driscoll, 1999; Redish,

2003). Later, the students will reevaluate their predictions and why they thought the way

they did. They will compare their own thoughts with the information presented by the

instructor. First, we must discuss the foundations for this paper, the roots of physics

education research.

What is PER?

For millennia, natural philosophers, alchemists, astronomers, and scientists have made

world-changing discoveries in order to teach the people of earth about the inner workings

of the universe. Why, after thousands of years, should we stop trying to spread the

knowledge? Years of research in education indicate various learning styles and cognitive

8

developmental differences. As a future teacher of physics, my ultimate goal is to

influence as many students as I can to see the importance of understanding the world

around them. As a student, I understand some of the difficulties in understanding the

counterintuitive ideas that present themselves in various physics topics. It is my goal to

bridge the gap between the student and the teacher by researching learning, and

specifically researching how students develop an understanding of physics. As a result, I

will have a better understanding of physical concepts, intuition, and the areas in which

the two overlap.

Researchers at the University of Colorado-Boulder use learning assistants (LAs) for

supplemental lab instruction. The LAs are students hired to assist faculty who want their

introductory physics courses to allow students to “have more opportunities to articulate

and defend their ideas and interact with one another” (Otero et. al., 2010). The figure

shows a redesign from the traditional class set up. The students in the transformed class

face each other, like in a laboratory setting, for the purpose of increasing student

discourse. The researchers use lessons which are “inquiry based and interactive” (Otero

et. al., 2010). This same sort of design can be implemented in the laboratory setting in

which the instructor acts a facilitator. By merely responding to the students’ questions by

asking probing questions, the instructor allows the students to discuss ideas with one

another rather than back and forth with the instructor. The research also shows that the

LAs learn more physics (Otero et. al., 2010).

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Figure 1. The transformed class at the UC-Boulder allows for student-student discussion with LAs facilitating discussion with questions that allow students to articulate their thought processes (Otero et. al, 2010).

Figure 2. The bar graph shows results from the Brief Electricity and Magnetism Assessment. The graph display pre and post test scores after students at the University of Colorado had LA-led recitation. The Learning Assistants also improved on the assessment (Otero et. al, 2010).

As instructors, is it not our duty to ensure that our students are more than robots listening

and repeating what the authorities say? Shouldn’t we be concerned that students are

reconciling any differences between common sense and correct physics knowledge?

There should be no difference. Instructors should entice students to accept

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misunderstanding and seek to resolve the misconceptions. We want our students walking

away from class embracing uncertainty, noticing it as an integral part of understanding.

For example we are uncertain of a particle’s momentum if we know its position, but this

helps us understand how particles behave. Admittedly, that may always be unclear to me

but what I will do, if it takes me the rest of my life, is figure out how to make

Heisenberg’s Uncertainty Principle and other physical concepts more intuitive to my

students.

Humans believed that the earth was flat and that teaching was an art form (Beichner,

2009). It took hundreds of years to convince people that the earth was spherical but

hopefully it will not take as long for us to realize that teaching is more than an art form.

Rather, teaching can use the scientific method for connecting students’ thoughts and

misconceptions and formulating adaptive teaching methods that actively engage students

in their own learning processes. Education research is nothing new, but education

research in the field of physics is still a young field of study due to the controversy

surrounding physics education research as a science.

Some physicists believe that PER should reside in schools of education. While that is a

good location, having PER faculty in physics departments can greatly influence the

quality of instruction in the physics departments because the researchers will actually be

teaching those courses. Some faculty in physics departments will only listen to other

physicists. They do not validate the work of science education researchers (Beichner,

2009). Wherever the researchers are located, all instructors can benefit from the work

11

conducted by physics education researchers as they strive towards further understanding

of students’ views of physics, interpretations of physical phenomena, and struggles

observed in the physics classroom.

