traditional vs. problem based approaches to teaching introductory physics 2001 science educators’...

Traditional vs. Problem Based Traditional vs. Problem Based Approaches to Teaching Approaches to Teaching

Introductory PhysicsIntroductory Physics

2001 Science Educators’ Conference2001 Science Educators’ Conference

David P. WickDavid P. Wick

Clarkson UniversityClarkson University

Acknowledgements: Michael W. Acknowledgements: Michael W. RamsdellRamsdell

Joseph HruskaJoseph Hruska

A Set of Goals Established by theA Set of Goals Established by the AAmerican merican AAssociation of ssociation of PPhysics hysics TTeacherseachers

A strong program should emphasize A strong program should emphasize experiential experiential learninglearning, , open-ended problem solvingopen-ended problem solving and and development of analytic and collaborative learning development of analytic and collaborative learning skills. skills.

Students should have the opportunity to Students should have the opportunity to experience all aspects of scientific analysis experience all aspects of scientific analysis including the including the designdesign, , developmentdevelopment and and executionexecution of a successful experimental investigation.of a successful experimental investigation.

Students should have access to experiences that Students should have access to experiences that encourage the development of encourage the development of verbalverbal and and mathematical modelsmathematical models used to mimic the natural used to mimic the natural world. world.

A strong program should provide exposure to A strong program should provide exposure to experimentalexperimental, , theoreticaltheoretical and and numericalnumerical development, allowing students to truly master a development, allowing students to truly master a variety of basic skills in problem solving and data variety of basic skills in problem solving and data analysis. analysis.

[i][i] American Association of Physic Teachers, "Goals of the Introductory American Association of Physic Teachers, "Goals of the Introductory

Physics Laboratory," Am. J. Phys. Physics Laboratory," Am. J. Phys. 66,66, 483-485 (1998). 483-485 (1998).

Outstanding challenges for the Outstanding challenges for the scientific community are to:scientific community are to:

Find innovative methods for achieving these goals.Find innovative methods for achieving these goals.

Develop tools for assessing the Develop tools for assessing the performanceperformance of our of our students and the students and the effectivenesseffectiveness of our methods. of our methods.

Physics Education Research is a work Physics Education Research is a work in progress…in progress…

PER has logged over PER has logged over threethree decades worth of scientific decades worth of scientific investigation with attention given to:investigation with attention given to:

- - IdentificationIdentification of student misconceptions. of student misconceptions.

- - DevelopmentDevelopment of pedagogical strategies to provide a of pedagogical strategies to provide a

more effective learning experience for students. more effective learning experience for students.

- - AssessmentAssessment of educational approaches. of educational approaches.

Misconceptions or Preconceptions?Misconceptions or Preconceptions?

Student minds are not blank slates. Student minds are not blank slates.

Many students defend their beliefs from the high seat of Many students defend their beliefs from the high seat of experience.experience.

Student difficulties are not reflections of “stupidity”, but Student difficulties are not reflections of “stupidity”, but rather deeply rooted and seemingly logical consequences rather deeply rooted and seemingly logical consequences of perception reinforced with personal experience. of perception reinforced with personal experience.

[2][2] Aarons, A. B.,Aarons, A. B., Teaching Introductory PhysicsTeaching Introductory Physics, John Wiley & Sons (1997)., John Wiley & Sons (1997).

Examples are well documented.Examples are well documented.

Example:Example: The Concept of Velocity The Concept of Velocity

Ball ABall A

Ball BBall B

Question:Question: Do these two balls ever have the same speed? Do these two balls ever have the same speed?

Study:Study: 300 student interviews at University of Washington 300 student interviews at University of Washington (calculus-based physics course).(calculus-based physics course).

Misconception:Misconception: The balls have the same speed at the moment one The balls have the same speed at the moment one 40%40% passes or is next to the other. Students associate passes or is next to the other. Students associate “ “same speed” with “passing” or “same position.” same speed” with “passing” or “same position.”

[3][3] McDermott, L. C.,McDermott, L. C., “Research on Conceptual Understanding in Mechanics,” Phys. “Research on Conceptual Understanding in Mechanics,” Phys.

Today, Today, 3737, 24-32 (1984)., 24-32 (1984).

