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The Role of Research in the Improvement of Physics Education


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Title: The Role of Research in the Improvement of Physics Education

The Role of Research in the Improvement of
Physics Education
  • David E. Meltzer
  • Department of Physics and Astronomy
  • Iowa State University
  • Ames, Iowa

  • Collaborators
  • Mani K. Manivannan
  • (Southwest Missouri State University)
  • Tom Greenbowe
  • (ISU, Chemistry)
  • Graduate Students
  • Jack Dostal (ISU/Montana State)
  • Ngoc-Loan Nguyen (ISU)
  • Tina Fanetti (ISU)
  • Supported in part by the National Science

  • What is meant by improved physics education?
  • The role of research
  • Some research findings wherein lies the problem?
  • Some applications of research possible solutions
  • Future outlook

Physics instruction may have multiple goals
  • Improve student attitudes toward and
    understanding of scientific process
  • Improve ability in quantitative problem solving
  • Improve students laboratory skills
  • Improve students understanding of physics
    concepts, and reasoning skills
  • Also instructors may target different
    segments of the student population (e.g., top
    10, middle 50, etc.)

Physics Education As a Research Problem
  • Within the past 25 years, physicists have begun
    to treat the teaching and learning of physics as
    a research problem
  • Systematic observation and data collection
  • Identification and control of variables
  • In-depth probing and analysis of students
  • Reproducible experiments

U.S. Physics Departments with Active Research
Groups in Physics Education
  • American University
  • Arizona State University
  • Black Hills State University
  • Boise State University
  • California Polytechnic State University, San
    Luis Obispo
  • California State University, Fullerton
  • California State University, San Marcos
  • Carnegie Mellon University
  • City University of New York
  • Clarion University
  • Grand Valley State University
  • Harvard University
  • Indiana University-Purdue University Fort Wayne
  • Iowa State University
  • Kansas State University
  • Montana State University
  • New Mexico State University
  • North Carolina AT University
  • North Carolina State University
  • Rensselaer Polytechnic Institute
  • San Diego State University
  • Southwest Missouri State University
  • Syracuse University
  • Texas Tech University
  • Tufts University
  • University of Central Florida
  • University of Maine
  • University of Maryland
  • University of Massachusetts Amherst
  • University of Minnesota
  • University of Nebraska
  • University of Northern Arizona
  • University of Northern Iowa
  • University of Oregon
  • University of Washington
  • University of Wisconsin Stout
  • offer Ph.D. in Physics Education in Physics

Goals of Physics Education Research
  • Improved learning by all students average as
    well as high performers
  • More favorable attitudes toward physics (and
    understanding of it) by nonphysicists
  • Better understanding of learning process in
    physics to facilitate continuous improvement in
    physics teaching
  • ? Not a search for the Perfect Pedagogy
  • There is no Perfect Pedagogy!

Role of Physics Education Research
  • Investigate learning difficulties
  • Develop and assess more effective curricular
  • Implement new instructional methods that make use
    of improved curricula

Tools of Physics Education Research
  • Conceptual surveys or diagnostics sets of
    written questions (short answer or multiple
    choice) emphasizing qualitative understanding
    (often given pre and post instruction)
  • e.g. Force Concept Inventory Force and
    Motion Conceptual Evaluation Conceptual
    Survey of Electricity
  • Students written explanations of their reasoning
  • Interviews with students
  • e.g. individual demonstration interviews (U.
    Wash.) students are shown apparatus, asked to
    make predictions, and then asked to explain and
    interpret results in their own words

Caution Careful probing needed!
  • It is very easy to overestimate students level
    of understanding.
  • Students frequently give correct responses based
    on incorrect reasoning.
  • Students written explanations of their reasoning
    are powerful diagnostic tools.
  • Interviews with students tend to be profoundly
    revealing and extremely surprising (and
    disappointing!) to instructors.