Over 100 years ago physicist Robert Millikan said “it can not be too strongly emphasized

it is it the grasp of principles, not skill in manipulation which should be the primary

object of General Physics courses” (Redish, 1999). As scientists, we try to unearth the

laws of nature, but in doing so we are trying to create the best way of thinking about the

world. This approach to science puts the knowledge in the mind of the scientist (Redish

1998), or the student of physics, for the purpose of this paper. In physics we may not

always follow the standard scientific method, but when we do physics we do use two

important tools, observation, and analysis.

In PER, we do just that, observe how students learn, analyze our observations using

appropriately developed instruments, and produce a method of research-based

instructional reform based on the analysis of the results (Beichner, 2009). Physics

education research is always changing because the students are always changing. We can

look at physics education research like we look at any other complex system full of

evolving variables, and many unknown or uncontrollable variables. Edward Redish

compares PER experiments with quantum mechanics experiments in that every student

behavior cannot be controlled or predicted, in the same way that one cannot predict the

behavior of an electron (Redish, 1999).

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Research Methods and Tools

As we look at previous research on student understanding of physics, we must take into

consideration how students are learning. As material becomes more complex, so do

student difficulties in understanding physics. To fully understand student interpretations

of physics we must not focus solely on teaching content: rather, we should look into ways

of investigating how students come to their own understanding of physical concepts.

Model of Learning Cycle

Curriculum Development

Instruction

Research/Evaluation Curriculum Development

Instruction

Research/Evaluation

Figure 3. The Model of Learning Cycle as shown by the Physics Education Research Group at the University of Maryland (Redish, 2003).

Researchers at the University of Maryland (UMd) have devised a Model of Learning

Cycle which uses research of students’ knowledge and comprehension of physics to

develop a curriculum to maximize student understanding of physics in an introductory

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physics course (Wittman, 1998). Researchers collect data based on observations via

personal interviews, written questions, and diagnostic tests. Personal interviews consist

of roughly 45 minute video sessions in which students are presented with a problem or

scenario and they are led to an understanding of the problem through probing questions

from the instructor. Researchers gain an insight into student comprehension via

questions on quizzes and tests at the beginning and end of lessons. Diagnostic tests could

include research-based surveys, questionnaires, or an inventory of concepts which are

specially designed to evaluate a class’ knowledge of physical concepts and principles

(Redish, 2003).

Observations can start at any point. Instructors may observe everything from students’

questions to results on quizzes or exams. Michael Wittman discusses in his doctoral

dissertation how we must not help students arrive at the right answer, rather, we should

discover what problems they are having with the physical concepts (1998). Data from

observations and personal interviews can come from probing questions resulting from a

student’s description of a physical concept. As part of the research at UMd, instructors

ask for volunteers (usually those who are making better grades are more willing and less

shy to answer questions about physics) to take part in personal interviews. The

interviews are loosely structured so that the instructor can adapt to the responses of the

students. All video interviews are transcribed to be analyzed. Many researchers other

than the instructor conducting the interview review the transcripts and videos to eliminate

bias when evaluating the students’ responses. The interviews from various students are

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compared and evaluated to show commonalities in student reasoning in problem solving

(Wittman, 1998).

Free response questions at the beginning and end of lessons, whether on quizzes or tests,

ask students to not only solve a problem, but also request that students explain how they

arrived at the solution. There can be different methods to attaining solutions but the

results give researchers insight into how students solve problems and how they interpret

the physical concepts related to the problems. The researchers at UMd have found that

the free response answers from the students do not always show all solutions to a

problem, which they believe shows some lack of understanding and that the students are

filtering their responses (Wittman, 1998).

