Motivation: Why study how students learn

PAGE 20

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 RepresentativeDirector of the Honors Scholars Program

University of North Carolina Wilmington

Wilmington, North Carolina

December 2010Table of Contents

Abstract3

Acknowledgements4

Introduction5

Motivation6

What is PER?8

Research Methods and Tools13

Students Use Mental Models16

Epistemology19

Implications from a Traditional LaboratoryObservations23

Lab I23

Lab II25

The PER-based Laboratory Exercise: A modified design26

How to Run the Laboratory Exercise27

Conclusion

Appendix A33

Appendix B33

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.

Acknowledgements

I would like to express my thanks to the Edward Redish and the University of Marylands 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. 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 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 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 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 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).

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? Shouldnt 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 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 particles 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 Heisenbergs 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 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).

Research Methods and ToolsAs 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

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 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 students 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 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).

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 ModelsFirst 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). 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 dont require a deep understanding of the physical concepts. They merely apply current knowledge from their schemata to correctly solve a 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). 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 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).

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.

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.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 LaboratoryObservations 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.

The professor described Hookes Law and its relation to Newtons 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 Hookes 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 working. The students rushed through the lab without any reflection on what they were actually doing, finished the experiment and left. LAB IIFor 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 instructors 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 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).

The PER-based Laboratory: A modified designIn 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 LabIn traditional laboratory exercises, students perform recipe-based experiments which verify physical phenomena presented in lecture. There is little time given to students to 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 small group or plenary level. The students should always be encouraged to ask questions, question their own and one others 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 anothers ideas. After approximately 10 minutes of discussion, the groups should begin to carry out the procedure they developed.

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 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 classmates 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. 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. Appendix AAn Introduction to Simple Harmonic Motion

Question

What is your groups spring constant? What does it signify? Explain. Purpose

Students will develop Hookes 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 instructors 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 BObservations 10/26/09

Simple Harmonic Motion

DeLoach 205

PHY 101 Lab

InstructorProfessor

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 Newtons second law, F=ma. Hookes 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.

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

Find k, the spring constant

Find T, the period

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.

InstructorGraduate 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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