Example:Example: Velocity vs. Speed Velocity vs. Speed Question:Question: A ball is thrown vertically upward from ground level A ball is thrown vertically upward from ground level

with an initial speed vwith an initial speed voo. The ball reaches a maximum . The ball reaches a maximum

height d and returns to ground level. Which statement height d and returns to ground level. Which statement is is TRUETRUE? ?

43%43% A) The initial velocity is equal to the final velocity; A) The initial velocity is equal to the final velocity; 32% 32% B)B) The average velocity for the entire flight is zero;The average velocity for the entire flight is zero; 9%9% C) The acceleration on the way down is greater than the C) The acceleration on the way down is greater than the acceleration on the way up;acceleration on the way up; 16%16% D) The average acceleration for the entire flight is zero. D) The average acceleration for the entire flight is zero.

Study:Study: 500 student responses at Clarkson University – Exam I 500 student responses at Clarkson University – Exam I (calculus-based physics course).(calculus-based physics course).

Misconceptions:Misconceptions: “Velocity” and “Speed” are interchangeable. “Velocity” and “Speed” are interchangeable. Acceleration depends on direction of motion.Acceleration depends on direction of motion.

We must eliminate misconceptions, but We must eliminate misconceptions, but students will only accept a scientific students will only accept a scientific concept if:concept if: They understand the concept.They understand the concept. It is believable.It is believable. It is useful.It is useful. It conflicts with their current beliefs.It conflicts with their current beliefs.

““Understanding the way students and scientists think is the key to developing Understanding the way students and scientists think is the key to developing more effective methods of science teaching and is itself an intellectual more effective methods of science teaching and is itself an intellectual challenge.”challenge.”

[4][4] Reif, F.,Reif, F., “Scientific Approaches to Science Education,” Phys. Today, “Scientific Approaches to Science Education,” Phys. Today, 3939, 48-53 (1986)., 48-53 (1986).

Current Strategies:Current Strategies: Interactive EngagementInteractive Engagement

Lecture-basedLecture-based (Peer instruction, Interactive (Peer instruction, Interactive Lectures, …)Lectures, …)

Recitation-basedRecitation-based (Tutorials, Cooperative Problem (Tutorials, Cooperative Problem Solving, …)Solving, …)

Lab-basedLab-based (Projects, Problems, Simulations, …) (Projects, Problems, Simulations, …)

CombinationCombination (Physics by Inquiry, Workshop (Physics by Inquiry, Workshop Physics, Physics Studio …)Physics, Physics Studio …)

[5][5] Redish, E.,Redish, E., “New Models of Learning and Teaching,” Conference of Physics “New Models of Learning and Teaching,” Conference of Physics Department Chairs (1997).Department Chairs (1997).

A typical first-exam grade distribution in A typical first-exam grade distribution in Physics I Physics I at Clarkson Universityat Clarkson University::

The bi-modal nature is indicative The bi-modal nature is indicative

of a well prepared and an ill of a well prepared and an ill

prepared group.prepared group.Physics I (60 point exam)

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0 5 10 15 20 25 30 35 40 45 50 55 60

Grade

Nu

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er

of

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Traditional Laboratory ExperienceTraditional Laboratory Experience

Typical Laboratory Manual Contains:Typical Laboratory Manual Contains:

TitleTitle

ApparatusApparatus – Description of equipment – Description of equipment

IntroductionIntroduction – Theory, figures, equations – Theory, figures, equations

ProcedureProcedure – – Step 1, Step 2, …Step 1, Step 2, …

Tables and Graphs, etc.Tables and Graphs, etc.

Current ApproachCurrent Approach: : Lab/Recitation-basedLab/Recitation-based

Modification of the traditional laboratory / recitationModification of the traditional laboratory / recitation to to incorporate a incorporate a problem basedproblem based learning experience with learning experience with an emphasis on open-ended problem solving.an emphasis on open-ended problem solving.

Provide students with the opportunity to: Provide students with the opportunity to: - Formulate verbal models- Formulate verbal models

- Develop mathematical models (theoretical and - Develop mathematical models (theoretical and numerical) numerical)- Design experimental procedures- Design experimental procedures- Test the predictive capability of their models.- Test the predictive capability of their models.