Sometimes, the researchers use multiple choice questions that may have multiple

answers. The students are asked to select all answers they believe are correct and explain

why. This gives the students a chance to think about their own learning and

comprehension of material covered in class. Sometimes researchers select students who

participated in the interviews to act as pupils for the free response and multiple-choice

multiple-response questions. Vice versa, selected students who participated in the written

questions and surveys participated in interviews. Then the researchers compare the

results of each method to see if students are consistent in their responses or if they

approach the problem differently. By doing so, the researchers began to see correlations

in student comprehension of the topic and will look to adopt a curriculum suited for the

most effective method of learning (Wittman, 1998).

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When researchers want a broader, statistical view of student performance and opinion

about physics, they distribute surveys and questionnaires to their students as well as

students at other institutions in the same or similar introductory physics courses. The

large sample allows researchers a chance to look more broadly at student opinions which

reveal certain personalities about physics. One particular survey is the Maryland Physics

Expectations Survey (MPEX). Since 1992, researchers led by Edward F. Redish at UMd

have been surveying “introductory” physics students and “expert” physics teachers. The

survey samples a wide range of physics students and experts which allows the researchers

to see the different attitudes that the instructors have from their students. The goal of the

MPEX Survey is to evaluate student attitudes, beliefs, and epistemologies that affect how

they learn physics (McCaskey, 2009).

The results from the interviews, questions, and surveys show correlations in students’

patterns of learning. In turn, and based on the data, the researchers can develop a

curriculum catered for student needs. They can get a better grasp on the traditional

methods of instruction while developing a new system of engaging students in order to

maximize students’ views on instruction and how they think they feel about physics.

Students Use Mental Models

First we must try to decipher how students are processing information. In a general

theory about cognitive developments in physics, Edward Redish states that “people tend

to organize their experiences and observations into patterns or mental models” (1994).

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Mental models are made of propositions, images, and procedures, some of which may be

contradictory or incomplete. Learners try to use as little mental energy as possible, like

the ground state energy of an atom. Different learners have different mental models for

describing the physical world. But Redish also argues that “mental models must be built”

and that “people learn better by doing than by watching something being done” (1994).

The thesis attempts to use this principle to design laboratory exercises in which students

begin to understand their own mental models from the building blocks of those models up

to full comprehension of the principle.

One component of the foundations of a mental model is a schema. Students use

schemata, coherent sets of knowledge, to solve problems (Sabella, 1999). They do not

integrate their qualitative and quantitative problem solving skills. The skills must be

integrated in order for students to have a complete understanding of the physical concept.

Researchers at UMd in the PER group found that students lack the ability to develop a

deep conceptual understanding when solving complex problems. When a student can

integrate the conceptual schemata with the qualitative problem solving schemata, they

can fully grasp the concept and solve the problem.

Students develop a rough knowledge of the concepts and the skills in order to solve the

problem using some formula that may or may not be derived in class. Students learn the

formulae and facts and in general, this is sufficient for passing the class and receiving a

good grade. These formulae and facts don’t require a deep understanding of the physical

concepts. They merely apply current knowledge from their schemata to correctly solve a

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problem. Students’ use of their skill sets becomes habit sufficient enough for them to

pass the course. But when the students are presented with novel problems, they often try

applying knowledge from their schemata in incorrect or inappropriate manners (Sabella,

1999).

Students become accustomed to their manner of solving problems, reverting back to their

ground state. As the course continues and concepts begin to build upon each other,

students struggle more with their qualitative interpretations. Some students may try to

apply a combination of intuition with the concepts from classroom experiences but are

seen reverting back to formulae and facts in order to solve the problems (Sabella, 1999).

Instructors in research based physics have found that a deep qualitative understanding

does not necessarily correlate with problems solving skills and a quantitative

understanding of the material. This means that a student can potentially find the correct

answer without fully comprehending the physics.

Researchers of PER have found that merely teaching qualitative and quantitative skills

are not enough. For a thorough conceptual understanding with the ability to relate

concepts to quantitative problems, instructors must integrate the two during instruction.