Excerpt from interview nontechnical physics
  • DEM Suppose she is speeding up at a steady rate
    with constant acceleration. In order for that to
    happen, do you need to apply a force? And if you
    need to apply a force, what kind of force would
    it be a constant force, increasing force,
    decreasing force?
  • STUDENT Yes you need to have a force.
  • It can be a constant force, or it could be
    an increasing force.
  • DEM . . .She is speeding up a steady rate with
    constant acceleration.
  • STUDENT Constantly accelerating? Then the force
    has to be increasing . . . Wait a minute . . .The
    force could be constant, and she could still be
  • DEM Are you saying it could be both?
  • STUDENT It could be both, because if the force
    was increasing she would still be constantly
  • DEM What do we mean by constant acceleration?
  • STUDENT Constantly increasing speed a constant
    change in velocity.

Some Specific Issues
  • Many (if not most) students
  • develop weak qualitative understanding of
    concepts (If lacking a quantitative problem
    solution, they are unable to determine relative
    magnitudes, directions, and rates of change)
  • have a strong tendency to view concepts as
    unrelated and context-dependent (not as
    interlinked aspects of broad universal
  • Lack a functional understanding of concepts
    (which would allow problem solving in unfamiliar

Testing Functional UnderstandingApplying the
concepts in unfamiliar situations Research at
the University of Washington McDermott, 1991
  • Even students with good grades may perform poorly
    on qualitative questions in unexpected contexts
  • Performance both before and after standard
    instruction is essentially the same
  • Example All batteries and bulbs in these three
    circuits are identical rank the brightness of
    the bulbs. Answer A D E gt B C
  • This question has been presented to over
    1000 students in algebra- and calculus-based
    lecture courses. Whether before or after
    instruction, fewer than 15 give correct

Investigations of Expert vs. Novice
Problem-Solving Methods Maloney, 1994
  • Novices fail to make use of qualitative analysis
    to construct appropriate representations.
    McMillan Swadener, 1991
  • Novices attempt to analyze problems based on
    surface features (spring problem,
    inclined-plane problem, etc.) instead of broad
    physical principles. Chi et al.,
  • Novices lack hierarchical, interlinked knowledge
    structures which provide a foundation for
    expert-like problem-solving technique. Reif, et
    al., 1982-84

Difficulties in Changing Representations or
  • Students are often able to solve problems in one
    form of representation (e.g. in the form of a
    graph), but unable to solve the same problem when
    posed in a different representation (e.g., using
    ordinary language).
  • Students are often able to solve problems in a
    physics context (e.g., a textbook problem using
    physics language), but unable to solve the same
    problem in a real world context (using
    ordinary words).

Changing Contexts Textbook Problems and Real
  • Standard Textbook Problem
  • Cart A, which is moving with a constant
    velocity of 3 m/s, has an inelastic collision
    with cart B, which is initially at rest as shown
    in Figure 8.3. After the collision, the carts
    move together up an inclined plane. Neglecting
    friction, determine the vertical height h of the
    carts before they reverse direction.
  • Context-Rich Problem (K. and P. Heller)
  • You are helping your friend prepare for the
    next skate board exhibition. For her program, she
    plans to take a running start and then jump onto
    her heavy-duty 15-lb stationary skateboard. She
    and the skateboard will glide in a straight line
    along a short, level section of track, then up a
    sloped concrete wall. She wants to reach a height
    of at least 10 feet above where she started
    before she turns to come back down the slope. She
    has measured her maximum running speed to safely
    jump on the skateboard at 7 feet/second. She
    knows you have taken physics, so she wants you to
    determine if she can carry out her program as
    planned. She tells you that she weighs 100 lbs.

2.2 kg
0.9 kg
Origins of Learning Difficulties
  • Students hold many firm ideas about the physical
    world that may conflict strongly with physicists
  • Most introductory students need much guidance in
    scientific reasoning employing abstract concepts.
  • Most introductory students lack active learning
    skills that would permit more efficient mastery
    of physics concepts.

Misconceptions/Alternative Conceptions
  • Student ideas about the physical world that
    conflict with physicists views
  • Widely prevalent there are some particular ideas
    that are almost universally held by beginning
  • Often very well-defined not merely a lack of
    understanding, but a very specific idea about
    what should be the case (but in fact is not)
  • Often -- usually -- very tenacious, and hard to
    dislodge Many repeated encounters with
    conflicting evidence required
  • Examples
  • An object in motion must be experiencing a force
  • A given battery always produces the same current
    in any circuit
  • Electric current gets used up as it flows
    around a circuit