Problem Based LearningProblem Based Learning Physics Team Design ProgramPhysics Team Design Program

Current Participation: Current Participation: 10-15 % of class10-15 % of class Lecture Component – Lecture Component – Traditional Traditional Lab/Recitation Component – Lab/Recitation Component – Problem BasedProblem Based

““Modeling is the name of the game in the NewtonianModeling is the name of the game in the Newtonian

World”World”

[6][6] Hestenes, David,Hestenes, David, “Modeling Games in the Newtonian World,” “Modeling Games in the Newtonian World,”

Am. J. Phys. Am. J. Phys. 60,60, 732-748 (1992). 732-748 (1992).

Traditional vs. Problem Based Traditional vs. Problem Based ApproachesApproaches

Physics IPhysics I – Modeling the Motion of a – Modeling the Motion of a

Matchbox CarMatchbox Car Physics IIPhysics II – Modeling the Motion of an – Modeling the Motion of an

Electric TrainElectric Train

Assessment:Assessment: Force Concepts InventoryForce Concepts Inventory

David Hestenes (Arizona State University) and David Hestenes (Arizona State University) and others have developed a others have developed a quantitativequantitative assessment assessment tool for checking a student's understanding of basic tool for checking a student's understanding of basic conceptsconcepts in physics. in physics.

FCIFCI topics cover the fundamental issues and topics cover the fundamental issues and concepts in concepts in NewtonianNewtonian dynamics. dynamics.

FCIFCI distractors (wrong answers) are “malicious” -- distractors (wrong answers) are “malicious” -- they are based on research that exploits students' they are based on research that exploits students' most common misconceptions.most common misconceptions.

Results of the Results of the FCIFCI are Disappointing! are Disappointing!

Richard Hake (Indiana University) conducted a study of Richard Hake (Indiana University) conducted a study of 6262 classes (classes (65426542 students) from around the country. He showed students) from around the country. He showed that for a wide range of initial pre-test scores, the fractional that for a wide range of initial pre-test scores, the fractional gain is similar for classes of similar instructional method. gain is similar for classes of similar instructional method.

For For TraditionalTraditional classes: classes: hh ~ 0.23 +/- 0.04 ~ 0.23 +/- 0.04 For For IEIE classes: classes: hh ~ 0.48 +/-0.14 ~ 0.48 +/-0.14[7][7] Hake, Richard,Hake, Richard, “Interactive Engagement vs. Traditional Methods,” “Interactive Engagement vs. Traditional Methods,”

Am. J. Phys. Am. J. Phys. 65,65, (1995). (1995).

) 100(

) (

averagepretest

averagepretestaverageposttesth

Force Concepts Inventory Force Concepts Inventory (FCI)(FCI)

Team Design Produced Significantly Team Design Produced Significantly Higher Gains ThanHigher Gains Than Traditional LabsTraditional Labs

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0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4

h

Conventional Labs

Team Design

Comparison Group?Comparison Group?

Team Design Produced Significantly Team Design Produced Significantly Higher Gains Than a Higher Gains Than a Comparison Comparison

GroupGroup

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Conventional Labs

Team Design

Comparison Group

Best of the Rest?Best of the Rest? – – High SATHigh SAT

Team Design Even Produced Higher Team Design Even Produced Higher Gains Than the Gains Than the High SATHigh SAT Group Group

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Conventional Labs

Team Design

Comparison Group

High SAT

Comparison TableComparison Table

GainGain SAT SAT (Verbal / Math)(Verbal / Math)

Final GradeFinal Grade

Conventional Conventional Labs (337)Labs (337)

0.240.24 11901190570 / 620570 / 620

7272C+C+

Team Design Team Design (54)(54)

0.370.37 13101310630 / 680630 / 680

8585B+B+


GainGain SAT SAT (Verbal / Math)(Verbal / Math)


Conventional Conventional Labs (337)Labs (337)

0.240.24 11901190570 / 620570 / 620

7272C+C+


0.370.37 13101310630 / 680630 / 680

8585B+B+

Comparison Comparison Group (54)Group (54)

0.250.25 13001300620 / 680620 / 680

7979BB


GainGain

hh

SAT SAT (Verbal / Math)(Verbal / Math)


Traditional Traditional Labs (337)Labs (337)