Instructors should state the connections among different principles, allow the students to

make their own connections among the principles, and integrate those connections with

their knowledge sets on solving real-world problems. Students must begin to make the

connections but the instructors can help with the development of the connections via

Socratic questioning which requires students to explain themselves (Hake, 1992).

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Students must increase their discussion and participation in class. Students develop

patterns in reasoning and struggle in adapting to new situations. With the prior methods

ingrained, students cannot build and integrate new concepts. Integration of students’

intuitions and physical phenomena should be the goal of the instructor.

Experts have an integrated knowledge of physical concepts, can adapt knowledge to new

situations, and correlate concepts with real world problems. They have a deeper

qualitative and quantitative understanding of physical concepts. This is very different

from students who struggle to make connections as principles and concepts build upon

each other. It is important for the instructor to understand how the students are learning

and interpreting the material being covered in the course so he or she can build better

communication with the students. Open communication and active discourse in the

classroom, whether it be in lecture or in lab, leads to students uncovering epistemological

issues.

Epistemology

As we investigate student learning it is important to address the significance of

epistemology within the context of the physics classroom. Epistemology refers to the

origin of knowledge and its limitations. Many student misunderstandings arise from

epistemological difficulties. In the context of learning physics, researchers are studying

students’ attitudes and perceptions of physics and how those attitudes and perceptions

affect the students’ learning of physics (McCaskey, 2009). Conflicts and epistemological

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issues can arise from students and teachers expecting different things out of a class. If an

instructor focuses on concepts and the student focuses on using equations, there is a

conflict. Likewise, if an instructor presents the students with equations requiring merely

substituting values for the variables, the student is likely to miss the concept when

required to connect multiple principles in one problem.

It is important that the instructor and the student understand the expectations of one

another within the scope of the classroom. We see often that students like to follow

instructions because using equations or following a procedure in a lab gets the student

straight to the answer. But getting the answer correct is not necessarily the goal of

education. As instructors we want our students to have a deeper understanding of the

content presented. This paper seeks to identify methods based on a collaboration of

physics research that engages the student in his or her own interpretation of the materials

presented in a physics class, namely through lab practice.

In PER, scientists investigate students’ learning of physics by analyzing data from

specific classes. Instead of the psychological research conducted relating to

epistemological issues, physics researchers use different methods for analyzing student

difficulties that focus on the learner. By better identifying those issues, physics

researchers are finding ways to deal with the epistemological road blocks when they arise

(McCaskey, 2009).

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The researchers at UMd have reformed their introductory physics courses based on prior

research in an effort to continue researching student difficulties with physics. An

underlying principle that is stressed throughout this paper is that instructors should

actively and intellectually engage students whether in a lecture, demonstration, help

session, or lab exercise. One recurring method of actively engaging students is to ask

students to reflect on the questions they are asked to answer (McCaskey, 2009). This can

be significant and useful in the physics lab. The students are asked to explain their

intuition and compare it with specific laws discussed in the lesson. If there are

discrepancies, students are asked to explain them. When students begin to articulate for

themselves, they begin on their journey to a deeper understanding of the topics at hand.

It is important that students do not sit back and get lost in the repetition of finding

solutions. Rather, as physicists, namely teachers of physics, it is our duty to serve the

individual and the entire class in their quest for a deeper knowledge of the workings of

the universe.

Instead of treating the class like a colloquium, we must engage the students in their own

learning processes in an effort to bring out their understanding rather than force it upon

them. There are times when it is necessary to use formal instruction and traditional

lectures; however, the majority of our time teaching physics should be spent eliciting

physical concepts from the observations of the students. Instructors should have the

students explain the physical concepts in their own words before, during, and after

introducing material. Continually engaging students makes students feel a part of their

own learning process.