Example Students Understanding of Gravitational
Forces Jack Dostal and D.E.M., 1999
  • Is the magnitude of the force exerted by the
    asteroid on the Earth larger than, smaller than,
    or the same as the magnitude of the force exerted
    by the Earth on the asteroid? Explain the
    reasoning for your choice.
  • This question was presented in the first week
    of class to all students taking calculus-based
    introductory physics at ISU during Fall 1999.
  • First-semester Introductory Physics (N 546)
    15 correct responses
  • Second-semester Introductory Physics (N 414)
    38 correct responses
  • Majority of students persist in claiming that
    Earth exerts greater force because it is larger
    or more massive

Another Example Students Beliefs About
Gravitation Jack Dostal and D.E.M., 1999
  • This question was presented in the first week of
    class to all students taking calculus-based
    introductory physics at ISU during Fall 1999.
  • First-semester Introductory Physics (N 534)
  • 32 state that it will float or float away
  • Second-semester Introductory Physics (N 408)
  • 23 state that it will float or float away
  • Significant fraction of students persist in
    claiming that there is no gravity or
    insignificant gravity on the moon

Imagine that an astronaut is standing on the
surface of the moon holding a pen in one hand. If
that astronaut lets go of the pen, what happens
to the pen? Why?
But some students learn efficiently . . .
  • Highly successful physics students (e.g., future
    physics instructors!) are active learners.
  • they continuously probe their own understanding
  • pose their own questions scrutinize implicit
    assumptions examine varied contexts etc.
  • they are sensitive to areas of confusion, and
    have the confidence to confront them directly
  • Great majority of introductory students are
    unable to do efficient active learning on their
    own they dont know which questions they need
    to ask
  • they require considerable prodding by
    instructors, aided by appropriate curricular
  • they need frequent confidence boosts, and hints
    for finding their way

Keystones of Innovative Pedagogy
  • To encourage active learning, students are led to
    engage during class time in deeply
    thought-provoking activities requiring intense
    mental effort. (Interactive Engagement.)
  • Instruction recognizes and deliberately elicits
    students preexisting alternative conceptions
    and other common learning difficulties.
  • The process of science (exploration and
    discovery) is used as a means for learning
    science. Students are not told things are true
    instead, they are guided to figure it out for
    themselves. (Inquiry-based learning )

Interactive Engagement
  • Interactive Engagement methods require an
    active learning classroom
  • Very high levels of interaction between students
    and instructor
  • Collaborative group work among students during
    class time
  • Intensive active participation by students in
    focused learning activities during class time

Elicit Students Pre-existing Knowledge Structure
  • Have students make predictions of the outcome of
    experiments. (Selected to address common
    conceptual stumbling blocks)
  • Require students to give written explanations of
    their reasoning. (Aids them to precisely
    articulate ideas.)
  • Pose specific problems that consistently trigger
    certain types of learning difficulties. (Based on
  • Structure subsequent activities to confront
    difficulties that were elicited. (Tested through

Inquiry-based Learning/ Discovery Learning
  • Pedagogical methods in which students are
    guided through investigations to discover
  • Targeted concepts are generally not told to the
    students in lectures before they have an
    opportunity to investigate (or at least think
    about) the idea
  • Can be implemented in the instructional
    laboratory (active-learning laboratory) where
    students are guided to form conclusions based on
    evidence they acquire
  • Can be implemented in lecture or recitation, by
    guiding students through chains of reasoning
    utilizing printed worksheets

Example Force and Motion
  • A cart on a low-friction surface is being
    pulled by a string attached to a spring scale.
    The velocity of the cart is measured as a
    function of time.
  • The experiment is done three times, and the
    pulling force is varied each time so that the
    spring scale reads 1 N, 2 N, and 3 N for trials
    1 through 3, respectively. (The mass of the
    cart is kept the same for each trial.)
  • On the graph below, sketch the appropriate
    lines for velocity versus time for the three
    trials, and label them 1, 2, and 3.

Key Themes of Research-Based Instruction
  • Emphasize qualitative, non-numerical questions to
    reduce unthoughtful plug and chug.
  • Make extensive use of multiple representations to
    deepen understanding.
  • (graphs, diagrams, sketches, simulations,
    animations, etc.)
  • Require students to explain their reasoning
    (verbally or in writing) to more clearly expose
    their thought processes.