0.240.24 11901190570 / 620570 / 620

7272


0.370.37 13101310630 / 680630 / 680

8585

Comparison Comparison Group (54)Group (54)

0.250.25 13001300620 / 680620 / 680

7979

High SAT High SAT (54)(54)

0.310.31 13501350650 / 700650 / 700

8282

Matchbox Car ProjectMatchbox Car Project

““Modeling the Motion of a Modeling the Motion of a MatchboxMatchboxTMTM Car” Car”

Problem Statement:Problem Statement:

Develop a theoretical modelDevelop a theoretical model describing the motion of a describing the motion of a Matchbox MatchboxTMTM car racing down an arbitrarily shaped track. car racing down an arbitrarily shaped track. Your model should describe the velocity of the car at Your model should describe the velocity of the car at any point along the track. any point along the track. (Identify the most important (Identify the most important effects that should be included in this model). effects that should be included in this model).

Design an experimental procedureDesign an experimental procedure to evaluate the to evaluate the predictive capability of your model.predictive capability of your model.

Facts:Facts: A typical MatchboxA typical MatchboxTMTM car has a die-cast body, two axles, car has a die-cast body, two axles, and four hard plastic wheels, with a total mass (m) of and four hard plastic wheels, with a total mass (m) of approx. 50 g. The combined mass of the wheels approx. 50 g. The combined mass of the wheels

is less is less than 3 % of the total mass of the car. than 3 % of the total mass of the car.

The plastic wheels rotate on the axle through direct The plastic wheels rotate on the axle through direct contact with a contact with a slidingsliding type motion. type motion. Air Air

resistanceresistance can be can be accentuated by mounting a shield of accentuated by mounting a shield of varying area.varying area. 2 .5 cm

N o S h ie ld

F ro n t V iew S id e V iew To p V iew(N o S h ie ld )

1 0 c m

2 .5 cm

3 .0 cm 7 .0 cm

1 .0 cm 4 .0 cm

Developing a Theoretical ModelDeveloping a Theoretical Model

Consider the forces acting on the car:Consider the forces acting on the car:

Frictional ModelFrictional Model

Drag Force ModelDrag Force Model

Applying Applying Newton’s Second LawNewton’s Second Law will allow us to will allow us to develop a model for the velocity of the car.develop a model for the velocity of the car.

Nμf k

22

2

1kvρAvCD d

m g

ND

f k

x

y

x ’

y ’

A

B

y

x

Case by Case AssumptionsCase by Case Assumptions

Case ACase A gravitational potential andgravitational potential and kinetic kinetic energies energies

Case BCase B sliding frictionsliding friction

Case CCase C track shapetrack shape

Case DCase D air resistanceair resistance

Hierarchical Structure of SolutionsHierarchical Structure of Solutions

CaseCase Solution (Model)Solution (Model)

AA

BB

CC

DD

This multi-level approach illustrates how each successive stage in This multi-level approach illustrates how each successive stage in model development provides a correction to the previous one.model development provides a correction to the previous one.

Designing an Experimental ProcedureDesigning an Experimental Procedure

Measuring friction and air dragMeasuring friction and air drag

We can extract values for and We can extract values for and kk by measuringby measuring

the velocity of the car at different points along a the velocity of the car at different points along a flat, flat,

horizontalhorizontal track using a series of photogates. track using a series of photogates.

kμ

S ta r tin gH e ig h t 5

F irs tP h o to g a te

1 0 c m

4L a stP h o to g a te

5 .0 m

3

2

1

Experimental Results for a Level TrackExperimental Results for a Level Track

0.049 0.049 (No Shield)(No Shield)

kk == 1.48 x 101.48 x 10-4-4 (kg/m) (kg/m) (No Shield)(No Shield)

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kμ

What About an Arbitrary Track?What About an Arbitrary Track?

Comparing Theory to ExperimentComparing Theory to Experiment

Velocity Vs. Track Position

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Case A

Case B

Case C

Case D

Experimental

Sample Challenge SessionSample Challenge Session

Goal:Goal: Predict where your car will first come Predict where your car will first come momentarily to rest. momentarily to rest.

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F erra riW a re h o u se

Electric Train ProjectElectric Train Project

Model Rocket ProjectModel Rocket Project