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How do we measure epistemological difficulties? The PER group at UMd has developed

surveys that help us answer questions about students’ epistemological difficulties with

physics (McCaskey, 2009). The Maryland Physics Expectation Survey 2 (MPEX2) was

developed in an effort to combine the original MPEX with EBAPS (Epistemological

Beliefs Assessment for Physical Science.). This survey is “designed to evaluate courses

by asking students questions relating to their views on knowledge coherence, learning

independence, and the relationship of concepts and equations in their physics course”

(McCaskey, 2009). By offering this survey, the researchers can collect data from a large

sample size used to evaluate the effectiveness of the course.

Another research tool, modified to elicit more accurate responses of true student beliefs

of physical concepts, is the Force Concept Inventory (FCI). The FCI is another survey

which provides information on the effectiveness of a physics course (McCaskey).

McCaskey found that several of the questions did not actually reveal whether or not

students intuitively understood the physical concepts. McCaskey altered and eliminated

questions based on his effort to see something new: that an epistemological belief about

correct physics is reconcilable with common sense and the conceptual knowledge to

make those connections (2009). He did so by asking students to answer the questions

on the survey in two methods: what they really believe and what they think a scientist

believes. This thesis seeks to incorporate these ideas into the physics laboratory.

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Along with surveys, observations can prove to be valuable assessment tools in

deciphering what students learn. During this investigation, I observed laboratory sessions

at the University of North Carolina Wilmington (UNCW) in the Fall 2009. From the

observations, I found that most students do not build upon any pre-existing knowledge

they may have had. Evidence for this claim comes from the lack of student interactions

in the exercises. Roughly half of the students actually worked through the procedure of

the traditional lab, while the remaining students sat at the lab tables without input to their

lab groups. Implications from traditional laboratory observations can be found in the

next section.

Implications from a Traditional Laboratory—Observations

LAB I

In the professor-led laboratory exercise, the professor began by introducing simple

harmonic motion in the context of the universe. He described to the students how

everything moves with simple harmonic motion all the way down to the atomic level. As

the professor spoke, the students listened. The lab introduction covered approximately 45

minutes of lab time. The students did not talk during this session except to one another at

the lab tables. The professor tried to elicit student input via Socratic questions (e.g.;

“What happens to make the spring stretch?”, “How can we measure how much force we

must apply to make the spring stretch?”) The students did not seem to want to engage in

these questions and therefore remained inactive at their seats.

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The professor described Hooke’s Law and its relation to Newton’s Second Law,

. He discussed that the suspended spring is in equilibrium every time you add

a weight to it. He proceeded to explain that the force down must equal the force up (i.e.,

the weight equals the magnitude of the force from the spring.) The professor notes that

the force from the spring is opposite the gravitational force and there must be a negative

sign in front of Hooke’s Law, .

The instructor then proceeded to tell the students how to calculate the period of

oscillations for a spring: stretch the spring, release the mass, count ten cycles, and divide

the time for ten cycles by ten to determine the time for one cycle, the period. The

professor stated that the period is independent of displacement and acceleration. This

means when the spring is displaced more, it accelerates more, but it has farther to travel

to reach equilibrium. He asked the students to really think about what he is saying and

not just take his word for it because this principle can help the students understand

matter.

Before allowing the students to begin, the professor ran through a few trials with the

apparatus to show the students how to perform the lab. He followed the procedure so that

the students would know what they were doing. He then encouraged them to have fun

and try to uncover some truths about the universe. The professor showed the students

how to tabulate data and how to represent the change in displacement from the

equilibrium positions of the spring. He noted that one measures the position from the

base of the weight hanger for consistency. After 45 minutes, he let the students begin

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working. The students rushed through the lab without any reflection on what they were

actually doing, finished the experiment and left.

LAB II

For the same lab exercise, a graduate student acted as the lab instructor. He read the

procedure to the students and told them to ask him if they had any questions. As students

entered the classroom, they began working immediately on the lab. The instructor did

not present the students with any background information, nor any discussion on simple

harmonic motion and its significance in explaining the universe. Many students asked

questions on how to set up the lab, how to measure displacement, and even how to

calculate the force they needed to apply to the spring to measure the spring constant. One

or two students took charge at each lab table. They seemed to understand the procedure

and what the lab handout asked them to do. The other students sat passively watching, or

talking socially, with one another. These students contributed little to the lab procedure

or the collecting of data.