New Approaches to Instruction on Problem Solving
  • A. Van Heuvelen Require students to construct
    multiple representations of problem (draw
    pictures, diagrams, graphs, etc.)
  • P. and K. Heller Use context rich problems
    posed in natural language containing extraneous
    and irrelevant information teach problem-solving
  • F. Reif et al. Require students to construct
    problem-solving strategies, and to critically
    analyze strategies
  • P. DAllesandris Use goal-free problems with
    no explicitly stated unknown
  • J. Mestre, W. Gerace, W. Leonard, R. Dufresne
    Emphasize student generation of qualitative
    problem-solving strategies

New Instructional MethodsActive-Learning
  • Microcomputer-based Labs (P. Laws, R. Thornton,
    D. Sokoloff) Students make predictions and carry
    out detailed investigations using real-time
    computer-aided data acquisition, graphing, and
    analysis. Workshop Physics (P. Laws) is
    entirely lab-based instruction.
  • Socratic-Dialogue-Inducing Labs (R. Hake)
    Students carry out and analyze activities in
    detail, aided by Socratic Dialoguist instructor
    who asks leading questions, rather than providing
    ready-made answers.

New Instructional Methods Active Learning
  • Electric and Magnetic Interactions, R. Chabay and
    B. Sherwood, Wiley, 1995.
  • Understanding Basic Mechanics, F. Reif, Wiley,
  • Physics A Contemporary Perspective, R. Knight,
    Addison-Wesley, 1997-8.
  • Six Ideas That Shaped Physics, T. Moore,
    McGraw-Hill, 1998.

Research-based Software/Multimedia
  • Simulation Software ActivPhysics (Van Heuvelen
    and dAllesandris) Visual Quantum Mechanics
    (Zollman, Rebello, Escalada)
  • Intelligent Tutors Freebody, (Oberem)
    Photoelectric Effect, (Oberem and Steinberg)
  • Reciprocal Teacher Personal Assistant for
    Learning, (Reif and Scott)

New Instructional MethodsUniversity of
Washington ModelElicit, Confront, Resolve
  • Most thoroughly tested and research-based
    physics curricular materials based on 20 years
    of ongoing work
  • Physics by Inquiry 3-volume lab-based
    curriculum, primarily for elementary courses,
    which leads students through extended intensive
    group investigations. Instructors provide
    leading questions only.
  • Tutorials for Introductory Physics Extensive
    set of worksheets, designed for use by general
    physics students working in groups of 3 or 4.
    Instructors provide guidance and probe
    understanding with leading questions. Aimed at
    eliciting deep conceptual understanding of
    frequently misunderstood topics.

Protocol for Testing Worksheets
  • 30 of recitation sections yielded half of one
    period for students to do worksheets
  • Students work in small groups
  • Remainder of period devoted to normal activities
  • No net additional instructional time on
  • Conceptual questions added to final exam with
    instructors approval

Pretest Question (Newtons third law)
  • Is the magnitude of the force exerted by the
    asteroid on the Earth larger than, smaller than,
    or the same as the magnitude of the force exerted
    by the Earth on the asteroid? Explain the
    reasoning for your choice.

Post-test Question (Newtons third law)
  • The rings of the planet Saturn are composed of
    millions of chunks of icy debris. Consider a
    chunk of ice in one of Saturn's rings. Which of
    the following statements is true?
  • The gravitational force exerted by the chunk of
    ice on Saturn is greater than the gravitational
    force exerted by Saturn on the chunk of ice.
  • The gravitational force exerted by the chunk of
    ice on Saturn is the same magnitude as the
    gravitational force exerted by Saturn on the
    chunk of ice.
  • The gravitational force exerted by the chunk of
    ice on Saturn is nonzero, and less than the
    gravitational force exerted by Saturn on the
    chunk of ice.
  • The gravitational force exerted by the chunk of
    ice on Saturn is zero.
  • Not enough information is given to answer this

Results on Newtons Third Law Questions(Students
who gave incorrect answer on pretest question)
N Post-test Correct
Worksheet 82 84
Non-Worksheet 289 58
(calculus-based course, first semester)
Post-test Question(Lead spheres)
  • Two lead spheres of mass M are separated by a
    distance r. They are isolated in space with no
    other masses nearby. The magnitude of the
    gravitational force experienced by each mass is
    F. Now one of the masses is doubled, and they
    are pushed farther apart to a separation of 2r.
    Then, the magnitudes of the gravitational forces
    experienced by the masses are
  • A. equal, and are equal to F.
  • B. equal, and are larger than F.
  • C. equal, and are smaller than F.
  • D. not equal, but one of them is larger than F.
  • E. not equal, but neither of them is larger
    than F.