The first instructor opened the lab with a discussion on simple harmonic motion.

However, the students were not engaged, and from observation it is impossible to tell

which students were listening and comprehending what the instructor presented. The

instructor’s goal was to clarify previous concepts discussed in lecture. One way we can

see what students learn from laboratory exercises is by surveying their views on the

purposes of the exercises. In Figure 4 data is presented which shows a comparison of

student views of traditional laboratory exercises and a scientific community lab created at

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the University of Maryland in 2003. This shows that almost 90% of students viewed the

main purpose of traditional labs as clarifying concepts in lecture while there is a more

even distribution with the scientific communities’ lab in which students are asked to

explain their methods. Approximately 30% of students view the main purpose of the

scientific community lab exercises to learn problem solving (Lippmann, 2003.)

Therefore, the science community lab enhances student perception on their ability to

solve problems.

Figure 4. The above table and graph show the percentage of how students view Scientific Communities and Traditional lab exercises (Lippmann, 2003).

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The PER-based Laboratory: A modified design

In the modified laboratory design, I seek to engage students in the opening discussion,

allowing them to talk freely with one another. The instructor asks the groups to compile

a list of anything they think acts like a spring. The list should focus the students on the

goal of the lab, which is to understand the necessity for equilibrium in nature. After a

brief discussion on things which act like springs, the groups share what they came up

with, noting similarities, differences, and even questioning one another if any

discrepancies arise. The modified lab also poses no strict procedure for the groups to

follow. The lab groups are expected to discuss with one another a plan of attack for

discovering the spring constant.

This is very different from the procedural-based, traditional lab. The goal of allowing

students to develop their own procedure is to allow the students to uncover the solutions

for themselves rather than mimic a demonstration by a professor and following a recipe.

I argue that when students follow a recipe, they are not actually developing any ideas on

their own. Students learn better from actively engaging themselves in the activities and

that includes developing and analyzing their own procedures.

How to Run the Lab

In traditional laboratory exercises, students perform recipe-based experiments which

verify physical phenomena presented in lecture. There is little time given to students to

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discuss their ideas with one another and the instructor, leaving the instructor no time to

figure out students’ misconceptions (Saul, 1998). The semester closes, the students either

pass or fail the course, and there is no evidence that the students posses deep conceptual

understanding of the physics. This method amplifies the view that learning science is

learning facts about the universe rather than making sense of those facts (Saul, 1998).

It may be difficult for student discourse in large introductory courses. However, learning

and discussion fits perfectly into lab courses. Group problem solving helps students

develop their own problem solving skills (Saul, 1998). Along with working together, the

plan of attack for students can be achieved through problem solving strategies as

developed at the University of Minnesota. The lab design is based on a five step strategy

(Heller, 1999):

1) Visualize the problem

2) Qualitative physics description

3) Planning a solution

4) Executing the experiment

5) Check and evaluate data

The lab write-up does not include background theory or very many direct instructions

(Saul, 1998). The development of the procedure is left for the lab groups to discover

based on the physics discussion at the beginning of the lab.

In Appendix A of this paper the reader will see an inquiry based lab. The lab is designed

in such a way as to maximize student participation in the class discourse whether on the

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small group or plenary level. The students should always be encouraged to ask questions,

question their own and one other’s beliefs, explain their reasoning, and to find other

methods for problem solving. The goal of the PER-based modified lab, An Introduction

to Simple Harmonic Motion Lab, is for students to understand the spring as a model for

the universe because everything is oscillating.

The instructor begins by discussing the significance of springs, oscillations, and simple

harmonic motion.  The instructor should ask the students to compile within their lab

groups a list of anything they think acts like a spring. After a few minutes of discussion,

the groups share their ideas with the rest of class. “Does anyone have more ideas on what

acts like a spring?” Questioning students is an essential aspect of creating a class

discussion.

The lab groups discuss for 5 minutes their ideas on how they can find their spring

constants.  Then, the whole class reconvenes and the instructor leads a discussion by

asking for group volunteers to share their ideas for solving the question "What is the

spring constant of your spring and what does it signify?"  The instructor should ask the

students to explain why their procedure for the experiment will help them discover their

spring constant.  "Does anyone else have another method of approach?" is an important

question the teacher should ask until the answer from the class is "No."  The instructor

should encourage the students to comment on, or question, one another’s’ ideas.  After

approximately 10 minutes of discussion, the groups should begin to carry out the

procedure they developed.

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At this point, all groups should have a grasp on how to tackle the problem.  There may be

many similar, but different, approaches to the procedure and the instructor should verify

that all groups are headed in a productive direction.  Most interpretations should reveal

themselves during whole-class discussions but the instructor should walk around the

classroom to answer further questions from the students.  While the groups collect data

and determine an effective way to model the data, the instructor should encourage student

discussion by asking periodic questions such as:

What forces are acting on the spring?

What can be said about the state of the system?

How much force stretches the spring 100m?

The students will be curious as how to answer these types of questions because intuition

tells them it the spring coils cannot stretch to be 100m long.  The instructor should

encourage the students to explain their thought processes and ask for several

interpretations.  When the groups finish data collecting, they will represent their data

appropriately.

Once the groups have finished, the class reconvenes for a summary discussion.  This is

when the groups share their results with the class.  They should justify their data

measurements, graphs, and the conclusions they found.  By articulating their

methodologies and interpretations, physics students practice discussing how they view

the physical concepts and the physical world.  They will, in time, learn new ways of

thinking from one another (Driscoll, 1999). The groups should compare and analyze data,

graphical methods, and discovered physical principles.  The students are encouraged to

30

ask one another questions about their methods.  The instructor may need to engage the

students by asking them guided questions such as (Driscoll, 1999; Redish 2003):

Why did you collect data in that way?

What are your independent/dependent variables and how do you know?

What rates of change do you notice and what do they signify?

What sort of limitations can be deduced from the experiment?

The questioning from the instructor is essential. In order to elicit deep thinking from the

students, the instructor should ask guiding questions. The students should be asked to

describe any patterns they see and if there is a generalization they can make from the

data. Students should be prompted to reflect on their own as well as their peers’ ideas.

These reflection questions ask students to explain their thinking, understand their

classmate’s reasoning, as well as make connections between different approaches. In

order to get the students to see the mathematical relationship developed in lab, the

instructor should ask the students to develop an equation modeling their data, making and

justifying generalizations. An example for how to ask students to make predictions about

physical phenomena pertaining to the lab in Appendix A is “If 220g are added to the

spring, how much do you expect the spring to stretch? Explain how you determine this.”

By attaching “Explain” to virtually every question forces the students to justify their

thinking and reason through their own thought processes.

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Conclusion

As the field of physics education research continues to grow, it is our duty as teachers of

physics to analyze our instructional methods. We should ask ourselves, “What gains did

the students make?” after every lesson taught. For example, one can collect pre and post

test data of physical concepts understanding from students in traditional and modified

labs. Implications from the data could prove to show the effectiveness. I hope to do this

with the modified lab presented in this paper so that I can improve my instruction.

The PER-based design enhances student recognition of his understanding of physical

concepts. This lab is presented as an alternate approach to traditional exercises which are

procedural-based. The modifications make it explicit for students to articulate their

thoughts and views on physics concepts and learning gains. We want our students to

leave class with an enhanced set of problem-solving skills.

Educators should constantly be looking for better ways to increase student understanding.