Results on Lead Spheres Question(Question
given on final exam)
N Correct
Worksheet 116 70
Non-Worksheet 384 45
(calculus-based course, first semester)
New Instructional MethodsActive Learning in
Large Classes
  • Active Learning Problem Sheets (A. Van
    Heuvelen) Worksheets for in-class use,
    emphasizing multiple representations (verbal,
    pictorial, graphical, etc.)
  • Interactive Lecture Demonstrations (R. Thornton
    and D. Sokoloff) students make written
    predictions of outcomes of demonstrations.
  • Peer Instruction (E. Mazur) Lecture segments
    interspersed with challenging conceptual
    questions students discuss with each other and
    communicate responses to instructor.
  • Workbook for Introductory Physics (D. Meltzer
    and K. Manivannan) combination of
    multiple-choice questions for instantaneous
    feedback, and sequences of free-response
    exercises for in-class use.

Active Learning in Large Classes
  • Drastic de-emphasis of lecturing Instead, ask
    students to respond to many questions.
  • Use of communication systems (e.g., Flash
    Cards) to obtain instantaneous feedback from
    entire class.
  • Cooperative group work using carefully structured
    free-response worksheets (e.g., Workbook for
    Introductory Physics)
  • Goal Transform large-class learning environment
    into office learning environment (i.e.,
    instructor one or two students)

Effectiveness of New Methods(I)
  • Results on Force Concept Inventory
    (diagnostic exam for mechanics concepts) in terms
    of g overall learning gain (posttest -
    pretest) as a percentage of maximum possible gain
  • Survey of 4500 students in 48 interactive
    engagement courses showed g 0.48 0.14
  • --gt highly significant improvement compared to
    non-Interactive-Engagement classes (g 0.23
  • (R. Hake, Am. J. Phys. 66, 64 1998)
  • Survey of 281 students in 4 courses using MBL
    labs showed g 0.34 (range 0.30
    - 0.40)
  • (non-Interactive-Engagement g 0.18)
  • (E. Redish, J. Saul, and R. Steinberg,
    Am. J. Phys. 66, 64 1998)

Effectiveness of New Methods (II)
  • Results on Force and Motion Conceptual
    Evaluation (diagnostic exam for mechanics
    concepts, involving both graphs and natural
  • Subjects 630 students in three noncalculus
    general physics courses using MBL labs at the
    University of Oregon
  • Results (posttest correct)
  • Non-MBL MBL
  • Graphical Questions
    16 80
  • Natural Language 24
  • (R. Thornton and D. Sokoloff, Am. J.
    Phys. 66, 338 1998)

Effectiveness of New Methods (III)
  • University of Washington, Physics Education
  • Results Problem given to students in
    calculus-based course 10 weeks after completion
    of instruction. Proportion of correct responses
    is shown for
  • Students in lecture
    class 15
  • Students in lecture
    tutorial class 45
  • (P. Shaffer and L. McDermott, Am.
    J. Phys. 60, 1003 1992)
  • At Southeastern Louisiana University,
    problem given on final exam in algebra-based
    course using Workbook for Introductory Physics
  • Results more than 50 correct responses.

Challenges Ahead . . .
  • Many (most?) students are comfortable and
    familiar with more passive methods of learning
    science. Active learning methods are always
    challenging, and frequently frustrating for
    students. Some (many?) react with anger.
  • Active learning methods and curricula are not
    instructor proof. Training, experience, energy
    and commitment are needed to use them effectively.

  • Much has been learned about how students learn
    physics, and about specific difficulties that are
    commonly encountered.
  • Based on this research, many innovative
    instructional methods have been implemented that
    show evidence of significant learning gains.
  • The process of improving physics instruction is
    likely to be endless we will never achieve
    perfection, and there will always be more to
    learn about the teaching process.