With continued work in PER, I hope to sharpen my skills as an instructor through

research and evaluation, curriculum design, and implementation of new, more effective

teaching methods. An analysis devise could be developed in order to measure certain

gains students make after experience with the PER-based design presented in this paper.

Hopefully, with the right support, I will be able to implement the PER-based design to

continue my study of how students come to an understanding of physics phenomena via

laboratory exercises, evaluate those designs, redesign, and practice.

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Appendix A

An Introduction to Simple Harmonic MotionQuestion

What is your group’s spring constant? What does it signify? Explain.

Purpose

Students will develop Hooke’s Law using graphing tool and data collected. Students will use springs as a model for representing the physical world and

simple harmonic motion.

Materials

Support Rod Table Clamp Mass Balance/Scale 2m Stick Springs Mass Hanger Slotted Masses

Procedure

Discuss with your group ideas you have on how to answer the question. Discuss with the class how your group plans to solve the problem, namely how

your group plans to record data. Finalize your procedure and get the instructor’s approval. Perform your experiment Draw force diagrams for at least 3 data points.

Analysis Graph your data and fit a regression curve for that data. What do the constants in your equations represent? Can you develop an equation that represents a spring force in general?

Appendix B

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Observations 10/26/09Simple Harmonic MotionDeLoach 205PHY 101 Lab

Instructor—Professor

Professor began with relating the lab to the class context. So far for the students,

springs represent simple harmonic motion, which is present everywhere.

Professor uses Socratic Method, asking for student input while explaining springs

in the context of Newton’s second law, F=ma.

Hooke’s Law- instructor describes the force as proportional to the compression or

extension of the spring. After describing the formula in words, the professor

explained F=-kx.

Professor described words such as equilibrium, displacement, net force, kinematic

equations and their relations to simple harmonic motion and springs.

Professor points out significance of negative sign in the formula and that it means

the force is an opposing force (in the opposite direction of the gravitational force)

k is a constant with units of Newton/meter. This number is a measurement of the

strength of the spring and of how much force is takes to stretch or compress a

spring 1 meter from equilibrium.

T represents the time period of one cycle of compression and extension. T is

independent of displacement and acceleration.

Instructor asks students to think about what he is saying and not just accept what

he has told them.

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When the spring is displaced more, it accelerates more because a greater force

within it, but it has to travel further to reach equilibrium

Professor says that springs can help you understand matter.

The professor discusses what to get out of the lab and the goals of the lab

o Find k, the spring constant

o Find T, the period

o Determine effective masses, disregarding spring mass and adding mass to

the end of the spring

The instructor encourages the students to have fun, let them know there was no

pressure, and to understand this is how the universe operates.

The instructor ran through experiment via a class demonstration where the

students gather around the professor at one of the lab tables and watched as he ran

through the fist few steps of the lab so that all of the students could visualize what

they were about to perform.

He showed the equilibrium position and displacement after adding mass to the

end of the spring and adding more mass while noting the displacement.

He took the time for ten cycles after displacing the spring and divided by 10 to

demonstrate how to calculate the period.

The instructor reviewed how to tabulate data and representing the change in the

displacement.

The professor asks a few questions such as what causes the spring to elongate and

waits for student responses.

Reviews how to represent data graphically using Microsoft Excel.

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Instructor—Graduate Student

Students enter the class and work immediately on the procedure.

There was no introduction or background information.

Instructor did not make a contextual connection of the spring lab to what students

are learning in lecture and what applications emerge from the lab.

Instructor did not mention oscillations or the significance of simple harmonic

oscillators.

The instructor read the lab procedure and analysis procedure.

The students paid little attention to the instructor. Some groups started the lab

early.

The students did not gain physics knowledge from the pre-lab discussion.

Many students immediately had questions on the set up of the lab.

One to two students at each lab table worked on the lab while others watched and

contributed little to performing the procedure and collecting data.

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